Pfizer has received approval from the European Commission (EC) to expand the indication of its haemophilia therapy Hympavzi to include patients aged 12 years and older weighing at least 35 kg with haemophilia A with factor VIII inhibitors or haemophilia B with factor IX inhibitors.

The expanded approval marks a milestone for patients with inhibitors, a subgroup of haemophilia patients who often face limited treatment options because inhibitory antibodies neutralise standard clotting factor replacement therapies, reducing their effectiveness in preventing or controlling bleeding episodes.

Hympavzi is administered as a once-weekly subcutaneous injection and does not require routine treatment-related laboratory monitoring. According to Pfizer, the therapy demonstrated strong bleed protection and a manageable safety profile in clinical studies involving haemophilia patients with inhibitors.

The approval is based on results from the Phase 3 BASIS trial, which evaluated the efficacy and safety of Hympavzi in adolescents and adults with severe haemophilia A or moderately severe to severe haemophilia B with inhibitors. During the active treatment period, Hympavzi achieved a statistically significant 93 percent reduction in mean treated annualised bleeding rate compared to on-demand therapy. The study also reported superiority across secondary endpoints including spontaneous bleeds, joint bleeds and total treated and untreated bleeding episodes.

Long-term extension data further showed that bleeding rates remained consistently low for patients treated with Hympavzi for up to 53 months. The therapy was generally well tolerated, with commonly reported adverse events including injection site reactions, headache, rash, pruritus and hypertension. Thrombosis was identified as the most serious adverse event observed during clinical studies.

Dr. Laurent Frenzel, Head of the Haemophilia Treatment and Research Centre at Necker-Enfants Malades Hospital in Paris, said inhibitors continue to present major challenges for people living with haemophilia by limiting the effectiveness of conventional factor replacement therapies. He added that the approval of Hympavzi offers patients in the European Union a once-weekly treatment option capable of significantly reducing bleeding episodes.

Alexandre de Germay, Chief International Commercial Officer and Executive Vice President at Pfizer, said recurring bleeding episodes in haemophilia patients with inhibitors can result in severe joint damage and disruptions to daily life. He noted that the approval addresses a critical unmet need and reflects Pfizer’s more than four decades of commitment to advancing haemophilia care globally.

The marketing authorisation is valid across all 27 European Union member states as well as Iceland, Liechtenstein and Norway. Separately, the US Food and Drug Administration has granted Priority Review for an application seeking expanded approval of Hympavzi in younger haemophilia patients with and without inhibitors, with a decision expected in the second quarter of 2026.

Hympavzi, discovered by Pfizer scientists, works through a differentiated mechanism targeting Tissue Factor Pathway Inhibitors (TFPI) rather than replacing missing clotting factors directly. By inhibiting TFPI, the therapy aims to rebalance the body’s clotting process and provide sustained bleed protection with simplified administration.

Pfizer continues to evaluate the long-term safety and efficacy of Hympavzi through ongoing extension studies and paediatric clinical trials, including the BASIS KIDS programme.