Fulcrum Therapeutics, Inc.

Bu siness. Overview We are a clinical-stage biopharmaceutical company focused on developing small molecules to improve the lives of patients with genetically defined rare diseases in areas of high unmet medical need. Our lead product candidate, pociredir, is an oral small molecule designed to induce fetal hemoglobin, or HbF, and is in clinical development for the treatment of sickle cell disease, or SCD. We completed dosing in the PIONEER trial, a Phase 1b clinical trial evaluating pociredir in adults with SCD. The PIONEER trial included 12 mg and 20 mg once-daily dose cohorts, and evaluated subjects over a 12-week treatment period. We have reported clinical data demonstrating clinically relevant HbF induction, including progression toward pan-cellular distribution, and improvements in markers of hemolysis and anemia. We are currently activating sites in an open-label extension trial to evaluate longer-term safety and pharmacodynamic, or PD, durability in patients who completed the PIONEER trial. We plan to provide details regarding the design of the next trial in the second quarter of 2026 following receipt of meeting minutes from our End-of-Phase meeting with the FDA. Pending feedback from the FDA, we plan to initiate a potential registration-enabling trial in the second half of 2026. In addition to our product candidates, we have developed a discovery approach that we use to identify and validate cellular drug targets that may modulate gene expression to treat the root causes of genetically defined rare diseases.