Rigel Pharmaceuticals to Present Phase 1b Data on MDS Treatment at ASH Annual Meeting

Rigel Pharmaceuticals is set to release updated clinical findings from its ongoing Phase 1b study of R289 at the 68th American Society of Hematology (ASH) Annual Meeting and Exposition in New Orleans. The presentation will focus on the dose escalation and expansion phases for patients with relapsed or refractory lower-risk myelodysplastic syndrome (MDS).

According to chief medical officer Dr. Alison L. Hannah, the study aims to demonstrate efficacy metrics, including a reduction in transfusion dependence, within a population that has historically been difficult to treat. As of mid-2026, the study had enrolled 64 patients, with the majority identified as having a high transfusion burden at baseline.

In addition to the R289 data, the company will present three poster sessions regarding the use of its marketed product, TAVALISSE (fostamatinib). These presentations will highlight real-world evidence from patients with immune thrombocytopenia (ITP) in Japan and further longitudinal data regarding hemoglobin response in patients with warm autoimmune hemolytic anemia (wAIHA). The ASH meeting, scheduled for December 12-15, serves as a platform for these updates.