MAGE-A inhibit apoptosis and promote proliferation in multiple myeloma through regulation of BIM and p21Cip1.

The type I Melanoma Antigen Gene (MAGE) A3 is a functional target associated with survival and proliferation in multiple myeloma (MM). To investigate the mechanisms of these oncogenic functions, we performed gene expression profiling (GEP) of p53 wild-type human myeloma cell lines (HMCL) after MAGE-A knockdown, which identified a set of 201 differentially expressed genes (DEG) associated with apoptosis, DNA repair, and cell cycle regulation. MAGE knockdown increased protein levels of pro-apoptotic BIM and of the endogenous cyclin-dependent kinase (CDK) inhibitor p21Cip1. Depletion of MAGE-A in HMCL increased sensitivity to the alkylating agent melphalan but not to proteasome inhibition. High MAGEA3 was associated with the MYC and Cell Cycling clusters defined by a network model of GEP data from the CoMMpass database of newly diagnosed, untreated MM patients. Comparative analysis of CoMMpass subjects based on high or low MAGEA3 expression revealed a set of 6748 DEG that also had significant functional associations with cell cycle and DNA replication pathways, similar to that observed in HMCL. High MAGEA3 expression correlated with shorter overall survival after melphalan chemotherapy and autologous stem cell transplantation (ASCT). These results demonstrate that MAGE-A3 regulates Bim and p21Cip1 transcription and protein expression, inhibits apoptosis, and promotes proliferation.

Autologous Lymphocyte Infusion Supports Tumor Antigen Vaccine-Induced Immunity in Autologous Stem Cell Transplant for Multiple Myeloma.

Autologous stem cell transplant (autoSCT), the standard consolidation therapy for multiple myeloma, improves disease-free survival, but is not curative. This could be an ideal setting for immunologic therapy. However, the immune milieu is impaired after autoSCT. We hypothesized that autologous lymphocyte infusion would restore immune competence, allowing immunotherapies such as cancer vaccines to elicit tumor antigen-specific immunity in the setting of autoSCT. In this pilot study (NCT01380145), we investigated safety, immunologic, and clinical outcomes of autologous lymphocyte infusion combined with peri-autoSCT immunotherapy with recombinant MAGE-A3 (a multiple myeloma-associated antigen) and adjuvant. Thirteen patients with multiple myeloma undergoing autoSCT were enrolled. Autologous lymphocyte infusion and MAGE vaccination were well tolerated. Combination immunotherapy resulted in high-titer humoral immunity and robust, antigen-specific CD4+ T-cell responses in all subjects, and the responses persisted at least one year post-autoSCT. CD4+ T cells were polyfunctional and Th1-biased. CD8+ T-cell responses were elicited in 3 of 13 subjects. These cells recognized naturally processed MAGE-A3 antigen. Median progression-free survival was 27 months, and median overall survival was not reached, suggesting no differences from standard-of-care. In 4 of 8 subjects tested, MAGE-A protein expression was not detected by IHC in multiple myeloma cells at relapse, suggesting therapy-induced immunologic selection against antigen-expressing clones. These results demonstrated that autologous lymphocyte infusion augmentation of autoSCT confers a favorable milieu for immunotherapies such as tumor vaccines. This strategy does not require ex vivo manipulation of autologous lymphocyte products and is an applicable platform for further investigation into combination immunotherapies to treat multiple myeloma.

A phase 2 study of panobinostat with lenalidomide and weekly dexamethasone in myeloma.

Phase 3 studies combining histone deacetylase inhibitors with bortezomib were hampered by gastrointestinal (GI) intolerance, which was not observed when combined with immunomodulatory drugs. This study is a single-center phase 2 study of panobinostat with lenalidomide and dexamethasone (FRD). Twenty-seven relapsed multiple myeloma patients were enrolled. Twenty-two patients (81%) were lenalidomide refractory and 9 (33%), 14 (52%), and 7 (26%) were refractory to pomalidomide, bortezomib, and carfilzomib, respectively. High-risk molecular findings were present in 17 (63%) patients. Responses included 2 complete responses (CRs), 4 very good partial responses (VGPRs), 5 partial responses (PRs), and 9 minimal responses (MRs) for an overall response rate of 41%, clinical benefit rate of 74%, and a disease control rate of 96%. The median progression-free survival (PFS) was 7.1 months. In the 22 lenalidomide-refractory patients, there were 1 CR, 4 VGPRs, 3 PRs, and 7 MRs, with a median PFS of 6.5 months. Median overall survival was not reached. Grade 3/4 toxicities were primarily hematologic. Gene expression profiling of enrollment tumor samples revealed a set of 1989 genes associated with short (<90 days) PFS to therapy. MAGEA1 RNA and protein expression were correlated with short PFS, and laboratory studies demonstrated a role for MAGE-A in resistance to panobinostat-induced cell death. FRD demonstrates durable responses, even in high-risk, lenalidomide-refractory patients, indicating the essential role of panobinostat in attaining responses. MAGEA1 expression may represent a functional biomarker for resistance to panobinostat. In contrast to PANORAMA 1, there were no significant GI toxicities and primarily expected hematologic toxicities. This trial was registered at www.clinicaltrials.gov as #NCT00742027.