MVA85A is the first novel, preventive TB vaccine candidate since BCG to complete a Phase IIb safety and efficacy study.
The study was successful in that the vaccine was well tolerated, there was no evidence of any harm to the trial participants, and it gave a clear answer. This study also showed it is possible to conduct a large infant efficacy clinical trial in an area of high TB incidence with robust endpoints for detecting disease, something that is expected to greatly benefit future testing of TB vaccine candidates.
Funding for this clinical trial was provided by Aeras, a nonprofit biotech with a social mission to develop TB vaccines, The Wellcome Trust, and the Oxford-Emergent Tuberculosis Consortium (OETC), a joint venture between the University of Oxford and Emergent BioSolutions. This Phase IIb study was sponsored by Aeras and conducted by the University of Cape Town’s South African Tuberculosis Vaccine Initiative (SATVI). The vaccine was originally developed and investigated by the University of Oxford.
It is anticipated that further analysis of the data and samples collected will be conducted for information that may be helpful for the development of new vaccine candidates. For example, blood samples will be used to identify markers that can predict whether a child will develop TB disease in the future. These biomarkers are termed “correlates of risk” and may substantially aid the development of new vaccines and contribute to different trial designs in the future.
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“Vaccine development is an incredibly difficult undertaking, and the scientific community has only become fully engaged in the development of TB vaccines in the last decade,” said Tom Evans, MD, Aeras interim CEO. “Because of the urgency to control the global TB epidemic, and despite these trial results, we remain steadfast in our belief that an improved TB vaccine will be developed and represents the best hope for eliminating the disease. The valuable scientific understanding gained from this trial will provide crucial information for the robust global portfolio of more than a dozen other TB vaccines undergoing clinical testing, a number that was unimaginable a decade ago.”
“While we are clearly disappointed in the results announced today, this study does demonstrate that a large-scale clinical trial testing a vaccine in infants can be designed and run efficiently, adhering to the highest standards of good clinical trial practices in a setting with a high TB burden,” said Dr. Steve Chatfield, EVP and president of the biosciences division at Emergent BioSolutions, and chairman of the Oxford-Emergent Tuberculosis Consortium. “We are proud to have been part of this broad international collaboration that brought together academic, product development, manufacturing, and clinical trial expertise in an effort to make a positive impact on global health.”
“Completion of the study has been a significant achievement by the MVA85A development partners and demonstrates the advantages of collaboration through a public-private partnership model to address global public health challenges,” said Dr. Jacqui Shea, general manager of OETC. “While MVA85A has not met its efficacy goal, this study should enable the TB vaccine community to better understand the immune response against TB and help to design future efficacy studies.”
"We are proud to have completed the first efficacy trial of a new TB vaccine in 90 years, and believe the results will guide the TB vaccine field in the future,” said Prof. Willem Hanekom, director of the South African TB Vaccine Initiative (SATVI). “The TB epidemic in our country is devastating – half a million South Africans develop the disease every year. Prevention by an effective vaccine would be the best way to get the epidemic under control. With this goal in mind, our group will continue to test multiple new vaccine candidates in the Worcester area. We are very grateful for the commitment of the local community in this effort.”
Dr. Ted Bianco, Director of Technology Transfer at the Wellcome Trust, said: “It is no mean feat to design and implement a trial of this kind and obtain a result as unequivocal as this. It is only through the difficult business of evaluating candidate vaccines in humans that we will really move forward in understanding how we might improve on BCG. I stand in admiration of the professionalism of this international team that understands the importance of well executed science, irrespective of the result one might have hoped for.”
About TB Vaccine Development
BCG is the only licensed vaccine to prevent TB and it is used extensively with approximately 100 million newborns being vaccinated globally each year
, according to the World Health Organization (WHO). While BCG can prevent severe forms of TB in some children, its widespread use in infants has failed to control the global epidemic.
This Phase IIb study was a double blind, randomized, placebo-controlled trial investigating the safety, immunogenicity and efficacy of MVA85A in BCG-vaccinated infants.