The Food and Drug Administration has alerted the public that the agency is currently reviewing all available information on the potential for increased risk of new malignancies associated with lenalidomide in patients treated for multiple myeloma or myelodysplatic syndromes.
The agency plans to communicate any new recommendations once it has completed its review of existing data, according to a safety announcement released on April 8, 2011. "At this time, [the] FDA recommends that patients continue their Revlimid [lenalidomide] treatment as prescribed by their health care provider," it said.
The concerns appear to be based in part on results from the phase III Cancer and Leukemia Group B (CALGB) 100104 trial of 460 patients with stage I-III multiple myeloma. In the trial, the estimated time to progression reached 42.3 months with lenalidomide maintenance following transplant vs. 21.8 months with placebo. (The results were reported at the 2010 annual meeting of the American Society of Hematology.)
As of late 2010, though, 25 patients had new malignancies: 15 patients in the lenalidomide group, 6 on placebo, and 4 who developed these before randomization. The second cancers included five cases of acute myeloid leukemia or myelodysplastic syndrome, three of which occurred in patients on lenalidomide maintenance.
Lenalidomide, a less-toxic thalidomide analogue, is one of the more important new therapies in multiple myeloma. In addition to the CALGB trial, results from the Intergroupe Francophone du Myélome (IFM) 2005-02 trial also support maintenance lenalidomide.
Lenalidomide is indicated for the treatment of multiple myeloma, in combination with dexamethasone, in patients who have received at least one prior therapy. It is also indicated for patients with transfusion-dependent anemia due to low- or intermediate-1-risk myelodysplastic syndromes associated with a deletion 5q abnormality with or without additional cytogenetic abnormalities.
"At this time, there is no recommendation to delay, modify, or restrict the use of Revlimid for patients being treated according to the FDA-approved indications," the agency noted. "[The] FDA believes the benefits of Revlimid continue to outweigh the potential risks."
The FDA is also currently reviewing all available information on this potential risk for thalidomide.
Physicians are encouraged to report adverse events involving lenalidomide to the FDA MedWatch program.