The FDA has approved a new drug called Revlimid to treat a type of the rare blood disorder, myelodysplastic syndrome (MDS), which can progress to become leukemia.

Revlimid treats a type of MDS involving a certain genetic abnormality.

Revlimid structurally resembles another drug, thalidomide, which is known to cause severe birth defects.

Studies of animals are under way to gauge the risk of birth defects when Revlimid is taken during pregnancy. Revlimid will get a "black box" warning about preventing fetuses from being exposed to Revlimid. A black box warning is the strongest type of warning that the FDA can require for a drug. Access to Revlimid will also be carefully monitored to avoid fetal exposure.

About MDS

MDS is a collection of disorders in which the bone marrow doesn't make enough normal blood cells.

MDS can develop following treatment with drugs or radiation therapy for other diseases, or it can develop without any known cause. Some forms of MDS can progress to acute myeloid leukemia (AML), a type of cancer in which too many white blood cells are made.

The FDA says that an estimated 7,000 to 12,000 new cases of MDS per year are diagnosed in the United States. Although MDS occurs in all age groups, it's most common in people older than 60. Typical symptoms include weakness, fatigue, infections, easy bruising, bleeding, and fever.

Less Need for Transfusions

Patients with MDS may need blood and platelet transfusions and antibiotic therapy for infections.

The FDA reports that in clinical trials, patients treated with Revlimid no longer needed transfusions. Most patients became free of transfusions by three months.

In those studies, patients taking Revlimid didn't need transfusions for an average of 44 weeks.

A study presented in May 2005 at the annual meeting of the American Society of Clinical Oncology showed less need for transfusions in MDS patients taking Revlimid.

Avoiding Fetal Exposure

Revlimid's maker, Celgene Corp., is marketing Revlimid under a risk-management plan called RevAssist, which is designed to prevent fetal exposure to Revlimid.

Under the plan, only pharmacists and prescribers registered with RevAssist will prescribe and dispense Revlimid.

Other rules include:

  • Patients must give informed consent before starting Revlimid.
  • Women taking Revlimid must get pregnancy tests.
  • Doctors must check the results of those pregnancy tests, limit Revlimid prescriptions to a one-month mail supply, and report any pregnancies to the FDA.

The FDA says it and Celgene will re-evaluate the risk-management plan when they get the results of additional animal studies on the risks of birth defects.

Additional Black Box Warnings

Revlimid will also get black box warnings about the potential need to lower the dose because of suppressed blood counts and increased risk of blood clots.

Common side effects reported with Revlimid include low platelet count (thrombocytopenia), low count of white blood cells (neutropenia), diarrhea, itch, rash, and fatigue.

FDA's Comments

Steven Galson, MD, the director of the FDA's Center for Drug Evaluation and Research, spoke about Revlimid in a news release.

"This new product will offer a much-needed treatment option for patients suffering from this rare illness that, in some cases, has been found to progress to fatal forms of leukemia," Galson says.

Written by Miranda Hitti. Reviewed by Louise Chang, MD.

SOURCES: News release, FDA. WebMD Medical News: "Pill Fights Deadly Blood Disorder."