The MDS Beacon™

The side effects of Revlimid (lenalidomide) in the treatment of myelodysplastic syndromes (MDS) are manageable and decrease with additional treatment cycles. Researchers working in multiple centers in Israel and throughout Europe presented these findings at the 2010 American Society of Clinical Oncology (ASCO) annual meeting on June 5.

Revlimid is approved for the treatment of lower risk MDS patients with the chromosomal mutation del-5q. This mutation is characterized by a missing ‘q’ arm in chromosome 5.  Revlimid can help these patients become transfusion independent.

The researchers conducted a closer analysis of Revlimid’s side effects found in a previous Phase 3 trial.  The participants were divided into three different groups: the first group received a placebo, the second group received high-dose Revlimid treatment (10 mg/day on days 1 to 21 of a 28 day cycle), and the third group received low-dose Revlimid treatment (5 mg/day on days 1 to 28). Dosage was decreased for patients who experienced severe side effects.

Up to 46 percent of patients in the high-dose Revlimid group experienced severe low white blood cell counts during the first two treatment cycles. The rate of severe low white blood cell counts  decreased to 7 percent over the following four treatment cycles. Severe low platelet counts also decreased from 28 percent to 2 percent during the first six cycles of treatment.

A similar trend during the first six treatment cycles was seen in the low-dose Revlimid group. Severe low white blood cell counts decreased from 46 percent to 15 percent, and severe low platelet counts decreased from 19 percent to 6 percent.

Other severe side effects observed included infection, urosepsis (a urinary tract infection that spreads to the kidneys), and fever.

In the high-dose Revlimid group, the dose of Revlimid had to be reduced in 38 percent of patients due to low white blood cell counts and in 23 percent of patients due to low platelet counts. In the low-dose Revlimid group, the dose of Revlimid had to be reduced in 28 percent of patients due to low white blood cell counts, in 12 percent due to low platelet counts, and in 3 percent due to fever.

The treatment had to be discontinued because of low red blood cells in 1 percent of patients in the high-dose Revlimid group and because of low white blood cell counts in 1 percent of patients in the high-dose group and 6 percent in the low-dose group.

Based on comparable side effect results for both groups but higher response rates in the 10 mg group, the researchers concluded that Revlimid treatment can be started at 10 mg. They recommended supplementing therapy with dose modifications and supportive care to achieve the best outcome.

For more information, please see abstract 6598 at the ASCO meeting website.