01:32 PM EST, 12/09/2024 (MT Newswires) -- Rigel Pharmaceuticals ( RIGL ) said Monday R289 showed "promising" initial efficacy and safety data in its ongoing phase 1b study evaluating safety and tolerability in patients with relapsed or refractory lower-risk myelodysplastic syndrome.

The drug candidate has demonstrated evidence of transfusion independence in elderly patients, Chief Medical Officer Lisa Rojkjaer said.

The company said R289 was "generally well-tolerated," with the most common treatment emergent adverse events being diarrhea and fatigue, and chills, nausea and pruritus, which were all grade 1/2.

One patient discontinued the study due to drug-related adverse events and another discontinued the trial due to adverse effects not related to the drug, the company said.

Rigel shares were down nearly 5% in recent trading.

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