Janux Therapeutics disclosed interim data for its lead candidate JANX007, a PSMA‑directed Tumor Activated T Cell Engager, on December 1, 2025. 109 patients were treated across Phase 1a dose‑escalation and Phase 1b expansion cohorts, with a median of four prior lines of therapy in the dose‑escalation group and taxane‑naïve status in the expansion group.
The data show a 30% confirmed or unconfirmed partial response rate among 27 RECIST‑evaluable patients, durable PSA declines, and radiographic progression‑free survival ranging from 7.9 to 8.9 months. Safety was favorable, with cytokine release syndrome limited to cycle 1 and predominantly grade 1 or 2 events, and a mitigation strategy that maintains this profile.
Compared with the December 2024 interim report, which reported a median rPFS of 7.4 months in the Phase 1a cohort, the current data represent a modest improvement but still fall short of the high expectations set by earlier pre‑clinical promise. The report also does not break down the 30% response rate into confirmed versus unconfirmed responses, a detail that analysts noted could temper enthusiasm.
Despite the positive clinical signals, investors reacted negatively, prompting several analysts to lower their price targets. The market’s concern centers on the perceived mixed efficacy—particularly the lack of a confirmed response breakdown—combined with the need for more mature data to demonstrate a clear advantage over established therapies such as Pluvicto. Execution risk and the competitive landscape also contributed to the cautious stance.
CEO David Campbell emphasized that the durable responses and manageable safety profile “compare favorably to both approved and investigational therapies in mCRPC” and highlighted the potential for earlier‑line use. Dr. Eleni Efstathiou, a trial investigator, described the data as “highly encouraging” and underscored the program’s transformative potential for patients.
The interim results support continued development of JANX007 but underscore the necessity of further data to convince the market of its clinical and commercial value. The TRACTr platform remains a promising technology, yet the company must demonstrate clear superiority and a differentiated positioning in a crowded mCRPC market to unlock its full potential.
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