Janux Therapeutics has announced encouraging results from its Phase 1a clinical trial of JANX007, a T-cell engager being developed for metastatic castration-resistant prostate cancer (mCRPC). The data, presented recently, have led to a surge in the company's stock price and positive assessments from analysts, who believe JANX007 could represent a significant advancement in the treatment of this challenging disease.
The early-stage study enrolled 16 heavily pre-treated patients with advanced prostate cancer. These patients had received a median of four prior treatments. According to the data cutoff on November 15, all 16 patients who had not previously received Novartis' Pluvicto achieved at least a 50% reduction in prostate-specific antigen (PSA) levels, a key marker indicative of treatment benefit in prostate cancer.
Efficacy and Durability
The results indicate promising durability, with 75% of patients experiencing at least a 50% decline in PSA levels maintaining those results for at least three months. Half of the patients who had 90% PSA declines saw their responses hold for at least three months. Furthermore, four of the eight patients who could be evaluated for tumor responses had a partial response to treatment.
Safety Profile
Importantly, the incidence of cytokine release syndrome (CRS) and other treatment-related side effects were largely mild to moderate in severity. Janux reported that the maximum tolerated dose for JANX007 has not yet been reached, suggesting the potential for testing higher doses in future trials. This favorable safety profile is a key differentiator for JANX007, as T-cell engagers are often associated with significant side effects that can limit dosing.
Analyst Perspectives
Analysts have responded positively to the data. William Blair analyst Matt Phipps noted that Janux is "raising the bar" for the treatment of mCRPC, applauding JANX007's efficacy and safety. Leerink Partners analyst Jeffrey La Rosa described the company demonstrated "best-in-disease" effects on PSA and a "best-in-class, differentiated safety profile."
Future Development
Janux has selected doses for Phase 1b expansion trials in patients who are earlier in their disease course and have not yet received Pluvicto. The company anticipates providing updated results next year. According to Janux CEO David Campbell, the company looks forward to rapidly advancing JANX007 into second- and third-line therapy where a substantial unmet need remains.
The mCRPC market is a significant one, with analysts at Stifel estimating it could surpass $10 billion annually in the U.S. alone by next decade. With its promising early data, JANX007 has the potential to become a significant player in this space.
