RE:RE:CD8+ TiLs and T-cell exhaustion Phase 1 data released in February 2024 from JANX007’s first-in-human Engager-PSMA-01 study, in metastatic castration-resistant prostate cancer patients as a median fifth-line therapy, used a stepwise dose escalation that focused on 18 of the 23 evaluable patients; these subjects had received a first JANX007 dose of at least 0.1mg, and Janux claimed a 56% rate of ≥50% PSA reduction.
On limited data, analysts zeroed in on just six patients given a first step dose of at least 0.2mg showed a PSA50 response of 83%. On this limited data, Evercore ISI’s Jonathan Miller called this the best early data he’d seen in metastatic castration-resistant prostate cancer, citing PSA50 rates of 52% for Ambrx’s ARX517 and 49% for Amgen’s AMG 509 in broadly similar populations. Prior to this data release in February Janux was trading at approximately US$8.00 before jumping to US$64.78 in May 2024.