Biopharmaceutical company Janux Therapeutics Inc (Nasdaq: JANX) on Monday reported positive initial Phase 1 results for JANX011 in healthy volunteers, supporting plans to advance the investigational therapy into clinical studies for autoimmune diseases, initially targeting immune thrombocytopenia (ITP) and rheumatoid arthritis (RA) in 2027.

Acording to Janux, a single subcutaneous dose of 3 mg produced greater than 90% peripheral B-cell depletion in three of five participants, including two whose B-cell counts fell below the limit of detection. Reductions persisted through Day 42. All observed cytokine release syndrome events were Grade 1, with no serious adverse events or dose-limiting toxicities reported among the 25 participants.

The study also demonstrated dose-responsive activation of the intended TRBV6-expressing T-cell subset, with limited activation of other T cells. The findings support the design of Janux's Adaptive Immune Response Modulator (ARM) platform, which aims to achieve targeted and sustained B-cell depletion while limiting broader immune activation.

Janux plans to initiate an ITP study in the first half of 2027, followed by a rheumatoid arthritis study in the second half. The company aims to establish clinical proof of concept and further assess dosing, durability, safety and efficacy.

JANX011 is the first clinical-stage candidate from the ARM platform and is designed to target CD19-positive B cells through selective T-cell recruitment.