Biohaven has concluded enrolment of 180 patients in a Phase III study evaluating taldefgrobep alfa as adjunctive therapy in patients with spinal muscular atrophy (SMA).

The pivotal, placebo-controlled, double-blind study is being carried out in nine countries.

The key goal of the trial is to establish the efficacy and safety of the myostatin inhibitor taldefgrobep alfa.

These parameters are determined by change from baseline in the 32 item Motor Function Measure (MFM-32) total score.

Patients who previously received treatments with either nusinersen, risdiplam, and onasemnogene abeparvovec-xioi are included in the study.

They will receive taldefgrobep alfa or placebo subcutaneously for 48 weeks.

Biohaven vice-president and SMA programme clinical development lead Lindsey Lair said: “Despite recent advances in SMA genetic treatments, patients still experience weakness and impairments in quality of life that can be alleviated by enhancing muscle mass and function, on top of what is delivered by current standard of care treatments.

“Our team has been inspired by the entire global SMA community of clinicians, patients and family members – we are particularly grateful to the patients and investigators who helped us complete enrolment ahead of our timelines.”

Taldefgrobep received both fast track and orphan drug designation from the US Food and Drug Administration and orphan drug designation from the European Union.

Taldefgrobep is a muscle-targeted recombinant protein targeting two key regulators of muscle mass and adipose tissue including myostatin and activin A signalling.

In combination with other therapies that increase SMN protein levels in the body, taldefgrobep alfa enhances muscle mass in SMA patients and further improves motor function.