Fulcrum Therapeutics (NASDAQ:FULC) soared 50% on Monday after unveiling upbeat preliminary findings from its Phase 1b PIONEER study evaluating pociredir in patients with sickle cell disease.
The biotech reported that the 20 mg cohort delivered a strong increase in fetal hemoglobin (HbF). By Week 6, mean absolute HbF had risen 9.9%—notably higher than the 5.6% increase seen at the same point in the prior 12 mg cohort. In addition, 58% of participants receiving the 20 mg dose achieved absolute HbF levels of at least 20%.
The initial readout also reinforced a dose-dependent effect. Patients who reached Week 12 of treatment recorded a greater than 3.75-fold average induction of HbF, compared with a 2.4-fold increase in the 12 mg group. Improvements were also observed in metrics of hemolysis and anemia, with mean hemoglobin rising 0.8 g/dL at Week 6.
“We are highly encouraged by these initial data from the 20 mg cohort, which show clear evidence of a dose-response and build on the strong profile established with the 12 mg cohort,” said Alex C. Sapir, Fulcrum’s President and Chief Executive Officer.
Pociredir continued to show a favorable safety profile, with no treatment-related serious adverse events reported. Two-thirds of participants (8 of 12) experienced no vaso-occlusive crises during the treatment period.
“FULC presented strong initial data from cohort 4 of the Ph 1b PIONEER study in sickle cell disease (SCD) which pleasantly surprised us and lands in our bull case scenario,” wrote Leerink Partners analyst Joseph P. Schwartz, who increased his price target to $24 from $20.
Fulcrum expects to release further trial updates in the first quarter of 2026.