FDA OKs First Therapy Indicated for Rare Blood Clotting Disorder

Officials with the FDA have approved caplacizumab-yhdp (Cablivi, Sanofi) injection for the treatment of adults with acquired thrombotic thrombocytopenic purpura (aTTP), a rare and life-threatening blood clotting autoimmune disorder.

With this approval, caplacizumab-yhdp is the first nanobody-based therapy specifically indicated, in combination with plasma exchange and immunosuppressive therapy, for this patient population. Nanobodies are a novel class of proprietary therapeutic proteins based on single-domain antibody fragments that contain the unique structural and functional properties of naturally-occurring heavy chain only antibodies, according to a Sanofi press release.

Patients with aTTP develop extensive blood clots in the small blood vessels throughout the body. Despite current treatments, it is estimated that up to 20% of patients die from aTTP episodes, with most deaths occurring within 30 days of diagnosis, Sanofi said.

Caplacizumab-yhdp is designed to target von Willebrand factor (vWF), a protein in the blood involved in hemostasis, to inhibit the interaction between vWF and platelets. According to the FDA, caplacizumab-yhdp is the first targeted treatment that inhibits the formation of blood clots.

The approval is based on efficacy data from the phase 3 HERCULES trial. In the study, 145 patients were randomized to receive either caplacizumab-yhdp or a placebo. In addition, patients in both groups were given plasma exchange and immunosuppressive therapy.

Patients who were treated with caplacizumab-yhdp plus plasma exchange and immunosuppression experienced a shorter time to platelet count response versus plasma exchange and immunosuppression alone, according to the data. Caplacizumab-yhdp also demonstrated a significant reduction in aTTP-related death, recurrence of aTTP, a major thromboembolic event during study drug treatment (12.7% vs. 49.3%; p <0.0001), and a significantly lower percentage of aTTP recurrence in the overall study period (13% vs. 38%; p<0.001).

The most commonly reported adverse events that occurred in the HERCULES and the phase 2 TITAN trials were epistaxis, headache, and gingival bleeding.

According to Sanofi, caplacizumab-yhdp should be administered upon initiation of plasma exchange therapy based on a diagnosis of aTTP. Caplacizumab-yhdp should be first administered as an 11 mg intravenous injection prior to plasma exchange followed by an 11 mg subcutaneous injection after completion of plasma exchange on day 1. During the daily plasma exchange period and 30 days following daily plasma exchange, patients will take daily 11 mg subcutaneous injections. Treatment can be further extended for a maximum of 28 days if symptoms are unresolved after initial treatment.

The FDA advises health care providers to monitor closely for bleeding when administering caplacizumab-yhdp to patients who currently take anticoagulants.

Caplacizumab-yhdp was previously granted Priority Review Designation and Orphan Drug Designation. The FDA granted approval to Ablynx, a subsidiary of Sanofi.

References

FDA approves first therapy for the treatment of adult patients with a rare blood clotting disorder [news release]. FDA. https://bit.ly/2UKSPMW. Accessed February 6, 2019.

FDA approves Cablivi (caplacizumab-yhdp), the first Nanobody-based medicine, for adults with acquired thrombotic thrombocytopenic purpura [news release]. Sanofi. https://bit.ly/2HYmAs3. Accessed February 6, 2019.