CYTOKINE STORM and the INFLUENZA PANDEMIC: Bird Flu VaccinesMarch 30, 2006: Mixed results for sanofi-aventis' experimental avian influenza vaccine
Results from a clinical study of an experimental H5N1 avian influenza vaccine produced by drug maker Sanofi-Aventis and published in the NEJM, found that the treatment protected only half the patients who received the highest dosage in the trial.
In the study, funded by the National Institutes of Health, 451 healthy volunteers aged 18 to 64 were administered one of four different doses of the vaccine or placebo two times over a 28-day interval. The results showed that 54 percent of patients who received the highest dose, 90 micrograms, developed levels of antibodies considered protective against the virus.(They were not actually exposed to the virus). Forty-three percent of patients who received the 45-microgram dosage achieved the targeted immune response, while 22 percent who received the 15-microgram dosage and 9 percent who received the 7.5-microgram dosage achieved the level of antibodies necessary to be considered protective.
Anthony Fauci, MD, director of the US National Institute of Allergy and Infectious Diseases, called the results "muted good news." The results show that "we have a vaccine we know can spur an immune response, albeit at very high doses. We're going in the right direction," Fauci said. However, he noted that "the sobering news is we have a long way to go." He added that the next step is to "give a booster to those who failed to respond" and added that the agency is "investigating other options that may allow us to reduce the dosage -- for example, adding an immune booster, or adjuvant, to the vaccine."
In an editorial in the journal, Dr. Gregory Poland indicated that the vaccine's level of effectiveness was "poor to moderate at best." The high doses required to elicit an immune response would mean that only about 1.25 percent of the global population could be fully immunised, Poland added, suggesting that sanofi's vaccine is "not the answer" to a potential pandemic, The Globe and Mail reports.
Sanofi Aventis responded that improving its experimental vaccine was "a top priority" and added that "to conclude that this result is as good as it gets would be premature, at least". The company is planning to increase its vaccine production capabilities in the future.
Source: The New England Journal of Medicine, a clinical study
March 30, 2006: GlaxoSmithKline begins trials for H5N1 influenza vaccines
Drug maker GlaxoSmithKline announced Thursday that it started clinical trials on two experimental vaccines against the H5N1 influenza strain (Bird Flu virus). Preliminary results are expected in the late summer of 2006 and the drugmaker anticipates starting production of a pandemic influenza vaccine before the end of the year.
One trial, in 400 healthy adult volunteers, will examine a pandemic influenza vaccine candidate in combination with a standard adjuvant to test immune response and whether the treatment lowers the amount of antigen required per dosage. The second trial, which also involves 400 healthy adult volunteers, will test an experimental pandemic vaccine that contains a novel adjuvant to determine whether this treatment elicits immune response to different H5N1 virus strains, which Glaxo believes may provide broader protection against a potential pandemic virus.
"The second vaccine may offer governments a preferred option to proactively stockpile and begin vaccination before the onset of a pandemic, significantly increasing the speed of a public health response in the event of an outbreak," commented Jean Stephenne, Glaxo's president of the vaccine division, news sources report.
Additionally, Glaxo indicated that it plans to start a clinical trial programme for an influenza vaccine developed using cell cultures later this year. Bruce Innis, director of clinical R&D and medical affairs, vaccines for virus diseases in North America, commented that a vaccine based on cell cultures would be a "medium to long-term solution for capacity issues."
Source: First Word
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