TAIPEI, Taiwan, Aug 28, 2026
Formosa Pharmaceuticals, Inc. announced the submission of a Clinical Trial Application (CTA) to European regulatory authorities for a pivotal clinical trial of TSY-110, an antibody-drug conjugate (ADC) biosimilar candidate referencing Roche’s Kadcyla® (ado-trastuzumab emtansine). The candidate is being developed for HER2-positive breast cancer, including metastatic and early-stage disease. The planned clinical study will evaluate the safety, tolerability, pharmacokinetics and immunogenicity of TSY-110 compared with the reference product. The regulatory milestone represents a step forward in the collaboration between Formosa Pharmaceuticals and EirGenix, Inc. to develop potentially more accessible biosimilar ADC therapies for regulated global markets. According to Formosa, TSY-110 is positioned as a potential biosimilar alternative to Kadcyla in major regulated markets, subject to successful clinical development and regulatory approval.
TSY-110 Advances Toward Pivotal Clinical Evaluation
The CTA submission moves TSY-110 into the clinical evaluation stage in Europe, with the planned pivotal trial designed in accordance with regulatory guidance from both U.S. and European authorities. The study will compare the investigational biosimilar candidate with its reference product across key parameters required for biosimilar development, including clinical safety, tolerability, pharmacokinetics and immunogenicity. TSY-110, also designated EG12043, is co-developed by Formosa Pharmaceuticals and EirGenix. The companies are pursuing the program with the goal of establishing a cost-effective biosimilar ADC option for patients and healthcare providers. Formosa said the CTA filing is an important milestone in its strategy to expand oncology development and potentially improve access to targeted cancer therapies. However, TSY-110 remains investigational and is not yet approved for commercial use, with its future availability dependent on clinical results and regulatory review.
ADC Targets HER2-Positive Breast Cancer
TSY-110 is designed as an antibody-drug conjugate targeting HER2-overexpressing cancer cells. The candidate combines the monoclonal antibody trastuzumab with the cytotoxic payload mertansine, creating a targeted therapeutic intended to deliver the cytotoxic component selectively to HER2-positive cancer cells while limiting systemic exposure. According to Formosa, comprehensive preclinical assessments demonstrated high biosimilarity, consistent drug-antibody ratio (DAR) and comparable plasma kinetics relative to the reference product. The development program addresses a significant area of oncology treatment, as HER2-positive breast cancer represents approximately 15–20% of breast cancer cases based on the prevalence estimate cited by the company. Formosa noted that approximately 2.4 million breast cancer cases were diagnosed globally in 2024, corresponding to an estimated 360,000 to 480,000 HER2-positive cases. HER2-targeted therapies remain an important component of modern breast cancer treatment, particularly as the therapeutic landscape continues to expand through biologics and ADC technologies.
Advertisement
Formosa and EirGenix Strengthen Biosimilar Strategy
The TSY-110 program also highlights the strategic capabilities of Formosa Pharmaceuticals and EirGenix across drug development, biologics manufacturing and commercialization. Formosa is developing pharmaceutical products across ophthalmology and oncology, supported by its proprietary APNT® nanoparticle formulation platform and a portfolio that includes biosimilar and novel oncology assets. EirGenix operates an integrated CDMO and product-development business, with capabilities spanning mammalian cell line development, microbial fermentation, research and development, manufacturing and analytical activities. The company also operates cGMP manufacturing facilities and emphasizes quality control and cost management across its vertically integrated operations. The companies aim to leverage these complementary capabilities to advance TSY-110 toward potential commercialization in regulated markets. If clinical development and subsequent regulatory assessments are successful, the program could contribute to broader availability of HER2-targeted ADC treatment while providing an additional biosimilar option in a competitive oncology market. The CTA filing represents an important regulatory milestone for TSY-110 and Formosa Pharmaceuticals’ oncology pipeline. The upcoming pivotal clinical trial will generate comparative clinical data needed to further characterize the biosimilar candidate and support future regulatory submissions. By advancing an ADC biosimilar referencing Kadcyla, Formosa and EirGenix are targeting a biologic oncology segment where treatment effectiveness, manufacturing quality and patient access are increasingly important considerations. Further progress will depend on clinical outcomes and regulatory evaluation in the targeted markets.
Source: Formosa Pharmaceuticals press release
