This is a Phase 1/2, open-label, non-comparative, multicenter, multi-arm study of the Wilms Tumor-1 (WT1)-targeting multivalent heteroclitic peptide immunotherapeutic vaccine galinpepimut-S in combination with the programmed death-1 (PD1) inhibitor pembrolizumab in patients with selected advanced cancers. This study will assess the efficacy and safety of galinpepimut-S and pembrolizumab and investigate the effect of galinpepimut-S and pembrolizumab on various tumor types. Patients will be followed long-term for OS and safety. The study will enroll approximately 90 patients at up to 20 centers in the United States.~Indications treated are colorectal (third or fourth line), ovarian (second or third line), small cell lung cancer (second line), breast cancer (triple negative; second line), acute myelogenous leukemia (unable to attain deeper morphological response than partial [PR] on hypomethylating agents and who are not eligible for allogeneic hematopoietic stem cell transplant).~The first 2 galinpepimut-S injections will initially be administered as monotherapy every 3 weeks (Week 0 and Week 3). Thereafter, galinpepimut-S will be co-administered with pembrolizumab every 3 weeks for 4 additional administrations (for the galinpepimut-S initial immunization induction phase series; weeks 6-15) to coincide with the per label pembrolizumab dosing frequency. After that, there will be one un-paired administration of pembrolizumab (week 18), and then galinpepimut-S will be resumed on an every 3-week schedule for 6 additional doses (early immune booster phase; weeks 21-36). At the end of this phase, there will be a 12-week interval where 3 unpaired administrations of pembrolizumab will occur (weeks 39-45), and then galinpepimut-S will be resumed on an every 12-week schedule for 4 additional doses (late immune booster phase; weeks 48-84). After 84 weeks, continuing non-progressed patients will be treated with pembrolizumab alone up until week 111.~Pembrolizumab will be administered at a dose of 200 mg intravenously every 3 weeks on Day 1 of each cycle (3 week cycles) starting on Study Week 6 and continuing for up to 2 years thereafter (Study Week 111). Galinpepimut-S will be administered 30-60 minutes after the completion of IV infusion of pembrolizumab on Day 1 of each cycle during which the 2 drugs are being co-administered.
To evaluate the safety and tolerability of galinpepimut-S in combination with pembrolizumab in patients with selected advanced cancers. Patients will be followed long-term for Overall Survival (OS) and safety. The study will enroll approximately 90 patients and maximum study treatment duration is approximately 2.13 years.