Toxicity and efficacy of biosimilar bevacizumab in the second-line therapy for metastatic colon cancer in routine clinical practice: results of an independent observational study

Abstract

Objective: to compare the efficacy and tolerability of second‑line chemotherapy with original bevacizumab (Avastin) and biosimilar bevacizumab produced by “Biocad” (Avegra) in patients with metastatic colon cancer.Materials and methods. This retrospective observational study included patients with metastatic colon cancer treated in 9 clinics in the Russian Federation. Inclusion criteria were as follows: metastatic or locally advanced colon cancer and second‑line therapy with bevacizumab (Avastin or Avegra). The primary outcome measure was overall survival (OS). Secondary outcome measures included progression‑free survival (PFS), disease control rate (DCR), and incidence of adverse events associated with antiangiogenic therapy.Results. We identified 209 patients with metastatic colon cancer who received second‑line therapy with biosimilar bevacizumab (n = 37; 17.7 %) or original bevacizumab (n = 90; 43 %) or no targeted therapy (n = 82; 39.3 %) between 2014 and 2018. Patients in these three groups were matched for their main prognostic characteristics. The DCR was 59.5 % in the group of biosimilar bevacizumab, 58.9 % in the group of original bevacizumab, and 50 % in the control group (without targeted therapy). PFS was 6 months in the chemotherapy group and 8 months in the groups of bevacizumab (hazard ratio (HR) 0.77; 95 % confidence interval (CI) 0.65–0.91; p = 0.002); the difference in PFS between patients receiving biosimilar bevacizumab and original bevacizumab was insignificant (HR 1.3; 95 % CI 0.81–2.1; р = 0.3). Median OS was 16 months in the chemotherapy group, 30 months in the biosimilar bevacizumab group, and 20 months in the original bevacizumab group (HR 0.89; 95 % CI 0.72–1.1; р = 0.3). We observed a tendency to longer OS in patients receiving biosimilar bevacizumab (HR 0.44; 95 % CI 0.17–1.1; р = 0.08). Bevacizumab‑ associated toxicity was limited to arterial hypertension and was registered in 4 patients with only one patient who developed grade III hypertension.Conclusions. There was no significant difference in PFS between patients receiving biosimilar and original drug, while OS was higher in the group of biosimilar bevacizumab. Both medicines demonstrated similar toxicity. Therapy with biosimilar bevacizumab ensured lower incidence of hypertension and proteinuria compared to the original drug. An additional prospective observational study assessing the efficacy and tolerability of biosimilar bevacizumab in colon cancer patients is needed.

Keywords

• colon cancer
• antiangiogenic therapy
• biosimilars
• bevacizumab
• avastin