Climb Bio (CLYM) investor relations material

Strategy and development priorities

• Pipeline includes two clinical-stage assets: CD19-targeted monoclonal antibody budo and APRIL-degrading CLYM116, focused on B-cell-targeted therapies for autoimmune diseases with unmet need.

• Ongoing studies are expected to inform dosing and potential advancement of one or more assets to phase III over the next 12 months.

Budo in PMN

• Prior phase Ib study enrolled 8 patients, with follow-up for 5; 60% had a complete renal response at 12 months, and 3 of 4 patients with anecdotal follow-up remained in remission off treatment.

• PrisMN’s 200 mg cohort had mean baseline proteinuria of 6 g/24 hours and ~73% lower PLA2R levels at week 12; the early signal aligned with phase Ib data.

• Enrollment at 600 mg is complete and 1,000 mg enrollment is ongoing; the 600 mg dose showed B-cell silencing and a dose response, with updates expected in 2027.

• Phase III dose selection will use 12-week PLA2R response and dose-response plateau; proteinuria takes about a year to mature and will not delay the phase III decision.

• PMN phase III planning uses a single-study precedent with complete renal response as the endpoint; a ~150-patient active-comparator design is a placeholder pending regulatory alignment.

Budo in ITP and SLE

• ITP phase Ib targets patients who exhausted available therapies and remain thrombocytopenic; an ASH update is expected in early December 2026 after early data at EHA in June.

• The efficacy focus is durable platelet response rather than transient increases; third-line studies typically achieve ~20% durable response, and phase III is a potential path if the target profile is met.

• Initial low-dose SLE data showed B-cell depletion with good safety and tolerability, alongside early efficacy signals; dosing is gradually escalated for medically frail patients with prior therapies.

• SLE benefit-risk findings are encouraging and may de-risk budo, but phase III is not a near-term priority given development complexity and resource needs; renal and non-renal doses may differ.