November 10, 2023
2 min read
The FDA approved the enzyme replacement therapy Adzynma for the prophylactic or on-demand treatment of adults and pediatric patients with congenital thrombotic thrombocytopenic purpura, a rare blood clotting disorder.
Congenital thrombotic thrombocytopenic purpura (cTTP) is caused by a mutation in the ADAMTS13 gene. Individuals with this condition are known to experience severe bleeding episodes, strokes and vital organ damage.
Adzynma (ADAMTS13, recombinant-krhn; Takeda Pharmaceuticals) is a first-in-class recombinant form of the ADAMTS13 enzyme — one of the enzymes responsible for blood clotting. The genetically engineered Adzynma acts as a replacement therapy in individuals with cTTP with low levels of the enzyme.
The agent can be provided as both a daily prophylactic enzyme replacement therapy and on-demand in response to acute cTTP-related adverse bleeding events.
Peter Marks
“The FDA remains deeply committed in our efforts to help facilitate the development and approval of safe and effective therapies for patients with rare diseases,” Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research, said in a press release.
“Without treatment, cTTP is ultimately fatal,” he added. “[This] approval reflects important progress in the development of much-needed treatment options for patients affected by this life-threatening disorder.”
FDA based approval on results from a multicenter phase 3 trial and data from its continuation study.
The open-label crossover trial evaluated the efficacy, pharmacokinetics and safety of Adzynma as prophylactic or on-demand enzyme-replacement therapy in 46 patients with cTTP.
Researchers randomly assigned study participants to receive 6 months of treatment with either Adzynma or plasma-based therapies (period 1). Study patients then switched to the other treatment strategy for another 6 months (period 2).
Investigators evaluated treatment efficacy based on the incidence of thrombotic thrombocytopenic purpura events and thrombotic thrombocytopenic purpura symtpoms, in addition to the need for supplemental treatment doses.
No subacute thrombotic thrombocytopenic purpura events occurred after treatment with Adzynma during period 1 or period 2 of the phase 3 study, compared with five events in four patients who received plasma-based therapy.
Two patients who received Adzynma prophylaxis experienced two subacute thrombotic thrombocytopenic purpura events during the continuation portion of the phase 3 study.
Results that included data from the continuation phase of the study showed a mean annualized event rate for thrombocytopenia manifestations of 2.0 ± 4.71 for patients who received Adzynma compared with 4.44 ± 6.31 among those who received plasma-based therapies.
The most common adverse events related to the use of Adzynma included headache, diarrhea, migraine, abdominal pain, nausea, upper respiratory tract infection, dizziness and vomiting.
References:
FDA approves first treatment for patients with rare inherited blood clotting disorder (press release). Available at: https://www.fda.gov/news-events/press-announcements/fda-approves-first-treatment-patients-rare-inherited-blood-clotting-disorder?utm_medium=email&utm_source=govdelivery. Published Nov. 9, 2023. Accessed Nov. 10, 2023.
Takeda’s Adzynma (ADAMTS13, recombinant-krhn) approved by U.S. FDA as the first and only recombinant ADAMTS13 enzyme replacement therapy for the treatment of congenital thrombotic thrombocytopenic purpura (press release). Available at: https://www.takeda.com/en-us/newsroom/news-releases/2023/takeda-adzynma-approved-by-fda-as-the-first-and-only-recombinant-adamts13-enzyme-replacement-therapy-for-the-treatment-of-congenital-thrombotic-thrombocytopenic-purpura. Published Nov. 9, 2023. Accessed Nov. 10, 2023.