REC-4881 Shows Reductions in Larger, Higher-Risk Polyps in Most Trial Patients
Key Facts
Recursion announced new analyses from its trial of investigational drug REC-4881 on November 2, showing reductions in the number of larger, higher-risk polyps in most patients, along with a decline in polyp burden in the lower gastrointestinal tract. The drug is an investigational oral MEK1/2 inhibitor being evaluated to treat familial adenomatous polyposis. The company described the results as an update to data from an open-label Phase 1b/2 study, an early stage of clinical development. The analyses were presented at the presidential session of the 2026 annual meeting of CGA-IGC. They were presented by Lisa Boardman, a professor of medicine at Mayo Clinic and an investigator in the TUPELO trial.
The new findings focus on larger, higher-risk polyps and the lower gastrointestinal tract, while the company's earlier data focused on the upper tract. The new announcement does not specify the percentage reduction or the number of patients who recorded a decline on these two measures, but says most participants saw reductions in both. This extends a set of clinical measures across different parts of the gastrointestinal tract, without turning the early-stage study results into proof of broader efficacy. In data announced by the company on October 15, median upper gastrointestinal polyp burden fell 55%. The company said at the time that 92% of patients still had a polyp burden below baseline 12 weeks after stopping treatment.
The company's disclosures break out the figures for the upper gastrointestinal tract: 92% of 13 evaluable patients recorded a reduction in polyp burden, and two patients achieved a reduction of at least 98%. Twelve weeks after stopping treatment, total burden remained below baseline in 85% of 13 patients, while upper gastrointestinal burden remained below baseline in 92%. These results measure change from baseline among participants, while follow-up after treatment cessation provides a picture of how long the reductions persisted. In a December 2025 update, the company reported a 43% median reduction in total polyp burden among 12 evaluable patients after 12 weeks. At week 25, the reduction persisted in 82% of evaluable patients, with a median decline of 53% from baseline.
REC-4881's results come against a backdrop in which medical sources say approved drug options for preventive treatment of the disease are limited. The U.S. National Cancer Institute says there are currently no FDA-approved drugs for chemoprevention of polyps in people with familial adenomatous polyposis. The institute says colectomy is the effective means of preventing colon cancer in managing this risk. This context underscores the importance of seeking treatment options in light of the unmet medical need, but does not change the fact that REC-4881 remains an investigational drug under evaluation. The TUPELO data presented to date also do not constitute regulatory approval for its use.
The next step depends on ongoing discussions between Recursion and the U.S. Food and Drug Administration over the design of the regulatory pathway. The company previously said it was targeting the start of a registration trial in the second half of 2027, subject to the outcome of those discussions. In another disclosure, it said it expects to start a registration trial in 2027 and will provide further details later in the year. The company also scheduled a live webcast on REC-4881 data and the CGA-IGC annual meeting for November 3, 2026, at 8:00 a.m. Eastern Time. The outcome of those discussions and the details the company plans to release remain the program's next two milestones.