UCB races to regulators after $2.5B rare disease bet delivers data for attack on AstraZeneca and argenx

UCB’s $2.5 billion gamble on Ra Pharmaceuticals has yielded positive phase 3 data. With the rare disease clinical trial hitting its primary endpoint, UCB is preparing to file to join AstraZeneca and argenx in an increasingly congested space.

The drug candidate, complement factor C5 inhibitor zilucoplan, traded hands in 2019 when UCB agreed to buy Ra in a $2.5 billion deal. By that time, zilucoplan was already in phase 3, setting up a wait to learn whether UCB’s bet would pay off or blow up in its face. Today, UCB took a step toward delivering a return on its investment in the treatment for the chronic autoimmune, neuromuscular disease myasthenia gravis.

UCB is yet to share the detailed data that will indicate whether zilucoplan is competitive, but the top-line update suggests it has a shot at winning approval. The placebo-controlled study of 174 patients linked the drug to a statistically significant improvement on a symptom score at Week 12.

That primary endpoint hit was backed up by successes against all key secondary endpoints, which looked at a set of other ways of grading the condition of patients with generalized myasthenia gravis. With the safety data free from red flags—and showing similar rates of serious treatment emergent adverse events in the treatment and control groups—UCB thinks it has the data to support filings for approval. 

RELATED: UCB strikes $2.5B deal to buy Ra for rival to Alexion's Soliris

UCB plans to proceed with regulatory submissions later this year. The U.S., the EU and Japan are on the hit list of the team handling the regulatory approval process for the complement factor C5 inhibitor. 

Zilucoplan is part of a pack of molecules targeting generalized myasthenia gravis. Alexion, now part of AstraZeneca, won approval for Soliris in the indication in 2017 and is closing in on approval of follow-on asset Ultomiris. Argenx won FDA approval for its challenger, Vyvgart, late last year, and other assets are coming up close behind. 

UCB’s own rozanolixizumab has already delivered positive phase 3 data, and, last year, Johnson & Johnson began a phase 3 clinical trial of nipocalimab, the anti-FcRn antibody it acquired in its $6.5 billion takeover of Momenta Pharmaceuticals.