Teriparatide (Forteo)

Number: 0666

Policy

1. Aetna considers daily injection of teriparatide (Forteo) medically necessary for women with post-menopausal osteoporosis (bone mineral density [BMD] T score 2.5 or more standard deviations below the mean (i.e., T score is less than -2.5) (a T score of -1.0 to -2.5 is classified as osteopenia, while a T score of -1.0 or higher is considered normal)Footnotes for gender specific database**);  who are at high-risk for fractures (e.g., those who have had an osteoporotic fracture, or have certain risk factors for fractureFootnotes for purpose of this policy ***), and who have failed or are unable to tolerate either 2 bisphosphonates (e.g., alendronate [Fosamax], ibandronate [Boniva], risedronate [Actonel], zoledronic acid [Zometa]) or 1 bisphosphonate plus 1 selective estrogen receptor modulator (SERM) (e.g., raloxifene [Evista])).

2. Aetna considers daily injection of teriparatide (Forteo) medically necessary for the treatment of men with primary or hypogonadal osteoporosis (T score of their BMD is 2.5 or more standard deviations below the mean value (i.e., T score is less than -2.5) (a T score of -1.0 to -2.5 is classified as osteopenia, while a T score of -1.0 or higher is considered normal)Footnotes for gender specific database**;) who are at high-risk for fractures (e.g., those who have had an osteoporotic fracture, or have certain risk factors for fractureFootnotes for purpose of this policy***), and who have failedFootnotes for treatment failure* or are unable to tolerate 2 bisphosphonates (e.g., alendronate [Fosamax], ibandronate [Boniva], risedronate [Actonel]), zoledronic acid [Zometa])).

3. Aetna considers daily injection of teriparatide (Forteo) medically necessary for the treatment of adults with glucocorticoid-induced osteoporosis (T score of their BMD is 2.5 or more standard deviations below the mean value (i.e., T score is less than -2.5) (a T score of -1.0 to -2.5 is classified as osteopenia, while a T score of -1.0 or higher is considered normal)Footnotes for gender specific database**), when both of the following criteria are met:

   1. Members are being treated with sustained long-term glucocorticoid therapy (i.e., a mean daily dose of 5 mg or more of prednisone or its equivalent for 3 or more consecutive months); and 
   2. Members are at high-risk for fractures (e.g., those who have had an osteoporotic fracture, or have certain risk factors for fractureFootnotes for purpose of this policy***), and have failedFootnotes for treatment failure* or are unable to tolerate 2 bisphosphonates (e.g., alendronate [Fosamax], ibandronate [Boniva], risedronate [Actonel]), zoledronic acid [Zometa]).

4. Teriparatide therapy is considered not medically necessary for members with the following contraindications to Forteo:

   • Paget’s disease or an unexplained increase in alkaline phosphatase
   • Osteopenia
   • Prior radiation treatment
   • Current or previous history of skeletal malignancies
   • Pre‐existing hypercalcemia
   • Hyperparathyroidism
   • Pregnancy or lactation
   • Metabolic bone disease other than osteoporosis
   • Hypersensitivity to teriparatide or any of its excipients.

5. Aetna considers teriparatide experimental and investigational for the following (not an all-inclusive list) because its effectiveness for these indications has not been established:

   • Hypoparathyroidism
   • Hungry bone syndrome
   • Joint erosions in rheumatoid arthritis
   • Orthopedic uses (e.g., articular cartilage repair, atypical femur fractures, and fracture repair, nonunion fractures, and osteonecrosis of the jaw)
   • Osteogenesis imperfecta
   • Osteoporosis associated with inflammatory bowel disease
   • Promotion of bone formation and consolidation in distraction osteogenesis
   • Post spinal cord injury osteoporosis
   • Prosthesis fixation following total knee replacement
   • Reducing pedicle screw loosening following spinal fusion
   • Stress fracture treatment
   • Vertebral compression fracture treatment

6. Footnotes for treatment failure* For purposes of this policy, treatment failure is defined as documented continued bone loss after 2 or more years despite treatment with a bisphosphonate or SERM.

   Footnotes for gender specific database** A gender-specific database should be used for diagnosing osteoporosis.

   Footnotes For purposes of this policy*** For purposes of this policy, independent risk factors for fracture include parental history of hip fracture, rheumatoid arthritis, alcohol use of 4 or more units per day, or current tobacco smoking. 

   Notes: There are two brands of parathyroid horome analogs on the market. There is a lack of reliable evidence that any one brand of parathyroid hormone analog is superior to other brands for medically necessary indications. Tymlos (abaloparatide) brand of parathyroid hormone  analog ("least cost brand of parathyroid hormone analog") is less costly to Aetna.  Consequently, because Forteo (teriparatide) is more costly than the least cost brand of parathyroid hormone analog, and least cost brand of parathyroid hormone analog is at least as likely to produce equivalent therapeutic results, Forteo brand of parathyroid hormone analog will be considered medically necessary only if the member has a contraindication, intolerance or incomplete response to Tymlos:
   
   Since the effects of long-term treatment with parathyrolid hormone analogs abaloparatide and teriparatide are not known at this time, therapy with these parathyroid hormone analogs for more than 2 years duration is considered experimental and investigational. 

   See also

   • CPB 0134 - Bone Mass Measurements, 
   • CPB 0524 - Zoledronic Acid,
   • and CPB 0562 - Biochemical Markers of Bone Remodeling.

Background

Approximately 10 million Americans (80 % of them women) suffer from osteoporosis, which may lead to an increased risk of spine, wrist, and hip fractures.  For post-menopausal women, age, personal or family history of fracture, Asian or Hispanic heritage, smoking, and cortisone use have been associated with significantly increased likelihood of osteoporosis; while higher body mass index (BMI), African American heritage, estrogen or diuretic use, and exercise have been associated with significantly decreased likelihood of osteoporosis (Siris et al, 2001).  Furthermore, Wu and colleagues (2002) reported that any fracture (unrelated to motor vehicle accidents) sustained between the ages of 20 and 50 years is associated with increased risk of fractures after the age of 50 years in women.  Although osteoporosis is usually considered a disease of women, up to 20 % of vertebral fractures and 30 % of hip fractures occur in men.  Risk factors for osteoporotic fractures in men include low BMI, smoking, high alcohol consumption, corticosteroid therapy, physical inactivity, and diseases that predispose to low bone mass (Eastell et al, 1998).  However, the exact mechanism of bone loss remains unknown in primary male osteoporosis (Legrand et al, 2001).

Bone mineral density (BMD) is useful in the diagnosis of osteoporosis.  It is usually provided as the T score -- the number of standard deviations (SDs) the BMD falls below or above the mean value in a reference population (young, healthy adults).  The World Health Organization (WHO) osteoporosis diagnostic classification assessment (1994) defines osteoporosis as a T score of 2.5 or more SDs below the mean (i.e., less than -2.5).  Osteopenia is defined as a T score of -1.0 to -2.5 and a T score of -1.0 or higher is considered normal.  It should be noted that a male database should be used for diagnosing osteoporosis in men.

Body (2002) stated that although hormone replacement therapy (HRT) is still considered as the mainstay for the prevention and the treatment of post-menopausal osteoporosis, there are several controversies regarding HRT.  Recent studies have challenged the assumption that HRT conveys real long-term benefits.  Raloxifene or other “selective estrogen receptor modulators” (SERMs) should progressively replace HRT in elderly women.  Bisphosphonates have been shown to be effective in the treatment of osteoporosis.  Alendronate (Fosamax) and risedronate (Actonel) have been the most extensively studied bisphosphonates under clinical trials conditions.  Both drugs can lower the risk of vertebral and hip fractures by 25 to 50 %.  However, oral bisphosphonates exhibit gastro-intestinal toxicity and strict adherence to constraining therapeutic schemes is mandatory.  Newer more potent bisphosphonates, such as oral ibandronate and intravenous zoledronic acid (Zometa), which will allow much less frequent administration, are currently being investigated (Reid et al, 2002).  Moreover, bone-forming agents (e.g., teriparatide) provide another therapeutic option for the treatment of severe osteoporosis.

Forteo (teriparatide) is a recombinant parathyroid hormone (PTH) product. It has an identical sequence to the 34 N‐terminal amino acids (the biologically active region) of the 84‐amino acid human PTH. Teriparatide and the active region of PTH bind to specific high‐affinity cell‐surface receptors with the same affinity.

Forteo (teriparatide) stimulates new bone formation on trabecular and cortical bone surfaces by preferential stimulation of osteoblastic activity over osteoclastic activity. It differs from PTH in that it is given subcutaneously once daily rather than being released endogenously. Teriparatide differs in chemical structure and pharmacological action from oral bisphosphonates, calcitonin, estrogen replacement therapy, and selective estrogen receptor modulators.

Forteo (teriparatide) is approved by the U.S. Food and Drug Administration (FDA) for the treatment of postmenopausal women with osteoporosis who are at high risk for fracture, to increase bone mass in men with primary or hypogonadal osteoporosis who are at high risk for fracture, and for treatment of men and women with glucocorticoid‐induced osteoporosis at high risk for fracture. High risk members include people who have had a history of osteoporotic fracture, multiple risk factors for fracture, or who have failed or are intolerant of previous osteoporosis therapy based on physician assessment.

Teriparatide (Forteo) is administered by once-daily subcutaneous injection in the thigh or abdomen.  The recommended dosage is 20 mcg/day.  Teriparatide is a portion of human parathyroid hormone (PTH 1-34), which is the primary regulator of calcium and phosphate metabolism in bones.  Daily injections of teriparatide stimulate new bone formation resulting in increased BMD.  Clinical studies showed that teriparatide lowered the risk of vertebral and non-vertebral fractures in post-menopausal women and increased BMD in men with primary or hypogonadal osteoporosis when compared to patients who received only calcium and vitamin D supplementation.

Forteo's product labeling carries a “black box” safety warning, which highlights the concern over the association between the drug and osteosarcomas in laboratory rats.  Because individuals with growing bones (namely children and adolescents with open epiphyses), persons with unexplained elevations in alkaline phosphatase, patients with prior external beam or implant irradiation of the skeleton, and patients with Paget's disease of the bone have a higher risk for developing osteosarcoma, the black box warning states that it is important that teriparatide not be used in these groups. Furthermore, the product labeling states that individuals with hypercalcemia, women who are pregnant or nursing, or those who have ever been diagnosed with bone cancer or other cancers that have metastasized to the bones, should not use teriparatide.  According to the product labeling, because the long-term effectiveness and safety of teriparatide treatment are not known at this time, therapy for more than 2 years is not recommended.

Rehman et al (2003) examined whether daily treatment with PTH 1-34 for 1 year was associated with a change in vertebral cross-sectional area, or vertebral size in post-menopausal women (n = 51), as measured by serial quantitative computed tomography scans.  The authors found that daily treatment with PTH 1-34 for 1 year increased vertebral size as measured by vertebral cross-sectional area and this increase was maintained after PTH 1-34 was discontinued.  Furthermore, Marcus et al (2003) reported that teriparatide offers clinical benefit to patients across a broad range of age and disease severity.

Body and co-workers (2002) compared the effects of teriparatide and alendronate on BMD, non-vertebral fracture incidence, and bone turnover in 146 post-menopausal women with osteoporosis.  Women were randomized to either once-daily subcutaneous injections of teriparatide 40 mcg plus oral placebo (n = 73) or oral alendronate 10 mg plus placebo injection (n = 73).  Median duration of treatment was 14 months.  At 3 months, teriparatide increased lumbar spine BMD significantly more than did alendronate.  Lumbar spine-BMD increased by 12.2 % in the teriparatide group and 5.6 % in the alendronate group.  Teriparatide increased femoral neck BMD and total body bone mineral significantly more than did alendronate, but BMD at the 1/3 distal radius decreased, compared with alendronate.  Non-vertebral fracture incidence was significantly lower in the teriparatide group than in the alendronate group.  Both treatments were well-tolerated despite transient mild asymptomatic hypercalcemia with teriparatide treatment.  These investigators concluded that teriparatide, a bone-forming agent, increased BMD at most sites and decreased non-vertebral fractures more than alendronate.  However, more comparative studies are needed to validate this finding.

Most adverse events reported in association with teriparatide in clinical trials were mild and included nausea, dizziness, and leg cramps.  During the clinical trials, early discontinuation due to adverse events occurred in 5.6 and 7.1 % of patients in the control and treatment groups, respectively.  Although not observed in human clinical trials, teriparatide is associated with development of osteosarcomas in animal studies.

In a review on the use of intermittent human PTH as a treatment for osteoporosis, Deal (2004) explained that patients who have Paget's disease, prior radiation therapy to the skeleton, as well as children and young adults with open epiphyses, are at higher risk for osteosarcoma and should not be given PTH.  Patients with hypercalcemia and hyperparathyroidism also should not receive the drug.

The Canadian Coordinating Office of Health Technology Assessment (Shulka, 2003) reached the following conclusions about teriparatide: "Although placebo-controlled trials show that teriparatide can reduce fractures, there is little information on its efficacy compared to available alternatives.  In the United States, the Food and Drug Administration (FDA) highlighted concerns about teriparatide's carcinogenic effects in rats.  Company-sponsored studies have been voluntarily stopped …. Because of safety concerns and the lack of efficacy and effectiveness data, it is difficult to define teriparatide's role in the treatment of osteoporosis.  This is compounded by the possible long-term antagonizing effect of bisphosphonates on teriparatide's bone-forming properties."

Guidance from the National Institute for Health and Clinical Excellence (2011) recommends teriparatide as an alternative treatment option for the secondary prevention of osteoporotic fragility fractures in postmenopausal women: 1) who are unable to take alendronate and either risedronate or etidronate, or have a contraindication to or are intolerant of alendronate and either risedronate or etidronate, or who have a contraindication to, or are intolerant of strontium ranelate, and 2) who have had an unsatisfactory response to treatment with alendronate, risedronate or etidronate and who are 65 years or older and have a T-score of –4.0 SD or below, or a T-score of –3.5 SD or below plus more than two fractures, or who are aged 55–64 years and have a T-score of –4 SD or below plus more than two fractures. For the purposes of this guidance, independent clinical risk factors for fracture are parental history of hip fracture, alcohol intake of 4 or more units per day, and rheumatoid arthritis. The guidance defines intolerance to bisphosphonates as persistent upper gastrointestinal disturbance that is sufficiently severe to warrant discontinuation of treatment, and that occurs even though the instructions for administration have been followed correctly. The guidance defines intolerance to strontium ranelate as persistent nausea or diarrhea, either of which warrants discontinuation of treatment. An unsatisfactory response is defined as occurring when a woman has another fragility fracture despite adhering fully to treatment for 1 year and there is evidence of a decline in BMD below her pre-treatment baseline.

The Australian Pharmaceutical Benefits Scheme (2009) has listed teriparatide for severe established osteoporosis in people at very high risk of fracture who develop one or more new symptomatic fractures despite at least 12 months of continuous antiresorptive therapy. Treatment with teriparatide is limited to a total of 18 months to reduce the risk of osteosarcoma. The PBS defines a vertebral fracture as a 20% or greater reduction in height of an anterior or mid-portion vertebral body relative to the posterior height of that body, or a 20% or greater reduction in any vertebral height compared with vertebral height above or below the affected vertebral body. For purposes of this policy, antiresorptive doses were defined as: alendronate 10 mg daily or 70 mg weekly, risedronate 5 mg daily or 35 mg weekly, raloxifene 60 mg daily (women only), etidronate 200 mg with calcium carbonate 1.25 g daily, strontium 2 g daily and zoledronic acid 5 mg once a year. If severe intolerance occurs that requires permanent withdrawal of one antiresorptive agent, the PBS requires a trial of an alternative antiresorptive agent so that a minimum of 12 months of continuous therapy is achieved.

The Canadian Expert Drug Advisory Committee (CEDAC, 2010) review on the use of teriparatide in severe osteoporosis in women found no randomized controlled trials meeting the Common Drug Review systematic review protocol that evaluated teriparatide in women previously treated with anti-resorptive therapy. The Committee considered the European Study of Forsteo (EUROFORS) and European Forsteo Observational Study (EFOS) studies, both of which included some patients who had received prior anti-resorptive therapy, but found that interpretation of data from these studies was limited. The CEDAC stated that, although EUROFORS is a randomized controlled trial, the effects of teriparatide in patients previously receiving anti-resorptive therapy were only evaluated in a subgroup analysis that did not include a comparative group, fracture outcomes were not reported, and all patients had previously been exposed to teriparatide for 12 months. The CEDAC noted that, although EFOS enrolled patients who had an insufficient response or who were intolerant to prior anti-resorptive therapy, it was an open-label uncontrolled study and a substantial proportion of patients did not complete the study on treatment.

The Canadian Expert Drug Advisory Committee did not reommend teraparatide for glucocorticoid-induced osteoporosis. CEDAC identified only one double-blind randomized-controlled trial (n =428) evaluating the effects of teriparatide on glucocorticoid-induced osteoporosis. The study found no differences between teraparatide and alendronate for incidence of non-verteral fracture (including hip fracture) or clinical (symptomatic) vertebral fracture. The incidence of radiographic vertebral fractures was statistically significantly lower in the teriparatide group compared with the alendronate group; however, a large proportion of patients were missing radiographic data, reducing confidence in these results.

Guidelines from the American Association of Clinical Endocrinologists (Watts, et al. 2012) recommend use teriparatide for patients with very high fracture risk or patients in whom bisphosphonate therapy has failed. They state that teriparatide is contraindicated in patients at increased risk of osteosarcoma (those with Paget disease of bone, open epiphyses, a history of irradiation involving the skeleton, or an unexplained elevation of alkaline phosphatase level of skeletal origin). Teriparatide should also not be administered to patients with primary or any form of secondary untreated or unresolved hyperparathyroidism.

Combination therapy with teriparatide or parathyroid hormone (1-84) and an anti-resorptive agent has not been proven to offer advantages over the use of parathyroid hormone or an anti-resorptive agent alone for osteoporosis.  Bilezikian and Rubin (2006) discussed the use of anabolic skeletal therapy for the treatment of post-menopausal and other forms of osteoporosis.  The authors stated that the only anabolic skeletal agent currently available is teriparatide.  Teriparatide improves bone quality by actions on bone turnover, bone density, bone size, and micro-architecture.  In post-menopausal women with osteoporosis, teriparatide reduces the incidence for vertebral and non-vertebral fractures.  In individuals who have been treated previously with an anti-resorptive agent (e.g., estrogen and bisphosphonates), the subsequent actions of teriparatide on bone density are delayed transiently if bone turnover is markedly suppressed.  The authors argued that combination therapy with teriparatide or PTH (1-84) and an anti-resorptive does not appear, at this time, to offer advantages over the use of PTH or an anti-resorptive alone.

In a randomized, open-labeled clinical study, Matsumoto et al (2006) examined the safety and effectiveness of nasal hPTH(1-34) spray in subjects with osteoporosis.  A total of 90 osteoporotic subjects aged 52 to 84 years (mean of 66.5 years) were randomly assigned to receive either 250 mcg (PTH250, n = 31), 500 mcg (PTH500, n = 30), or 1,000 mcg (PTH1000, n = 29) of daily nasal hPTH(1-34) spray for 3 months.  All subjects received daily supplements of 300 mg calcium and 200 IU vitamin D(3).  Daily nasal hPTH(1-34) spray for 3 months increased lumbar BMD (L-BMD) in a dose-dependent manner, and the PTH1000 group showed a 2.4 % increase in L-BMD from baseline.  Only the 1,000-mcg dose produced consistent and statistically significant changes in markers of bone turnover; after 3 months, median serum type I procollagen N-propeptide (PINP) and osteocalcin increased 14.8 % and 19.4 % from baseline, while urinary type I collagen N-telopeptide (NTX) decreased 16.4 %.  Seven subjects developed transient hypercalcemia at 3 hours after nasal hPTH(1-34) spray, but none of the subjects developed sustained hypercalcemia.  The authors concluded that these findings showed that nasal hPTH(1-34) spray is safe and well-tolerated and can rapidly increase L-BMD.  They noted that the results warrant further studies to examine its long-term effectiveness on bone mass and fractures.

Glucocorticoid-Induced Osteoporosis

In July 2009, the FDA expanded the indications for teriparatide to include adults with a high-risk for fracture related to glucocorticoid-induced osteoporosis.  The FDA's decision was based on data from an 18-month randomized, double-blind, controlled clinical trial that compared teriparatide with alendronate in 428 women and men with osteoporosis (aged 22 to 89 years) who had received sustained glucocorticoid therapy.  Sustained glucocorticoid therapy was defined as a mean daily dose of 5 mg or more of prednisone or its equivalent for at least 3 months.  A total of 214 patients received 20 mcg of teriparatide once-daily, and 214 received 10 mg of alendronate once-daily.  The primary outcome was the change in BMD at the lumbar spine.  Secondary outcomes included changes in BMD at the total hip and in markers of bone turnover, the time to changes in BMD, the incidence of fractures, and safety.  At the last measurement, the mean (+/- SE) BMD at the lumbar spine had increased more in the teriparatide group than in the alendronate group (7.2 +/- 0.7 % versus 3.4 +/- 0.7 %, p < 0.001).  A significant difference between the groups was reached by 6 months (p < 0.001).  At 12 months, BMD at the total hip had increased more in the teriparatide group.  Fewer new vertebral fractures occurred in the teriparatide group than in the alendronate group (0.6 % versus 6.1%, p = 0.004); the incidence of non-vertebral fractures was similar in the 2 groups (5.6 % versus 3.7 %, p = 0.36).  Significantly more patients in the teriparatide group had at least one elevated measure of serum calcium.  The authors concluded that among patients with osteoporosis who were at high-risk for fracture, BMD increased more in patients receiving teriparatide than in those receiving alendronate (Saag et al, 2007).

Losada et al (2009) compared teriparatide versus alendronate on BMD in Hispanic (n = 61) and non-Hispanic (n = 367) patients with glucocorticoid-induced osteoporosis.  Data from the 18-month study from all patients (n = 428) in a double-blind trial of teriparatide (20 mcg per day) and alendronate (10 mg per day) who had taken glucocorticoids for 3 or more months were analyzed (Saag et al, 2007).  At the last measurement, the mean (+/- SE) BMD at the lumbar spine in the Hispanic cohort had increased more in the teriparatide versus alendronate group (9.8 % +/- 1.7 % versus 4.2 % + /-1.4 %; p < 0.001) and total hip BMD (5.9 % +/- 1.6 % versus 3 % +/- 1.3 %, p < 0.001), with no significant difference between groups at the femoral neck (4.3 % +/- 2.2% versus 2.0 % +/- 1.8 %, p = 0.228).  Within each treatment group, the BMD responses were not significantly different in the Hispanic versus non-Hispanic cohort.  The number of patients reporting 1 or more adverse event was not significantly different between treatments in either cohort, with more patients reporting nausea in the teriparatide group.  The authors concluded that teriparatide was more efficacious than alendronate in increasing BMD in Hispanic and non-Hispanic patients with glucocorticoid-induced osteoporosis and that both treatments were generally well tolerated.

Osteoporosis Associated with Inflammatory Bowel Disease

Rodríguez-Bores et al (2007) stated that inflammatory bowel disease (IBD) has been associated with an increased risk of osteoporosis and osteopenia and epidemiological studies have reported an increased prevalence of low bone mass in patients with IBD.  Certainly, genetics play an important role, along with other factors such as systemic inflammation, malnutrition, hypogonadism, glucocorticoid therapy in IBD and other lifestyle factors.  At a molecular level the pro-inflammatory cytokines that contribute to the intestinal immune response in IBD are known to enhance bone resorption.  There are genes influencing osteoblast function and it is likely that LRP5 may be involved in the skeletal development.  Also the identification of vitamin D receptors (VDRs) and some of its polymorphisms have led to consider the possible relationships between them and some autoimmune diseases and may be involved in the pathogenesis through the exertion of its immunomodulatory effects during inflammation.  These researchers found that there is increasing evidence for the integration between systemic inflammation and bone loss likely mediated via receptor for activated nuclear factor kappa-B (RANK), RANK-ligand, and osteoprotegerin, proteins that can affect both osteoclastogenesis and T-cell activation.  Although glucocorticoids can reduce mucosal and systemic inflammation, they have intrinsic qualities that negatively impact on bone mass.  It is still controversial if all IBD patients should be screened, especially in patients with pre-existing risk factors for bone disease.  Available methods to measure BMD include single energy x-ray absorptiometry, dual energy x-ray absorptiometry, quantitative computed tomography, radiographical absorptiometry, and ultrasound.  Dual energy x-ray absorptiometry is the establish method to determine BMD, and routinely is measured in the hip and the lumbar spine.  There are several treatments options that have proven their effectiveness, while new emergent therapies such as calcitonin and teriparatide among others remain to be assessed.

Osteogenesis Imperfecta

In a review on bisphosphonates and other new therapeutic agents for the treatment of osteogenesis imperfecta (OI), Yamashita (2009) stated that OI is a genetic disorder characterized by fragile bone and reduced BMD.  Cyclic intravenous pamidronate is now the standard treatment for moderate-to-severe forms of OI, however clinical studies are not yet sufficient to conclude appropriate annual dose and ideal duration of therapy at present time.  Oral alendronate is also effective in milder forms of OI.  Zoledronic acid has undergone international multi-center clinical trials to examine effectiveness and long-term side effects including osteonecrosis of the jaw.  Teriparatide and denosumab have the potential for managing patients with OI. Gene therapy and stem cell are currently being actively investigated and may become clinically applicable in the near future.

Fracture Repair

Bukata and Puzas (2010) reviewed the current animal and human reports available on the uses of teriparatide in musculoskeletal diseases beyond osteoporosis.  In the treatment of osteoporosis, teriparatide works as an anabolic agent stimulating bone formation throughout the skeleton by principally enhancing osteoblast-derived bone formation relative to osteoclast-derived bone resorption.  The net effect is increased bone mass.  For patients with a fracture, a similar process of increased bone formation is needed transiently at the fracture site for repair.  Teriparatide has been investigated in animal models as well as in patients as a potential agent to enhance fracture repair. Furthermore, evidence that teriparatide enhances chondrogenesis has generated interest in using the agent for articular cartilage repair.  Research is currently underway to understand the effects teriparatide may have on mesenchymal stem cells, and on other effects that have been reported anecdotally in patients using the drug for osteoporosis care, including the healing of fracture nonunions and a decreased incidence of back pain.

In a prospective, randomized, double-blind study, Aspenberg et al (2010) tested the hypothesis that recombinant teriparatide, at the 20 microg dose normally used for osteoporosis treatment or higher, would accelerate fracture repair in humans.  Post-menopausal women (45 to 85 years of age) who had sustained a dorsally angulated distal radial fracture in need of closed reduction but no surgery were randomly assigned to 8 weeks of once-daily injections of placebo (n = 34) or teriparatide 20 microg (n = 34) or teriparatide 40 microg (n = 34) within 10 days of fracture.  Hypotheses were tested sequentially, beginning with the teriparatide 40 microg versus placebo comparison, using a gatekeeping strategy.  The estimated median time from fracture to first radiographical evidence of complete cortical bridging in 3 of 4 cortices was 9.1, 7.4, and 8.8 weeks for placebo and teriparatide 20 microg and 40 microg, respectively (overall p = 0.015).  There was no significant difference between the teriparatide 40 microg versus placebo groups (p = 0.523).  In post-hoc analyses, there was no significant difference between teriparatide 40 microg versus 20 microg (p = 0.053);  however, the time to healing was shorter in teriparatide 20 microg than placebo (p = 0.006).  The primary hypothesis that teriparatide 40 microg would shorten the time to cortical bridging was not supported.  The shortened time to healing for teriparatide 20 microg compared with placebo still may suggest that fracture repair can be accelerated by teriparatide, but this result should be interpreted with caution and warrants further study.

In a prospective, controlled, randomized, open-label, 2-year study, Lyritis et al (2010) examined changes in back pain in post-menopausal women with severe osteoporosis who received teriparatide for 24 months or switched at 12 months to raloxifene or no active treatment.  A total of 868 post-menopausal women with osteoporosis and a recent fragility fracture wer enrolled in this study.  After 12 months of teriparatide (20 microg/day), 507 patients were randomised to further teriparatide (n = 305), raloxifene 60 mg/day (n = 100), or no active treatment (n = 102) for another 12 months (substudy 1); in substudy 2, 199 patients continued teriparatide.  All received calcium and vitamin D supplementation. Back pain was self-assessed by patients using a visual analog scale (VAS; 0 to 100 mm).  Changes in back pain were analysed using a mixed model for repeated measures.  During year 1, back pain decreased from a mean (SD) of 48.9 mm (24.0) at baseline by 11.5 mm (p < 0.001) in the total study population.  In substudy 1, mean change in back pain from month 12 (randomization) to 24 months was -2.2, -4.4 and +0.7 mm in the teriparatide (p = 0.076), raloxifene (p = 0.041), and no active treatment groups (p = 0.751).  There were no between-group differences from randomization to 18 or 24 months. In a sensitivity analysis excluding patients with low baseline back pain (VAS les than 30 mm), mean change from randomization to endpoint was significant for teriparatide (-3.9 mm, p = 0.006) and raloxifene (-6.3 mm, p = 0.018) groups.  Subgroup analyses of 503 patients who received teriparatide for up to 2 years showed that patients with a recent vertebral fracture had a greater decrease in back pain than those without (p < 0.05).  Those with and without mild back pain (greater than or equal to 30 mm), and those with and without severe back pain (greater than or equal to 60 mm) at baseline all had a statistically significant reduction in back pain after 24 months (p < 0.05).  The authors concluded that teriparatide treatment is associated with significant reductions in back pain regardless of the presence of recent vertebral fracture. Moreover, they stated that these results need to be considered with caution due to the open-label design of the study.

Borges et al (2013) noted that satisfactory healing of the osteoporotic fracture is critically important to functional recovery, morbidity, and quality of life.  Some therapies for osteoporosis may affect the processes associated with bone repair.  For example, bisphosphonates in experimental models are associated with increased callus size and mineralization, reduced callus remodeling, and improved mechanical strength.  Local and systemic bisphosphonate treatment may improve implant fixation.  No negative impact on fracture healing has been observed, even after major surgery or when administered immediately after fracture.  For the osteo-anabolic agent teriparatide, case reports and a randomized controlled trial (RCT) have produced mixed results, but they are consistent with a positive impact of teriparatide on fracture healing.  Some of the agents currently being developed for osteoporosis, notably sclerostin and DKK1 antibodies have shown a beneficial effect on fracture healing.  At this point, therefore, there is no evidence that osteoporosis therapies are detrimental to fracture healing with some promising experimental evidence for positive effects on healing, notably for those agents whose actions are primarily anabolic.

Zhang et al (2014) performed a systematic literature review on the use of recombinant PTH in human fracture healing to

1. evaluate the evidence for recombinant PTH in human fracture healing, and
2. examine if there are notable differences between prior case reports and prospective trials.

These researchers performed a literature search in PubMed, EMBASE, Web of Science, and the Cochrane Database of Systematic Reviews for "teriparatide", "PTH (1-84)", "fracture", and "healing".  References of retrieved articles were screened for additional studies, and exclusion criteria were applied.  Due to the limited publications on the subject, case reports and case series were included in the data analysis.  Due to the limited publications on the subject, the data were presented in simple tabular format.  The authors concluded that the literature review yielded 16 publications on the use of recombinant PTH in human fracture healing, and 2 RCTs with 1 retrospective subgroup analysis.  There continues to be anecdotal evidence for the use of recombinant PTH to enhance fracture healing.  There are discrepancies in study design in the RCTs and the majority of case reports; the authors stated that additional prospective studies are warranted.

In a meta-analysis, Shi and associates (2016) evaluated the effectiveness of teriparatide for fracture healing.  These investigators searched PubMed, the Cochrane Library, and Embase in August 2016 for RCTs that concerned the treatment of teriparatide for fracture healing.  This meta-analysis included 5 trials with a total of 380 patients.  There was a significant effectiveness with regards to function improvement in patients following fracture, however, there was no significant effectiveness with regards to time of radiographic fracture healing, fracture healing rate and reduction in pain.  The authors concluded that the findings of this analysis showed that administration of teriparatide following fracture lacked the effectiveness for fracture healing.  Moreover, teriparatide administration had no apparent adverse effects.  They stated that these results should be interpreted with caution because of some r limitations.  They stated that more high-quality RCTs are needed to confirm whether teriparatide improves fracture healing.

Kim and colleagues (2017) evaluated the evidence of teriparatide for fracture healing and functional recovery in osteoporotic patients.  They performed a literature search in PubMed, Embase, Web of Science, and the Cochrane Library using terms including "Fracture" [tiab] AND "Teriparatide [tiab] OR "PTH" [tiab].  This systematic review included 6 randomized clinical trials, 4 well-controlled retrospective studies, and 1 retrospective post-hoc subgroup analysis.  Fracture location was 2 in pelvis, 3 in proximal femur, 1 in distal femur, 1 in shoulder, 2 in wrist and 2 in spine.  The use of teriparatide yielded positive effects on radiographic bone healing in 6 studies, but was not associated with better radiographic outcome in 3.  In terms of functional recovery, teriparatide injection was related with decrease in pain or shorter time to mobilization in 6 studies, but not related with pain numerical scale and mobility in 3.  The authors concluded that these findings suggested that teriparatide provided selective advantages to fracture healing or functional recovery in the management of osteoporotic fractures.  Moreover, they stated that a better understanding of the role of teriparatide on osteoporotic fractures requires greater evidences from large volume prospective trials.

Loosening of Pedicle Screws

Ohtori and colleagues (2013) stated that failure of fixation caused by loosening of pedicle screws (PSs) in osteoporosis is a problem in spinal surgery.  Oral administration of bisphosphonate or intermittent injection of PTH increases bone mass and reduces the risk of osteoporotic vertebral fractures.  Although these treatments may play a role in improving bone quality, a clinical study of the effectiveness of bisphosphonate or PTH for reducing PS loosening that addresses the quality of the bone marrow and pedicle cortex has not yet been reported.  In a prospective study, these researchers examined the effectiveness of teriparatide or bisphosphonate treatment to reduce PS loosening after instrumented lumbar postero-lateral fusion in post-menopausal women with osteoporosis.  A total of 62 women with osteoporosis diagnosed with degenerative spondylolisthesis were divided into 3 groups:

1. a teriparatide group (daily subcutaneous injection of 20 μg of teriparatide, n = 20),
2. a bisphosphonate group (daily oral administration 2.5 mg of risedronate, n = 20), and
3. a control group (without medication for osteoporosis, n = 22).

All patients underwent decompression and 1- or 2-level instrumented postero-lateral fusion with a local bone graft.  Loosening of PSs and surgical outcome were evaluated radiographically, clinically, and by computed tomography 12 months after surgery.  At 12-month follow-up, the incidence of PS loosening was 7 % to 13 % in the teriparatide group, 13 % to 26 % in the risedronate group, and 15 % to 25 % in the control group.  The incidence of PS loosening in the teriparatide group was significantly lower than that in the risedronate or the control group (p < 0.05).  In contrast, the extent of PS loosening in the risedronate group was not significantly different from that in the control group (p > 0.05).  The authors concluded that these findings suggested that administration of teriparatide increased the quality of the lumbar spine bone marrow and pedicle cortex.  These preliminary findings need to be validated by well-designed studies.

Hungry Bone Syndrome

An UpToDate review on “Hungry bone syndrome following parathyroidectomy” (Berkoben and Quarles, 2014) does not mention the use of teriparatide as a therapeutic option.

Distraction Osteogenesis

Atypical Femur Fractures

The American Society for Bone and Mineral Research Task Force’s 2nd report on “Atypical subtrochanteric and diaphyseal femoral fractures” (Shane et al, 2014) stated that “In the absence of a randomized, placebo‐controlled trial, no definite conclusion can be reached regarding the efficacy of TPTD [teriparatide] treatment of patients with AFF [atypical femur fractures]”.

Furthermore, an UpToDate review on “The use of bisphosphonates in postmenopausal women with osteoporosis” (Rosen, 2015) states that “Atypical femur fractures -- Another option in some cases would be the use of parathyroid hormone (PTH) in conjunction with comprehensive orthopedic intervention and surveillance. In some, but not all, case reports, teriparatide treatment improved fracture healing and pain in patients with atypical fractures. There are no randomized trials to definitively determine the efficacy of teriparatide in patients with atypical fractures. The results of randomized trials of teriparatide or PTH 1-84 in patients with distal radial or pelvic fractures (i.e., not atypical fractures) are conflicting, with one showing no benefit in fracture healing, and another showing benefit”.

Nonunion Fractures

In a case-series study, Mancilla et al (2015) examined the effect of teriparatide on the healing of long bone nonunion fractures. These investigators performed a retrospective chart review of patients with fracture nonunion, aged 10 to 99 years who were treated with teriparatide. The primary end-points were radiographic evidence of callus formation and fracture union, ability to bear weight without affected limb limp, and normal range of motion (ROM) and strength. A total of 6 patients aged 19 to 64 years with tibial or femoral fractures that had not healed for 3 to 36 months were treated with teriparatide 20 μg/day. Accelerated healing of fracture nonunion was confirmed in 5 of 6 patients with time to complete union of 3 to 9 months. The shortest time to recovery was observed in younger patients without co-morbidities. Treatment was well-tolerated. The authors concluded that teriparatide is a promising treatment for nonunion fractures, but its response depends on associated co-morbidities. They stated that the potential benefit of teriparatide as an adjunct to treat nonunion justifies RCTs to determine its safety and effectiveness in broader populations.

Osteonecrosis of the Jaw

Kim and colleagues (2014) noted that the administration of teriparatide in conjunction with periodontal care could provide faster and more favorable clinical outcomes in previously refractory bisphosphonate (BP)-related osteonecrosis of the jaws (BRONJ) cases compared to conventional dental care, combination of surgery and anti-microbial treatment. These investigators also found that underlying vitamin D levels might influence the response to teriparatide treatment. A total of 24 cases of intractable BRONJ were included: 15 subjects were assigned to the teriparatide group and the other 9 subjects, who refused teriparatide administration, were assigned to the non-teriparatide group. All subjects in both groups continued calcium and vitamin D supplementation and the teriparatide group additionally received a daily subcutaneous injection of 20 μg teriparatide for 6 months. While 60.0 % of the non- teriparatide group showed 1 stage of improvement in BRONJ, 40.0 % of the group did not show any improvement in disease status. In the teriparatide group, 62.5 % of the treated subjects showed 1 stage of improvement and the other 37.5 % demonstrated a marked improvement, including 2 stages of improvement or complete healing, and there was not a single case that did not improve. The clinical improvement of BRONJ was statistically better in the teriparatide group after the 6-month treatment (p < 0.05). Moreover, patients with higher baseline serum 25(OH)D levels showed better clinical therapeutic outcomes with teriparatide. The authors observed the beneficial effects of teriparatide on BRONJ, and subjects with optimal serum vitamin D concentrations seemed to reap the maximum therapeutic effects of TPTD. They stated that a prospective RCT is needed to further evaluate the therapeutic efficacy of teriparatide in the resolution of BRONJ.

Khan et al (2015) provided a systematic review of the literature from January 2003 to April 2014 pertaining to the incidence, pathophysiology, diagnosis, and treatment of osteonecrosis of the jaw (ONJ), and offered recommendations for its management based on multi-disciplinary international consensus. Osteonecrosis of the jaw is associated with oncology-dose parenteral anti-resorptive therapy of BP and denosumab (Dmab). The incidence of ONJ is greatest in the oncology patient population (1 % to 15 %), where high doses of these medications are used at frequent intervals. In the osteoporosis patient population, the incidence of ONJ is estimated at 0.001 % to 0.01 %, marginally higher than the incidence in the general population (less than 0.001 %). New insights into the pathophysiology of ONJ include anti-resorptive effects of BPs and Dmab, effects of BPs on gamma delta T-cells and on monocyte and macrophage function, as well as the role of local bacterial infection, inflammation, and necrosis. Advances in imaging include the use of cone beam computerized tomography assessing cortical and cancellous architecture with lower radiation exposure, magnetic resonance imaging, bone scanning, and positron emission tomography, although plain films often suffice. Other risk factors for ONJ include glucocorticoid use, maxillary or mandibular bone surgery, poor oral hygiene, chronic inflammation, diabetes mellitus, ill-fitting dentures, as well as other drugs, including anti-angiogenic agents. Prevention strategies for ONJ include elimination or stabilization of oral disease prior to initiation of anti-resorptive agents, as well as maintenance of good oral hygiene. In those patients at high risk for the development of ONJ, including cancer patients receiving high-dose BP or Dmab therapy, consideration should be given to withholding anti-resorptive therapy following extensive oral surgery until the surgical site heals with mature mucosal coverage. Management of ONJ is based on the stage of the disease, size of the lesions, and the presence of contributing drug therapy and co-morbidity. Conservative therapy includes topical antibiotic oral rinses and systemic antibiotic therapy. Localized surgical debridement is indicated in advanced non-responsive disease and has been successful. The authors noted that early data have suggested enhanced osseous wound healing with teriparatide in those without contraindications for its use. Experimental therapy includes bone marrow stem cell intralesional transplantation, low-level laser therapy, local platelet-derived growth factor application, hyperbaric oxygen, and tissue grafting.

An UpToDate review on “Medication-related osteonecrosis of the jaw in patients with cancer” (Berenson and Stopeck, 2015) states that “Other nonsurgical treatment strategies -- Limited data suggest potential benefit for a variety of other nonsurgical treatment strategies including pentoxifylline and vitamin E, low-level laser irradiation, hyperbaric oxygen, parathyroid hormone, and topical application of medical ozone, although none can be considered a standard approach at this time”.

Fragility Fractures in Diabetics

Gonnelli et al (2015) stated that patients with diabetes mellitus (DM) are at greater risk of fractures mostly due to not only extra-skeletal factors, such as propensity to falls, but also to bone quality alteration, which reduces bone strength. In patients with DM, insulin deficit and hyperglycemia seem to play a role in determining bone formation alteration by advanced glycation end-product (AGE) accumulation which directly influences osteoblast activity. Although there are conflicting data in the literature, adequate glycemic control with hypoglycemic treatment may be an important element in preventing bone tissue alterations in both type 1 and type 2 DM. Diabetes status is a predictive of future hip and major osteoporosis fractures independently of BMD and the Fracture Risk Assessment Tool (FRAX) probability (FRAX computes the 10-year probability of hip fracture or a major osteoporotic fracture [clinical spine, hip, forearm or humerus]). Attention should be paid to the use of thiazolidinediones, especially in older women, because the direct negative effect on bone could exceed the positive effect of glycemic control. Systematic screening for complications and fall prevention efforts, along with calcium and vitamin D repletion and adequate physical activity, represents the mainstay of fracture prevention in DM patients. All anti-catabolic drugs (raloxifene, BP, denosumab) seem to be effective in DM patients. On the basis of pathophysiological evidence that suggested low bone formation in DM patients, osteo-anabolic therapies such as teriparatide might represent an important therapeutic option for DM patients with severe osteoporosis and/or multiple fractures. The search for better methods for the identification of fragility fracture risk in the growing population of adult and elderly subjects with DM might be considered a clinical priority which could improve the prevention of fracture in DM patients.

An UpToDate review on “Bone disease in diabetes mellitus” (Hordon, 2015) does not mention teriparatide as a therapeutic option.

Vertebral Collapse after Vertebral Fracture

Tsuchie et al (2015) noted that vertebral fracture is often seen in osteoporotic patients. Teriparatide is expected to promote bone union. These researchers evaluated the action of vertebral collapse prevention by administering teriparatide to vertebral fracture patients. A total of 34 patients with fresh vertebral fracture (48 vertebrae) participated in this study. They were administered either teriparatide (daily 20 µg/day or weekly 56.5 µg/week) or risedronate (17.5 mg/week): 10 patients (20 vertebrae) received teriparatide daily (Daily group), 11 patients (15 vertebrae) received teriparatide weekly (Weekly group), and 13 patients (14 vertebrae) received risedronate (RIS group). These investigators compared some laboratory examination items, VAS of low back pain, vertebral collapse rate and local kyphotic angle, and the cleft frequency. In addition, they evaluated 22 vertebral fracture patients (24 vertebrae) who did not take any osteoporotic medicines (Control group). There was no significant difference in any of the scores at the start of treatment. At 8 and 12 weeks after the initial visit, VAS scores in the Daily and Weekly groups were significantly lower than in the RIS group (p < 0.05). At 8 and 12 weeks, the vertebral collapse rate and local kyphotic angle in the Daily group were significantly lower than in the RIS and Control groups (p < 0.01 and p < 0.05, respectively), and those in the Weekly group were significantly lower than in the Control group (p < 0.05). The cleft frequency in the Daily group was significantly lower than in the RIS group (p < 0.05). The authors concluded that teriparatide is a promising approach for the prevention of vertebral collapse progression after vertebral fracture.

Hypoparathyroidism

In a prospective, open-label study, Upreti and colleagues (2017) evaluated the effectiveness of teriparatide in the treatment of patients with hypoparathyroidism.  All patients with hypoparathyroidism presented to the endocrinology out-patient department were included and were exhibited injection teriparatide 20 μg twice-daily that was gradually reduced to 10 μg twice-daily along with calcium, active vitamin D (alfacalcidol), and hydrochlorothiazide.  Oral calcium and alfacalcidol doses were also reduced to maintain serum calcium within normal range.  The quality of life (QOL) score was calculated using RAND 36 QOL questionnaire at baseline and termination of the study.  Paired t-test was used to calculate pre- and post-treatment variables.  A total of 8 patients (2 males) were included in this study with mean age of 35.8 years.  Teriparatide treatment led to the improvement in serum calcium (6.81 to 8.84 mg/dL), phosphorous (5.8 to 4.2 mg/dL), and 24-h urinary calcium excretion (416 to 203.6 mg).  Parameters of QOL showed the improvement in overall QOL, physical performance, energy, and fatigue scores.  No major adverse events (AEs) were noted.  The authors concluded that treatment of hypoparathyroidism with teriparatide resulted in improvement in calcium profile, reduction in hypercalciuria, and improvement in QOL, and treatment was well-tolerated.  Moreover, they stated that further larger studies are needed to establish the clinical value of teriparatide in the treatment of hypoparathyroidism.  The main drawback of this study were its small sample size (n = 8) and non-evaluation of bone turnover markers.

Joint Erosions in Rheumatoid Arthritis

In a RCT, Solomon and colleagues (2017) evaluated the effects of teriparatide on joint erosion volume in rheumatoid arthritis (RA) patients treated with a tumor necrosis factor inhibitor (TNFi).  Participants included 24 patients with erosive RA, osteopenia, and disease activity controlled on a TNFi for at least 3 months; 50 % were randomized to receive teriparatide for 1 year and the others constituted a wait-list control arm.  Subjects and primary rheumatologists were not masked to treatment assignment, but assessment of all outcomes was blinded.  The primary outcome was change in erosion volume measured by computed tomography at 6 anatomic sites.  Significance within each hand and anatomic site was based on a 2-tailed test, with p-value < 0.05 considered statistically significant.  Baseline characteristics of the treatment arms were well balanced.  After 52 weeks, median (interquartile) erosion volume change in the teriparatide group was -0.4 mm3 (-34.5 to 29.6) and did not differ significantly from that in controls of 9.1 mm3 (-29.6 to 26.4) (p = 0.28).  No significant change in erosion volume was noted at the radius, ulna, or metacarpophalangeal joints; BMD improved at the femoral neck and lumbar spine in the teriparatide group.  The authors concluded that teriparatide treatment for 1 year did not significantly reduce erosion volume in the hands or wrists of patients with established RA, controlled on TNFi treatment.

Post Spinal Cord Injury Osteoporosis

In a pilot study, Gordon et al (2013) evaluated the response of bone to 2 anabolic stimuli, teriparatide and mechanical loading, in subjects with spinal cord injury (SCI).  This study consisted of 12 non-ambulatory chronic SCI  subjects.  The subjects were administered open-label teriparatide 20 μg/day while undergoing robotic-assisted stepping 3 times a week for 6 months, followed by 6 months of teriparatide alone.  Bone status was evaluated at 3, 6, and 12 months by using dual-energy x-ray absorptiometry to calculate bone mineral density (BMD) at the spine and hip, magnetic resonance imaging to assess bone microarchitecture of the distal tibia, and serum bone markers.  Mean (SD) baseline BMD measurements at the spine and the left and right total hip were 1.05 ± 0.162 g/cm(2), 0.638 ± 0.090 g/cm(2) and 0.626 ± 0.088 g/cm(2), respectively.  After 6 months of treatment, BMD changed 2.19 % ± 3.61 %, 0.02 % ± 2.21 %, and 0.74 % ± 2.80 % at the spine, and left and right total hip, respectively.  These changes were not statistically significant (p > 0.05 for all).  Magnetic resonance imaging supported an anabolic effect after 3 months of treatment with significant (p < 0.05) changes in trabecular thickness, 4.4 % ± 4.06 %; surface-to-curve ratio, 23.6 % ± 22.3 %; and erosion index, -17.04 % ± 12.9 %.  Although the trend remained after 6 months, statistical significance was not retained.  At 6 months, bone markers indicated an increase in mean levels of bone-specific alkaline phosphatase, 53.8 % ± 62.9 %; C-terminal telopeptides of type I collagen, 137.6 % ± 194.6 %; and intact amino-terminal propeptide of type I procollagen, 61.4 % ± 99.3 %.  The authors concluded that in this limited pilot study, teriparatide and mechanical loading resulted in a numerical but not statistically significant increase in lumbar spine BMD and no significant BMD changes at the hip.  Magnetic resonance imaging at the distal tibia suggested an anabolic effect, but the high sensitivity offered by this technique was challenged by the limited ability to obtain analyzable data from all the subjects.  They stated that further studies that involve longer treatment periods and greater mechanical loading are needed.

Furthermore, an UpToDate review on “Chronic complications of spinal cord injury” (Abrams and Wakasa, 2018) states that “Osteoporosis affects bones below the level of the SCI and increases the risk of fracture.  The role of bisphosphonates in this setting is under investigation”. 

Prosthesis Fixation Following Total Knee Replacement

Ledin and colleagues (2017) noted that aseptic loosening is a main cause of late revision in total knee replacement (TKR).  Teriparatide stimulates osteoblasts and has been suggested to improve cancellous bone healing in humans.  This might also be relevant for prosthesis fixation.  In a RCT with blind evaluation, these researchers employed radio-stereometric analysis (RSA) to examine if teriparatide influences prosthesis fixation.  Early migration as measured by RSA can predict future loosening.  A total of 50 patients with osteoarthritis (OA) of the knee were allocated to a teriparatide treatment group (Forteo, 20 μg daily for 2 months post-operatively) or to an untreated control group; RSA was performed post-operatively and at 6 months, 12 months, and 24 months.  The primary effect variable was maximal total point motion (MTPM) from 12 to 24 months.  Median MTPM from 12 to 24 months was similar in the 2 groups (teriparatide: 0.14 mm, 10 % and 90 % percentiles: 0.08 and 0.24; control: 0.13 mm, 10 % and 90 % percentiles: 0.09 and 0.21).  The 95 % confidence interval (CI) for the difference between group means was -0.03 to 0.04 mm, indicating that no difference occurred.  The authors reported that contrary to expectation, they were unable to demonstrate any effects of teriparatide treatment on prosthesis migration at any time-point.  Moreover, the CI for the difference between group means excluded any meaningful differences.

Prevention of Site-Specific Non-Vertebral Fractures at the Wrist and Hip

In a systematic review, Chen and colleagues (2019) updated the treatment with teriparatide for fracture prevention.  Electronic databases, including OVID Medline, OVID Embase, and the Cochrane Library, were searched on February 9, 2018, to identify published systematic reviews and meta-analyses addressing treatment with teriparatide for fracture prevention, and A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) was used to assess the quality of included studies.  A total of 17 studies were included; 3 were rated as high quality, 3 were rated as moderate quality, 6 were rated as low quality, and 5 were rated as critically low quality.  Teriparatide reduced vertebral and overall non-vertebral fractures in osteoporotic patients regardless of the existence of precipitating conditions, including post-menopausal status, glucocorticoid treatment, and chronic kidney disease, as compared with placebo, but not the site-specific non-vertebral fractures of the wrist and hip.  Teriparatide did not more effectively reduce fracture risks when compared with other medications, such as bisphosphonates, SERMs, RANKL (receptor activator of nuclear factor kappa-beta ligand) inhibitor, or strontium ranelate.  The authors concluded that teriparatide was safe and was not associated with an increased rate of AEs when compared with other drugs.  Teriparatide was effective for the prevention of vertebral and overall non-vertebral fractures in osteoporotic patients but not for the prevention of site-specific non-vertebral fractures at the wrist and hip.  Level of Evidence = I.

Treatment of Osteoporotic Vertebral Compression Fracture

In a retrospective, comparative study, Iwata and co-workers (2017) examined the effects of teriparatide versus a bisphosphonate on radiographic outcomes in the treatment of osteoporotic vertebral compression fractures (OVCF).  A total of 98 patients undergoing non-operative treatment for recent single-level OVCF were reviewed retrospectively; 38 patients were treated by a once-daily subcutaneous injection of 20 μg of teriparatide (TPD group), whereas 60 patients received 35 mg of alendronate weekly (BP group).  Except for these medications, the same treatment protocol was applied to both groups.  The radiographic assessments included union status, vertebral kyphosis, and mid-vertebral body height.  The rates of fracture site surgical intervention were also compared between the 2 groups.  The mean follow-up period was 27 months (median of 22.5, range of 2 to 75 months).  Cox regression analysis showed that TPD reduced the time-to-union (adjusted relative HR: 1.86, 95 % CI: 1.21 to 2.83).  The union rate at 6 months after treatment was 89 % in the TPD group and 68 % in the BP group; the surgical intervention rate was significantly higher in the TPD group (p = 0.026, adjusted OR: 8.15, 95 % C.: 2.02 to 43.33).  The change in local kyphosis was 4.6° in the TPD group and 3.8° in the BP group (p = 0.495, paired t-test).  The change of mid-vertebral body height was 4.4 mm in the TPD group and 3.4 mm in the BP group (p = 0.228, paired t-test).  Fracture site surgical interventions were not needed in the TPD group; however, 2 patients in the BP group eventually underwent surgical treatment for symptomatic non-union or vertebral collapse.  The authors concluded that this retrospective study suggested that teriparatide may enhance fracture healing and improve the union rate in OVCF.

The authors stated that this study had several drawbacks.  This was a retrospective comparative study that included different sample sizes and demographics between the 2 treatment groups.  The inter-group difference in the ratio of prior bisphosphonate use was a potential source of selection bias in this study.  To adjust for heterogeneity between the 2 treatment groups, these researchers used multiple logistic regression analysis.  The biological aspects of fracture healing should be examined prospectively using bone metabolic markers, vitamin D, and parathyroid hormone (PTH) level status to determine whether the state of bone turnover was comparable between the TPD group and the BP group at baseline and to examine if treatment affected bone turnover in these patients.  Due to the nature of retrospective investigation, serum bone markers could be collected only in a very limited number of patients.  In this retrospective study, the follow-up duration after 3 months following treatment differed for each doctor.  Considering the follow-up duration differences, these investigators showed the union rate on the Kaplan-Meier survival curve as the time course of vertebral union for each medication.  An MRI study might help evaluate the early phase of fracture healing.

Kang and colleagues (2019) stated that osteoporosis is one of the most common causes of VCFs.  Teriparatide is the first anabolic agent for the treatment of osteoporosis.  These researchers examined if 3 months of TPD could be effective for patients with OVCF at the thoracolumbar spine.  They reviewed 25 patients with thoracolumbar osteoporotic compression fractures between July 2012 and October 2016 who could be followed-up for more than 1 year.  Patients were divided into 2 groups depending on the use of TPD: 14 patients received TPD through subcutaneous injection (group I); and 11 patients did not receive TPD (group II).  Demographic data, BMD, hospitalization period, changes in the VAS score, BMI, and medical history such as smoking, alcohol, diabetes, and steroid usage were reviewed.  Radiographs were also reviewed to evaluate vertebral body compression percentages and kyphotic angles.  Overall changes of VAS score between injury and follow-up were statistically improved in both groups at 2 to 3 weeks post-injury.  However, difference in VAS improvement at a specific time between the 2 groups was not statistically significant.  Overall kyphotic angle and compression percentage between injury and follow-up time were increased in group II than those in group I, although the difference between the 2 groups was not statistically significant.  The authors concluded that 3-month of TPD did not show protective effects on progression of fractured vertebral body collapse or kyphotic changes in patients with osteoporosis.  These researchers stated that further prospective studies are needed to evaluate the relative indication and effective treatment period for osteoporotic compression fracture in patients with thoracolumbar VCF.

The authors stated that this study had several drawbacks.  This was a retrospective analytic study; these investigators were unable to conduct a RCT.  Prospective studies are needed to determine the progression of vertebral collapse with longer follow-up period.  Longer period of TPD usage is also needed to determine the optimal period for fracture healing.  Long-term follow-up with many patients could powerfully analyze positive effects of TPD in conservative treatment after OVCFs.  Furthermore, only pain and radiologic factors were considered in this study; economic outcomes were not analyzed.

In an open-label, non-randomized, prospective study, Kitaguchi and associates (2019) examined the effect of once-weekly TPD administration on vertebral stability and bony union after acute osteoporotic vertebral fracture (OVF).  A total of 48 subjects with acute OVF were assigned to receive activated vitamin D3 and calcium supplementation or once-weekly subcutaneous injection of TPD (56.5 μg) in combination with activated vitamin D3 and calcium supplementation for 12 weeks.  Vertebral stability was assessed using lateral plain radiography.  Vertebral height at the anterior location (VHa) and the difference in VHa {ΔVHa = VHa (supine position) - VHa (weight-bearing position)} were measured at baseline and 12 weeks after starting treatment.  Bony union was defined as the absence of a vertebral cleft or abnormal motion (ΔVHa greater than 2 mm).  Although not significant, ΔVHa, indicating vertebral stability, tended to be lower in the TPD group at 12 weeks (p = 0.17).  As for subjects with severe osteoporosis, ΔVHa at 12 weeks was significantly lower in the TPD group than in the control group (mean ΔVHa: control group, 3.1 mm (n = 15); TPD group, 1.4 mm (n = 16); p = 0.02).  The rate of bony union was significantly higher in the TPD group than in the control group (control group, 40 %; TPD group, 81 %; p = 0.03).  The authors concluded that the findings of this study indicated that once-weekly administration of TPD promoted bony union of fractured vertebra in patients with severe osteoporosis.  This approach appeared to promote the stability of fractured vertebrae by preventing further vertebral collapse during the immediate post-injury period.

The authors stated that this study had several drawback.  First, this study was not a double-blind, randomized prospective study.  To examine the issues more precisely, a double-blind, randomized prospective study should be carried out.  However, in the design of such a study, the control group would be required to interrupt anti-osteoporotic drugs for a fixed period of time.  Termination of anti-osteoporotic drugs could cause additional vertebral fractures and would therefore be ethically unacceptable.  Second, the number of subjects in both groups was relatively small.  Unlike previous studies, these researchers excluded cases of stable acute OVF that showed no or little change in ΔVHa, thereby limiting the patient population to those with vertebral instability and decreasing the number of participants included in the study.  Third, a study period of 3 months was relatively brief.  However, pain and other symptoms caused by acute OVF normally resolve within 3 months.  Vertebral collapse is most common within 3 months of injury; it was therefore reasonable to examine the effects of TPD on vertebral fractures within a 3-month period.

Treatment of Stress Fracture

Gende and colleagues (2019) noted that pelvic stress fractures are rare and present unique challenges for medical personnel.  Delayed healing can lead to increased physical, psychological, and social stress for athletes.  Recent literature suggested effective use of teriparatide to enhance healing of delayed-union stress fractures.  These researchers presented the case of a female National Collegiate Athletic Association (NCAA) Division I gymnast who successfully returned to play after a 12-week course of teriparatide injections for an ischio-acetabular stress fracture.  

Furthermore, UpToDate reviews on “Overview of stress fractures” (deWeber, 2019), “Stress fractures of the tibia and fibula” (Fields, 2019), “Stress fractures of the metatarsal shaft” (Clugston and Hatch, 2019), and “Femoral stress fractures in adults” (Jackson, 2019) do not mention teriparatide as a therapeutic option.

Appendix

According to the FDA-approved labeling, teriparatide (Forteo) is contraindicated in any of the following individuals:

• Children and adolescents with open epiphyses; or
• Individuals who have been diagnosed with bone cancer or other cancers that have metastasized to the bones; or
• Individuals with hypercalcemia; or
• Individuals with Paget's disease of the bone; or
• Individuals with prior radiation therapy to the skeleton; or
• Women who are pregnant or nursing.

Forteo (teriparatide) is available as Forteo, a colorless, clear, isotonic, sterile solution for subcutaneous injection containing 250mcg/mL. The following package is available: 20 mcg per dose, 28 days of use, 2.4 mL prefilled pen.

The FDA-approved labeling of Forteo has the following recommendations regarding dosing and administration:

• Recommended dose is 20 mcg subcutaneously once a day.
• Administer as a subcutaneous injection into the thigh or abdominal wall.
• Administer initially under circumstances in which the patient can sit or lie down if symptoms of orthostatic hypotension occur.
• Use of the drug for more than 2 years during a patient’s lifetime is not recommended.
  
  

Table: CPT Codes / HCPCS Codes / ICD-10 Codes

Code	Code Description
Information in the [brackets] below has been added for clarification purposes.   Codes requiring a 7th character are represented by "+":
Other CPT codes related to the CPB:
20100 - 29999	Musculoskeletal system [e.g. articular cartilage repair and fracture repair]
76977	Ultrasound bone density measurement and interpretation, peripheral sites(s), any method
77078 - 77081	Computed tomography, bone mineral density study, one or more sites; axial skeleton (e.g., hips, pelvis, spine), appendicular skeleton (peripheral) (e.g., radius, wrist, heel) or dual energy x-ray absorptiometry (DXA), bone density study, one or more sites: axial skeleton (e.g., hips, pelvis, spine), appendicular skeleton, (peripheral) (eg, radius, wrist, heel), or vertebral fracture assessment
HCPCS codes covered if selection criteria are met:
J3110	Injection, Teriparatide, 10 mcg
Other HCPCS codes related to the CPB:
E0747	Osteogenesis stimulator, electrical, noninvasive, other than spinal applications
E0760	Osteogenesis stimulator, low intensity ultrasound, noninvasive
J1740	Injection, ibandronate sodium, 1 mg
J3489	Injection, zoledronic acid, 1mg
ICD-10 codes covered if selection criteria are met:
M80.00x+ - M81.6	Osteoporosis
M81.8	Other osteoporosis without current pathological fracture [not covered for drug-induced osteoporosis and osteoporosis associated with inflammatory bowel disease]
ICD-10 codes not covered for indications listed in the CPB (not all-inclusive):
C40.00 - C41.9	Malignant neoplasm of bone and articular cartilage
C79.51 - C79.52	Secondary malignant neoplasm of bone and bone marrow
D16.00 - D16.9	Benign neoplasm of bone and articular cartilage
D48.0	Neoplasm of uncertain behavior of bone and articular cartilage
D49.2	Neoplasm of unspecified behavior of bone, soft tissue, and skin
E20.0 - E20.9	Hypoparathyroidism
E21.0 - E21.3	Hyperparathyroidism and other disorders of parathyroid gland
E83.52	Hypercalcemia (idiopathic)
E83.81	Hungry bone syndrome
M05.0 - M05.09, M05.20 - M06.39, M06.80 - M06.9	Rheumatoid arthritis [joint erosions]
M83.0 - M83.9	Adult osteomalacia [metabolic bone disease other than osteoporosis]
M84.30xx+ - M84.38xx+	Stress fractures
M84.3 - M84.9	Disorder of continuity of bone [metabolic bone disease other than osteoporosis]
M85.80 - M85.89	Other specified disorders of bone density and structure [osteopenia]
M87.08	Idiopathic aseptic necrosis of bone, other site [jaw]
M88.0 - M88.9	Osteitis deformans [Paget's disease of bone]
Numerous options	Nonunion of fracture [7th character "K"]
O00.00 - 098.53	Pregnancy, childbirth , and the puerperium
Q78.0	Osteogenesis imperfecta
S12.000+ - S12.9xx+, S22.000+ - S22.089+, S32.000+ - S32.059+	Fracture of cervical vertebra and other parts of neck, thoracic vertebra, lumbar vertebra
S72.001+ - S72.92x+	Fracture of femur [for the treatment of atypical femur fractures]
T66.xxx+	Radiation sickness, unspecified
T84.030+ - T84.039+	Mechanical loosening of internal prosthetic joint [reducing pedicle screw loosening following spinal fusion]
Z33.1	Pregnant state, incidental
Z34.00 - Z34.93	Encounter for supervision of normal pregnancy
Z39.1	Encounter for care and examination of lactating mother
Z92.3	Personal history of irradiation

The above policy is based on the following references: