On 6 February 2019, the US Food and Drug Administration (FDA) approved caplacizumab-yhdp (CABLIVI, Ablynx NV) for adult patients with acquired thrombotic thrombocytopenic purpura (aTTP), in combination with plasma exchange and immunosuppressive therapy.
Approval was based on a multicentre, randomised, double-blind, placebo-controlled trial (HERCULES) (NCT02553317) that enrolled 145 patients randomised to caplacizumab-yhdp (n=72) or placebo (n=73). Patients in both groups received plasma exchange and immunosuppressive therapy. Patients received a single 11 mg caplacizumab-yhdp bolus intravenous injection or placebo prior to the first plasma exchange on trial, followed by a daily subcutaneous injection of caplacizumab-yhdp (11 mg) or placebo after completion of plasma exchange, for the duration of the daily plasma exchange period and for subsequent 30 days. If after the initial treatment course, signs of persistent underlying disease such as suppressed ADAMTS13 activity levels remained present, treatment was extended for 7-day intervals for a maximum of 28 days.
The efficacy of caplacizumab-yhdp was established based upon time-to-platelet count response (platelet count ≥150,000/µL followed by cessation of daily plasma exchange within 5 days). Time-to-platelet count response was faster among patients treated with caplacizumab-yhdp, compared to placebo. Treatment with caplacizumab-yhdp resulted in a lower number of patients with TTP-related deaths (0 vs. 3) and TTP recurrence (3 vs. 28) during the treatment period. The proportion of patients with a recurrence of TTP in the overall study period (the drug treatment period plus the 28-day follow-up period after drug treatment discontinuation) was lower in the caplacizumab-yhdp group (9/72 patients [13%]) compared to those receiving placebo (28/73 patients [38%]; p < 0.001).
The most common adverse reactions in at least 15% of patients receiving caplacizumab-yhdp were epistaxis, headache, and gingival bleeding.
The recommended first dose of caplacizumab-yhdp is 11 mg bolus intravenous injection at least 15 minutes prior to plasma exchange followed by a 11 mg subcutaneous injection after completion of plasma exchange continuing daily for 30 days following the last plasma exchange. For additional dosing information, full prescribing information is available here.
FDA granted this application priority review and orphan product designation.
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