Efficacy and safety of Id-protein-loaded dendritic cell vaccine in patients with multiple myeloma--phase II study results.

In a phase II clinical study, pretreated multiple myeloma patients with relapsing or stable disease received autologous anticancer vaccine containing dendritic cells loaded with Id-protein. Patients received a total of 6 vaccine doses intradermally in monthly intervals. No clinical responses were observed. During the follow-up with a median of 33.1 months (range: 11-43 months), the disease remained stable in 7/11 (64%) of patients. Immune responses measured by ELISpot were noted in 3/11 (27%) and DTH skin test for Id-protein was positive in 8/11 (73%) of patients; out of those, 1/11 (9%) and 5/11 (46%), respectively, had preexisting immune response to Id-protein before the vaccination began. Outcomes were compared to those of a control group of 13 patients. A trend to lower cumulative incidence of progression in the vaccinated group was observed at 12 months from the first vaccination (p = 0.099). More patients from the control group compared to vaccinated patients required active anticancer therapy [4/11 (36%) vs. 8/13 (62%)]. Vaccines based on dendritic cells loaded with Id-protein are safe and induce specific immune response in multiple myeloma patients. Our results suggest that the vaccination could stabilize the disease in approximately two-thirds of patients.