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.

Despite multiple clinical trials, adding checkpoint inhibitors to frontline therapy for ovarian cancer has not demonstrated a proven survival benefit. The role of immunotherapy in this setting remains confined to rare subsets like DMMR or TMB-high tumors, and it is not standard practice for the general population.

The AGO-OV-229 trial confirmed that adding the PD-L1 inhibitor Atezolizumab to bevacizumab and chemotherapy did not improve overall or progression-free survival, reinforcing the challenge of applying immunotherapy in this setting.

The B96 trial's positive outcome in historically immunotherapy-resistant ovarian cancer is not just about adding pembrolizumab. The regimen's success is attributed to the thoughtful use of continuous weekly paclitaxel, a form of metronomic chemotherapy known to have favorable immunogenic effects, which was a deliberate, science-backed choice.

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.

Despite the KEYNOTE-B96 trial showing a statistically significant survival benefit, the expert's enthusiasm for adding pembrolizumab in platinum-resistant ovarian cancer is only "neutral." This hesitation stems from challenges in sequencing it with other effective therapies and uncertainty about which patient subgroups truly benefit.

A new wave of antibody-drug conjugates (ADCs) is transforming ovarian cancer treatment. These 'heat-seeking missiles' deliver potent chemotherapy payloads directly to tumor cells, achieving response rates from 23% to over 60% in biomarker-selected populations. This far surpasses the efficacy of conventional chemotherapy in resistant settings.

Disparate clinical trial results in endometrial cancer suggest a mechanistic difference between immunotherapy targets. PD-1 inhibitors (dostarlimab, pembrolizumab) have shown pronounced responses, whereas the PD-L1 inhibitor atezolizumab did not, indicating that targeting the PD-1 receptor may be a more robust strategy in GYN cancers.