Adcentrx Therapeutics, a California-based clinical-stage biotechnology company announced on Tuesday that the US Food and Drug Administration (FDA) has granted orphan drug designation to ADRX-0405, for the treatment of patients with gastric cancer.

ADRX-0405 is a clinical-stage next-generation Antibody-Drug Conjugate (ADC) targeting six-transmembrane epithelial antigen of the prostate 1 (STEAP1), a cell surface protein that is upregulated in prostate cancer and certain other cancers with limited expression in normal healthy tissue.

ADRX-0405 is a STEAP1 ADC being evaluated in the Phase 1a portion of an ongoing Phase 1a/b clinical trial (NCT06710379) for the treatment of select advanced solid tumours, including metastatic castration resistant prostate cancer, gastric cancer, and non-small cell lung cancer.

While STEAP1 is primarily associated with prostate cancer, there is a meaningful amount of target expression in gastric cancer, making this a potential indication of interest for future clinical development.