The U.S. Food and Drug Administration (FDA) has granted Fast Track designation to galinpepimut-S for the treatment of multiple myeloma. Galinpepimut-S is licensed from Memorial Sloan Kettering Cancer Center and targets the Wilms tumor 1 (WT1) protein, which is present in an array of tumor types. Final clinical and immunologic data from a phase II clinical trial for galinpepimut-S in the treatment of high-risk multiple myeloma was presented at the 44th Annual European Society for Blood and Marrow Transplantation (EBMT) Meeting.
“The designation of Fast Track for [galinpepimut-S] represents important recognition by the FDA of the potential of this novel immunotherapeutic to address the significant unmet need in the treatment of patients with high-risk multiple myeloma in patients with poor-risk cytogenetics at diagnosis who still harbor minimal residual disease (MRD) after autologous stem cell transplant,” said Angelos Stergiou, MD, ScD hc, President and Chief Executive Officer of SELLAS.
About the Phase II Study
The open-label, phase II study consisted of 19 patients with multiple myeloma who had high-risk cytogenetics at initial diagnosis and remained at least MRD-positive after a successful autologous stem cell transplant (ASCT). Galinpepimut-S was administered to patients in the study who achieved a stable disease or better status (per International Myeloma Working Group criteria) following ASCT. Galinpepimut-S was evaluated as consolidation therapy to potentially stimulate a highly-specific immune response against WT1 in order to prevent or delay myeloma progression. Median progression-free survival (PFS) of 23.6 months was reported in the high-risk disease setting, compared to historically inferior outcomes while on an immunomodulatory drug (IMID) or proteasome inhibitor post-ASCT maintenance. Median overall survival has not been reached to date. Galinpepimut-S stimulated time-dependent and robust CD4+ T cell or CD8+ T-cell immune responses specific for all four WT1 peptides within galinpepimut-S, two of which are heteroclitic (mutated, by design). In addition, galinpepimut-S stimulated similar immune responses against the two counterpart native peptides. The responses were confirmed in up to 91% of patients across HLA allele types, with multivalent responses emerging in up to 64% of patients. Multifunctional cross-epitope T-cell reactivity was observed in 75% of patients to antigenic epitopes against which hosts were not specifically immunized, in a pattern akin to epitope spreading. A link of clinical activity to antigen-specific immune responses was suggested.
Galinpepimut-S is a heteroclitic multivalent, multipeptide cancer immunotherapeutic agent composed of four peptides, addressing over 20 epitopes, and derived from the WT1 protein, which has been ranked by the National Cancer Institute as a top priority among cancer antigens for immunotherapy. Importantly, because the WT1 antigen is overexpressed in many malignancies, and is not found in most normal tissues, galinpepimut-S has the potential to be a broad immunotherapy, effective across many cancer types and patient populations.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.