Tonix Pharmaceuticals Holding Corp. presented Phase 1 data for its Lyme‑disease antibody TNX‑4800 at the 4th Annual Ticks and Tick‑borne Diseases Symposium hosted by Johns Hopkins University on April 29‑30, 2026. The presentation, led by a team from UMass Chan Medical School, demonstrated that a single subcutaneous dose of TNX‑4800 was safe, well tolerated, and achieved serum concentrations that could provide protection within two days of exposure to infected ticks.
The Phase 1 study enrolled 44 subjects, 41 of whom completed the trial, and evaluated single subcutaneous doses of 0.5, 1.5, 5, or 10 mg/kg. Results showed protective blood levels at two days post‑dose, with those levels sustained for at least four months thanks to the antibody’s extended half‑life design.
Tonix outlined an adaptive, randomized, double‑blind, placebo‑controlled Phase 2 field study that is expected to begin in the first half of 2027, pending FDA agreement. The study will test a two‑dose regimen—an initial spring dose followed by a summer booster two months later—to evaluate prevention of Lyme disease for six months after the first injection. The design is intended to demonstrate rapid, long‑lasting protection without the multi‑dose schedule required by current vaccine candidates.
"We plan to initiate an adaptive Phase 2 field study in the first half of 2027 pending FDA agreement. We intend to test a two‑dose regimen of TNX‑4800, with the first dose administered in the Spring and a second dose administered two months later, for protection against Lyme disease for six months following the initial dose as the primary endpoint. We believe the Phase 1 pharmacokinetic (PK) data support this study design," said Dr. Seth Lederman, CEO of Tonix. "As a monoclonal antibody, we believe TNX‑4800 offers significant advantages over vaccines in development. Lyme disease vaccines that elicit antibodies to OspA currently in development take more than six months to offer protection and require complex immunization schedules."
"Our study demonstrated potentially protective blood levels of TNX‑4800 at two days, with protective blood levels sustained for at least four months due to its extended half‑life design," said Dr. Mark S. Klempner, Professor of Medicine at UMass Chan and inventor of TNX‑4800. "Additionally, with its differentiated mechanism of action, TNX‑4800 has the potential to provide passive immunity by directly supplying neutralizing antibodies, bypassing the need for a vaccine to induce a patient's immune system to generate its own antibodies, which can be associated with other issues."
Tonix licensed TNX‑4800 from UMass Chan in 2025 and has scheduled a Type C meeting with the FDA early in the third quarter of 2026 to discuss the Phase 2 study design. No FDA‑approved Lyme‑disease prophylaxis exists in the United States; the disease affects an estimated 450,000 people annually and 87 million people live in tick‑endemic areas. This milestone moves the product toward regulatory approval and potential commercialization, but the company remains in a net‑loss position with significant R&D expenses, making its cash runway a critical factor for continued development.
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