Dendritic Cell–Based Vaccine Induces Immune Response in Multiple Myeloma

NEW ORLEANS—Vaccinating multiple myeloma patients with their own idiotype-loaded dendritic cells appears to be a safe way of stimulating immune responses against the cancers, according to two poster presentations at the ASH meeting.

One presentation specifically looked at dendritic cell-based idiotype vaccination as maintenance therapy following autologous peripheral blood cell transplant, while the other presentation tested the efficacy of a dendritic cell-based preparation for advanced refractory multiple myeloma.

“Our approach to treating multiple myeloma is to vaccinate the patient against their own idiotype protein using dendritic cells obtained from the patient as the vehicle to stimulate the patient’s own immunity,” Frank Valone, MD, said in an interview with Oncology News International. Dr. Valone is senior vice president of medical and regulatory affairs at the Dendreon Corporation a private biotech company in Seattle, Wash., and a co-presentor at the poster sessions.

Nontoxic Immunity Boost

In one of the studies, headed by Martha Lacy, MD, of the Mayo Clinic in Rochester, Minn., dendritic cells were taken from 12 multiple myeloma patients 60 to 120 days after peripheral blood stem cell transplants, by which time the patients had achieved the maximal posttransplant cytoreduction. The dendritic cells were partially purified, then incubated with serum containing the patient’s own monoclonal idiotype protein, which had been collected before the patient’s transplant. After 2 days of culture, the researchers infused the patients with their own idiotype-loaded dendritic cells. Each patient received further infusions in weeks 2, 4, and 16.

Of the 12 patients, 2 achieved a complete clinical response and 1 a partial clinical response. In two other patients, M protein (idiotype), which had been at measurable amounts, declined to a concentration detectable only by immunofixation.

Six patients were stable, and one patient had a rise in monoclonal protein 3 months after receiving the final vaccine. No patient had any toxicity from the vaccines.

“This appears to be a nontoxic way of boosting somebody’s immunity,” Dr. Valone said. “The initial clinical results suggest that it’s effective for treating low-tumor-burden multiple myeloma.”

Refractory Disease

Dendritic cell-based vaccine was also shown to induce antigen-specific immune responses in patients with advanced multiple myeloma resistant to chemotherapy, according to the other poster presentation. Some patients had undergone as many as eight different chemotherapy regimens.

In addition, 16 of the 38 evaluable subjects had undergone radiation therapy, and 14 had stem-cell transplants. The patients received infusions of dendritic cell vaccine on four occasions in a multicenter phase I/II trial.

There were six adverse events. Four were grade 1 or 2 (mild high blood pressure, sore arm, fever), and two were grade 3 or 4 (dypsnea). Of 34 patients who could be evaluated for treatment efficacy, 5 had a minor response, and 12 were stable for at least 24 weeks. Median time to progression of the myeloma was 37.3 weeks.