The novel drug-delivery system, developed by undergraduate biomedical engineering students at the university, promises to save on storage and transport costs where current rotavirus vaccines in liquid form fail. This would be particularly advantageous in impoverished areas. The thin film vaccine takes its idea from a breath-freshener, allowing the medication to be swallowed after the film melts in the mouth, and delivered to the small intestine where it triggers an immune response.
"The idea is that you would place one of these dissolving strips on the infant's tongue. Because the strips are in a solid form, they would cost much less to store and transport than the liquid vaccine. We wanted this to be as simple and as inexpensive as possible," John Hopkins University department of materials science and engineering and Whitaker Biomedical Engineering Institute associate professor Hai-Quan Mao said. To protect the vaccine from stomach acid, the vaccine has been coated in a top-secret but FDA-approved biocompatible polymer. It is pH-responsive, so it can deliver its medical payload only when the acid-alkaline level in its environment is appropriate.
"The most important aspect of this technology is the polymer coating that makes the mucosal delivery more efficient," Mao told US-PharmaTechnologist.com. "This system has great potential for oral delivery of other therapeutics that are sensitive to enzymes and acid environment in the stomach, such as delivery of protein vaccines orally to generate mucosal immunity," he said.
While further refinement is needed to maintain the stability and shelf-life of the vaccine, the university researchers, who are working in conjunction with Aridis Pharmaceutics, where the idea for the delivery system originated, say the delivery system appears sound and shows future promise. Already an application for a provisional patent is in place, as are talks for further funding. Animal testing could begin later this year. Aridis cofounder and chief scientific officer Vu Truong said: "It's still very early in the process, but the pieces they've come up with have been very encouraging. We have the delivery vehicle prototype. I'm optimistic that we can make this work with our vaccine. This is probably the second-most important childhood vaccine needed in the developing world, right behind a malaria vaccine. The mortality rate is high."
Rotavirus is a common cause of severe diarrhea and vomiting in children, leading to about 600,000 deaths annually, with most occurring in developing nations. The economic burden from rotavirus disease in the US alone is estimated at more than $1bn in direct medical and indirect societal costs. There are two current vaccines on the market for rotavirus: Rotateq from Merck & Co and Rotarix from GlaxoSmithKline (GSK).
Rotateq, an oral vaccine in three doses, was licensed by the Food and Drug Administration (FDA) in February 2006 with studies indicating the vaccine prevents around 74 per cent of all rotavirus cases and about 98 per cent of the most severe ones, including 96 per cent of those requiring hospitalization. Meanwhile, Rotarix, an oral vaccine in two doses, gained marketing approval in July 2004 and has since been approved in 65 countries worldwide. Rotarix studies have demonstrated that the vaccine provides 96 per cent protection against severe rotavirus and prevents 100 per cent of hospitalizations due to rotavirus-induced gastroenteritis.
The history of rotavirus vaccines has not been rosy, with Wyeth having to withdraw its vaccine RotaShield in 1999, after only being on the market for just little over a year, because of side effects. Debates on the safety of the current vaccines have also occurred.
The John Hopkins project was funded by the Mao lab and by a $16,000 E-Team grant from the National Collegiate Inventors and Innovators Association.