Rigosertib Plus Pembrolizumab in Treating Patients With Unresectable/Metastatic Melanoma Refractory to PD-1 Inhibitors

This phase II clinical trial tests how well rigosertib plus pembrolizumab workings in treating patients with melanoma which cannot be removed by surgery (unresectable) or that has spread from where it first started (primary site) to other places in the body (metastatic), and that has not responded to previous treatment with PD-1 or PD-L1 inhibitors (refractory). Rigosertib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth and may change the immune system to make immunotherapy more effective. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Giving rigosertib in combination with pembrolizumab may be more effective in treating patients with unresectable metastatic melanoma that has not responded to previous treatment with PD-1 or PD-L1 inhibitors than giving either drug alone.