Climb Bio's CLYM116 Demonstrates Clean Phase 1 Safety Profile, Advancing Toward IgAN Patient Studies in 2026
核心洞察
CLYM116, an anti-APRIL (搜索) monoclonal antibody, showed a favorable safety profile in Phase 1 healthy volunteer studies with no serious adverse events, dose-limiting toxicities, or discontinuations at single doses up to 320 mg.
The antibody employs a novel pH-dependent "sweeper" mechanism that promotes lysosomal degradation of APRIL (搜索) and recycles the antibody, potentially enabling less-frequent dosing than first-generation anti-APRIL therapies.
Mabworks (搜索), Climb Bio (搜索)'s Greater China partner, expects to initiate dosing in IgAN patients in the Phase 2 portion of its ongoing study in Q3 2026.
Climb Bio (搜索) presented initial Phase 1 safety data for CLYM116, its anti-APRIL (搜索) monoclonal antibody, at the European Renal Association (ERA) Congress 2026 in Glasgow this week, revealing a clean safety profile that supports advancing the candidate directly into patients with IgA nephropathy (搜索) (IgAN). The data, pooled across parallel Phase 1 studies in Australia and China, encompassed approximately 80 healthy volunteers dosed from 25 mg to 640 mg, with 49 participants receiving single doses up to 320 mg or placebo.
All adverse events observed were Grade 1–2, transient, and self-resolving. Two injection site reactions, both Grade 1, resolved without intervention. No serious adverse events, dose-limiting toxicities, or adverse event-related discontinuations were reported.
"We are encouraged by the safety profile observed to date with CLYM116 in healthy volunteers at doses up to 320 mg," said Edgar Charles, M.D., Chief Medical Officer of Climb Bio (搜索). "Together with the translational and pharmacometric modeling results, these data support our belief that CLYM116 could potentially offer a differentiated approach in IgAN, with the potential for substantial IgA reduction and less frequent dosing."
A Differentiated Mechanism of Action
CLYM116 distinguishes itself within the anti-APRIL (搜索) class through a pH-dependent "sweeper" mechanism. Rather than simply blocking APRIL signaling, the antibody promotes lysosomal degradation of APRIL and then recycles the antibody itself, extending its half-life. This design, in theory, enables less-frequent dosing than first-generation anti-APRIL approaches.
A translational PK/PD model built on pooled non-human primate (NHP) data projected dose-dependent IgA suppression in humans consistent with this mechanistic hypothesis. Literature analysis further demonstrated a strong correlation in IgA reduction between NHP and healthy volunteer studies, providing pharmacometric scaffolding for dose selection in the upcoming Phase 2 study.
Competitive Landscape and Next Steps
The IgAN treatment field has transformed materially over the past year. Sparsentan received full FDA approval in September 2024, and sibeprenlimab earned accelerated approval in November 2025 based on a 51% placebo-adjusted proteinuria reduction in the VISIONARY trial. Additionally, telitacicept — which also targets APRIL (搜索) — demonstrated a 58.9% UPCR reduction at 39 weeks versus 8.8% on placebo in an interim Phase 3 analysis.
Mabworks (搜索), Climb Bio (搜索)'s partner in Greater China, expects to initiate dosing in IgAN patients in the Phase 2 portion of its ongoing study in the third quarter of 2026. Climb Bio retains global rights to CLYM116 outside of Greater China.
The company plans to share initial pharmacokinetic and pharmacodynamic (PK/PD) data, along with updated safety results from the ongoing Phase 1 studies, at its R&D Spotlight event in late summer. The proteinuria reduction that CLYM116 achieves in the Mabworks (搜索) Phase 2 cohort will be the critical metric determining whether the antibody's mechanistic differentiation translates into a competitive efficacy signal — one sufficient to justify a later-entry Phase 3 program in a market that now has approved standards of care.