Atezolizumab Combo Does Not Significantly Boost Survival in Ovarian Cancer

Combining atezolizumab (Tecentriq) with bevacizumab (Avastin) and non-platinum chemotherapy did not significantly prolong progression-free survival (PFS) or overall survival (OS) among patients with recurrent ovarian cancer, according to data from the phase 3 AGO-OVAR 2.29/ENGOT-ov34 study (NCT03353831) published in the Journal of Clinical Oncology.¹

Data showed a median PFS of 6.4 months (95% CI, 6.1-7.8) for patients who received the atezolizumab combination vs 6.7 months (95% CI, 6.2-8.1) among those who received placebo plus bevacizumab and chemotherapy (HR, 0.87; 95% CI, 0.73-1.04; P = .12). Additionally, the median OS was 14.2 months (95% CI, 13.0-16.1) vs 13.0 months (95% CI, 11.9-15.1) in each respective arm, with 2-year OS rates of 31% vs 23% (HR, 0.83; 95% CI, 0.68-1.01; P = .06).

The atezolizumab regimen produced an overall response rate (ORR) of 40% (95% CI, 34%-46%) vs 44% (95% CI, 37%-50%) with the placebo combination. The median duration of response (DOR) was 8.6 months and 6.1 months in the experimental and placebo arms, respectively (HR, 0.69; 95% CI, 0.51-0.93).

According to subgroup analyses, patients who received prior bevacizumab experienced improved outcomes with the atezolizumab combination for PFS (HR, 0.76; 95% CI, 0.61-0.93) and OS (HR, 0.74; 95% CI, 0.59-0.93). The effect of atezolizumab appeared to be pronounced when combined with paclitaxel rather than pegylated liposomal doxorubicin (PLD), although investigators observed no significant predictive effect for OS or PFS.

“In the AGO-OVAR 2.29/ENGOT-ov34 trial, adding atezolizumab to single-agent non–platinum-based chemotherapy and bevacizumab did not significantly improve PFS or OS… Safety findings were consistent with the known toxicity profiles of the agents investigated,” lead study author Philipp Harter, MD, from the Department for Gynecology and Gynecologic Oncology, Evang at Kliniken Essen-Mitte; Philipps-University of Marburg; and the AGO Study Group in Wiesbaden, Germany, wrote with coauthors in the publication.¹ “Future clinical development is likely to focus on combining various strategies for the most difficult-to-treat populations, using insights from molecular analysis of both positive and negative trials to devise more targeted trials in specific populations.”

In the international, double-blind phase 3 trial, all patients received bevacizumab at 10 mg/kg on days 1 and 15 plus paclitaxel at 80 mg/m² on days 1, 8, 15, and 22 or PLD at 40 mg/m² on day 1 for every 28-day cycle. Additionally, investigators assigned patients 1:1 to receive atezolizumab at 840 mg on days 1 and 15 every 28 days (n = 285) or matched placebo (n = 289).

The trial’s primary end points were PFS and OS across the intent-to-treat (ITT) population. Secondary end points included ORR, DOR, safety, and patient-reported outcomes.

Patients 18 years and older with histologically diagnosed ovarian, fallopian tube, or primary peritoneal cancer; relapsed disease; a maximum of 3 prior therapies; and measurable disease were eligible for enrollment on the trial.² Other eligibility criteria included having an ECOG performance status of 0 or 1; an estimated life expectancy of at least 3 months; and adequate hematological, renal, and hepatic function.

The median age was 62 years (IQR, 56-70) in the atezolizumab arm and 61 years (IQR, 53-70) in the placebo arm. Most patients in each arm had an ECOG performance status of 0 (57% vs 53%), high-grade serous disease (75% vs 80%), 2 prior lines of treatment (39% vs 40%), prior treatment with bevacizumab (74% vs 71%), and PD-L1–negative disease (66% vs 64%).

All patients (100%) experienced adverse effects (AEs) of any grade in the atezolizumab and placebo arms; 72% and 70% of patients in each arm had grade 3 or higher toxicities. Additionally, 64% vs 51% of patients had serious AEs, 16% vs 14% had toxicities leading to discontinuation of atezolizumab or placebo, and 22% vs 19% experienced AEs leading to discontinuation of bevacizumab.

In the atezolizumab and placebo arms, respectively, the most common any-grade AEs included fatigue (63% vs 64%), abdominal pain (40% vs 43%), neuropathy (40% vs 42%), neutropenia (34% vs 26%), and anemia (33% vs 27%). Additionally, grade 3 or higher toxicities in each arm included anemia (8.2% vs 3.5%), gastrointestinal obstruction (7.8% vs 8.4%), fatigue (7.1% vs 5.6%), and neuropathy (6.8% vs 7.0%).

References

1. Harter P, Marmé F, Redondo A, et al. Atezolizumab with bevacizumab and nonplatinum chemotherapy for recurrent ovarian cancer: final results from the placebo-controlled AGO-OVAR 2.29/ENGOT-ov34 phase III trial. J Clin Oncol. 2026;44(2):103-116. doi:10.1200/JCO-25-01210.
2. Atezolizumab with bevacizumab and chemotherapy vs bevacizumab and chemotherapy in early relapse ovarian cancer. ClinicalTrials.gov. Updated April 6, 2025. Accessed January 12, 2026. https://tinyurl.com/2jbapfww