The US Food and Drug Administration (FDA) has approved the targeted drug Gleevec (imatinib mesylate) for use against 5 additional diseases. They are:

• Dermatofibrosarcoma protuberans, a solid tumor that usually begins as a hard lump in the skin of the chest, abdomen, or leg
• Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL) that has come back after treatment or no longer responds to treatment
• Certain forms of myelodysplastic syndrome and myeloproliferative disorders, which are bone marrow diseases
• Another form of leukemia known as hypereosinophilic syndrome/chronic eosinophilic leukemia
• Aggressive systemic mastocytosis, a disease the creates too many mast cells, a type of white blood cell

Gleevec was previously approved for use against chronic myelogenous leukemia (CML) and gastrointestinal stromal tumor (GIST).

Side effects from Gleevec are typically mild, according to drug manufacturer Novartis. The most common are nausea, swelling, muscle cramps, skin rash, diarrhea, and fatigue.

In a recent letter to doctors, however, Novartis and the FDA also warned that Gleevec may be associated with heart problems in some patients.

Specifically, the drug was linked to the development of congestive heart failure in a few patients. This condition, in which the heart isn't able to pump enough blood to the organs, affected mostly older people who already had other medical conditions and risk factors for heart disease.

Both Novartis and the FDA advised doctors to monitor patients on Gleevec for signs of heart trouble (especially those with a history of heart disease) and treat them if it develops.

According to the American Heart Association, symptoms of heart failure can include shortness of breath, persistent coughing or wheezing, and fluid retention that may cause swelling in the legs or abdomen. People may also experience fatigue, lack of appetite, nausea, confusion, and increased heart rate.