Rigel Pharmaceuticals Highlights Initial Data From Ongoing Phase 1b Study Evaluating R289 In LR-MDS At The 66th ASH Annual Meeting; R289 Was Generally Well Tolerated And Demonstrated Signs Of Preliminary Clinical Activity In Elderly Heavily Pretreated LR-MDS Patients

• R289 was generally well tolerated and demonstrated signs of preliminary clinical activity in elderly heavily pretreated LR-MDS patients
• RBC-TI/HI-E responses occurred in 40% of evaluable TD patients receiving R289 doses ≥500 mg QD

SOUTH SAN FRANCISCO, Calif., Dec. 9, 2024 /PRNewswire/ -- Rigel Pharmaceuticals, Inc. (NASDAQ:RIGL), a commercial stage biotechnology company focused on hematologic disorders and cancer, today announced initial data from its ongoing Phase 1b study evaluating R2891, an oral prodrug of R835, a potent and selective dual inhibitor of IRAK1 and IRAK4, in patients with relapsed or refractory (R/R) lower-risk myelodysplastic syndrome (LR-MDS). The data is being presented today by Dr. Guillermo Garcia-Manero (Poster #: 4595) at the 66th American Society of Hematology (ASH) Annual Meeting and Exposition being held December 7-10, in San Diego, California and virtually.