The US Food and Drug Administration (FDA) announced today that it has halted a clinical trial of the anti-cancer drug Revlimid (lenalidomide) due to safety concerns.

The drug, manufactured by Celgene, is a derivative of the infamous drug thalidomide, and is approved as a treatment for multiple myeloma, myelodysplastic syndrome (MDS) and mantle cell lymphoma.

However, due to its side effects, it is also subject to a rigorous Risk Evaluation and Mitigation Strategies (REMS) program that includes a Medication Guide and elements to assure safe use. For example, women taking the drug are instructed not to become pregnant four weeks before, during or after starting Revlimid.

The drug was undergoing further clinical testing to evaluate its potential therapeutic effects in patients 65 years of age and older with chronic lymphocytic leukemia (CLL), but FDA said it has now halted the Phase III trial due to "higher rates of death" in the treatment group receiving Revlimid versus the group treated with chlorambucil.

"The clinical trial is unlikely to achieve its main objective to reduce the amount of time for the leukemia to progress or the patient to die," FDA explained in a statement. Data released by FDA showed a 92% increased risk of death compared to chlorambucil-an increase of 16 deaths (34 versus 18) overall.

In a statement, Celgene said confirmed the cessation of the trial, named the ORIGIN Trial, as a result of FDA's 12 July 2013 clinical hold. "All clinical investigators in ongoing chronic lymphocytic leukemia studies using lenalidomide will be officially advised of this action and instructed to inform their patients accordingly," the company said.

Celgene added that "No specific causality for this imbalance has been identified to date," but that trial results would be presented at an unspecified upcoming medical conference.

FDA Notice

Celgene Statement