This study is a Phase 1, open-label, dose escalation, and cohort expansion study designed to characterize the safety, tolerability, PK, pharmacodynamics, immunogenicity, and preliminary antitumor activity of the combination of obrindatamab and retifanlimab, each of which is administered by IV infusion. The study consists of a Dose Escalation Phase to determine the Maximum Tolerated Dose (MTD) or Maximum Administered Dose (MAD) (if no MTD is defined) of the combination, followed by a Cohort Expansion Phase to further define the safety and initial antitumor activity of the combination with the doses established in the Dose Escalation Phase. Patients with B7-H3-expressing unresectable, locally advanced, or metastatic solid tumors of any histology will be enrolled in the Dose Escalation Phase. Following the establishment of an MTD, additional patients with specific tumor types will enroll in the Cohort Expansion Phase.
The purpose of this study is to evaluate the safety and tolerability, pharmacokinetics (PK) pharmacodynamics and preliminary antitumor activity of obrindatamab administered in combination with retifanlimab in patients with B7-H3- expressing tumors.