Climb Bio, Mabworks report Phase 1 data for IgA nephropathy antibody CLYM116/MIL116

Climb Bio, Inc. and Beijing Mabworks Biotech Co., Ltd. announced additional Phase 1 data on October 23, 2026 for CLYM116/MIL116, an anti-APRIL monoclonal antibody being developed for IgA nephropathy. The data were presented at the American Society of Nephrology Kidney Week 2026, held October 21-25, 2026, in Denver, Colorado.¹

The antibody is being tested in two parallel Phase 1 studies, one in Australia and one in China, both randomized, double-blind, placebo-controlled, ascending-dose trials in healthy volunteers, enrolling 46 and 42 participants respectively.¹

On pharmacodynamics, near-complete free APRIL suppression was sustained through 12 weeks following a single subcutaneous dose of 480 mg or more.¹ After a single 800 mg dose, the companies reported roughly a 70% reduction in Gd-IgA1 and a 60% reduction in IgA at 12 weeks.¹

On pharmacokinetics, results were consistent between the two trials, showing linear exposure with no target-mediated drug disposition across the effective dose range.¹ The estimated half-life was about 33 days, which the companies said is 3.5 times that reported for sibeprenlimab.¹ Together, the companies said the PK and PD findings support an every-12-week dosing regimen.¹

On safety, the antibody was generally well tolerated, with no dose-limiting toxicities, treatment-related serious adverse events, or hypogammaglobulinemia.¹ Injection site reactions occurred in 5 of 88 participants across both studies, all Grade 1 and resolved without intervention.¹

The ongoing NAVIGATE-2 Phase 2 trial is enrolling IgA nephropathy patients to confirm the quarterly dosing regimen, with a global Phase 3 trial expected to begin in 2027 pending regulatory feedback.¹ Initial NAVIGATE-2 data are expected in the first half of 2027.¹ Climb Bio holds worldwide rights to CLYM116/MIL116 outside Greater China, while Mabworks retains rights within Greater China.¹