Janux Therapeutics’ stock plunged after the company released a new early-stage data cut showing a lower-than-expected response rate for JANX007, its masked T-cell engager in metastatic castration‑resistant prostate cancer. The update reduced investor expectations despite management framing the safety and other biomarker signals as still supportive of continued development. Analysts noted the market reaction reflected recalibrated probability of success for TCE programs in solid tumors, where efficacy and tolerability balance is challenging. Janux will likely need additional cohorts or combination strategies to restore confidence. The setback underscores investor sensitivity to early immuno-oncology readouts and the high bar for T-cell engagers in prostate cancer.