Pfizer releases positive phase 3 results for HYMPAVZI in Hemophilia A or B with inhibitors

Pfizer announces their new positive topline results from the Phase 3 BASIS study evaluating HYMPAVZI for adults and adolescents living with hemophilia A or B with inhibitors. Note that this study met the primary endpoint and key secondary bleeding endpoints demonstrating the superiority of once-weekly subcutaneous HYMPAVZI in improving key bleeding outcomes compared to on-demand treatment in a patient population where less burdensome treatment approaches are needed.

Note that inhibitors or antibodies, which neutralize factor replacement therapies and render them ineffective, may develop in people living with hemophilia. Inhibitors can be diagnosed with a blood test. Of the more than 800,000 people in the world living with hemophilia A or hemophilia B, approximately 20% of people with hemophilia A and 3% of people with hemophilia B are unable to continue taking factor replacement therapies because they develop inhibitors to FVIII and FIX  and these therapies no longer prevent or stop bleeding episodes.

“Patients with inhibitors tend to face frequent complications, and navigating the treatment landscape can introduce complexities and increase disease burden,” said Davide Matino, M.D., M.Sc., BASIS Principal Investigator, Associate Professor of Medicine, McMaster University. “The strong bleed reduction with HYMPAVZI compared to on-demand treatment in the Phase 3 BASIS study, coupled with its weekly administration method, offers exciting potential for these patients who are in critical need of treatment options.”

Nonetheless the BASIS trial demonstrates that prophylactic treatment with HYMPAVZI resulted in a statistically significant and clinically relevant reduction in annualized bleeding rate of treated bleeds in people living with severe hemophilia A or hemophilia B with inhibitors. 48 people living with hemophilia were treated with HYMPAVZI during a 12-month period versus an on-demand intravenous regimen with bypassing agents, administered as part of usual care in the six-month lead-in period. HYMPAVZI was superior to on-demand treatment with a 93% reduction in ABR over 12 months.

“These encouraging results demonstrate HYMPAVZI’s potential to help people living with hemophilia A or B with inhibitors, meeting an important need for patients with antibodies that neutralize most factor-based prophylactic options used to manage bleeding episodes,” said Michael Vincent, M.D., Ph.D., Chief Inflammation & Immunology Officer, Pfizer. “HYMPAVZI represents Pfizer’s latest contribution in more than 40 years of working to advance hemophilia care, as a generally well-tolerated treatment option that could offer bleed protection with a straightforward, once-weekly subcutaneous administration in a pre-filled pen for patients with inhibitors, if approved in this patient population.”

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Related Topics and Keywords

Hemophilia A or B, hympavzi, Pfizer, Phase 3 trial