TB vaccine failure prompts Emergent to take second look -- Gazette.Net


A Rockville biotech might pull its financial backing from a joint venture developing a new tuberculosis vaccine, after a clinical study on infants showed it worked no better than a placebo.

Emergent BioSolutions, whose big money-maker is its anthrax vaccine, was working with Aeras, a Rockville nonprofit that focuses on new tuberculosis vaccines, and with other institutions on the project.

The vaccine is designed to boost immunity that already has been primed by the currently licensed and widely used tuberculosis vaccine, according to a joint statement released Monday.

Emergent is part of the Oxford-Emergent Tuberculosis Consortium, a joint venture with the vaccine’s developer, the University of Oxford (U.K.).

Although the candidate, dubbed MVA85A, was well tolerated in a safety and efficacy study, it did not provide statistically significant protection in preventing tuberculosis in infants previously vaccinated with the current vaccine, Bacille Calmette-Guerin, according to the study.

The study, which was published Monday in the British medical journal The Lancet, showed that the single dose of MVA85A that was given to the subjects did not sufficiently boost immunity more than a placebo.

Emergent, which had been preparing since 2008 to commercialize the vaccine, might not put any more money into the project, which probably will go back to the research stage, CEO Dan Abdun-Nabi said. However, Emergent will continue to support the program in other ways and will help find new partners and new financial avenues, he said.

Emergent posted a profit of $7.4 million for the first nine months of 2012, compared with a net loss of $5.6 million in the prior-year period, according to filings with the Securities and Exchange Commission.

Abdun-Nabi also pointed out that the TB vaccine candidate is the focus of two studies: a two-dose study involving HIV-infected adults and a study in which it is administered before the currently licensed vaccine. The vaccine might prove more effective in those studies, he said.

Officials with the latest trial’s partners, which include a British charity, the Wellcome Trust, will discuss during the next few weeks what to do regarding the other two studies and whether future studies will be conducted, said Thomas Evans, interim CEO of Aeras. Evans took over Friday after former CEO James Connolly resigned for personal family reasons, according to an Aeras statement in December.

More data to be analyzed

While Emergent’s potential withdrawal from the project is a concern because the remaining players would need to find another industrial partner, Evans said he hopes Emergent waits a bit for other data from the latest study before making a decision.

Even though the vaccine didn’t boost immunity more than the placebo, that was a secondary endpoint for the trial. The primary endpoint was to determine its safety.

“The data is being presented essentially as soon as it is known, so there simply hasn’t been the time for the researchers to discuss next steps more fully as yet,” Oxford spokesman Jonathan Wood wrote in an email to The Gazette. He said more can be done through looking at the data from the study in more detail and analyzing blood samples taken from the babies soon after vaccination.

“It should be possible to understand more about the type and level of immune response the body needs to generate against TB. Does it just need to be a greater immune response, or a particular type or something completely different?” Wood said, adding that the study is a step on a “long road” toward an effective vaccine.

“We learned an incredible amount from the study and have a broad pipeline of other studies,” he said. “While these results are disappointing, they’re not a major setback. We’re excited for other uses going forward.”

Evans said the candidate has produced good immunology results when combined with other vaccines, so it has potential there, too.

Abdun-Nabi praised the study, saying that for years many people were skeptical about whether such a study could be conducted on infants. MVA85A is the first novel, preventive tuberculosis vaccine candidate since the current licensed vaccine to complete a phase 2b safety and efficacy study.

The study ran 3.5 years and involved about 3,000 infants in the Western Cape province of South Africa. Infants were chosen because they represent 30 percent of the tuberculosis population, Abdun-Nabi said, adding that if the vaccine had been successful, it would have been “huge” in regard to public health.

“We’re proud to have been associated with this study,” Abdun-Nabi said. “We’re grateful the study was completed successfully, and we think it will be benefit more research in this field for years to come.”

Two billion people, or one out of every three people worldwide, are infected with tuberculosis, according to the World Health Organization. The disease killed 1.4 million people in 2010.

“Vaccine development is an incredibly difficult undertaking, and the scientific community has only become fully engaged in the development of tuberculosis vaccines in the last decade,” Evans said in a statement. “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.”