The introduction of ADCs into frontline ovarian cancer treatment creates a new challenge: conflicting biomarkers. A patient's tumor might be positive for both HER2 (an ADC target) and a BRCA mutation (a PARP inhibitor target), forcing clinicians to choose between two effective targeted therapies without clear guidance.

The treatment landscape for platinum-resistant ovarian cancer has rapidly evolved into a biomarker-driven paradigm. Clinicians must now test for and choose between therapies targeting distinct markers like folate receptor alpha (mirvetuximab), HER2 (T-DXd), and PD-L1 (pembrolizumab), requiring a sophisticated sequencing strategy.

The B96 trial's potential approval for platinum-resistant ovarian cancer introduces a new treatment sequencing challenge. Clinicians must decide between this immunotherapy combination and the ADC mervituximab, which has a clear biomarker (foliate receptor alpha). The lack of a reliable biomarker for the B96 regimen complicates this decision-making process for patients.

The novel drug relacorilant overcomes taxane resistance in ovarian cancer by targeting glucocorticoid receptors. It blocks stress-induced steroid signaling that promotes anti-apoptotic proteins, effectively re-sensitizing tumors to chemotherapy. This represents a completely new mechanism of action for this patient population.

Unlike in breast cancer, where HER2 IHC 2+ requires FISH confirmation, in gynecologic cancers an IHC 2+ result is often considered directly actionable for prescribing HER2-targeted ADCs like T-DXD. This reflects a different, less stringent clinical standard for biomarker-guided therapy in this setting.

Emerging antibody-drug conjugates (ADCs) targeting folate receptor alpha, such as Sofiem and T-SAM, are demonstrating strong response rates in ovarian cancer patients with both high and low FRα expression, challenging the current high-expression requirement for approved ADCs like mirvetuximab.

Unlike early ADCs requiring high biomarker expression (e.g., mirvetuximab), next-generation agents show efficacy even in low-expressing tumors. This allows for broader, "all-comer" clinical trial inclusion criteria instead of biomarker-gated entry, potentially expanding patient access to these novel therapies.

After a decade with no new therapies improving survival, the landscape for platinum-resistant ovarian cancer is transforming. The recent successes of mirvetuximab, the pembrolizumab/paclitaxel combo, and relacorilant/nab-paclitaxel have all demonstrated statistically significant overall survival benefits, heralding a new era of effective options.

The future of GYN oncology immunotherapy is diverging. For responsive cancers like endometrial, the focus is on refining biomarkers and overcoming resistance. For historically resistant cancers like ovarian, the strategy shifts to using combinatorial approaches (e.g., CAR-NKs, vaccines) to fundamentally alter the tumor microenvironment itself, making it more receptive to an immune response.