Emerging ADC Targets Beyond HER2 and CD30
Antibody Drug Conjugates (ADCs) have revolutionized targeted cancer therapy, initially focusing on well-characterized tumor markers such as HER2 and CD30. However, a new wave of innovation is broadening the spectrum of viable targets, propelling the Antibody Drug Conjugate Market into a transformative phase of diversification and personalized oncology.
Beyond HER2, emerging targets like TROP-2, CEACAM5, LIV-1, and B7-H3 are gaining traction in preclinical and clinical studies. These targets are often overexpressed in a wide range of solid tumors, including triple-negative breast cancer (TNBC), non-small cell lung cancer (NSCLC), and colorectal cancers, representing a high unmet need segment. TROP-2, in particular, has shown promise in clinical trials, with agents like sacituzumab govitecan already making their mark.
Similarly, CEACAM5, a carcinoembryonic antigen, is being explored for its selective expression in gastrointestinal malignancies. Targeting these markers allows researchers to expand ADC application into tumors previously thought untreatable with conventional antibody-based therapies.
Another notable advancement is the focus on antigens expressed in the tumor microenvironment or cancer stem cells. This shift enables a broader mechanism of action, addressing tumor heterogeneity and overcoming resistance. For example, ROR1 (Receptor tyrosine kinase-like Orphan Receptor 1) is under investigation for its expression in a variety of malignancies with minimal presence in normal adult tissues—an ideal target for ADCs.
The exploration of novel targets is not without challenges. Heterogeneous antigen expression and potential cross-reactivity with healthy cells require a meticulous design of the ADC architecture, including highly specific monoclonal antibodies and optimized linkers that remain stable in circulation but release the payload efficiently within the tumor.
Furthermore, the development of bispecific antibodies that can bind to more than one tumor marker is expanding the possibilities even further. By targeting two or more antigens, these ADCs can offer enhanced tumor selectivity and cytotoxic delivery while reducing off-target effects.