Climb Bio reports early PrisMN Phase 2 data for budoprutug in kidney disease

Climb Bio, Inc. announced on October 24, 2026 new clinical data for budoprutug, its anti-CD19 monoclonal antibody, in primary membranous nephropathy (pMN) and minimal change disease (MCD), presented at American Society of Nephrology (ASN) Kidney Week 2026 in Denver, held October 21-25, 2026.

PrisMN is a Phase 2 dose-escalation study testing budoprutug at 200 mg, 600 mg, and 1000 mg in patients with moderate to severe pMN.¹ Enrolled patients had already received prior treatment and showed high proteinuria and elevated PLA2R antibody levels at the start of the study.¹

In the 200 mg cohort, the mean PLA2R antibody reduction was 70% at Week 12, and five of 13 patients (38%) achieved immunologic remission.¹ Among patients whose baseline PLA2R antibody readings were under 175 RU/mL, the average reduction reached 80% by Week 12.¹ The company said these Phase 2 Week 12 results in the 200 mg group matched earlier Phase 1b findings across B-cell depletion, antibody reduction, and remission rate.¹

Early results from the 600 mg cohort pointed to greater drug exposure and deeper peripheral B-cell depletion compared with 200 mg.¹ Mean peripheral CD20+ B-cell suppression at Week 4 reached 98% in the 600 mg group versus 74% at 200 mg, and a population pharmacokinetic analysis across roughly 120 patients found that those with high proteinuria cleared the drug at least twice as fast as non-proteinuric patients, supporting testing of higher doses.¹

On safety, the company reported budoprutug was generally tolerated well across the two cohorts, with follow-up data spanning 12 weeks for the 200 mg group and 6 weeks for the 600 mg group; most adverse events were mild to moderate, and no treatment-related serious adverse events, discontinuations, or deaths were recorded.¹ Enrollment in the 1000 mg cohort continues, and the company expects to report further PrisMN Phase 2 results in 2027.¹

Separately, a case study described one MCD patient who received 100 mg of budoprutug and experienced three years of steroid-free remission, remaining in remission for a year after B-cell levels recovered.¹