Epigenetic induction of adaptive immune response in multiple myeloma: sequential azacitidine and lenalidomide generate cancer testis antigen-specific cellular immunity

Patients with multiple myeloma (MM) undergoing high dose therapy and autologous stem cell transplantation (SCT) remain at risk for disease progression. Induction of the expression of highly immunogenic cancer testis antigens (CTA) in malignant plasma cells in MM patients may trigger a protective immune response following SCT. We initiated a phase II clinical trial of the DNA hypomethylating agent, azacitidine (Aza) administered sequentially with lenalidomide (Rev) in patients with MM. Three cycles of Aza and Rev were administered and autologous lymphocytes were collected following the 2nd and 3rd cycles of Aza-Rev and cryopreserved. Subsequent stem cell mobilization was followed by high-dose melphalan and SCT. Autologous lymphocyte infusion (ALI) was performed in the second month following transplantation. Fourteen patients have completed the investigational therapy; autologous lymphocytes were collected from all of the patients. Thirteen patients have successfully completed SCT and 11 have undergone ALI. Six patients tested have demonstrated CTA up-regulation in either unfractionated bone marrow (n = 4) or CD138+ cells (n = 2). CTA (CTAG1B)-specific T cell response has been observed in all three patients tested and persists following SCT. Epigenetic induction of an adaptive immune response to cancer testis antigens is safe and feasible in MM patients undergoing SCT.