Caplacizumab-yhdp (Cablivi)

Number: 0949

Policy

Note: REQUIRES PRECERTIFICATION

Precertification of caplacizumab is required of all Aetna participating providers and members in applicable plan designs.  For precertification of caplacizumab, call (866) 503-0857, or fax (866) 267-3277.

Aetna considers caplacizumab-yhdp (Cablivi) medically necessary for treatment of persons with acquired thrombotic thrombocytopenic purpura (aTTP) when the following criteria are met:

For Treatment During Plasma Exchange

For initiation of treatment

• Member is caplacizumab-naïve OR Member has not experienced more than 2 recurrences of aTTP, while on caplacizumab; and 
• The first dose is administered in the inpatient setting by a healthcare provider as a bolus intravenous injection; and
• Used in combination with plasma exchange; and
• Used in combination with immunosuppressive therapy.

For subsequent treatment

• Subsequent treatment is administered as subcutaneous injection; and
• Used in combination with plasma exchange; and
• Used in combination with immunosuppressive therapy; and
• Member has not experienced more than 2 recurrences of aTTP, while on caplacizumab.

For Treatment Continuation After Plasma Exchange

• For treatment continuation as subcutaneous injection for 30 days following the last daily plasma exchange; and
• Used in combination with immunosuppressive therapy (Note: Treatment with immunosuppressive therapy may be tapered to achieve clinical response); and
• Member has not experienced more than 2 recurrences of aTTP, while on caplacizumab.

For Refractory aTTP

• Member continues to experience signs of persistent underlying disease after completing 30 days of treatment beyond the last plasma exchange; and
• Extension of treatment will not exceed 28 days; and
• Member has not experienced more than 2 recurrences of aTTP, while on caplacizumab; and
• Member continues to experience signs of persistent underlying disease with documentation of either of the following:
   
  • suppressed ADAMTS13 (i.e. ADAMTS13 activity less than 10%); or
  • member meets all of the following criteria: 
     
    • microangiopathic hemolytic anemia (MAHA) (presence of schistocytes on peripheral smear); and
    • thrombocytopenia (low platelets, per laboratory reference range); and
    • elevated lactate dehydrogenase (LDH; per laboratory reference range); and
      
      

• Used in combination with immunosuppressive therapy.

Note: Member has not experienced more than 2 recurrences of aTTP, while on caplacizumab (i.e., the member has not received more than 2 distinct courses of caplacizumab therapy).

Aetna considers caplacizumab-yhdp (Cablivi) experimental and investigational for all other indications.

See also CPB 0285 - Plasmapheresis/Plasma Exchange/Therapeutic Apheresis.

See also CPB 0780 - ADAMTS13 Assay for Thrombotic Thrombocytopenic Purpura (TTP).

Dosing Recommendations

Caplacizumab should be administered upon the initiation of plasma exchange therapy. Discontinue caplacizumab if the patient experiences more than 2 recurrences of aTTP, while on caplacizumab.

Withhold caplacizumab for 7 days prior to elective surgery, dental procedures or other invasive interventions. If emergency surgery is needed, the use of von Willebrand factor concentrate may be considered to correct hemostasis. After the risk of surgical bleeding has resolved, and caplacizumab is resumed, monitor closely for signs of bleeding. 

The recommended dose of caplacizumab is as follows:

Treatment during plasma exchange:

• First day of treatment: 11 mg bolus intravenous injection administered by a healthcare provider at least 15 minutes prior to plasma exchange followed by an 11 mg subcutaneous injection in the abdomen after completion of plasma exchange on day 1. Avoid injections around the navel. Do not administer consecutive injections in the same abdominal quadrant.
• Subsequent treatment: 11 mg subcutaneous injection once daily following plasma exchange.

Treatment after the plasma exchange period: 

• 11 mg subcutaneous injection once daily for 30 days beyond the last plasma exchange.

Refractory aTTP treatment:

• If after initial treatment course, sign(s) of persistent underlying disease remain present, treatment with 11 mg subcutaneous injection once daily may be extended for a maximum of 28 days.

Source: Genzyme 2019.

Background

Thrombotic thrombocytopenic purpura (TTP) is characterized by severely reduced activity of the von Willebrand factor-cleaving protease ADAMTS13 (A Disintegrin And Metalloproteinase with ThromboSpondin‐1 motifs; 13th member of the family). An ADAMTS13 deficiency results in an accumulation of ultra-large von Willebrand factor (vWF), which leads to extensive clot formation in small blood vessels throughout the body, and ultimately causing severe thrombocytopenia, microangiopathic hemolytic anemia, and ischemia. Acquired TTP occurs in approximately three in one million adults and 1 in 10 million children annually and the incidence is increased in females and blacks. The diagnosis of acquired TTP is confirmed by the finding of severe ADAMTS13 deficiency (e.g., activity less than 10 percent of normal) and the presence of an ADAMTS13 inhibitor (autoantibody) in the appropriate clinical setting (e.g., a patient with microangiopathic hemolytic anemia and thrombocytopenia that responds to plasma exchange). However, some individuals with acquired TTP may have higher levels of ADAMTS13 activity, and in some an inhibitor may not be detectable. Diagnosis should not be considered confirmed (or excluded) based on ADAMTS13 testing alone. Initial symptoms of microangiopathic hemolytic anemia and thrombocytopenia may include fatigue, dyspnea, petechiae, or other bleeding. Patients may have symptoms of anemia and thrombocytopenia. However, not all patients are critically ill; some may have only minor complaints of weakness, dizziness, or gastrointestinal symptoms. In some patients, the diagnosis of TTP may not be considered until the complete blood count (CBC) reveals severe thrombocytopenia and microangiopathic hemolytic anemia. Neurologic and renal abnormalities may be seen but are not always present; when these occur, they are often mild (George 2018a).

TTP had been a fatal diagnosis until the use of therapeutic plasma exchange in the early 1990s. The use of plasma exchange in association with corticosteroids until durable remission had been the standard of care for TTP treatment. Glucocorticoids are thought to reduce production of the ADAMTS13 inhibitor, thereby reducing the number of required plasma exchanges. The discovery of a dysfunction in ADAMTS13, provided a rationale for the evaluation of B‐cell depleting therapies. Rituximab is a monoclonal chimeric antibody against the CD20 antigen on the surface of B-cells and causes a rapid and profound decrease in circulating B cells. The addition of rituximab to the standard regimen in the mid‐2000s is now increasingly used frontline (George 2018b).

Two major challenges with aTTP are the risks of recurrence and relapsed aTTP. Recurrence has been defined as a new decrease in the platelet count that necessitated the re-initiation of plasma exchange after normalization of the platelet count had occurred. An exacerbation is defined as a recurrence that occurred within 30 days after the last plasma exchange. A relapse is defined as a recurrence of an acute episode, manifested by thrombocytopenia and microangiopathic hemolytic anemia, in a patient who had a disease remission (i.e., normal platelet count for 30 days after stopping plasma exchange) following an episode of TTP. The continued presence of severe ADAMTS13 deficiency is consistent with continued activity of TTP as the cause of persistent or recurrent thrombocytopenia; however results of ADAMTS13 activity testing are not available immediately, and clinical assessment based on symptoms and platelet count are the most relevant information for decision making. However, if the initial diagnosis of acquired TTP was supported by the presence of severe ADAMTS13 deficiency (ie, activity <10 percent) and the presence of an inhibitor, and facilities for prompt measurements are available, a repeat ADAMTS13 activity measurement may be helpful, especially in situations where the diagnosis is uncertain. Conversely, non-severely deficient ADAMTS13 activity (ie, activity >10 percent) in a patient who has not received very recent plasma exchange therapy is suggestive of an alternative process. Lastly, refractory aTTP can be defined as disease that does not respond to initial therapy or TTP that initially responds with a normal platelet count followed by an exacerbation (recurrent thrombocytopenia and/or neurologic symptoms within the first 30 days of stopping plasma exchange therapy).

On February 6, 2019, the FDA approved Cablivi (caplacizumab-yhdp) injection, the first therapy specifically indicated, in combination with plasma exchange and immunosuppressive therapy, for the treatment of adult patients with acquired thrombotic thrombocytopenic purpura. Caplacizumab-yhdp targets the A1-domain of vWF, and inhibits the interaction between vWF and platelets, thereby reducing both vWF-mediated platelet adhesion and platelet consumption. The efficacy of caplacizumab was studied in a clinical trial of 145 patients who were randomized to receive either caplacizumab or a placebo (Scully et al; HERCULES trial). Patients in both groups received the current standard of care of plasma exchange and immunosuppressive therapy. The results of the trial demonstrated that platelet counts improved faster among patients treated with caplacizumab, compared to placebo. Treatment with caplacizumab also resulted in a lower total number of patients with either aTTP-related death and recurrence of aTTP during the treatment period, or at least one treatment-emergent major thrombotic event (where blood clots form inside a blood vessel and may then break free to travel throughout the body).

Scully et al (2019; HERCULES trial; NCT02553317) stated in acquired thrombotic thrombocytopenic purpura (TTP), an immune-mediated deficiency of the von Willebrand factor-cleaving protease ADAMTS13 allows unrestrained adhesion of von Willebrand factor multimers to platelets and microthrombosis, which result in thrombocytopenia, hemolytic anemia, and tissue ischemia. Caplacizumab, an anti-von Willebrand factor humanized, bivalent variable-domain-only immunoglobulin fragment, inhibits interaction between von Willebrand factor multimers and platelets. In this double-blind, controlled trial, 145 patients with TTP were randomly assigned to receive caplacizumab (10-mg intravenous loading bolus, followed by 10 mg daily subcutaneously) or placebo during plasma exchange and for 30 days thereafter. The primary outcome was the time to a response, which was defined as the time from the first intravenous administration of caplacizumab or placebo to normalization of the platelet count (i.e., a platelet count of at least 150,000 per cubic millimeter), with discontinuation of daily plasma exchange within 5 days thereafter. The four key secondary outcomes, which were hierarchically ranked on the basis of clinical relevance, were: a composite of TTP-related death, recurrence of TTP, or a major thromboembolic event during the trial treatment period; recurrence of TTP at any time during the trial, including the follow-up period; refractory TTP (defined by the lack of a doubling of the platelet count after 4 days of treatment and a lactate dehydrogenase level that remained above the upper limit of the normal range); and the time to normalization (i.e., to a level below the defined upper limit of the normal range) of three organ-damage markers (lactate dehydrogenase, cardiac troponin I, and serum creatinine).

The median time to normalization of the platelet count was shorter with caplacizumab than with placebo (2.69 days [95% confidence interval {CI}, 1.89 to 2.83] vs. 2.88 days [95% CI, 2.68 to 3.56], P=0.01), and patients who received caplacizumab were 1.55 times as likely to have a normalization of the platelet count as those who received placebo. The percentage of patients with a composite outcome event was 74% lower with caplacizumab than with placebo (12% vs. 49%, P<0.001). The percentage of patients who had a recurrence of TTP at any time during the trial was 67% lower with caplacizumab than with placebo (12% vs. 38%, P<0.001). Refractory disease developed in no patients in the caplacizumab group and in three patients in the placebo group. Patients who received caplacizumab needed less plasma exchange and had a shorter hospitalization than those who received placebo. The most common adverse event was mucocutaneous bleeding, which was reported in 65% of the patients in the caplacizumab group and in 48% in the placebo group. During the trial treatment period, three patients in the placebo group died. One patient in the caplacizumab group died from cerebral ischemia after the end of the treatment period. The authors concluded that among patients with TTP, treatment with caplacizumab was associated with faster normalization of the platelet count; a lower incidence of a composite of TTP-related death, recurrence of TTP, or a thromboembolic event during the treatment period; and a lower rate of recurrence of TTP during the trial than placebo.

Knoebl et al (2020) studied patients who experienced an exacerbation while on blinded study drug treatment during the HERUCLES trial and were switched to receive open-label caplacizumab plus re-initiation of daily therapeutic plasma exchange (TPE). Exacerbations were defined as recurrence of disease occurring within 30 days after cessation of daily TPE. Thirty-one patients (placebo, n = 28; caplacizumab, n = 3) had an exacerbation during double-blind treatment. Twenty-eight patients switched to open-label caplacizumab (placebo, n = 26; caplacizumab, n = 2); the three others discontinued upon exacerbation. Median time to platelet count response (≥150 × 10⁹ /L) was 3.49 days upon receiving caplacizumab. There were no deaths. During open-label treatment, further exacerbation or a major thromboembolic event (vena cava thrombosis) was experienced by one patient (3.6%) each. Consistent with the double-blind phase, the most frequent treatment-emergent adverse events were catheter site hemorrhage (28.6%), headache (21.4%), and epistaxis (17.9%). These results suggest that caplacizumab was efficacious and well tolerated in patients with aTTP who experienced a disease exacerbation during double-blind treatment in HERCULES.

Peyvandi et al (2016; TITAN trial) stated acquired thrombotic thrombocytopenic purpura (TTP) is caused by aggregation of platelets on ultralarge von Willebrand factor multimers. This microvascular thrombosis causes multiorgan ischemia with potentially life-threatening complications. Daily plasma exchange and immunosuppressive therapies induce remission, but mortality and morbidity due to microthrombosis remain high. Caplacizumab, an anti-von Willebrand factor humanized single-variable-domain immunoglobulin (Nanobody), inhibits the interaction between ultralarge von Willebrand factor multimers and platelets. In this phase 2, controlled study, patients with acquired TTP were randomly assigned to subcutaneous caplacizumab (10 mg daily) or placebo during plasma exchange and for 30 days afterward. The primary end point was the time to a response, defined as confirmed normalization of the platelet count. Major secondary end points included exacerbations and relapses. Seventy-five patients underwent randomization (36 were assigned to receive caplacizumab, and 39 to receive placebo). The time to a response was significantly reduced with caplacizumab as compared with placebo (39% reduction in median time, P=0.005). Three patients in the caplacizumab group had an exacerbation, as compared with 11 patients in the placebo group. Eight patients in the caplacizumab group had a relapse in the first month after stopping the study drug, of whom 7 had ADAMTS13 activity that remained below 10%, suggesting unresolved autoimmune activity. Bleeding-related adverse events, most of which were mild to moderate in severity, were more common with caplacizumab than with placebo (54% of patients vs. 38%). The frequencies of other adverse events were similar in the two groups. Two patients in the placebo group died, as compared with none in the caplacizumab group. The authors concluded that caplacizumab induced a faster resolution of the acute TTP episode than did placebo. The platelet-protective effect of caplacizumab was maintained during the treatment period. Caplacizumab was associated with an increased tendency toward bleeding, as compared with placebo.

Common side effects of caplacizumab reported by patients in clinical trials were bleeding of the nose or gums and headache. The prescribing information for caplacizumab includes a warning to advise health care providers and patients about the risk of severe bleeding. Health care providers are advised to monitor patients closely for bleeding when administering caplacizumab to patients who currently take anticoagulants. Caplacizumab dosing should be interrupted if clinically significant bleeding occurs and if needed, von Willebrand factor concentrate may be administered to rapidly correct hemostasis. Caplacizumab should be stopped for 7 days prior to elective surgery, dental procedures or other invasive interventions. If emergency surgery is needed, the use of von Willebrand factor concentrate may be considered to correct hemostasis.

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:
36514	Therapeutic apheresis; for plasma pheresis
96365 – 96368	Intravenous infusion administration
96372	Therapeutic, prophylactic, or diagnostic injection (specify substance or drug); subcutaneous or intramuscular
96401	Chemotherapy administration, subcutaneous or intramuscular; non-hormonal anti-neoplastic
96409 – 96411	Chemotherapy administration, intravenous push technique
96413 – 96417	Chemotherapy administration, intravenous infusion technique
HCPCS codes covered if selection criteria are met:
C9047	Injection, caplacizumab-yhdp, 1 mg
ICD-10 codes covered if selection criteria are met:
D69.3	Immune thrombocytopenic purpura [acquired thrombotic thrombocytopenic purpura (aTTP)]
M31.1	Thrombotic microangiopathy [acquired thrombotic thrombocytopenic purpura (aTTP)]

The above policy is based on the following references: