FDA Names Cancer Vaccine Galinpepimut-S Orphan Drug as Possible Multiple Myeloma Treatment

The investigational cancer vaccine galinpepimut-S (GPS) has been designated an orphan drug by the U.S. Food and Drug Administration as a possible treatment of multiple myeloma, Sellas Life Sciences announced.

The FDA’s orphan drug designation is expected to support and expedite the clinical development and regulatory review of galinpepimut-S. The act provides incentives for rare-disease therapies, such as seven-year market exclusivity, tax credits for clinical testing, and an exemption from application fees.

“We are delighted to receive this orphan drug designation as it underscores the great need for innovative, effective treatments for this rare cancer, and recognizes the potential benefits that GPS may provide for patients with MM,” Angelos Stergiou, MD, president & chief executive officer of Sellas, said in a press release.

Galinpepimut-S is a cancer vaccine that targets the Wilms Tumor 1 (WT1) protein. WT1 is found at high levels in several cancers and is considered the No. 1 target for cancer immunotherapy by National Cancer Institute.

The treatment was developed to induce a strong immune response against cancer cells expressing the WT1 protein by activating two T-cell subsets, CD4+ and CD8+ T-cells.

In a recent Phase 2 trial (NCT01827137), galinpepimut-S was tested as a maintenance therapy to prevent or delay disease progression in 19 high-risk myeloma patients who had achieved at least stable disease after a stem cell transplant. Despite the transplants’ success, all still had cancer cells in their blood or bone marrow.

While patients with high-risk myeloma usually see a their cancer return in less than a year, those who received the cancer vaccine went for a median of 23.6 months — a significant 2.5-fold increase in time — before disease progression.

Eighteen months after receiving the vaccine, 88% of patients remained alive.

“We have reported median progression-free survival (PFS) of 23.6 months in the high-risk MM [multiple myeloma] disease setting, compared to historically inferior outcomes in such a patient cohort of around 12 months, and [galinpepimut-S] stimulated time-dependent and robust CD4+ T cell or CD8+ T cell immune responses as well as multifunctional cross-epitope T cell reactivity,” Stergiou said.

“Receiving orphan drug designation for the treatment of MM is a significant regulatory milestone in the development of GPS,” he added.

Galinpepimut-S previously was given orphan drug status by the FDA to potentially treat acute myeloid leukemia and malignant plural mesothelioma.

Sellas is developing  galinpepimut-S on a license from Memorial Sloan Kettering Cancer Center in New York.