Shares of Climb Bio Inc. surged 17% on Thursday after the company reported positive results from a Phase 1 trial of its experimental drug CLYM116, an anti-APRIL monoclonal antibody being developed for IgA nephropathy.
In the randomized, double-blind, placebo-controlled Phase 1 study involving 46 healthy volunteers, a single 320 mg dose of CLYM116 demonstrated near-complete suppression of APRIL and reduced IgA and Gd-IgA1 levels by 60% to 75% over 12 weeks. Free APRIL suppression exceeded 90% following the dose. The drug’s half-life of approximately 29 days was reported to be three times longer than that of sibeprenlimab, a comparator therapy.
The biotech firm also disclosed that CLYM116 was generally well-tolerated in the Phase 1 trial, with no serious adverse events, dose-limiting toxicities, or cases of hypogammaglobulinemia reported. Climb Bio is now advancing the candidate into the Phase 2 NAVIGATE-2 trial, which will evaluate an 800 mg loading dose followed by either 400 mg every eight or 12 weeks.
A high-concentration formulation allows delivery of 400 mg in a single subcutaneous injection, and the company has completed development of a pre-filled syringe for the upcoming Phase 3 registrational study. An autoinjector is also under development. Climb Bio plans to initiate the Phase 3 trial in 2027, with initial Phase 2 data expected in the first half of next year. Additional Phase 1 data will be presented at a medical meeting in the fourth quarter of 2026.
