Adding atezolizumab to bevacizumab and platinum-based chemotherapy does not improve progression-free survival (PFS) in patients with recurrent, platinum-sensitive ovarian cancer, according to a study published in the Journal of Clinical Oncology.
This phase 3 trial (ClinicalTrials.gov Identifier: NCT02891824) enrolled patients with recurrent epithelial ovarian cancer who had received 1 to 2 prior lines of chemotherapy and had a platinum-free interval of more than 6 months.
A total of 614 patients were randomly assigned to receive atezolizumab (n=410) or placebo (n=204), each in combination with bevacizumab and platinum-based chemotherapy (carboplatin and gemcitabine, carboplatin and paclitaxel, or carboplatin and pegylated liposomal doxorubicin).
Patients received 6 cycles of chemotherapy and bevacizumab, with or without atezolizumab. This was followed by bevacizumab maintenance until disease progression, unacceptable toxicity, or patient withdrawal. Baseline characteristics were well balanced between the treatment arms.
At a median follow-up of 36.6 months, there was no significant difference in PFS between the treatment arms in the intent-to-treat (ITT) population or among patients with PD-L1-positive tumors.
In the ITT population, the median PFS was 13.5 months in the atezolizumab arm and 11.3 months in the placebo arm (hazard ratio [HR], 0.83; 95% CI, 0.69-0.99; P =.041). The 1-year PFS rate was 56% and 46%, respectively. The 2-year PFS rate was 20% and 12%, respectively.
In the PD-L1-positive population, the median PFS was 15.2 months in the atezolizumab arm and 13.1 months in the placebo arm (HR, 0.86; 95% CI, 0.63-1.16; P =.30). The 1-year PFS rate was 64% and 55%, respectively. The 2-year PFS rate was 28% and 19%, respectively.
There were no significant differences in overall survival (OS) between the treatment arms, but OS data were immature. In the PD-L1-positive population, the median OS was 40.7 months in the atezolizumab arm and 33.6 months in the placebo arm (HR, 0.90; 95% CI, 0.61-1.32).
In the ITT population, the median OS was 35.5 months in the atezolizumab arm and 30.6 months in the placebo arm (HR, 0.81; 95% CI, 0.65-1.01). The 1-year OS rates were 89% and 87%, respectively. The 2-year OS rates were 67% and 62%, respectively. The 3-year OS rates were 49% and 38%, respectively.
Adverse events (AEs) occurred in 88% of patients in the atezolizumab arm and 87% of those in the placebo arm. The rate of grade 3 or higher treatment-related AEs was 33% and 35%, respectively.
There were 5 fatal treatment-related AEs. Three of these occurred in the atezolizumab arm (cardiac arrest, peritonitis, and acute myeloid leukemia), and 2 occurred in the placebo arm (pulmonary embolism and bowel perforation).
“Although PFS differences did not reach statistical significance, preliminary OS results showed an encouraging signal and warrant further analyses with longer follow-up,” the researchers wrote.
Disclosures: This research was supported by F. Hoffmann-La Roche, Ltd. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Kurtz JE, Pujade-Lauraine E, Oaknin A, et al. Atezolizumab combined with bevacizumab and platinum-based therapy for platinum-sensitive ovarian cancer: Placebo-controlled randomized phase III ATALANTE/ENGOT-ov29 trial. J Clin Oncol. Published online August 29, 2023. doi:10.1200/JCO.23.00529