Sep 28, 2005 (CIDRAP News) – The federal government and MedImmune Inc. announced today they will collaborate to develop vaccines for potential pandemic strains of influenza, using the technology that was used to create the company's nasal-spray flu vaccine, FluMist.
The National Institute of Allergy and Infectious Diseases (NIAID) will work with MedImmune, based in Gaithersburg, Md., to develop vaccines for many flu virus strains, a project that will take years, according to a Department of Health and Human Services (HHS) announcement.
The company said in a news release, "MedImmune scientists will work together with leading researchers of the NIAID Laboratory of Infectious Diseases to produce and test versions of MedImmune's attenuated, live intranasal influenza vaccine for use against different types of potential pandemic influenza strains, including one based on H5N1," the avian flu strain now endemic in Southeast Asia.
HHS said the plan calls for inserting "selected genes from avian flu viruses with pandemic potential into a weakened human flu virus" to create several live virus vaccine candidates. The NIAID part of the effort will be led by Kanta Subbarao, MD, MPH, and Brian Murphy, MD.
HHS Secretary Mike Leavitt said the partnership "will help speed the process of developing vaccines we will need to fight an outbreak if the avian flu starts to spread rapidly through the human population."
NIAID Director Anthony S. Fauci, MD, said he couldn't predict how long it might take to ready the first candidate vaccines for clinical trials. "But given the fact that these are things we do regularly, I wouldn't be surprised if the first one went into clinical trials in a year or two," he told CIDRAP News.
NIAID and MedImmune will develop at least one vaccine for each of the 16 different forms of hemagglutinin, a key protein on the surface of flu viruses, HHS officials said. (Hemagglutinin is represented by the H in the names of flu strains, such as H5N1.)
The partners "will develop vaccines for the highest priority hemagglutinin subtypes first," HHS said. "The researchers say it will take years to systematically develop vaccines for all the hemagglutinin subtypes. Having effective vaccines against all subtypes will help us prepare for influenza pandemics in the future, explains NIAID's Dr. Subbarao."
Fauci said there is no preset time frame for the collaboration. "They're just going to work closely and aggressively to get this library of viruses that covers the entire span of the hemagglutinin spectrum," he said. "This is a years-long collaboration; it's not going to be six months or something like that."
HHS and MedImmune officials wouldn't say how the partnership will work financially.
"What I can say is that MedImmune will not be reimbursed for any costs associated with development of vaccines, because MedImmune and NIAID are truly working in collaboration," MedImmune spokeswoman Clarencia Stephen told CIDRAP News.
The company said live attenuated vaccines may generate a broader immune response than injected vaccines. "One of the unique attributes of FluMist is that it provides both local and systemic immunity," said Stephen. "It first induces an immune response in the nose, because it's administered as a mist in the nose, and that’s typically where the flu virus enters the body. And then it also works systemically through the bloodstream.
Fauci agreed that live vaccines can trigger "a more potent and broader immune response." He added, "That's very important when you're dealing with pandemic flu. Virus drifts from the original vaccine, so you want a vaccine that covers that drift. Live vaccines do that better than killed vaccines."
HHS said the partners will develop many of the vaccines in the NIAID's labs in Bethesda, Md. "Both NIAID and MedImmune will initially conduct laboratory studies of the vaccines," the announcement said. "MedImmune then will manufacture the vaccines for human clinical trials, which NIAID will run through a contract facility, pending Food and Drug Administration approval."
The plan calls for the partners to use reverse genetics and "classical reassortment" to insert hemagglutinin genes into a weakened human flu virus, according to HHS. Reverse genetics is the use of lab methods to "custom make" a vaccine by assembling genes that code for desired features. Reassortment is the exchange of gene segments between two different viral strains inside a host cell to create a new strain.
HHS said the partnership will build on research launched by the NIAID's Murphy with John Maassab of the University of Michigan in the 1970s. They created a flu vaccine from a live but weakened flu virus. For added safety, they grew the vaccine in progressively cooler temperatures so it couldn't spread beyond the relatively cool upper respiratory tract.
This "cold-adapted" flu virus, owned by MedImmune, is the basis of FluMist, which also was developed jointly with NIAID, HHS said. "The researchers will use the same cold-adapted virus as the backbone for the pandemic influenza vaccines."
The government is already building a supply of an experimental vaccine for the H5N1 virus. The first clinical trial results were announced in August, and HHS announced on Sep 15 the award of a $100 million contract to Sanofi Pasteur to manufacture the vaccine. It is not yet known how many doses that contract will be worth, because the optimal dose has not been established.
Sept 28 HHS news release