On August 28, 2026 Formosa Pharmaceuticals, Inc. (TWSE: 6838), reported the submission of a Clinical Trial Application (CTA) to European regulatory authorities to conduct a pivotal clinical trial for TSY-110. TSY-110 is a biosimilar candidate referencing Roche’s antibody-drug conjugate (ADC) Kadcyla (ado-trastuzumab emtansine), indicated for HER2-positive metastatic and early-stage breast cancer.
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Designed following regulatory guidance from both US and EU authorities, the upcoming trial will evaluate the safety, tolerability, pharmacokinetics, and immunogenicity profile of TSY-110 compared with the reference product. This milestone advances Formosa Pharmaceuticals’ and EirGenix’s shared goal of providing cost-effective biosimilar ADC treatments to patients across regulated global markets.
"Filing this CTA marks a significant achievement for Formosa Pharmaceuticals and underscores our strategic alliance with EirGenix," said Erick Co, Ph.D., President and Chief Executive Officer of Formosa Pharmaceuticals. "Antibody-drug conjugates have established themselves as mainstays in oncology, including HER2-positive breast cancer care, but patient access remains constrained by high treatment costs. Advancing TSY-110 into clinical evaluation is a momentous step toward fulfilling our goal of delivering world-class, accessible ADC options to oncologists and patients."
About TSY-110
TSY-110, also designated as EG12043, is an antibody-drug conjugate (ADC) biosimilar co-developed by Formosa Pharmaceuticals and EirGenix, Inc. (TWSE: 6589). The conjugate links HER2 monoclonal antibody, trastuzumab, with a cytotoxic payload (mertansine) to selectively eradicate HER2-overexpressing cancer cells while minimizing systemic toxicity. Comprehensive preclinical assessments demonstrate high biosimilarity, drug-antibody ratio (DAR) consistency, and comparable plasma kinetics to the reference product.
About HER2-Positive Breast Cancer Market
HER2-positive breast cancer accounts for a significant portion of all breast cancer diagnoses globally. Approximately 2.4 million breast cancer cases were diagnosed in 2024, with HER2+ disease affecting roughly 360,000 to 480,000 of these patients based on the standard 15–20% prevalence rate. HER2-targeted therapies continue to be a prominent tool in modern oncological care. Kadcyla, approved by the FDA in 2013, generated approximately $2.5 billion in global sales in 2025.
(Press release, Formosa Pharmaceuticals, AUG 28, 2026, View Source [SID1234670411])