Study CP-MGD019-03 is an open-label study of lorigerlimab in participants with platinum-resistant ovarian cancer (PROC) or clear cell gynecologic cancer (CCGC). Approximately 80 participants will be enrolled. The study will assess the efficacy and safety of lorigerlimab in participants with PROC or CCGC.

Participants will receive lorigerlimab by intravenous (IV) infusion on Day 1 of every 21-day treatment cycle. Treatment cycles will continue until progression of cancer, unacceptable side effects, withdrawal of consent by the participant, or the study ends.

Participants will be monitored closely for side effects by physical exam and routine laboratory tests every cycle. Tumor status will be checked approximately every 9 weeks for the first year, then every 12 weeks for the duration of treatment. Participants will have a safety followup performed within 30 days after treatment discontinuation. Participants who discontinue study treatment for reasons other than progression of cancer, will continue CA-125 and tumor assessments every 12 weeks. Participants who discontinue study treatment for progression of cancer will enter the 6-month survival follow up portion of the study.

Inclusion Criteria:

• Histologically confirmed high-grade serous epithelial ovarian cancer, including primary peritoneal, or fallopian tube cancer, resistant to platinum based chemotherapy. OR
• Histologically confirmed clear cell carcinoma of the ovary (including primary peritoneal and fallopian tube), endometrium, vagina, vulva, or cervix.
• Persistent or recurrent disease with documented disease progression.
• Participants with PROC must have received at least 1 but not more than 3 prior lines of therapy for PROC.
• Participants with CCGC must have received at least 1 prior line of therapy for CCGC.
• Participants with a known breast cancer (BRCA) mutation (germline or somatic) must have received a Poly ADP-ribose polymerase (PARP) inhibitor, if locally approved and available, and experienced disease progression or intolerance on the PARP inhibitor.
• Participants must have at least one lesion that meets the definition of measurable disease by RECIST v1.1.
• Participants must have an available archival or formalin-fixed paraffin-embedded tumor tissue, or be willing to undergo a biopsy procedure to obtain a fresh tumor sample.
• Participants have acceptable physical condition and laboratory values.
• Participants of childbearing potential must agree to use highly effective methods of birth control.
• Participants must not be pregnant, planning to be pregnant, or breastfeeding.

Exclusion Criteria:

• Any underlying medical or psychiatric condition impairing participant's ability to receive, tolerate, or comply with the planned treatment or study procedures.
• Primary platinum-refractory disease, defined as disease that did not respond to (CR or PR) or has progressed within 3 months of the last dose of first-line platinum- containing chemotherapy.
• Prior treatment with a checkpoint inhibitor (e.g., anti-PD-1/PD-L1, anti-PD-L2, anti-CTLA-4). Prior use of immune checkpoint inhibitors (e.g., anti-PD-1, anti-PD-L1, anti-CTLA-4) is allowed for clear cell endometrial and clear cell cervical cancer.
• Active brain metastases or leptomeningeal metastases.
• Prior stem cell, tissue, or solid organ transplant.
• Paracentesis (removal of fluid from the abdomen) within 4 weeks prior to initiation of study treatment.
• Another hematologic or solid tumor ≥ stage 1 malignancy that completed surgery, last dose of radiotherapy, or last dose of systemic anti-cancer therapy ≤ 3 years from first dose of study treatment. Participants with another tumor that has a negligible risk for metastasis or death such as, adequately controlled basal-cell carcinoma or squamous-cell carcinoma of the skin, or carcinoma in situ of the cervix or breast are eligible.