Bevacizumab can reduce the risk of progression in patients with ovarian cancer for about 1 year after treatment initiation, but discontinuing the drug increases the risk of progression, according to research published in JAMA Network Open.
Researchers found that bevacizumab initially prolonged progression-free survival (PFS), when compared to standard treatment, but discontinuing the drug resulted in a rebound of tumor growth, and patients treated with bevacizumab ultimately had worse PFS than patients who received standard treatment.
In this cohort study, researchers analyzed data from ovarian cancer patients enrolled in 7 phase 3 randomized clinical trials of bevacizumab (ICON7, GOG-0218, BOOST, GOG-0213, OCEANS, AURELIA, and MITO16B).
Ancillary analyses of the ICON7 trial were used to generate the ICON7-A cohort, which included 745 patients treated with bevacizumab (n=384) or standard treatment (n=361).
Overall, there was no significant difference in PFS between the bevacizumab and standard therapy groups in the ICON7-A cohort (restricted mean survival time ratio [RMSTR], 1.07; 95% CI, 0.97-1.17; P =.16).
However, prior to discontinuation of bevacizumab, patients in that arm had significantly longer PFS than patients in the standard treatment arm (RMSTR, 1.08; 95% CI, 1.05-1.11; P <.001).
After bevacizumab discontinuation, patients treated with bevacizumab had significantly worse PFS than those in the standard treatment arm (RMSTR, 0.79; 95% CI, 0.69-0.90; P <.001).
A post hoc analysis was conducted to determine whether this association would be seen in certain subgroups. In patients with nonserous histology, PFS was improved with bevacizumab before discontinuation (RMSTR, 1.11; 95% CI, 1.05-1.18; P <.001), but there was no significant difference in PFS between the treatment arms after bevacizumab discontinuation (RMSTR, 0.94; 95% CI, 0.78-1.15; P =.57).
In patients with serous ovarian cancer, PFS was improved with bevacizumab before discontinuation (RMSTR, 1.07; 95% CI, 1.04-1.11; P <.001), but PFS was inferior in the bevacizumab arm after discontinuation (RMSTR, 0.74; 95% CI, 0.62-0.87; P <.001).
Patients with serous histology were also examined on the basis of homologous recombination deficiency (HRD) status. In patients with HRD, bevacizumab was associated with improved PFS prior to discontinuation (RMSTR, 1.05; 95% CI, 1.02-1.09; P <.001) and worse PFS after discontinuation (RMSTR, 0.79; 95% CI, 0.63-0.98; P =.04).
For patients without HRD, bevacizumab was associated with improved PFS prior to discontinuation (RMSTR, 1.08; 95% CI, 1.03-1.15; P <.001) and worse PFS after discontinuation (RMSTR, 0.71; 95% CI, 0.56-0.90; P =.004).
Results from the GOG-0218 trial were similar to those seen with the ICON7 data. However, there was no apparent rebound effect in the GOG-0213, OCEANS, AURELIA, and MITO16B trials, in which bevacizumab treatment was not stopped until disease progression.
“The findings of this cohort study suggest that the association of bevacizumab administration with the risk of ovarian cancer progression varies over time,” the researchers concluded. “Considering that rebound occurs after completion of bevacizumab in the first-line treatment of serous ovarian cancer, bevacizumab may be most useful for patients who are less likely to be affected by the rebound, ie, those with an expected survival of less than 1 year.”
Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Takamatsu S, Nakai H, Yamaguchi K, Hamanishi J, Mandai M, Matsumura N. Time-dependent changes in risk of progression during use of bevacizumab for ovarian cancer. JAMA Netw Open. Published online August 2, 2023. doi:10.1001/jamanetworkopen.2023.26834
This article originally appeared on Cancer Therapy Advisor