Progress Continues in Vaccine and Antiviral Development

Promising results of clinical studies and increased statewide funding continue to drive influenza vaccine development and pandemic preparation while FDA approves a second antiviral for flu prevention. And, a previously pulled rotavirus vaccine aims for a commercial comeback.

New H5N1 Vaccine Study in Humans Shows Mixed Results
Results of a two-stage, in-human safety and immunogenicity study of a new subvirion influenza A (H5N1) vaccine of hemagglutinin antigen shows that the drug is safe, but has limited effectiveness, and that only at the highest concentration. “It's a bit of a muted good news, but we have a long way to go," said Anthony Fauci, MD, director of the NIH's National Institute of Allergy and Infectious Diseases, which funded the research. The investigation was published in the Mar. 30 New England Journal of Medicine (J.J. Treanor, MD, et al., NEJM354 (13), 1343-1351 [2006]).

Investigators generated the seed virus from the A/Vietnam/1203/2004 strain and grew the virus in eggs. The virions were purified, inactivated, and filtered, and the formulated vaccine at various concentrations was administered without adjuvant. Although the formulation of 90 microgram of hemagglutinin protein per milliliter (the highest concentration) did not cause severe side effects, only a small majority (54%) of the subjects who received two doses at this concentration generated adequate neutralizing antibody response related to influenza protection. Lower percentages of antibody response were seen in patients who had been administered the 45, 15, and 7.5 microgram concentrations.

In the study, the investigators concluded that the need to rapidly produce a sufficient number of 180-microgram treatment doses would be a challenge in the event of a pandemic and encouraged the pursuit of dose-sparing approaches, including the use of adjuvants. Further investigations into wider populations are currently being conducted.

The National Institute of Allergy and Infectious Diseases and investigators from the University of Rochester designed the study, and Sanofi Pasteur manufactured the vaccine.

BIOVIRx and IDT to Develop Rotavirus Vaccine
BIOVIRx (Minneapolis, MN, www.biovirx.com) and Impfstoffwerk Dessau-Tornau GmBH (IDT, Tornau, Germany, www.idt-direct.de) have agreed to commercially develop the “RotaShield” oral vaccine for the prevention of rotavirus-related diarrheal diseases in children.

The drug is the initial product of BIOVIRx and was acquired in an exclusive worldwide license from the US National Institutes of Health. IDT already holds vaccine production capacity for RotaShield and has begun expanding this capacity with the construction of a manufacturing facility in Dessau-Tornau, Germany.

RotaShield first received FDA approval in 1998 but was voluntarily withdrawn in 1999 because of its association with intussusception (blockage of the intestine). The companies claim that upon reanalysis of the data, however, the high risks of intussusception were related to the drug being administered to infants older than the recommended age. According to the companies, BIOVIRx and IDT plan to meet with regulatory authorities regarding the requirements for reintroducing the vaccine.

FDA Approves GSK’s Relenza Antiviral for Flu Prevention
The Food and Drug Administration has approved "Relenza" (zanamivir for inhalation) produced by GlaxoSmithKline (Research Triangle Park, NC, www.gsk.com) for the prevention of influenza A and B (seasonal influenza) in adults and children over 5 years of age. The antiviral was previously approved for the treatment of flu. In a prepared release, FDA emphasized the drug was not a substitute for flu vaccine, which is the “primary means for preventing influenza,” and advised consumers to continue receiving an annual flu vaccination.

States Move Forward in Preparing for Influenza Pandemic
State and local preparations for pandemic influenza continued this week with Health and Human Services (Washington, DC, www.hhs.gov) Secretary Mike Leavitt holding state summits in Puerto Rico, Colorado, Utah, Idaho, Texas, New Mexico, and Oklahoma. Summits in Oregon and California are scheduled for Mar. 30 and state meetings are planned in Nashville, Tennessee (Apr. 10), Anchorage, Alaska (Apr. 13), and Tacoma, Washington (Apr. 14).

As part of each pandemic planning summit, the state will receive a portion of the $100 million in federal funding allocated to help government, healthcare, and emergency management organizations prepare for an influenza pandemic. All 50 states, 7 territories, the Commonwealth of Puerto Rico, and the District of Columbia will receive a minimum of $500,000, with additional funds determined according to population. In addition to state grants, funds will be allocated to New York City ($2,466,271), Los Angeles County ($2,900,529), and Chicago ($1,197,706).

According to HHS, these funds are meant to “accelerate and intensify current planning efforts for pandemic influenza and to exercise their plans. The focus is on practical, community-based procedures that could prevent or delay the spread of pandemic influenza, and help to reduce the burden of illness communities would contend with during an outbreak.”