Tonix Pharma Announces Promising TNX-801 Vaccine Candidate Findings

Tonix Pharma (TNXP) has announced promising findings for its TNX-801 vaccine candidate, which shows durable immunity against mpox and smallpox with a single dose. The vaccine is significantly less virulent than traditional smallpox vaccines and effective when administered subcutaneously. Preclinical studies demonstrated robust immune responses in various animal models, including immunocompromised subjects.

Tonix Pharmaceuticals Holding Corp. (TNXP) has made significant strides in its development of TNX-801, a recombinant horsepox-derived vaccine candidate designed to prevent orthopox viruses and provide durable humoral and cellular immunity from a single dose. The company presented new findings on TNX-801 at the Vaccine Congress 2025 in Vienna, highlighting its potential to offer robust protection against mpox and smallpox.

TNX-801, up to 100,000-fold less virulent than live smallpox vaccine strains, demonstrated robust immunogenicity and protection against mpox and rabbitpox in animal models. Preclinical studies showed that a single dose of TNX-801 produced strong binding and neutralizing antibody responses across various species, including immunocompromised animals. All vaccinated macaques survived lethal Clade I mpox challenge without lesions, and rabbit models remained fully protected for fourteen months.

One of the notable advancements is the successful subcutaneous (s.c.) administration of TNX-801, which yielded equivalent protection to the traditional percutaneous administration. This route of administration offers potential benefits such as decreased administration-site bacterial superinfection, scarring, and inadvertent transfer to other body sites by itching. The company plans to develop the s.c. product first due to these advantages.

Dr. Sina Bavari, Executive Vice President of Infectious Disease Research and Development at Tonix, noted that TNX-801 dissociates immune protection from some of the side-effects associated with traditional vaccinia-based vaccines, potentially offering a unique risk-benefit profile for mpox and smallpox prevention. The World Health Organization and the Centers for Disease Control and Prevention continue to classify mpox as an ongoing public-health concern, and a single-dose vaccine with the attenuation and immunogenicity profile demonstrated by TNX-801 could streamline outbreak response by reducing the need for approved multi-visit immunization schedules.

Tonix Pharmaceuticals Holding Corp. is a fully integrated biopharmaceutical company with a pipeline of development candidates, including TNX-801 for mpox and smallpox, as well as TNX-102 SL for fibromyalgia management. The company's infectious disease portfolio also includes TNX-4200, a small molecule broad-spectrum antiviral agent targeting CD45 for the prevention or treatment of infections.

[1] https://ir.tonixpharma.com/news-events/press-releases/detail/1582/tonix-pharmaceuticals-announces-presentation-of-new-data-on