“Because the starting material is a DNA sequence, it eliminates a lot of steps you have to go through, because the flu virus itself is not part of this production process,” says John Treanor, a medical advisor to the company and professor of microbiology and immunology at the University of Rochester Medical Center in New York. “You also don’t have concerns of workers getting infected, versus using a growing virus.”
Treanor headed four clinical trials to test the vaccine for effectiveness against seasonal flu. The trials compared the effects of the company’s vaccine against a conventional one in 3,231 people aged 18 and older.
The company presented its results to the FDA advisory board. While the new vaccine was found to protect against seasonal flu symptoms in those 18 to 49, it was not possible to draw significant conclusions for older participants. Several older subjects suffered from facial swelling after receiving the vaccine, and one developed a temporary paralysis on one side of the face. This might have been a preexisting condition, but researchers couldn’t be sure if the condition was independent of the vaccine. “When you have one case, it’s hard to know,” says Treanor.
The FDA panel recommended that the company expand the patient group to determine whether the vaccine is safe in a larger, older population.
Other companies seeking FDA approval for similar cell-based vaccines include Novartis, which opened a vaccine manufacturing plant in North Carolina this week and plans to produce vaccines from dog kidney cells.
FluGen, a vaccine company based in Madison, WI, has also entered the race. It is growing flu virus in manipulated hamster ovary cells–a cell line that has already been approved by the FDA for producing drugs to treat rheumatoid arthritis. FluGen is a little behind its bigger competitors, but CEO Paul Radspinner says he will take a lesson from Protein Sciences’ experience when it comes time to seek FDA approval. “Maybe it’s a learning point,” says Radspinner. “We’ll be very careful with where we go with clinical trials where there’s a database of patients coming through, and [make sure] that preexisting conditions are being noted.”