A press release on the initial results of the ENGOT-ov65/KEYNOTE-B96 trial was published in May 2025, and the latest promising results were presented at the ESMO Congress in Berlin at the weekend. This international phase III trial investigated whether the combination of pembrolizumab (an immune checkpoint inhibitor) and paclitaxel (a chemotherapeutic agent), with or without bevacizumab (an angiogenesis inhibitor), can prolong the survival of patients with platinum-resistant ovarian cancer .

The results show: Although the gain in progression-free survival (PFS), i.e. the time until the disease continues to grow, was rather small at around 2 months, this difference was clinically relevant. However, the significant advantage in overall survival (OS) is decisive: patients whose tumors were PD-L1-positive (a marker for response to immunotherapy) lived an average of 18.2 months compared to 14.0 months in the comparison group that only received chemotherapy.

This means that for the first time in this difficult disease, where previous therapies are often only effective in the short term, a real survival benefit has been shown with immunotherapy – and in a patient group that has not been pre-selected.

The safety profile of the combination therapy was also acceptable overall, although grade 3 or higher side effects occurred in around two thirds of patients. Particularly noteworthy: the survival benefit was independent of whether or not bevacizumab was also given.

Experts see these data as a potential turning point in the treatment of platinum-resistant ovarian cancer. Until now, the effectiveness of immunotherapies in this type of cancer has been limited. This could now change, especially for patients with PD-L1-positive tumors.

Nevertheless, experts such as Dr. Rebecca Kristeleit (London) emphasize that the results should be interpreted with caution. The clinical benefit must be weighed against possible side effects and costs. It also remains to be seen whether the combination will be approved in the future or can only be recommended for certain subgroups.

Finally, future combination therapies were also discussed in Berlin: so-called antibody-drug conjugates (ADCs) could be used together with immunotherapies in the future and thus offer further hope for patients with this difficult form of tumor.

Source: ESMO Congress Report (the article is in English)