SELLAS and Merck Plan Phase 1/2 Trial of Galinpepimut-S and Keytruda in Five Cancers

SELLAS and Merck Plan Phase 1/2 Trial of Galinpepimut-S and Keytruda in Five Cancers

SELLAS Life Sciences and Merck will collaborate on a Phase 1/2 clinical trial assessing the galinpepimut-S vaccine in combination with Keytruda (pembrolizumab) as a treatment for a number of cancers.

Galinpepimut-S is a peptide immunotherapy that SELLAS licensed from Memorial Sloan Kettering Cancer Center. It targets the Wilms tumor-1 (WT1) protein present in a number of tumors. A peptide is a component of a protein.

Researchers will evaluate a combination of galinpepimut-S and Merck’s Keytruda as a treatment for five blood and solid cancers. Keytruda is an approved cancer therapy targeting PD-1, a protein inhibiting the immune system that is found in many cancers.

A Phase 2 clinical trial showing that galinpepimut-S generated an immune response to cancer prompted the U.S. Food and Drug Administration to give the therapy orphan drug and fast track status as a treatment for acute myeloid leukemia (AML) and malignant pleural mesotheliomia (MPM). The European Medicines Agency designated it an orphan drug as well.

In addition to leukemia and mesothelioma, rresearchers are developing galinpepimut-S as a treatment for multiple myeloma and ovarian cancer.

The Phase 1/2 trial will evaluate galinpepimut-S and Keytruda as a treatment for WT1-positive relapsed or refractory tumors, particularly in AML and in colorectal, ovarian, small cell lung and triple-negative breast cancers.

Researchers will compare the safety and effectiveness of the combination with those of Keytruda alone. The main yardsticks will be overall patient response rates and the immune response biomarkers that the combo generates, versus those that Keytruda generated as a stand-alone treatment in comparable studies.

A key question researchers want answered is whether the combo will work better against a macroscopic cancer — that is, one you can see with your eye rather than a microscope — than either agent alone.

“SELLAS is enthused to embark upon this trial with MSD (U.S. Merck) as we look to expand the utility of galinpepimut-S in combination with other agents,” Angelos Stergiou, vice chairman and chief executive officer of SELLAS, said in a press release. “The Keytruda/galinpepimut-S active immunotherapy combination is positioned to exploit the unique features of each of these two agents through potential synergistic immune-based mechanisms of antitumor action. If positive, this clinical effort will allow us to evaluate indications whereby galinpepimut-S and Keytruda could be further studied in combination, providing the basis for a potentially promising cancer immunotherapy approach in the future.”

The Phase 1/2 clinical trial is expected to begin in the first half of 2018.