Biosimilar comparable to trastuzumab in efficacy for breast cancer subset
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HD201, a trastuzumab biosimilar candidate, demonstrated equivalent efficacy to referent trastuzumab among patients with ERBB2-positive early breast cancer, according to phase 3 study results published in JAMA Oncology.
The agents also had similar safety profiles.
Rationale and methods
“Trastuzumab [Herceptin, Genentech] has dramatically changed the natural history of [ERBB2-positive breast cancer],” Xavier Pivot, MD, PhD, researcher at the Institute of Cancer Strasbourg in France, told Healio. “However, in many countries, patients have only limited access due to the high costs. The need for less expensive alternatives to trastuzumab can potentially be met by the introduction of new biosimilars. In this context, HD201 [Prestige BioPharma Ltd.] was developed, and this published study represents the ultimate steps in the development.”
Pivot and colleagues sought to evaluate and compare HD201 with trastuzumab in the neoadjuvant setting for eight cycles plus four cycles of docetaxel, followed by four cycles of epirubicin and cyclophosphasmide, among 502 women (mean age, 53 years) with ERBB2-positive early breast cancer receiving treatment across 70 centers in 12 countries. Overall, the study included 195 (38.8%) women with hormone receptor-negative tumors and 213 (42.4%) with clinical stage III disease. Following surgery, women received 10 cycles of adjuvant HD201 or trastuzumab.
Total pathologic complete response after neoadjuvant therapy served as the primary endpoint. Other objectives included breast pathologic complete response, overall response, EFS, OS, safety, pharmacokinetics and immunogenicity.
Median follow-up was 31 months.
Key findings
Researchers reported that 474 women (94.2%) were eligible for inclusion in the per-protocol set.
Results showed total pathologic complete response rates of 45% with HD201 and 48.7% with trastuzumab, with an insignificant difference between the two arms of 3.8 percentage points (95% CI, 12.8 to 5.4). The two arms had a total pathologic complete response rate ratio of 0.92 (95% CI, 0.76-1.12).
Overall, 433 patients (86.1%) experienced 2,232 treatment-emergent adverse events of special interest for trastuzumab during the entire treatment period, including 220 patients (88%) assigned HD201 and 213 patients (84.5%) assigned trastuzumab.
“HD201 is equivalent to trastuzumab in terms of efficacy and toxicity,” Pivot said. “All sensitivity analysis and secondary endpoints confirmed the robustness of this claim.”
Implications
“This study represents the ultimate step in the comparability exercise demonstrating the equivalence between HD201 and trastuzumab,” Pivot told Healio. “The next step will be the approval for routine use by regulatory agencies.”
For more information:
Xavier Pivot, MD, PhD, can be reached at Institute of Cancer Strasbourg, 17 rue Albert Calmette, 67033, Strasbourg, France; email: x.pivot@icans.eu.
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