Freeze-dried TB vaccine candidate enters Phase 1 human clinical trial

A freeze-dried, temperature-stable formulation of an experimental tuberculosis (TB) vaccine candidate is being tested in a Phase I human clinical trial by researchers from the Infectious Disease Research Institute (IDRI) in Seattle, US.

Many vaccines require a temperature-controlled system during transport, which can be costly and logistically challenging. However, freeze-dried powder vaccines can be distributed at a cheaper cost to remote, low-resource settings.

“To our knowledge, the freeze-dried formulation of ID93 (a recombinant vaccine candidate made from four proteins of Mycobacterium tuberculosis) plus GLA-SE (an immune response-stimulating protein) represents the first time a thermostable vaccine candidate containing a modern immune-boosting substance has reached clinical testing,” said Christopher Fox, PhD and vice president of Formulations at IDRI. “Implementing technologies designed for low-resource settings early in product development could help accelerate vaccine rollout in hard-to-reach areas.”

The trial will enrol as many as 48 healthy adult volunteers, aged 18 to 55 years. The investigators will examine if a freeze-dried powder formulation combining ID93 and the adjuvant GLA-SE in a single vial, reconstituted with sterile water, is as effective at inducing an immune response in participants as the previously tested two-vial combination of powdered ID93 and liquid GLA-SE.

All participants will receive two vaccinations 56 days apart. Half of those enrolled will receive the single-vial formulation and the remaining participants will receive the previously tested two-vial presentation.

Currently, Bacillus Calmette-Guérin (BCG) is the only FDA-approved TB vaccine. It is commonly given to babies in TB-endemic regions to protect children against meningitis and disseminated disease. However, the vaccine does not adequately prevent TB disease in adolescents and adults.

ID93 + GLA-SE is being developed as a vaccine candidate that could be administered to people who have already received the BCG vaccine or have already been exposed to TB, to prevent reactivation or reinfection.

The vaccine was recently shown to be safe and immunogenic in a Phase 2a clinical trial that enrolled adults in South Africa who had recently been cured of TB with standard therapy. Other early-stage clinical trials showed ID93 + GLA-SE is safe and immunogenic in healthy adults in the United States and in BCG-vaccinated adults in South Africa.

“Tuberculosis remains the leading infectious cause of death worldwide, and a highly effective vaccine would be a crucial tool in ending this pandemic,” said National Institute of Allergy and Infectious Diseases (NIAID) Director Anthony S. Fauci, M.D. “A vaccine that did not require a cold chain could be much more easily distributed to communities in need.”