US Food and Drug Administration Approval Summary: Imetelstat for Selected Patients With Low- to Intermediate-1 Risk Myelodysplastic Syndromes With Transfusion-Dependent Anemia

N Nina Kim (1FDA, Silver Spring, United States) E E. Dianne Pulte (2U.S. Food and Drug Administration, Silver Spring, United States) L Lori A. Ehrlich (Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD) A Alexei C. Ionan (Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD) S Spencer Haupert (Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD) J Jonathon Vallejo (Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD) F Francis Green (Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD) N Nan Zheng Y Yun Wang J Jiang Liu J Javier G. Blanco (Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD) S Sarah E. Dorff (Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD) B Brian Booth (Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD) M Moran Choe (Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD) B Brenda Gehrke (Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD) V Vishal Bhatnagar M Marc Theoret (Oncology Center of Excellence, US Food and Drug Administration, Silver Spring, MD) R Richard Pazdur (From the Oncology Center of Excellence (G.U.M., R.P.) and the Office of the Commissioner (N.N.B., R.M.C.), Food and Drug Administration, Silver Spring, MD.) R R. Angelo de Claro (Center for Drug Evaluation and Research, Silver Spring, MD) K Kelly J. Norsworthy (Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD)

Abstract

On June 6, 2024, the US Food and Drug Administration (FDA) approved imetelstat (RYTELO, Geron) for adults with low- to intermediate-1 risk myelodysplastic syndromes (MDS) with transfusion-dependent anemia requiring ≥4 red blood cell units over 8 weeks who have not responded to or have lost response to or are ineligible for erythropoiesis-stimulating agents. The approval was based on a randomized (2:1), double-blind, placebo-controlled multicenter trial, Study MDS3001. In the protocol-specified primary analysis, the ≥8-week RBC transfusion independence (RBC-TI) rate was 39.8% (95% CI, 30.9 to 49.3) in the imetelstat group versus 15% (95% CI, 7.1 to 26.6) in the placebo group ( P < .001). This was supported by the rate of ≥24-week RBC-TI of 28% (95% CI, 20.1 to 37) in the imetelstat group versus 3.3% (95% CI, 0.4 to 11.5) in the placebo group ( P < .001). However, there was no major difference between arms regarding the key secondary end point of erythroid response (HI-E) per International Working Group 2006 criteria or secondary end points reflective of a disease-modifying effect such as complete remission rate and overall survival. The most common adverse reactions were thrombocytopenia, leukopenia, neutropenia, increased liver enzymes, fatigue, prolonged partial thromboplastin time, arthralgia/myalgia, COVID-19, and headache. The rate of grade 3 to 4 neutropenia and thrombocytopenia were 72% and 65%, respectively, in the imetelstat arm compared with 7% and 8% in the placebo arm. Despite the high incidence of neutropenia and thrombocytopenia, the FDA determined that the benefits outweighed the risks in this patient population with high unmet need. Postmarketing requirements were issued to evaluate long-term safety and to conduct a randomized trial comparing at least two dosages of imetelstat to potentially minimize risks of imetelstat treatment and improve tolerability.

Article Details

Volume / Issue Vol. 43, Issue 35
Published December 10, 2025
Pages 3760-3768
ISSN 0732-183X
Publisher Lippincott Williams & Wilkins

Journal Info

Journal of Clinical Oncology

Lippincott Williams & Wilkins

ISSN: 0732-183X Health Sciences

Authors (20)

N

Nina Kim

1FDA, Silver Spring, United States

E

E. Dianne Pulte

2U.S. Food and Drug Administration, Silver Spring, United States

L

Lori A. Ehrlich

Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD

A

Alexei C. Ionan

Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD

S

Spencer Haupert

Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD

J

Jonathon Vallejo

Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD

F

Francis Green

Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD

N

Nan Zheng

Y

Yun Wang

J

Jiang Liu

J

Javier G. Blanco

Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD

S

Sarah E. Dorff

Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD

B

Brian Booth

Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD

M

Moran Choe

Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD

B

Brenda Gehrke

Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD

V

Vishal Bhatnagar

M

Marc Theoret

Oncology Center of Excellence, US Food and Drug Administration, Silver Spring, MD

R

Richard Pazdur

From the Oncology Center of Excellence (G.U.M., R.P.) and the Office of the Commissioner (N.N.B., R.M.C.), Food and Drug Administration, Silver Spring, MD.

R

R. Angelo de Claro

Center for Drug Evaluation and Research, Silver Spring, MD

K

Kelly J. Norsworthy

Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD