Fulcrum Therapeutics Inc. (NASDAQ:FULC) saw its stock drop 17% on Tuesday, wiping out earlier gains following the release of data from the 12 mg dose cohort in its Phase 1b PIONEER trial of pociredir for sickle cell disease.
The Cambridge, Massachusetts-based biopharma reported an absolute mean fetal hemoglobin (HbF) induction of 8.6% from baseline after 12 weeks of treatment, with 7 out of 16 patients reaching absolute HbF levels above 20%. While the company described these outcomes as “positive,” investors reacted negatively, pushing shares lower.
The trial also showed pan-cellular induction of HbF, with the proportion of F-cells increasing from an average 34% at baseline to 67% at 12 weeks. Improvements were noted in key hemolysis markers, alongside a 0.9 g/dL mean rise in total hemoglobin. Additionally, encouraging trends were observed in reducing vaso-occlusive crises compared to baseline.
“We are highly encouraged by these data from the 12 mg cohort of the PIONEER trial and believe they represent an important milestone in our mission to transform the treatment of sickle cell disease,” said Alex C. Sapir, Fulcrum’s President and Chief Executive Officer.
Pociredir was generally well tolerated, with no treatment-related serious adverse events reported. All treatment-related side effects were Grade 1, the company stated.
To date, 135 adults have been dosed with pociredir, including 76 subjects across multiple cohorts with treatment durations up to 12 weeks. Fulcrum plans to share further observations following the 4-week follow-up for the 12 mg cohort at an upcoming medical conference.