Janux Therapeutics (JANX) Status Update summary

Clinical program and efficacy update

• Interim data for JANX007 show 100% of patients achieving PSA50, 63% reaching PSA90, and 31% achieving PSA99, indicating deep and durable PSA declines in heavily pretreated prostate cancer patients.

• Objective response rate (ORR) is 50% and disease control rate (DCR) is 63% in RECIST-evaluable patients, with robust anti-tumor activity and favorable comparisons to standard-of-care and competitor programs.

• JANX007 demonstrates efficacy in both wild-type and mutant prostate cancer, including those with resistance driver mutations, and is unaffected by prior taxane or ARPI treatments.

• Higher target doses (6 mg and 9 mg) correlate with deeper and more durable responses; a 12 mg cohort is under evaluation for further improvement.

• The drug supports use in combination with enzalutamide and in earlier lines of therapy, with broad applicability across patient populations.

Safety and adverse event profile

• Adverse events are predominantly grade 1 or 2, mainly in cycle one, with grade 3 events rare and transient.

• Cytokine release syndrome (CRS) is predictable, short-lived, and mostly limited to the first cycle; overuse of steroids post-CRS can blunt efficacy.

• No evidence of chronic or cumulative toxicity, with safety attributed to the drug’s design limiting active T-cell engager accumulation in healthy tissue.

• Grade 3 liver enzyme elevations are transient and linked to cytokine release, not direct liver toxicity.

• Serious adverse events are infrequent and primarily related to cytokine release, with improved site management reducing their occurrence.

Clinical development strategy and future plans

• Focus is on pre-Pluvicto, second- and third-line metastatic CRPC, with expansion into earlier lines and combinations with ARPIs planned.

• Two step-dose regimens (6 mg and 9 mg) selected for expansion; 12 mg may be included if durability and safety are confirmed.

• Q2W dosing cohorts are being evaluated for potential maintenance therapy and commercial advantages.

• I-B expansion studies are expected to begin in 2025, with updates on JANX007, JANX008, and other pipeline programs planned.

• Multiple programs are advancing to clinical studies, supported by a robust $658 million cash position as of September 30, 2024, expected to support operations through 2027.