On 31 August 2026, Taiwan-based Formosa Pharmaceuticals announced that it has submitted a Clinical Trial Application (CTA) to European regulators for a pivotal clinical trial of TSY-110, biosimilar to Roche’s Kadcyla® (trastuzumab emtansine). Kadcyla® is an antibody drug conjugate (combining Herceptin® with the cytotoxic payload, mertansine), indicated for HER2-positive metastatic and early-stage breast cancer
The clinical trial of TSY-110 will evaluate its safety, tolerability, pharmacokinetics and immunogenicity profile compared with Kadcyla®. The trial has been designed following regulatory guidance from US and European authorities.
TSY-110 (also known as EG12043) was co-developed by Formosa and EirGenix under a March 2022 agreement. According to Formosa, TSY-110 is “positioned to become the first biosimilar alternative to Kadcyla® in major regulated markets”.
The first reported Kadcyla® biosimilar anywhere in the world was Zydus’ Ujvira®, which was launched in India in May 2021. Intas’ trastuzumab emtansine biosimilar received Indian marketing approval in July 2026.
Various trastuzumab emtansine biosimilars are under development including by Biocad (BCD-237; commenced Ph 3 clinical trial enrolment in June 2026) and Zhejiang Hisun Pharmaceutical (HS630; reported results of a nonclinical study of the biosimilar in 2025).