A recent study investigated the safety, efficacy, and maximum tolerated dose of pomalidomide for patients with multiple myeloma whose disease relapsed after treatments with other drugs such as bortezomib and lenalidomide. This phase I clinical trial enrolled 38 patients. Pomalidomide provided a minimal or better response for 42% of the patients, a partial response or better for 21%, and a complete response for 3%.

According to the authors, almost all patients with multiple myeloma who are treated with bortezomib, lenalidomide, or thalidomide relapse. Survival times shorten progressively with each subsequent relapse. Effective new treatments that re-establish tumor response are urgently required to improve outcomes for these patients.

“This open-label, phase I, dose-escalation study was primarily conducted to evaluate the maximum tolerated dose of pomalidomide,” said study co-author Daniel Sullivan, MD, of the Moffitt Cancer Center in Tampa, Florida. “The secondary objective was to assess safety of pomalidomide when given with or without dexamethasone.”

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The researchers found that pomalidomide, given in escalating doses (from 2 mg to 5 mg per day for 21 of 28 days) in combination with low doses of dexamethasone, demonstrated “encouraging activity with manageable toxicity.” The researchers noted that there was a low incidence of peripheral neuropathy in their study patients, all of whom had eventually failed past treatment with drugs known to be associated with neurotoxicity. Common adverse events included neutropenia, anemia, thrombocytopenia, and fatigue. These adverse events were generally manageable and were not unexpected in this clinical situation.

The patients had a median duration of response of 4.6 months. Their median progression-free survival was also 4.6 months, and their median overall survival was 18.3 months.

Ongoing phase II studies have confirmed the safety and efficacy of this drug in patients with relapsed myeloma. The Food and Drug Administration is considering the drug for approval for this patient population. This study was published in Blood (2012; doi:10.1182/blood-2012-08-450742).