The Food and Drug Administration (FDA) has granted Orphan Drug designation to tamibarotene for the treatment of myelodysplastic syndrome (MDS).

Tamibarotene is an oral first-in-class selective retinoic acid receptor alpha (RARα) agonist that is being developed for patients whose disease is characterized by overexpression of the RARA gene.

The Company is currently evaluating the efficacy and safety of tamibarotene in combination with azacitidine in RARA-positive newly diagnosed adults with higher-risk MDS in the randomized, double-blind, placebo-controlled phase 3 SELECT-MDS-1 trial ( Identifier: NCT04797780). 

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“The FDA’s Orphan Drug designation is an important milestone in the development of tamibarotene as a treatment for MDS,” said David A. Roth, MD, Syros’ Chief Medical Officer. “We believe tamibarotene’s novel mechanism of action, promising clinical activity data, oral delivery, and favorable tolerability profile supports a potential new option for the approximately 30% of HR-MDS patients who are RARA-positive.”

The FDA’s Orphan Drug designation is granted to medicines intended to treat or prevent rare diseases or disorders that affect fewer than 200,000 individuals.

Tamibarotene is also being evaluated in combination with venetoclax and azacitidine in the phase 2 SELECT-AML-1 study ( Identifier: NCT04905407) in RARA-positive newly diagnosed adult patients with acute myeloid leukemia who are not suitable candidates for standard chemotherapy. 

Trial findings showed an overall response rate of 67% and a composite complete response rate of 61% with tamibarotene plus azacitidine. The combination was generally well tolerated with no evidence of increased myelosuppression.


  1. Syros receives FDA Orphan Drug designation for tamibarotene for the treatment of MDS. News release. Syros Pharmaceuticals. Accessed February 4, 2022.
  2. Syros announces first patient dosed in SELECT-AML-1 Trial of tamibarotene in combination with venetoclax and azacitidine in newly diagnosed unfit AML. News release. Syros Pharmaceuticals. September 9, 2021. Accessed February 4, 2022.

This article originally appeared on MPR