At the 2026 ASCO Annual Meeting, researchers shared updated results from a clinical trial called PRESERVE-004/GOG-3081, which studied a new chemotherapy-free combination treatment for platinum-resistant ovarian cancer. This is a group of cancers that has stopped responding to standard chemotherapy, which often makes treatment more difficult.
What the study tested
The study looked at two therapies used together: gotistobart (an investigational drug) and pembrolizumab (Keytruda). Both treatments help the immune system recognize cancer cells and fight them more effectively, but they work in slightly different ways.
Many patients in the study had already been through several treatments before joining the trial, so this was a group with limited remaining options.
What the results showed
Even in this heavily pretreated group, some patients benefited from the combination. A portion of patients saw their cancer shrink or stay stable for a period of time. Researchers also found that patients in one group lived about 18–19 months on average, which is encouraging in this setting where outcomes are often shorter.
Side effects of the combination
Because these treatments “turn up” the immune system, side effects were fairly common. Some patients experienced inflammation in areas like the colon, liver, or hormone glands. While these side effects could be serious, many were manageable when found early and treated by the care team.
Why these results matter
What makes this study encouraging is that it suggests a chemotherapy-free treatment approach may help some patients even after many prior therapies. In a cancer type where options are limited, even early signs of benefit are meaningful and give researchers a new direction to explore.
What happens next
This is still an early study, so the results need to be confirmed in larger trials. Researchers will also try to understand which patients are most likely to benefit and how to best balance effectiveness with side effects.
For now, these findings offer early hope that new immunotherapy combinations could expand treatment options for people with platinum-resistant ovarian cancer in the future.
Want a summary of ASCO 2026 ovarian cancer highlights? Here’s an overview of key takeaways from this year’s event.
