Janux Therapeutics’ stock plunged after the company released a fresh cut of early‑stage data for JANX007, its masked T‑cell engager in metastatic castration‑resistant prostate cancer. The updated dataset showed a lower response rate than earlier presentations, prompting investors to reprice risk despite Janux characterizing the Phase I safety and pharmacology profile as intact. Company releases and market reports indicate the revised objective response rate and additional patient heterogeneity drove the selloff. Management stressed continued enrollment and that exploratory signals remain for some subgroups, and analysts noted the data do not eliminate the molecule’s potential but do raise questions about durability and selection strategy. The episode illustrates how sensitive equity valuations remain to early oncology readouts and how incremental dataset updates can materially alter investor confidence.