Celgene could have to wait an extra three months before hearing whether the US Food and Drug Administration will approve its Revlimid (lenalidomide) product for the treatment of anaemia associated with myelodysplastic syndromes.

The agency had been due to rule on Celgene’s application by October 7, but said it would put back the deadline until January 7. Revlimid is a derivative of the notorious drug thalidomide, which caused thousands of children to be born with birth defects in the late 1950s and early 1960s, and the FDA wants more time to evaluate the risk-management programme Celgene has proposed to ensure its safe use.

Celgene has already submitted details of the plan, which aims to make sure women of child-bearing age are not exposed to the drug without comprehensive contraceptive cover, as well as providing details how to manage the risk of cytopenia or a reduction in blood cells which can be a rare side effect of treatment.

An FDA advisory committee gave its backing to the drug earlier this month for use of the drug to treat an MDS associated with a chromosomal abnormality known as a 5q deletion [[15/09/05c]], despite concerns raised in an FDA briefing paper about the design of the clinical studies used to show efficacy and the tolerability of the dose used.

Celgene said it was ready to launch Revlimid as soon as approval is granted by the FDA, and also reiterated its plan to file for a second indication - the treatment of patients with relapsed or refractory multiple myeloma, a haematological cancer - even though a few days ago the company had to stop a trial of the drug in these patients because some developed blood clots [[28/09/05h]]. Analysts have predicted that, with additional indications, Revlimid could achieve sales upwards of $500 million dollars a year.

Revlimid is the first of Celgene's immunomodulatory drug products to reach this stage of development and, if approved by the FDA, will join a crop of new treatments for MDS, including Cell Therapeutics' Trisenox (arsenic trioxide) and Pharmion's Vidaza (azacitidine). Also under regulatory review for MDS are MGI Pharma and SuperGen's Dacogen (decitabine), which was filed in the US last year.

Shares of Celgene lost nearly 2% on the announcement, but recovered with interest and closed yesterday higher by nearly 1% at $54.58.