TORONTO, Oct. 13 /PRNewswire-FirstCall/ -- MedImmune, Inc. today announced results of a study that demonstrated higher influenza serum antibody responses in children receiving its next-generation, investigational intranasal influenza vaccine, CAIV-T (cold adapted influenza vaccine, trivalent), than in children who received the traditional injectable trivalent inactivated flu vaccine (TIV). In this study involving 52 children between six and 35 months of age, CAIV-T prompted significantly higher seroconversion rates and higher antibody titers than TIV. CAIV-T also demonstrated significantly more cross-reactivity to the mismatched strain that predominantly circulated during the 2004-2005 season. The results were presented here today at the 44th Annual Meeting of the Infectious Diseases Society of America (IDSA).
“These data are consistent with the results from our Phase 3 study conducted during the 2004-2005 season that demonstrated CAIV-T’s increased efficacy against matched and mismatched strains in children under five years of age compared to TIV,” said Robert Belshe, M.D., director of the Center for Vaccine Development at Saint Louis University School of Medicine.
In the study titled Immunogenicity of Cold-Adapted Influenza Vaccine, Trivalent (CAIV-T) Compared with Trivalent Inactivated Influenza Vaccine (TIV) in Children 6-35 Months of Age, a group of influenza-vaccine-naive children (randomized 1:1) received two doses of CAIV-T or TIV approximately 35 days apart. The children’s immune responses (measured by serum hemagglutination inhibition [HAI] antibody levels) were evaluated at the time of enrollment, just prior to and approximately 30 days after the second dose. Study results indicated that CAIV-T produced significantly higher antibody responses than TIV against vaccine-like virus strains (matched) as well as against mismatched viruses that were circulating during the 2004-2005 season in seronegative children. Higher antibody responses were seen for CAIV-T after both the first and second doses.
Strain-specific Seroconversion Rates in Seronegative Children Post dose 1 CAIV-T vs. TIV Post dose 2 CAIV-T vs. TIV Matched A/H1N1 Matched A/H1N1 53% vs. 0%* 94% vs. 8%* Matched A/H3N2 Matched A/H3N2 100% vs. 29%* 100% vs. 100% Mismatched A/H3N2 Mismatched A/H3N2 93% vs. 0%* 93% vs. 14%* Matched B Matched B 67% vs. 17% 78% vs. 57% Mismatched B Mismatched B 50% vs. 13% 100% vs. 60%* *Significant difference between CAIV-T and TIV Regulatory Status of CAIV-T
The U.S. Food and Drug Administration (FDA) is currently reviewing a supplemental biologics licensing application (sBLA) submitted by MedImmune to switch formulations from frozen FluMist(R) (Influenza Virus Vaccine Live, Intranasal), currently approved in healthy individuals 5 to 49 years of age, to the refrigerator-stable CAIV-T formulation, for the same population. MedImmune has also submitted a separate sBLA to the FDA seeking an expanded label for CAIV-T for use in children between 12 months and 59 months of age who do not have a history of wheezing or asthma. A response from the FDA for this sBLA is anticipated in the second quarter of 2007 and pending positive outcome, MedImmune plans to commercially provide CAIV-T for the 2007-2008 influenza season.
About CAIV-T
CAIV-T is an investigational intranasal, cold-adapted trivalent influenza vaccine. It is the refrigerator-stable formulation of FluMist, which is a frozen, live attenuated cold-adapted trivalent influenza vaccine. To date, the safety, tolerability and efficacy of CAIV-T has been studied in both healthy and at-risk populations between the ages of 6 weeks and 98 years.
On May 1, 2006 at the Pediatric Academic Societies’ annual meeting, MedImmune presented its pivotal Phase 3 study for CAIV-T, entitled, “Comparison of the Efficacy and Safety of Cold-Adapted Influenza Vaccine, Trivalent with Trivalent Inactivated Influenza Vaccine in Young Children 6 to 59 Months of Age.” The study included 8,475 children at 249 sites in 16 countries in North America, Europe, the Middle East and Asia. Study participants were randomized one-to-one to receive either CAIV-T or the flu shot during the 2004-2005 influenza season. Each participant also received a placebo nasal spray or placebo injection to preserve the double-blind design of the study. Participants were followed through the influenza season and evaluated to identify illnesses caused by influenza virus. The trial included more than 6,300 previously unvaccinated children and nearly 50 percent of the children enrolled were less than 2 years of age.
The results of this trial showed that CAIV-T was 55 percent more effective than the trivalent injectable inactivated influenza vaccine (TIV) in reducing influenza illness caused by any influenza strain in children 6 months to 59 months of age, including both matched and mismatched strains. The influenza attack rate was 8.6 percent for study participants receiving the flu shot compared to 3.9 percent for those who received CAIV-T (P<0.001). Against matched strains alone, CAIV-T was 45 percent more effective than the flu shot (attack rates: TIV = 2.4 percent, CAIV-T = 1.4 percent; P<0.001). In this study, CAIV-T was also shown to be 89 percent more effective than the flu shot in reducing influenza illness caused by the matched H1N1 A strain (attack rates: TIV = 0.7 percent, CAIV-T = 0.1 percent; P<0.001) and 79 percent more effective than the flu shot against the circulating mismatched H3N2 A strain (attack rates: TIV = 4.5 percent, CAIV-T = 0.9 percent; P<0.001). There were no cultures of mismatched H1N1 strains or matched H3N2 strains detected in the trial. While there were 16-percent fewer children with illnesses associated with B strains in the CAIV-T group compared to TIV (attack rates: TIV= 3.5 percent, CAIV-T = 2.9 percent), this difference was not statistically significant.
In the study, the overall incidence of adverse events and serious adverse events was similar in both groups except for a higher incidence of runny nose and nasal congestion in CAIV-T recipients (4.4 - 11.1 percent increase) and a higher incidence of injection site reactions in those receiving the flu shot (3.6 - 7.6 percent increase). A statistically significant increase in the incidence of medically significant wheezing was seen in CAIV-T recipients 6 months to 23 months of age within 42 days following vaccination. Post-hoc analyses showed higher all-cause hospitalizations occurring through 180 days after vaccination in CAIV-T recipients 6 months to 11 months of age. Risk- benefit analyses showed a favorable profile for CAIV-T as compared to TIV in children 12 months to 59 months of age without a prior history of wheezing or asthma.
About FluMist
FluMist is indicated for active immunization for the prevention of disease caused by influenza A and B viruses in healthy children and adolescents, 5 to 17 years of age, and healthy adults, 18 to 49 years of age. There are risks associated with all vaccines, including FluMist. Like any vaccine, FluMist does not protect 100 percent of individuals vaccinated. In studies of people between the ages of 5 and 49 years, runny nose was the most commonly reported side effect. Other common side effects included various cold-like symptoms, such as headache, cough, sore throat, tiredness/weakness, irritability, and muscle aches.
FluMist should not be used, under any circumstances, in anyone with an allergy to any part of the vaccine, including eggs; in children and adolescents receiving aspirin therapy; in people who have a history of Guillain-Barre syndrome; and in people with known or suspected immune system problems. Pregnant women and people with certain medical conditions, asthma, or reactive airways disease should not get FluMist.
Please see the Prescribing Information at http://www.flumist.com/pdf/prescribinginfo.pdf, visit http://www.flumist.com, or call 1-877-633-4411 for additional information.
About MedImmune
MedImmune strives to provide better medicines to patients, new medical options for physicians, rewarding careers to employees, and increased value to shareholders. Dedicated to advancing science and medicine to help people live better lives, the company is focused on the areas of infectious diseases, cancer and inflammatory diseases. With more than 2,400 employees worldwide, MedImmune is headquartered in Maryland. For more information, visit the company’s website at http://www.medimmune.com.
This announcement contains, in addition to historical information, certain “forward-looking statements” relating to CAIV-T and FluMist. Such forward- looking statements are based on current expectations and involve inherent risks and uncertainties, including factors that could delay, divert or change current expectations and could cause actual outcomes and results to differ materially from current expectations. In addition to risks and uncertainties discussed in MedImmune’s filings with the U.S. Securities and Exchange Commission, no assurance exists that development efforts for CAIV-T will succeed, that CAIV-T will receive required regulatory approval or that, even if regulatory approval is received, CAIV-T will be commercially successful. MedImmune undertakes no obligation to update any forward-looking statement, whether as a result of new information, future events or otherwise except as may be required by applicable law or regulation.
MedImmune, Inc.
CONTACT: Media: Karen Lancaster, +1-301-398-5864, or Jamie Lacey,+1-301-398-4035, or Investors: Peter Vozzo, +1-301-398-4358, all ofMedImmune, Inc.
