BREAKTHROUGHS BLOG

June 19, 2016

Research Roundup: Priority Review Voucher legislation, Toxic Shock Syndrome vaccine, and repurposing existing drugs

Senior Program Assistant
GHTC

The House Energy & Commerce Committee recently passed an amendment—attached to an unrelated bill—that would add requirements for eligibility to the Tropical Disease Priority Review Voucher (PRV) program at the US Food and Drug Administration (FDA). The PRV program, established by Congress in 2007, is intended to incentivize research and development (R&D) for drugs for which there is a critical need but a limited market opportunity. Under the program, the regulatory sponsor of an approved drug for a tropical or rare pediatric disease is awarded a voucher which expedites FDA review of a future product by four months. These vouchers enable companies to enter the market sooner, and several have been sold between companies for up to US$350 million. Of the three vouchers that have been awarded for tropical disease drugs, two were awarded to companies that weren’t actually involved in the drug’s development—they had merely acquired rights to the drug—and in one case, the drug was already approved by other regulatory authorities and available in 80 countries. The amendment, introduced by Congressman G.K. Butterfield (D-NC), would require the regulatory sponsor to demonstrate the need for the product (i.e., the global burden of the disease and demand for the product) and elucidate their plan to ensure access to the product.

Vienna-based researchers have developed a vaccine against Toxic Shock Syndrome (TSS), a rare, life-threatening condition resulting from an extreme immune system response to a Staphylococcus infection. TSS is associated with the use of super absorbent tampons, and an estimated half of cases occur in menstruating women. In a phase 1 clinical trial, the vaccine candidate—which contains a detoxified strain of Staphylococcus—proved to be safe and successfully prompted an immune response. The vaccine will next be tested in a larger, phase 2 trial. The team anticipates the vaccine will last for five years and will be used to protect individuals with a compromised immune system who are at greater risk for TSS.

Nature took an in-depth look at drug repositioning, in which a medicine developed to treat one disease or condition is used to treat another. Drug repositioning is not a new concept; leading drugs against HIV/AIDS and erectile dysfunction were once intended to treat cancer and angina, respectively. However, the practice is becoming more common. Since 2011, the number of journal articles published on repurposed drugs has increased sixfold to an average of 30 per month and each year three to four new companies focused solely on the practice are established. Generic medicines are a common target, however, there are also many drugs that have passed phase 1 or clinical trials, proving to be safe for use in humans, but that did not have the intended effect. This approach makes drug development cheaper and faster, as phase 1 trials can often be skipped. Repositioning a drug costs $300 million and takes 6.5 years, compared to $2 to 3 billion and 13 to 15 years when starting from scratch. However, phase 1 trials may still be needed if the drug needs to be delivered in a different way or if a different dose is needed. Additionally, many pharmaceutical companies have massive, untapped compound libraries and new technology and software have made it easier to discover ways in which distinct conditions manifest similarly on a molecular level, which allows them to better identify promising compounds to screen for a given condition or disease.

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