Multiple Myeloma Treatment, Galinpepimut-S, Receives FDA Fast Track Designation

This morning, July 20, 2018, galinpepimut-S (GPS), a multiple myeloma treatment with a target for the Wilms Tumor 1 (WT1) protein, received a fast track designation from the US Food and Drug Administration (FDA).

The heteroclitic multivalent, multi-peptide cancer immunotherapeutic agent is manufactured by SELLAS Life Sciences Group Inc. and licensed by Memorial Sloan Kettering Cancer Center. Composed of 4 peptides, GPS addresses over 40 epitopes derived from the WT1 protein, a designated top priority among cancer antigens for immunotherapy by the National Cancer Institute.

President and chief executive officer of SELLAS, Angelos Stergiou, MD, ScD hc, expressed his excitement for the designation in a recent statement. “The designation of Fast Track for GPS 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,” he said.

The designation largely stems from positive data reported from GPS’s phase 2 clinical trial, which was presented at the 44th Annual European Society for Blood and Marrow Transplantation (EBMT) Meeting in Lisbon, Portugal.

The open-label phase 3 study enrolled 19 patients with multiple myeloma who had high-risk cytogenetics at initial diagnosis and remained at least minimal residual disease (MRD)-positive after a successful autologous stem cell transplant (“ASCT”). After ASCT, GPS was given to patients who had achieved a stable disease or better status. Evaluated as a consolidation therapy, GBS was used to encourage a highly specific immune response against WT1 in an effort to prevent or delay myeloma progression.

In the high-risk disease setting, a median progression-free survival (PFS) of 23.6 months was reported in comparison with previously established inferior outcomes that were found while on an immunomodulatory drug (IMID) or proteasome inhibitor post-ASCT maintenance. To date, median overall survival has yet to be reached.

GPS was also observed to stimulate time-dependent and robust CD4+ T cell or CD8+ T cell immune responses (IRs) specific for all 4 WT1 peptides within GPS, 2 of which are heteroclitic (mutated, by design). GPS was also found to stimulate similar IRs against the 2 counterpart native peptides. Furthermore, in up to 91% of patients across HLA allele types, the IRS were confirmed; multivalent IRs occurred in up to 64% of patients. Additionally, 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 similar to epitope spreading, according to a recent release. A suggested link between clinical activity and antigen-specific immune responses was also made.

GPS was previously granted orphan drug designation for malignant pleural mesothelioma, acute myeloid leukemia. It has also been granted fast track designation for the treatment of malignant pleural mesothelioma (MPM) and acute myeloid leukemia (AML).

“We are fully committed to working closely with the FDA as we continue development of our potential first-in-class novel WT1-targeting cancer vaccine for select high-risk MM patients in the post-autotransplant maintenance setting after standard first-line treatment,” added Dr Stergiou.

Plans for phase 3 clinical trials are currently underway—pending funding availability—for GPS in 2 indications, AML and MPM and is also developing GPS as a potential treatment for multiple myeloma and ovarian cancer.