During ESMO 2019, Researchers Report That Biosimilar SB8 is Equivalent to Avastin in Best ORR

During this week’s European Society for Medical Oncology (ESMO) Congress 2019, held September 27 to October 1 in Barcelona, Spain, a research team presented findings from a phase 3 trial of Samsung Bioepis’ SB8, a proposed bevacizumab biosimilar referencing Avastin.

The study compared the efficacy, safety, pharmacokinetics, and immunogenicity of SB8 to the reference in patients with metastatic or recurrent non-squamous non-small cell lung cancer (NSCLC).

In total, 379 patients were randomized to receive the proposed biosimilar together with paclitaxel and carboplatin every 3 weeks, and 384 were randomized to receive the reference bevacizumab together with the same chemotherapy combination.

Treatment was followed by biosimilar or reference bevacizumab maintenance therapy until disease progression, unacceptable toxicity, death, or 1 year from randomization of the last patient. Baseline characteristics between the patients were well balanced.

The study’s primary endpoint was the best overall response rate (ORR) by 24 weeks of chemotherapy. The risk ratio (RR) was analyzed in the full analysis set (FAS), and the risk difference (RD) was analyzed in the per-protocol set (PPS).

In the FAS, the best ORR was 47.6% in the biosimilar arm versus 42.8% in the reference arm. The RR was 1.11 (95% CI, 0.975-1.269), which fell within the prespecified equivalence margin of 0.737-1.357.

In the PPS, the best ORR was 50.1% in the biosimilar arm and 44.8% in the reference arm. The RD was 5.3% (95% CI, −2.2% to 12.9%). The lower margin was contained within the prespecified equivalence margin of −12.5% to 12.5%, but the upper margin fell outside of this margin.

Median progression-free survival was 8.50 months in the biosimilar arm versus 7.90 months in the reference arm; median overall survival was 14.90 months in the biosimilar arm versus 15.80 months in the reference arm, and median duration of response was 5.60 months in the biosimilar arm versus 5.85 months in the reference arm.

The overall incidence of treatment-emergent adverse events (TEAEs) was comparable between arms, at 92.1% in the biosimilar arm and 91.1% in the reference arm. The most frequently reported TEAEs were alopecia, anemia, and nausea.

Pharmacokinetic parameters, as well as the incidence of antidrug antibodies, were comparable in the 2 treatment arms.

According to the researchers, this study demonstrated equivalence between the proposed biosimilar and its reference in terms of the best ORR risk ratio in patients with NSCLC.

Samsung Bioepis now awaits regulatory action on its marketing authorization application for the biosimilar, which it submitted to the European Medicines Agency for review in July 2019.

Reference

Reck M, et al. A phase III study comparing SB8, a proposed bevacizumab biosimilar, and reference bevacizumab in patients with metastatic or recurrent non-squamous NSCLC. Presented at: European Society for Medical Oncology Congress 2019; September 27 to October 1, 2019; Barcelona, Spain. Abstract 1565P.