Rigel Announces First Patient Enrolled in the Dose Expansion Phase of its Phase 1b Study of R289 in Patients with Lower-Risk MDS

Core Insights - Rigel Pharmaceuticals has initiated the dose expansion phase of the Phase 1b study for R289, targeting patients with transfusion-dependent relapsed or refractory lower-risk myelodysplastic syndrome (MDS) [1][2] - The study aims to determine the recommended Phase 2 dose (RP2D) of R289, a dual inhibitor of IRAK1/4, which has shown potential in addressing unmet medical needs in lower-risk MDS patients [2][3] Company Overview - Rigel Pharmaceuticals, Inc. is a biotechnology company focused on developing therapies for hematologic disorders and cancer, founded in 1996 and based in South San Francisco, California [5] - The company is publicly traded on Nasdaq under the ticker RIGL [5] Product Details - R289 is a prodrug of R835, designed to inhibit IRAK1/4, and has demonstrated the ability to block inflammatory cytokine production in preclinical studies [4] - The FDA has granted R289 Orphan Drug and Fast Track designations for the treatment of myelodysplastic syndromes and previously-treated transfusion-dependent lower-risk MDS, respectively [3] Study Design - The ongoing Phase 1b study includes a dose expansion phase where up to 40 patients will be randomized to receive either 500 mg of R289 once or twice daily [2] - The study's primary focus is on evaluating safety, tolerability, pharmacokinetics, and preliminary activity of R289 in the specified patient population [2]