A Study of HST-1011 Given as Monotherapy and in Combination With an Anti-PD1 Antibody

This is a Phase 1/2 study of HST-1011, a CBL-B inhibitor, being developed for the treatment of patients with advanced solid tumors, who relapsed while on or are refractory to approved anti-PD(L)1 therapies or other standard of care. In Phase 1 patients will receive HST-1011 as either monotherapy (Parts A1 and A2) or in combination with the anti-PD1 antibody, cemiplimab (Part B1 and B2). Part A1 is a monotherapy dose escalation in which cohorts of patients will receive increasing doses of HST-1011. Upon completion of Part A1 dose escalation, an HST-1011 monotherapy dose optimization will commence (Part A2). Part B1 is a dose escalation of HST-1011 given in combination with the standard dose/regimen of cemiplimab. Dosing in Part B1 may commence prior to the completion of Part A1. Upon completion of Part B1 dose escalation, an HST-1011 dose optimization in combination with cemiplimab will commence (Part B2). Phase 2 will evaluate the preliminary antitumor activity of HST-1011 in combination with anti-PD(L)1 antibody or other standard of care therapies.