CHICAGO, Ill. -- Samsung Bioepis has proved its quality control ability, as the company reached the halfway mark of a six-year follow-up study of its phase 3 clinical trial of Ontruzant, a biosimilar for treating breast cancer.

The company presented the data at a poster session during the American Society of Clinical Oncology (ASCO) 2019 on Sunday, which suggested that the event-free survival (EFS) rates for Herceptin differ based on a shift in the antibody-dependent cell-mediated cytotoxicity activities (ADCC).

Samsung Bioepis had monitored the quality characteristics of Herceptin and found that antibody-dependent cell-mediated cytotoxicity activities (ADCC) were significantly lowered in the original lot from December 2019.

ADCC is a mechanism that allows immune cells to perform a killing function on cancer cells overexpressing the HER2 gene. Regardless of whether the drug is an original drug or a biosimilar, differences in the composition of ADCC occur due to differences in production batches.

Within the Herceptin group, the research labeled patients exposed to at least one shifted ADCC lot as “exposed” and those never exposed to shifted ADCC lot during the neoadjuvant period as “unexposed.”

At a median follow-up duration of 40.8 months in SB3 and 40.5 months in Herceptin, three-year EFS rates were 92.5 percent in SB3, 94.5 percent in Herceptin-unexposed group, and 82.5 percent in Herceptin-exposed. OS rates were 97, 100, and 90.6 percent, respectively.

Samsung Bioepis Senior Vice President of Clinical Sciences Division Kim Chul stands in front of the company’s poster board in ASCO 2019 at the McCormick Place in Chicago, Ill., on Sunday.

“Since biopharmaceuticals are biological agents, quality control is crucial in the manufacturing process,” said Kim Chul, senior vice president for Clinical Sciences Division at Samsung Bioepis. “Through our follow-up study, we have confirmed in part that quality could affect clinical practice.”

The company views that quality control can be a competitive edge for biosimilars. It added, however, the result is not a piece of direct evidence that the shift suggests a clinical impact on patient outcomes.

“It is impossible for the quality standards of biopharmaceutical to be same for every batch,” Kim said. “The company also agrees with the consensus that this is not a piece of direct evidence as the trial was not originally designed to answer these questions statistically.”

The U.S. Food and Drug Administration approved Ontruzant in this past January. Although the timing of the U.S. market launch is unclear due to patent issues, the company has been selling the products in Europe since March 2017.

The U.S. market, which was considered to have a high entry barrier compared to Europe, has recently shown a favorable atmosphere for biosimilars. Such a change was visible during the ASCO 2019 poster presentation, as many attendees showed high interest in Samsung’s presentation, according to Samsung executive.

“The importance of biomedicine manufacturing quality management is becoming more and more emphasized,” Kim said. “Global consensus is also changing that manufacturing quality can also impact clinical outcomes.”

By strengthening quality control standards, Samsung Bioepis will secure differentiated competitiveness in the U.S. and global markets, he added.

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