Janux Therapeutics (San Diego, USA) announced the discontinuation of its clinical development program for JANX008, an EGFR-targeted Tumor Activated T Cell Engager (TRACTr). The decision was taken following completion of the Phase I dose escalation and expansion portion of a Phase I/Ib study in advanced or metastatic solid tumors, and is reflected in the registry record for NCT05783622.
Initiated in March 2023, open-label, multicenter study enrolled patients across multiple solid tumor indications including non-small cell lung cancer, renal cell carcinoma, and squamous cell carcinoma of the head and neck, with a planned enrollment of 80 patients. Primary objectives centered on safety, tolerability, and early activity assessment across dose escalation and expansion cohorts.
The sponsor said the decision followed an internal review of Phase Ia data measured against predefined development criteria, noting that while durable responses were observed in a subset of patients, the overall magnitude and consistency of activity were not sufficient to support continued investment relative to other pipeline programs. No clinical data were released. The company did disclose that cytokine release syndrome was infrequent and predominantly Grade 1, and that musculoskeletal adverse events were dose-limiting, a finding it attributed to EGFR target biology rather than the TRACTr format itself.
Janux has four active clinical programs remaining. Its lead asset, JANX007, is a PSMA-targeted TRACTr in Phase I evaluation for metastatic castration-resistant prostate cancer. JANX014, a double-masked PSMA TRACTr, is also in Phase I, as is JANX011, a CD19-targeted Adaptive Immune Response Modulator being assessed in healthy volunteers for autoimmune indications. JANX013, a CD28 co-stimulatory Tumor Activated Immunomodulator, is designed for combination use with JANX007. The company framed the JANX008 discontinuation as program-specific and said it does not alter the broader TRACTr platform strategy.