JANX007 is Janux’s lead novel Tumor Activated T Cell Engager (TRACTr). JANX007 is designed to target PSMA, a protein expressed in prostate cancer tumors and the vasculature of tumors and is in development for the treatment of metastatic castration-resistant prostate cancer (mCRPC).
Prostate cancer is the second most common cancer in men, leading to over 34,000 deaths in the United States annually. PSMA is known to be highly expressed in prostate cancer which has led to the development of PSMA-targeted biologics, including T cell engagers (TCEs). A third-party clinical trial with a continuously infused PSMA-TCE (no longer in development) demonstrated clinical benefit, suggesting the potential of a PSMA-TCE approach.
Given the challenges of continuous infusion, other companies are developing traditional TCEs that enable once-weekly or longer dosing. However, clinical trial results with these have shown dose-limiting cytokine release syndrome (CRS) toxicities as single agents, highlighting the limitations of unmasked traditional TCEs.
Unlike existing traditional TCE approaches to prostate cancer that have been limited to-date by dose-limiting toxicities, poor pharmacokinetic (PK) profiles and attenuated efficacy, JANX007 is designed as a highly potent and safer anti-tumor approach to mCRPC. In preclinical studies, JANX007 demonstrated potent cleavage dependent anti-tumor activity and was well tolerated in non-human primates, with limited CRS and healthy tissue toxicities. Additionally, JANX007 exhibited enhanced safety and PK properties relative to unmasked TCEs.
In October 2022, Janux announced that the first patient has been dosed in a Phase 1 clinical trial of JANX007. This trial will assess the safety, tolerability, pharmacokinetic, pharmacodynamic, and the preliminary efficacy of JANX007 as a single agent in adult subjects with mCRPC.