The Rationale of Maintenance With Durvalumab With or Without Olaparib in Patients With Endometrial Cancer

Shannon Westin, MD, MPH, FACOG, a gynecologic oncologist at The University of Texas MD Anderson Cancer Center, discusses the rationale of using durvalumab (Imfinzi), a PD-L1 inhibitor, with or without olaparib (Lynparza).

Westin, who discusses the regimen more at this year’s Society of Gynecologic Oncology (SGO) 2021 Annual Meeting on Women’s Cancer, says that the use of immune checkpoint inhibitors in endometrial cancer is driven by the 30% or so of tumors with microsatellite instability. There is an opportunity for synergy between chemotherapy and immune checkpoint inhibitors like durvalumab. According to Westin, if given together, the tumor is more likely to respond to both.

Cancer tends to recure by evading the immune system, Westin says. This means that continuing on an agent that will stimulate the immune system makes sense once you have a complete response to therapy.

The addition of a PARP inhibitor, like olaparib, may also be highly beneficial, according to Westin. PARP inhibitors have already proven themselves highly active in certain cancers like breast and ovarian cancer, mainly due to homologous recombination deficiency. Westin says that high levels of homologous recombination deficiency have been seen in endometrial cancers. According to her, up to 50% of patients with endometrial cancer or more could be helped by the addition of a PARP inhibitor.