IDRI wins potential US$11.9m contract to develop thermostable TB vaccine

Will use freeze-drying process to overcome cold-chain transportation issues

Dr Christopher Fox of IDRI leads efforts to develop a thermostable tuberculosis vaccine

The Infectious Disease Research Institute (IDRI), based in Seattle, US, has been awarded a contract from the National Institute of Allergy and Infectious Diseases, to develop a thermostable lyophilised formulation of its vaccine candidate to prevent tuberculosis.

The contract is initially worth US$3.6m; this could be rise to $11.9m if all milestone-driven options are exercised.

'You can have the best vaccine in the world, but if it's damaged during the delivery process, it does no good,' said Steven Reed, IDRI President, Founder and Chief Scientific Officer.

'Thermostable vaccines could have great economic and health benefits for the recipients by ensuring that vaccines are intact and effective when delivered.'

According to Doctors Without Borders, the need to maintain vaccines in a temperature-controlled supply chain all the way to the patient is one of the biggest barriers to effective vaccination, particularly when they live in remote areas. Vaccines lose potency over time, with the rate of potency loss related to temperature; most currently used vaccines have a shelf life of two years or longer only if they are continuously stored at refrigerated conditions of 36–46ºF.

Thermostable vaccines could have great economic and health benefits for the recipients

'Too often in vaccine development, the question of deliverability isn't asked until it's too late in the process,' said Christopher Fox, Director of IDRI's Adjuvant Formulations Program, who will lead the team of scientists at IDRI.

'We are nimble enough that we can get in the door with a new process early in the development cycle that addresses this issue, including the added challenge that comes with lyophilising vaccines containing complex multi-component formulations.'

Next-generation vaccines such as IDRI's TB vaccine contain both an antigen and an adjuvant. However, the two components are often kept in separate vials that must be mixed in exact proportions just in advance of the vaccine being administered, and the cold-chain process must be maintained for long-term stability. Using lyophilisation – or freeze-drying – increases the shelf life of a vaccine and addresses the issue of maintaining the cold chain.

IDRI's vaccine component, ID93 (which consists of a recombinant fusion of four TB antigens), has recently completed a Phase 1 clinical trial demonstrating good safety at different doses in healthy adult volunteers. The adjuvant component, GLA-SE, was evaluated with ID93 as a liquid mixture in the same clinical trial at two different adjuvant doses, and maintained a good safety profile.

The ultimate test will be completing a Phase 1 clinical trial that shows safety and immunogenicity of a lyophilised adjuvanted vaccine

'To provide the foundation for our product development plan for this contract, IDRI conducted successful preliminary studies showing that ID93 and GLA-SE can be co-lyophilised to generate a single-vial dried vaccine that maintains protective biological activity even after exposure to 122ºF for one month,' said Fox. The results of those preliminary studies were published in the Journal of Controlled Release earlier this year.

'The ultimate test will be completing a Phase 1 clinical trial that shows safety and immunogenicity of a lyophilised adjuvanted vaccine,' he added.

According to Fox, the result of this contract will be the first clinical emulsion-based adjuvant formulation to be successfully lyophilised.

'To our knowledge, no one has demonstrated being able to lyophilise an oil-in-water emulsion-based adjuvant that maintains the same physicochemical properties after reconstitution as it had before lyophilisation, so this will be a new step in creating temperature stable vaccines for the future,' he said.

IDRI's partners for this contract include Lyophilization Technology, a contract development and manufacturing organisation (CDMO), which provides lyophilisation services for the development of healthcare products.

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