Climb Bio, Inc.: Climb Bio Announces CLYM116 Phase 1 Data Demonstrating Prolonged Half-Life and Best-In-Class APRIL Suppression Supporting Every-12-Week Dosing in IgA Nephropathy

Climb Bio (CLYM) presented Phase 2 trial data for budoprutug, an anti-CD19 antibody, showing B-cell depletion and PLA2R antibody reductions in kidney disease patients. The 200 mg dose achieved 70% mean antibody reduction, with 5/13 patients in remission. The 600 mg dose showed deeper B-cell depletion. The drug was well-tolerated. Climb Bio expects more data in 2027. Primary membranous nephropathy affects 75,000 people in the U.S. without FDA-approved treatments.

Climb Bio (CLYM) reported early Phase 2 data for budoprutug in pMN, showing B-cell depletion, antibody reduction, and immunologic remission at 12 weeks. Both 200 mg and 600 mg doses were generally well tolerated. The company expects further data in 2027.

Climb Bio (CLYM) presented Phase 2 data for budoprutug, its anti-CD19 mAb, at ASN Kidney Week. The 200 mg dose showed B-cell depletion, PLA2R Ab reduction, and immunologic remission in pMN patients. A separate case study reported 3-year steroid-free remission in an MCD patient. Additional data is expected in 2027. The drug was generally well-tolerated.

Climb Bio (CLYM) and Beijing Mabworks reported Phase 1 data showing their anti-APRIL antibody reduced Gd-IgA1 by ~70% and IgA by ~60% at 12 weeks in healthy volunteers. The trials involved 88 participants across Australia and China. The antibody was well-tolerated, with no serious adverse events. The company plans to initiate a Phase 3 trial in 2027, pending regulatory feedback.

Climb Bio reported Phase 1 results for CLYM116, showing sustained APRIL suppression through 12 weeks and reductions in IgA and Gd-IgA1. A single dose of at least 480 mg suppressed free APRIL by 90% or more, supporting a potential every-12-week regimen. The antibody was generally well tolerated. Phase 2 trial is enrolling, with initial data expected in the first half of 2027, and a Phase 3 trial is expected to begin in 2027, pending regulatory feedback.

Climb Bio, Inc. (CLYM) filed an SEC Form 8-K — Other Events. Exhibit 99.1 Climb Bio and Mabworks Announce CLYM116/MIL116 Data Demonstrating Deep, Durable APRIL Suppression and ~70% Gd-IgA1 Reduction at ASN Kidney Week 2026 >90% free APRIL suppression sustained through 12 weeks, supporting Q12W dosing interval ~70% reduction in Gd-IgA1 at 1