PSMA-TRACTr (JANX007)
In December 2025, Janux announced updated interim data for JANX007.
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 the clinic for the treatment of metastatic castration-resistant prostate cancer (mCRPC).
Prostate cancer is the most common type of cancer in men and the second most common type of cancer overall in the United States. 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.
We designed our PSMA-TRACTr drug candidate as a single-masked TRACTr in which the PSMA-binding domain is unmasked. The T cell-specific binding domain, CD3, is masked to help minimize CRS.
Traditional T cell engager approaches in prostate cancer have been limited by dose-limiting toxicities, suboptimal pharmacokinetic (PK) profiles, and constrained efficacy. JANX007 is a tumor-activated PSMA-TRACTr designed to enable potent anti-tumor activity with a differentiated safety and pharmacokinetic profile in metastatic castration-resistant prostate cancer (mCRPC).
Clinical data from JANX007 have demonstrated encouraging antitumor activity, including meaningful PSA reductions and objective tumor responses, with a manageable safety profile in patients with mCRPC. The program has advanced into taxane-naïve mCRPC expansion cohorts evaluating optimized dosing regimens designed to improve tolerability and durability of response. JANX007 is also being evaluated in combination with darolutamide to explore opportunities to further enhance clinical benefit.