The treatment of platinum-resistant ovarian cancer is an area of ongoing research efforts in the gynecologic oncology community. New treatments for patients with platinum-resistant ovarian cancer, including relacorilant and rinatabart sesutecan (Rina-S), were discussed at the 2025 ASCO Annual Meeting.

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Following these presentations, featured expert Alexander B. Olawaiye, MD, FRCOG, FACOG, FACS, was interviewed by Conference Reporter Medical Director Lauren Weinand, MD. Clinical perspectives from Dr Olawaiye on these findings are presented here.

When treating ovarian cancer, there are no known factors that tell us if the cancer may become resistant to platinum-based chemotherapy. We do know that patients who have suboptimal cytoreductive surgery tend not to have very good outcomes. They may have chemotherapy-resistant tumors, but there are no tests to identify chemotherapy-resistant cancers up front. Historically, there were very few treatment options for platinum-resistant ovarian cancer. In the last few years, however, newer agents have been investigated specifically for treating platinum-resistant ovarian cancer, and one, mirvetuximab soravtansine, has become US Food and Drug Administration (FDA) approved, which is exciting.

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At ASCO 2025, I presented results from the phase 3 ROSELLA trial (abstract LBA5507). ROSELLA is unique because it studied relacorilant, a first-in-class SGRM. Glucocorticoid receptor expression is associated with a worse prognosis in ovarian cancer, so blocking its signaling could benefit patients with ovarian cancer. Its efficacy was first confirmed in a phase 2 trial that reported numerically improved median progression-free survival in patients with platinum-resistant/refractory ovarian cancer.

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At the first interim analysis, ROSELLA met its progression-free survival end point with a hazard ratio of 0.7 and showed a clinically meaningful extension of overall survival, although the data for overall survival are not yet mature. Relacorilant combined with nab-paclitaxel weekly infusion does not require biomarker testing. The trial recruited some groups with very high-risk prognoses, including patients with short platinum-free intervals and those who were previously treated with PARP inhibitors, a group of patients whose ovarian cancer tends to be resistant to subsequent treatment. In a subgroup analysis, we saw that this group benefited from treatment with relacorilant. The adverse events were also manageable, and most were consistent with the toxicities associated with the use of nab-paclitaxel.

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At ASCO this year, the design of the phase 3, randomized, open-label RAINFOL-OV2 study of the ADC Rina-S vs investigator’s choice of chemotherapy in patients with platinum-resistant ovarian cancer was presented by Angeles Alvarez Secord, MD, MHSc (abstract TPS5627). This trial is enrolling patients now, with results to come. The payload in Rina-S is the TOP1 inhibitor exatecan, and the target is folate receptor alpha. In the phase 1/2 RAINFOL-01 trial, more than 90% of patients in cohort B1 had platinum-resistant ovarian cancer and demonstrated a 55.6% objective response rate. The toxicity profile was also acceptable, and the drug appeared to be well tolerated.

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Although not presented at ASCO 2025, the phase 3 MK-3475-B96/KEYNOTE-B96/ENGOT-ov65 trial is evaluating the combination of pembrolizumab plus chemotherapy with or without bevacizumab in patients with platinum-resistant/recurrent ovarian cancer. It was recently announced that the trial is positive at a prespecified interim analysis, but further details have not been released yet. Every time there is something that may improve the outcomes of patients with platinum-resistant ovarian cancer, I am very excited. So, I cannot wait to see further details from the KEYNOTE-B96 trial.