The final results of the AGO-OVAR 2.29 (ENGOT-ov34) study were published in December 2025.

This large international phase III trial investigated whether the additional administration of the immunotherapy drug atezolizumab together with bevacizumab and non-platinum-based chemotherapy can prolong the survival of patients with recurrent ovarian cancer.
This form of cancer recurs even though platinum-based chemotherapy has already been given and is considered particularly difficult to treat.

A total of 574 patients were randomized in the study and received either the standard treatment (chemotherapy + bevacizumab + placebo) or atezolizumab in addition.

What did the study show?

➡️ No clear survival benefit was found with the addition of atezolizumab:

• The median overall survival (OS) was around 14.2 months with atezolizumab and 13.0 months in the control group – this difference was not statistically significant, i.e. not clear enough to speak of a reliable advantage.

• The median progression-free survival (PFS) – i.e. the time during which the tumor does not grow again – was practically the same with atezolizumab compared to 6.7 months in the control group and also without a statistically proven advantage.

💡 This means that immunotherapy with atezolizumab did not lead to a clear improvement in disease control or prolongation of life when given in addition to bevacizumab and chemotherapy in this study.

What about side effects?

Severe side effects (grade ≥ 3) occurred slightly more frequently in patients receiving atezolizumab (72% vs. 69%), but overall the safety profile was comparable to that already known for the individual drugs.

Was a difference observed depending on PD-L1 status?

The study also investigated whether patients with PD-L1-positive tumors (a possible indication of a better response to immunotherapy) benefit more from atezolizumab. This was not the case – the results were similar regardless of whether the tumor was PD-L1-positive or -negative.

Important contribution to research
Even if these particular results are negative, such large studies are important in order to understand exactly which therapies really help in which situations – and where we still need new approaches.

💡 Standards remain unchanged
For patients with platinum-resistant relapse, the established treatment options, such as chemotherapy with bevacizumab or other effective combinations, currently remain the recommended standard. Immunotherapy such as atezolizumab is currently not demonstrably more effective than standard treatment in this setting.

Source: Publication from ASCO (the article is in English)