Combination Therapy Effective Against Multiple Myeloma

Treatment with a combination of clarithromycin, lenalidomide and dexamethasone is successful in most patients with newly diagnosed symptomatic multiple myeloma, according to New York-based researchers.

"This paper," lead investigator Dr. Ruben Niesvizky told Reuters Health, "reports the efficacy and safety of a novel induction regimen, which has shown higher complete and overall response rates than other induction therapies."

In a phase II trial, Dr. Niesvizky of the New York Presbyterian Hospital-Cornell Medical Center and colleagues treated 72 patients in 28-day cycles. The patients were given dexamethasone 40 mg once weekly, clarithromycin 500 mg twice daily and lenalidomide 25 mg daily on days 1 to 21.

With response defined as a decrease in monoclonal protein of at least 50% in serum and 90% in urine, 65 of the patients (90.3%) had an objective response, the authors report in the February 1st issue of Blood. In total, 73.6% of the subjects achieved a decrease in monoclonal protein of 90% or greater.

The 52 patients who did not undergo hematopoietic stem cell transplant continued on therapy, and 37% of these patients had a complete response and 33% had a "very good" partial response. "The median event-free survival has not been reached," the researchers added, "and the actuarial 2-year event-free survival has reached 97.2%."

These results, Dr. Niesvizky said, are "comparable to high-dose chemotherapy programs." In the transplant patients, the investigators were able to "collect stem cells after lenalidomide therapy with successful engraftment after transplant."

Among other new findings, Dr. Niesvizky added, was "the safety and efficacy of dexamethasone in a once-weekly schedule" rather than the more toxic pulsing approach.

"Most adverse events were manageable," the researchers report. "The most common grade 3 or higher hematologic toxicities were neutropenia (19.4%), anemia (13.8%) and thrombocytopenia (22.2%). The most serious non-hematologic side effect was myopathy."

The results support further exploration of the approach for induction therapy, the researchers conclude, "because it produces high response rates and may increase disease-free and overall survival when used in conjunction with autologous transplantation."

SOURCE: Blood 2008;111:1101-1109.