IIMGN151-1001 is a Phase 1, first in human, open-label dose-escalation, optimization, and expansion study designed to characterize the safety, tolerability, pharmacokinetics (PK), immunogenicity, and preliminary antitumor activity of IMGN151 in adult participants with recurrent endometrial cancer; recurrent, high-grade serous epithelial ovarian, fallopian tube, and primary peritoneal cancers; or recurrent cervical cancers. All participants will be, in the opinion of the investigator, appropriate for nonplatinum single-agent therapy for their next line of therapy.