AstraZeneca's Klygefa wins EU CHMP nod for myasthenia gravis

AstraZeneca announced on September 21, 2026, that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency has issued a positive opinion recommending the approval of Klygefa (gefurulimab). The drug is proposed as an add-on therapy for generalized myasthenia gravis (gMG) in adult patients who are positive for anti-acetylcholine receptor (AChR) antibodies.

If approved by the European Union, Klygefa would become the first and only dual-binding nanobody C5 inhibitor for this patient population in the bloc. The treatment is administered subcutaneously once weekly via an autoinjector. Across five major European countries, an estimated 82,500 people live with gMG, including approximately 66,000 who are AChR antibody-positive. The drug is already approved in Japan and other countries, while reviews remain ongoing in the United States and China.

The recommendation was supported by data from the pivotal Phase III PREVAIL trial. The study met its primary endpoint, showing that Klygefa produced a greater improvement in the MG-ADL daily living score than placebo at week 26, with a treatment difference of -1.6. Clinically meaningful improvements appeared as early as week one and lasted through week 26, with safety in line with AstraZeneca's marketed C5 inhibitors, Soliris and Ultomiris.

Year to date, AstraZeneca shares have fallen 8.8%, compared with a 7.8% gain for the broader industry.