Positive Phase 1b/2 Results from Ongoing REC-4881 TUPELO Trial Demonstrate Rapid and Durable Reductions in Polyp Burden in Familial Adenomatous Polyposis (FAP) at 25 Weeks

Core Insights - Recursion announced positive Phase 1b/2 data from the TUPELO trial for REC-4881, an investigational allosteric MEK1/2 inhibitor targeting familial adenomatous polyposis (FAP) [1][3] Efficacy and Results - REC-4881 demonstrated a 43% median reduction in polyp burden after 12 weeks of treatment, with 75% of evaluable patients showing reductions [4][16] - At Week 25, 82% of evaluable patients maintained reductions in polyp burden, with a 53% median decrease from baseline [4][17] - The treatment showed a significant improvement in Spigelman stage, with 40% of patients achieving a ≥1-point improvement [4][16] Safety Profile - The safety profile of REC-4881 was consistent with MEK1/2 inhibitors, with 94.7% of patients reporting at least one treatment-related adverse event, primarily Grade 1 or 2 [19][24] - Grade 3 treatment-related adverse events occurred in 15.8% of patients, with no Grade ≥4 events reported [19][24] Mechanism and Discovery - REC-4881 was identified through an AI-driven phenotypic screening approach, highlighting MEK1/2 inhibition as a therapeutic strategy for FAP [2][8] - The drug represents a precision-medicine approach targeting the causal biology of FAP, a disease with no approved medical therapies [5][6] Future Plans - The company plans to engage with the FDA in the first half of 2026 to define a potential registration pathway and expand the patient population eligibility from ≥55 to ≥18 years old [4][29]