As Revlimid ^[1] (lenalidomide) and Velcade ^[2] (bortezomib) have become standard therapies in the treatment of multiple myeloma, managing side effects is important for patients who want to maintain their treatment while minimizing toxicity.

A recent report published in the journal Community Oncology discusses the management of side effects associated with these agents. Overall, the most commonly observed toxic effects include myelosuppression, gastrointestinal effects, peripheral neuropathy, and thromboembolic events.

Myelosuppression is a condition in which bone marrow activity is decreased, resulting in fewer red blood cells, white blood cells, and platelets. Revlimid causes both a lower-than-normal number of infection-fighting white blood cells and an abnormally small number of platelets in the blood. Patients treated with Velcade tend to have predictable levels of infection-fighting white blood cells, but a low number of platelets.

With Velcade, these side effects are resolved quickly when dosage is terminated. With Revlimid, a dose modification may be required.

Gastrointestinal side effects have been reported in up to half of all patients receiving treatment with Velcade or Revlimid. The most common symptoms include diarrhea, constipation, nausea, and vomiting.

A previous consensus from the International Myeloma Foundation (IMF) Nurse Leadership Board stated that it is important to manage these side effects in order to prevent further complications, such as weight loss, dehydration, bowel obstruction, and electrolyte disturbances. Prevention can usually be achieved by the use of laxatives, antidiarrheals, adequate fluid intake, or changes in the diet.

The more serious side effect of peripheral neuropathy occurs when nerves that connect the brain and spinal cord to the body are damaged. In its most common form, neuropathy causes pain and numbness in the hands and feet.

In patients using Velcade, 18 percent to 30 percent develop grade 3/4 neuropathy, where sensory loss interferes with activities of daily life. The grading scale for neuropathy measures the severity of the side effects. While grade 4 neuropathy can lead to permanent sensory loss, grade 1/2 normally does not effect daily activities.

Prompt identification of milder symptoms, such as tingling, is required to prevent grade 1 or 2 neuropathy from progressing to grade 3 or 4, however. In effect, physicians recommend that dose modifications should begin when patients develop grade 1 or 2 neuropathy.

Although Revlimid may also cause peripheral neuropathy, a Phase 3 study of treatment with Revlimid and dexamethasone ^[3] showed that neurological side effects are generally mild. Only 2 percent to 3 percent of patients in the study developed grade 3/4 neuropathy.

The prevention of thromboembolism has been achieved primarily by adding anticoagulation drugs to treatment regimens. Thromboembolism is caused when a blood clot forms in one blood vessel, breaks loose, then migrates through the blood stream to block another blood vessel. This can potentially lead to a stroke or heart attack.

Recently, the International Myeloma Working Group recommended using drugs that prevent blood clotting with thalidomide ^[4] (Thalomid) and Revlimid. For patients with two or more risk factors—such as obesity, diabetes, history of blood clots, cardiovascular disease—recommendations included full-dose anticoagulation with either Coumadin (warfarin) or some types of heparin. For patients with one risk factor, daily use of aspirin is recommended. For patients taking Revlimid in combination with a high dose of dexamethasone, full-dose anticoagulation was recommended, regardless of risk factors.

For more information, please see the full article at the OncologyStat ^[5] Web site.