Real-World Outcomes Explored in Studies of Bevacizumab Biosimilar for Metastatic Colorectal Cancer

Two abstracts presented at the recent 2022 American Society of Clinical Oncology Annual Meeting discussed research on the real-world effectiveness and safety outcomes of patients with metastatic colorectal cancer (mCRC) treated with bevacizumab-awwb.

Bevacizumab-awwb, sold as Mvasi, launched in July 2019 in the United States and was the first biosimilar to the originator product, Avastin, to gain FDA approval. The approval for all oncology indications, including mCRC, was based on extrapolation from a single study of adult patients with advanced non-squamous non-small cell lung cancer.

In one abstract, researchers conducted a retrospective medical chart review to evaluate patient clinical characteristics and outcome data.¹

Patients included in the review were adult patients with a confirmed diagnosis of mCRC who initiated bevacizumab-awwb between July 19, 2019, and April 30, 2020, identified by the Concert AI Definitive Oncology EMR Dataset.

The Kaplan-Meier analysis focused on events of interest and overall survival probability of the subset of patients who initiated first-line bevacizumab-awwb containing therapy with no prior use of Avastin, the reference product for the biosimilar.

Researchers followed the patients from initiation of first-line therapy until death, end of record, or the end of the study period in June 2021.

The median duration of available follow-up data was 10.7 months.

Of the 129 patients who initiated bevacizumab-awwb as a first-line treatment in combination with chemotherapy, 78.3% were treated at clinical oncology practices in a community setting.

Approximately 34.9% of patients had non-metastatic disease at the initial diagnosis; 38.8% had undergone surgical resection.

During the study, 100 of 129 patients had disease progression. Of patients with disease progression, 46 had a record of death.

The analysis showed that 12-month overall survival probability was 71.4% (95% CI, 61.0%-79.5%).

The 20 events of interest that occurred during treatment with bevacizumab-awwb were reported in 18 patients (14%), none of which resulted in death. Generally, reported events of interest were considered manageable.

These findings suggest that biosimilar bevacizumab was well tolerated for patients with mCRC in the real-world setting, according to the authors.

The second abstract and its accompanying poster evaluated the effectiveness and safety outcomes of patients with mCRC initiated on bevacizumab-awwb compared with bevacizumab in an integrated health care delivery system. ^{2, 3}

Researchers conducted an observational cohort study consisting of adult patients with mCRC in Kaiser Permanente California, Colorado, and Mid-Atlantic states who started on bevacizumab-awwb between July 2019 and March 2020 or reference bevacizumab between July 2015 and June 2018.

Researchers excluded patients with history of bevacizumab use in the 6 months prior to the index treatment date.

The study followed patients util 12 months after treatment initiation, end of plan membership, or death.

The primary outcome of the analysis was overall survival, though researchers included secondary outcomes of proportion of bevacizumab-awwb patients switching to the reference and incidence of serious adverse events.

The analysis included 1445 total patients, with 239 starting on bevacizumab-awwb and 1206 initiated on bevacizumab.

Mean (SD) overall age was 60 (13). Of the patients, 54% were male.

The overall survival rate was 72.8% for patients receiving bevacizumab-awwb and 73.1% for patients receiving bevacizumab (P < .01). Therefore, overall survival was non-inferior among patients who received bevacizumab-awwb compared with patients who received bevacizumab.

The adjusted hazard ratio for mortality was 1.01 (0.77-1.33, P = .93).

No statistically significant differences in secondary outcomes between the 2 study groups were found.

The researchers concluded that bevacizumab-awwb is a safe and effective option for the treatment of mCRC when compared with the reference bevacizumab, in line with the other study presented.

However, the authors suggested that future studies evaluate outcomes after longer follow-up times and in different cancer types.

References

1. Jin R, Ogbomo AS, Accortt NA, Lal LS, Bishi G, Sandschafer D, et al. Real-world outcomes among patients with metastatic colorectal cancer treated first line with bevacizumab-awwb. Presented at: ASCO Annual Meeting; June 3-8, 2022; Chicago, Illinois. Abstract e15581.

2. Pham C, Niu F, Delate T, Buchschacher GL, Li Y, Ekinci E, et al. Real-world outcomes of biosimilar bevacizumab-awwb versus reference bevacizumab in patients with metastatic colorectal cancer. Presented at: ASCO Annual Meeting; June 3-8, 2022; Chicago, Illinois. Abstract 3552.

3. Pham C, Niu F, Delate T, Buchschacher GL, Li Y, Ekinci E, et al. Real-world outcomes of biosimilar bevacizumab-awwb versus reference bevacizumab in patients with metastatic colorectal cancer. Presented at: ASCO Annual Meeting; June 3-8, 2022; Chicago, Illinois. Poster 3552.