Human rhinoviruses (HRV) are the leading cause of common colds and virus-induced exacerbation of asthma and chronic pulmonary diseases. In addition, HRV can cause severe lower respiratory tract infections in children, the elderly, and immune-compromised patients. The economic burden of the common cold is estimated to be about $40B each year in the US in terms of direct medical expenses and lost work and productivity and HRV accounts for more than half of these expenses. A reduction in the rate and severity of common colds would greatly reduce our healthcare burden and improve the quality of life for millions of individuals. Infection with HRV stimulates antibodies that can prevent re-infection by the same virus; however, the immune response is highly serotype-restricted and directed against only the homologous virus. Since there are over 100 serotypes of HRV-A and -B and 50 genotypes of HRV-C, humans typically suffer 2 or 3 HRV illnesses and several more asymptomatic infections each year. The large numbers of serotypes and the serotype-restricted immune responses have complicated the design of HRV vaccines. In a Phase I SBIR-AT grant, BMI produced a set of ten HRV-A antigens that stimulate significantly enhanced cross-serotype neutralizing antibodies. Using algorithms that included sequence alignments, in vitro and in vivo virus evolution studies, and structural epitope analyses, the sites that contribute to the serotype restricted responses were identified. The test antigens contained amino acid substitutions designed to reduce the antigenicity towards these genetically variable, serotype-restricted sites and to redirect immunity towards more highly conserved sites that had been less immunogenic, such as those in the receptor-binding site. Sera from rabbits immunized with the engineered antigens contained unprecedented levels of cross-neutralizing activity which are the direct correlate of protection from infection. Sera from the lead antigen, 39M7, neutralized 41 of the 61 serotypes of viruses tested including 13 of the HRV-B serotypes. The data have been reviewed by independent experts and represents ground-breaking advances in the design of vaccines that are able to stimulate broad immunity against multiple serotypes or strains of viruses. In thi SBIR-AT Phase II application, we propose to continue the development of the 39M7 lead candidate through pre-clinical studies. Our partner, C-PERL will produce 1-gram test lots of the VLP antigen using their innovative insect larva expression system to provide sufficient sample for process development. 1-gram near-GMP lots will be prepared in the final stages of process development and used to assess stimulation of cross-neutralizing antibodies as a function of dose, route, adjuvant, and excipients in non-GLP rabbit studies. cGMP material will be prepared, certified, and tested for immunogenicity and toxicity in mice and rabbits. Because of the specialized nature of the project, we have recruited consultants seasoned in GLP, cGMP, statistical analysis, and other regulatory affairs. The consultants will also assist in meetings wih the FDA and preparation of IND filings. We have also retained long-time collaborator, Dr. Ron Turner, a highly respected pediatric clinical scientist who, in the event of our continued success, will oversee future clinical studies at the University of Virginia. In summary, we have assembled a unique team with disruptive insights and innovative capabilities to develop a vaccine against a pathogen previously thought to be resistant to vaccine technologies. In the process, we have developed a coherent path towards the development and commercialization of a product that could make a significant impact on the overall health of our population while reducing this burden on our national healthcare system.
Human rhinoviruses cause approximately 50% of all common colds which account for an economic burden of about $40B each year in the US. In a Phase I SBIR-AT project, BMI applied its proprietary Immune Refocusing Technology to design a set of 10 novel HRV antigens which were produced as recombinant HRV viruses and as baculovirus-expressed capsid/VLPs. Sera from rabbits immunized with the HRV antigens demonstrated unprecedented cross-neutralized activities. Sera from the best performing antigen neutralized 41 of 61 serotypes tested. We propose to follow up with a Phase II SBIR-AT study designed to develop the leading VLP antigen through pre-clinical studies so that FDA filings and Clinical Trials can be started to analyze the safety and immunogenicity of the vaccines in humans. If successful, the project will lead to the commercialization of the first effective vaccine against human rhinoviruses.
