US-based clinical-stage biotechnology company Adcentrx Therapeutics announced on Monday that the first patient has been dosed in the Phase 1a/b study of ADRX-0405 for the treatment of advanced solid tumours.

ADRX-0405 is a next-generation antibody-drug conjugate (ADC) composed of a humanised IgG1 antibody targeting six-transmembrane epithelial antigen of the prostate 1 (STEAP1), a cell surface protein that is upregulated in prostate cancer and certain other cancers, yet has limited expression in normal healthy tissue.

The first-in-human Phase 1a/b clinical trial of ADRX-0405 is an open-label dose escalation and dose expansion study being conducted across sites in the United States. It is enrolling patients with certain advanced solid tumours, with the primary objectives of characterising the safety and tolerability of ADRX-0405 and determining its optimal dose. The company anticipates an initial data readout in the fourth quarter of 2025.

Hui Li, PhD, Adcentrx founder and CEO, said: "Advancing our second programme into clinical trials marks an important milestone for Adcentrx and further validates the potential of our ADC technology platform. STEAP1 is an attractive ADC target, and we are excited about the first-in-class potential for ADRX-0405. We believe this novel ADC offers a unique approach to treating patients with STEAP1-expressing cancers, such as metastatic castration-resistant prostate cancer, where a significant unmet need remains for new targeted therapies."