(HealthDay)—Pomalyst (pomalidomide) has been approved by the U.S. Food and Drug Administration to treat cases of multiple myeloma that have not responded to other therapies.

The disease, a form of blood cancer, affects some 21,700 Americans annually and nearly 10,700 die from it each year, the agency said Friday in a news release.

Pomalyst is designed to spur the immune system to destroy and inhibit , the FDA said. The drug's safety and effectiveness were evaluated in a clinical study of 221 people with advanced .

The drug's label will contain a boxed warning that it shouldn't be used by pregnant women since it can cause life-threatening birth defects and blood clots, the FDA said.

More common side effects could include a drop in infection-fighting , fatigue, weakness, other blood disorders, back pain and fever.

The drug is marketed by Celgene, based in Summit, N.J.

More information: The U.S. National Library of Medicine has more about multiple myeloma.