Janux Therapeutics Stock Hits 52-Week Low After Trial Update

Core Viewpoint - Janux Therapeutics Inc. has experienced a significant decline in stock price following the release of interim data for its JANX007 Phase 1 program targeting metastatic castration-resistant prostate cancer (mCRPC) [1] Patient Data - A total of 109 patients have been treated in the Phase 1a dose escalation and Phase 1b expansion trials of JANX007 as of the data cutoff on October 15, 2025 [1] - Patients in the Phase 1a trial had a median of four prior lines of therapy, while those in the Phase 1b trial were taxane-naïve [2] Efficacy Results - High prostate-specific antigen (PSA) response rates and significant PSA declines were observed in patients from the Phase 1 trials [3] - Anti-tumor activity was noted with confirmed and unconfirmed partial responses in 30% (8 out of 27) of RECIST-evaluable patients [3] - Radiographic progression-free survival (rPFS) ranged from 7.9 to 8.9 months, with the Q2W expansion group showing favorable results compared to the QW expansion group [4] Safety Profile - JANX007 exhibited a manageable safety profile, with cytokine release syndrome (CRS) primarily occurring in cycle 1 and at grades 1 and 2 [5] - A CRS mitigation strategy was identified that maintains the grade 1 and 2 CRS profile [5] Development Strategy - Janux is focusing on advancing JANX007 as a monotherapy and in combination with darolutamide for taxane-naïve mCRPC patients, and plans to evaluate it in PARP inhibitor-refractory patients for expedited approval [6] Analyst Commentary - Analysts from William Blair noted that the decline in Janux shares is an overreaction based on the overall data from various dosing regimens and CRS mitigation strategies [7] - Analyst Matt Phipps highlighted that despite some criticisms, the potential for JANX007 to achieve a best-in-disease profile and blockbuster sales remains strong [8] - The next update from the Phase Ib trial is anticipated in 2026, which is expected to restore investor confidence in the program [8] Market Reaction - Janux Therapeutics shares were reported down 47.82% at $17.73 at the time of publication [9]