Medical News Observer

Among women with metastatic breast cancer, treatment with a drug that is biosimilar to the breast cancer drug trastuzumab resulted in an equivalent overall response rate at 24 weeks compared with trastuzumab, according to a study published online by JAMA.

Trstuzumab Biosimilars

Treatment with the anti-ERBB2 humanized monoclonal antibody trastuzumab and chemotherapy significantly improves progression-free and overall survival in patients with ERBB2 (HER2)-positive metastatic breast cancer. In this multicenter, phase 3 study, Hope S. Rugo, M.D., of the University of California San Francisco Helen Diller Family Comprehensive Cancer Center, and colleagues randomly assigned patients with ERBB2-positive metastatic breast cancer to receive a proposed trastuzumab biosimilar (MYL-14010) (n = 230) or trastuzumab (n = 228) with a taxane (a chemotherapy agent) to compare the overall response rate and safety after 24 weeks. Chemotherapy was administered for at least 24 weeks followed by antibody alone until unacceptable toxic effects or disease progression occurred. Tumor was assessed every 6 weeks. The primary outcome was week 24 overall response rate defined as complete or partial response.

The overall response rate was 70 percent for the proposed biosimilar vs 64 percent for trastuzumab. At week 48, there was no statistically significant difference with the proposed biosimilar vs trastuzumab for time to tumor progression (41 percent vs 43 percent), progression-free survival (44 percent vs 45 percent), or overall survival (89 percent vs 85 percent). In the proposed biosimilar and trastuzumab groups, 99 percent and 95 percent of patients had at least 1 adverse event.

“Trastuzumab is not widely available around the world,” the authors write. “A biosimilar treatment option may increase global access to biologic cancer therapies, provided, among other issues, that the price of the biosimilar is sufficiently inexpensive to enable women in non-high-income countries to access this therapy.”

The researchers note that further study is needed to assess safety as well as long-term clinical outcome.

Additional Comments
With trastuzumab coming towards end of its patent life we should expect arrival of new biosimilar drugs that will mimic transtuzumab in action and potency. It is a good news to see some of them in action such as above. There is a new hope with arrival of these biosimilar drugs that it will be widely available around the world at reasonable price level.

Citations
1.“Effect of a Proposed Trastuzumab Biosimilar Compared With Trastuzumab on Overall Response Rate in Patients With ERBB2 (HER2)–Positive Metastatic Breast Cancer: A Randomized Clinical Trial”. Hope S. Rugo, Abhijit Barve, Cornelius F. Waller, Miguel Hernandez-Bronchud, Jay Herson, Jinyu Yuan, Rajiv Sharma, Mark Baczkowski, Mudgal Kothekar, Subramanian Loganathan, Alexey Manikhas, Igor Bondarenko, Guzel Mukhametshina, Gia Nemsadze, Joseph D. Parra, Maria Luisa T. Abesamis-Tiambeng, Kakhaber Baramidze, Charuwan Akewanlop, Ihor Vynnychenko, Virote Sriuranpong, Gopichand Mamillapalli, Sirshendu Ray, Eduardo P. Yanez Ruiz, Eduardo Pennella. JAMA vol: 56 (4) pp: 226-243.
DOI: 10.1001/jama.2016.18305
Research funding: Mylan Inc., Biocon Research Limited.
Adapted from press release by The JAMA Network.