The U.S. is coming off the worst influenza season in nearly a decade, highlighting the potential benefit of a universal flu vaccine that could protect against multiple strains of the disease.
One company developing an experimental universal flu vaccine is FluGen, a Madison, WI-based startup that on Wednesday announced it had kicked off a clinical trial to test its vaccine candidate’s ability to protect against so-called drifted—or mismatched—flu strains. Forecasters sometimes err when predicting the predominant strain in a given flu season, and a universal flu vaccine could help protect people from getting infected even when experts’ forecasts fail to identify the strain that ends up being predominant.
FluGen has made progress in early-stage trials of its vaccine, which it calls RedeeFlu, including positive results from a Phase 1a study that was aimed at ensuring RedeeFlu was safe and immunogenic, and evaluating subjects’ antibody and T-cell responses to the vaccine. To support its efforts to commercialize RedeeFlu, the startup has brought in funding from investors and outside organizations, such as the U.S. Department of Defense, which in October awarded FluGen a $14.4 million grant for the recently launched study. Still, it will likely be a few years before the startup will be ready to apply for FDA clearance for RedeeFlu, says Paul Radspinner, co-founder and CEO of FluGen.
The startup’s latest clinical trial, which is taking place in Belgium and is likely to enroll nearly 100 patients, is a so-called “challenge” study, Radspinner says. Subjects will receive a vaccine designed to primarily protect against one specific strain of flu, then will be “challenged” by being dosed with a different strain of the virus, he says.
A major benefit of a versatile flu vaccine would be the ability to protect against strains of the virus that vary from the ones that public health groups such as the Centers for Disease Control and Prevention and World Health Organization predict will be the predominant strain in a particular flu season. Those forecasts, which tend to vary in accuracy from year to year, influence vaccine manufacturers’ decisions around what goes in the flu shots tens of millions of Americans get in the fall each year.
Half of the subjects in FluGen’s new study will be dosed with RedeeFlu, which is manufactured with a strain of flu that was used in vaccines during the 2008 through 2010 flu seasons, the startup says. The other half will receive a placebo nasal spray (that’s the way RedeeFlu is administered).
All patients will then be infected with the H3N2 flu strain, a genetically drifted strain that caused outbreaks in 2015, FluGen says. After that, researchers will follow the subjects for four months in order to track how RedeeFlu compares to the placebo spray in protecting patients against the H3N2 virus.
RedeeFlu is made up of a live flu virus from which a key gene, known as M2, has been deleted. The vaccine virus is able to live in the body just long enough to trigger a strong immune response, but thanks to the deleted gene it’s not able to cause disease or spread to other people, according to FluGen.
FluGen says that patients naturally infected with “wild-type” influenza are frequently protected from getting the flu for several years. RedeeFlu is designed to make a patient’s body think it got the flu so that it protects against future infections, without actually making the person ill.
“By tricking the body into believing it has been infected with influenza, the [RedeeFlu] vaccine is designed to activate this broad and durable wild-type immune response, without causing influenza disease,” the company says in a news release.
Other companies, such as Fort Collins, CO-based Vivaldi Biosciences, are developing vaccines that have similarities to RedeeFlu, but Radspinner says he does not know of any that remove the M2 gene.
Meanwhile, FluGen plans to conduct two other studies of RedeeFlu in the near to medium term. One will be trial involving “older kids” (ages 9 to 18), which will likely take place this summer and be supported by the National Institutes of Health, Radspinner says. The other planned study, a Phase 1b trial of RedeeFlu in elderly adults, will likely start sometime in 2019, he says. Flu vaccine efficacy tends to be worse among children and the elderly, Radspinner says.
