UCB: FDA green light for Zilbrysq auto-injector in myasthenia gravis
The Belgian pharmaceutical company announced, in a press release published on October 16, 2026, that the U.S. health authority has approved a self-injectable form of its treatment for generalized myasthenia gravis. UCB plans commercial availability of this device in the first quarter of 2027.
A daily auto-injector, bioequivalent to the prefilled syringe
The authorization covers daily subcutaneous administration, self-administered by the patient, in adults with generalized myasthenia gravis who are carriers of anti-acetylcholine receptor antibodies. Until now, Zilbrysq (zilucoplan) was only available as a prefilled self-administered syringe. The new device automatically injects a predefined dose when activated against the skin. According to UCB, Zilbrysq is the first and only macrocyclic peptide inhibitor of C5 authorized in the United States in this form.
The decision is based on data demonstrating bioequivalence between the auto-injector and the existing syringe. The full dose was delivered in 99.8% of administrations, across 449 auto-injectors used and returned. The company reports that patients expressed high satisfaction with self-injection using this device.
"This authorization addresses a question on which we have focused relentlessly: how to continue improving an already effective therapy, used every day?", declared Kimberly Moran, Head of Rare Diseases in the United States at UCB.
A safety profile governed by a restricted risk management program
The safety profile of the product remains governed in the United States by a warning concerning serious meningococcal infections. The press release recalls that meningococcal infections that were life-threatening, sometimes fatal, have occurred in patients treated with complement inhibitors. For this reason, Zilbrysq is accessible only through a restricted risk evaluation and mitigation strategy (REMS) program, which notably requires patient vaccination.
Cases of pancreatitis and pancreatic cysts have also been reported. In the placebo-controlled study, the most frequent adverse effects were injection site reactions, upper respiratory tract infections, and diarrhea.
"For a chronic disease such as generalized myasthenia gravis, having different administration options allows patients to choose the approach that best suits their preferences and lifestyle," indicated Donatello Crocetta, Medical Director of UCB. The company's portfolio in this condition also includes Rystiggo (rozanolixizumab), an antibody targeting the neonatal Fc receptor. UCB emphasizes the fact of offering, with two medications with distinct mechanisms of action, a choice of targeted therapies from a single company.
