Tonix enrolled 44 healthy adults in a single‐dose, placebo‐controlled Phase 1 study of TNX-4800 at 0.5, 1.5, 5 and 10 mg/kg. The injection was well tolerated, with no significant clinical or laboratory safety signals and mostly mild to moderate adverse events reported.

TNX-4800 achieved peak serum levels within two days and maintained quantifiable concentrations beyond 200 days in 80% of low‐dose subjects and up to 350 days at higher doses. Mean half-life ranged from 62 to 69 days and the 5 mg/kg cohort sustained serum levels about twice the minimum effective concentration at four months.

Pending FDA clearance, the company will launch a randomized, double‐blind, placebo‐controlled adaptive Phase 2 field study in H1 2027 using a fixed 350 mg subcutaneous dose. The trial will enroll adolescents and adults in Lyme‐endemic U.S. areas, with prevention of confirmed Lyme disease at four months as the primary endpoint and prevention at six months as a key secondary endpoint.