Preliminary Data on Croup Vaccine Trial Also Reported
KAPALUA, Hawaii, Dec. 5 /PRNewswire/ -- Data from two important studies
with FluMist(TM), Aviron's (Nasdaq: AVIR) investigational intranasal influenza
vaccine, were presented here today at the International Symposium on Influenza
and Other Respiratory Viruses. Results presented included those from a study
of the effectiveness of FluMist(TM) in healthy working adults and a pediatric
influenza challenge trial. In addition, results from a clinical trial
evaluating a new vaccine for prevention of parainfluenza (croup) in children
were also presented.
Study In 4561 Healthy Working Adults
Preliminary results from a Phase 3 trial in 4561 healthy working adults
showed that those receiving FluMist(TM) experienced reductions in
illness-associated missed work days and health care provider visits, as well
as prescription and over-the-counter medication use associated with illness.
Today's symposium is sponsored by the International Society for Antiviral
Research and the National Institute of Allergy and Infectious Disease (NIAID).
The data were presented by Kristin Nichol, M.D., M.P.H., chief of medicine,
Minneapolis Veterans Affairs Medical Center, Minneapolis, Minn., chair of the
study's analysis committee. A complete analysis of the data will be submitted
for publication to a peer-reviewed journal. FluMist(TM) is being developed as
part of a Collaborative Research and Development Agreement (CRADA) between
Aviron and NIAID.
Study results show FluMist(TM) recipients had reductions in the occurrence
of illness by multiple definitions measured in the study including severe
influenza-like illness (18 percent less) and febrile upper respiratory tract
illness (23 percent less). The numbers of days of illness was also reduced in
FluMist(TM) recipients by 23-28 percent, depending on the specific illness
definition. (For disease definitions, see Appendix I at end of release.)
The trial was a double-blind, placebo-controlled study conducted in
13 clinical sites nationwide during the 1997-98 flu season. Most study
subjects self-administered FluMist(TM) under supervision of investigators at
their worksite or a nearby clinic. Study participants reported their symptoms
and health events monthly. Because laboratory tests were not performed to
diagnose influenza, several pre-specified illness definitions were used to
identify health events which could have been due to influenza virus infection.
These included a very broad definition of influenza-like illness, which did
not necessarily include respiratory tract symptoms, as well as more severe
influenza-like illness and febrile upper respiratory tract illness (upper
respiratory illness with fever).
FluMist(TM) recipients were 9.8 percent less likely than placebo
recipients to develop influenza-like illness, designated as the primary
endpoint of the study. Although reductions in occurrences using this broad
definition did not reach statistical significance, the study demonstrated
reductions in the occurrence of illness by the other pre-specified
definitions.
Effectiveness Against Work Loss and Health Care Utilization
Reductions in illness-associated absenteeism and health resource use were
consistently seen across all illness definitions. Illness event rates were
reported in units of days per 1000 participants, per seven-week influenza
outbreak period. Those receiving FluMist(TM) missed 28.8 percent fewer days
of work (107 days vs. 150 for placebo) due to febrile upper respiratory
illness and had 40.9 percent fewer days of health care provider visits
(24 days vs. 40 for placebo). In addition, this group experienced a 45.5
percent reduction in days of prescription antibiotic use (140 days vs. 257 for
placebo), a 17.0 percent reduction in days of non-antibiotic prescription drug
use (43 days vs. 52 for placebo) and 28 percent fewer days of OTC medicine use
(442 days vs. 614 for placebo). Findings consistent with these were observed
for each of the other illness definitions.
"This study is important in expanding our understanding of the impact of
influenza illness patterns in the workplace and the potential economic benefit
that can be realized through flu vaccination in adults," Dr. Nichol said.
"Previous studies have shown vaccination with the flu shot can contribute to
reductions in work loss and physician visits associated with influenza. This
new study shows influenza prevention can also impact the use of medication.
These data are particularly exciting to me because an unexpected strain of
influenza known as A/Sydney was the dominant circulating strain during the
1997-98 flu season."
Protection rates against health events such as those reported here are
typically lower than in laboratory-documented efficacy studies because they
measure disease impact from a variety of causes, not just influenza. Efficacy
of FluMist(TM) to prevent laboratory-documented influenza was not measured in
this trial.
Challenge Trial Evidence of Protection Against Third Strain of Flu
A separate study of FluMist(TM), presented at the meeting by John Treanor,
M.D., associate professor of medicine, University of Rochester School of
Medicine and Dentistry, suggests that FluMist(TM) could be useful in the
prevention of A/H1N1 influenza. The flu shot is formulated each year to
protect against three strains of virus: influenza A/H3N2, influenza B, and
influenza A/H1N1. Because the influenza A/H1N1 strain did not occur during
the two years of observation of Aviron's successful pediatric Phase 3 efficacy
trial, the protective efficacy of FluMist(TM) against A/H1N1 viruses was
assessed by performing an investigational challenge with high-dose live,
monovalent cold-adapted influenza A/H1N1 vaccine in a subset of 222 of the
children who participated in the Phase 3 trial.
Vaccination with FluMist(TM) resulted in an 83 percent reduction in the
rate of shedding of the challenge virus when compared to children who had
previously received placebo. Four percent of the FluMist(TM) recipients (6 of
142) shed the challenge virus compared to 25 percent of the placebo recipients
(19 of 77) in the study.
"Experimental challenge studies of this sort are a well-established means
of assessing vaccine protection when a particular type of flu is not
circulating in the community," Dr. Treanor said. "This study completes the
picture of FluMist(TM) by showing activity for the third component of the
trivalent vaccine."
"These two studies add important elements to the clinical profile of
FluMist(TM)," said J. Leighton Read, M.D., Aviron's chairman and chief
executive officer. "The adult clinical trial provided an opportunity to
evaluate FluMist(TM) among those in the workforce, where flu accounts for
nearly 70 million lost work days annually. In our continuing program of
pediatric studies, the children's challenge trial provides useful information
on FluMist's(TM) activity against a strain of influenza that did not circulate
during our field trials."
Phase 2 Study of Croup Vaccine Successful
Also presented were results of Aviron's first Phase 2 clinical study of an
intranasal vaccine against parainfluenza virus type 3 (PIV-3), a common
childhood virus that is the leading cause of croup, bronchiolitis and
pneumonia. This double-blind placebo-controlled trial enrolled 192 children
who were given the study vaccine at two, four and six months of age during
their doctor visits for routine immunization. The new vaccine was found to be
well-tolerated. After three doses, 79 percent (45 of 57) of the vaccine
recipients showed evidence of immunization, as assessed by viral shedding or
antibody responses to the vaccine compared to 7 percent (2 of 27) of placebo
recipients. Based on this data, the company intends to move forward with
additional clinical trials.
This vaccine is adapted from a bovine PIV-3 virus originally developed by
the NIAID and for which Aviron has obtained exclusive commercial rights.
PIV-3 is the second leading cause of pneumonia and bronchiolitis in infants
younger than six months of age. In the U.S., 80 percent of children are
infected by PIV-3 by age four. The data were presented by Paul Mendelman,
M.D., vice president, clinical research at Aviron.
Aviron is a biopharmaceutical company based in Mountain View, CA focused
on prevention of disease. The company's goal is to develop products which
offer cost-effective prevention of a wide range of infections that affect the
general population. The majority of Aviron's products under development are
live vaccines against viral infections. These include intranasal vaccines
under development for respiratory infections and their complications --
influenza, parainfluenza (PIV-3), and respiratory syncytial virus (RSV), and
injectable vaccines to prevent cytomegalovirus (CMV) and genital herpes
(HSV-2). Aviron is also developing, in collaboration with SmithKline Beecham
Biologicals, a subunit vaccine against Epstein-Barr Virus (EBV) infection, a
major cause of infectious mononucleosis.
This press release contains forward-looking statements. Actual results
may differ materially from those suggested here. Factors that could cause
actual results to differ include, but are not limited to, failure in a
clinical trial, failure to demonstrate stability or to validate equipment or
the manufacturing process. Risk factors also include the assessment by the
FDA that the company's future license applications for its intranasal
influenza vaccine are incomplete or inadequate to approve the product for
marketing to one or more target populations. Additional information
concerning factors that could cause such a difference is contained in Aviron's
Annual Report on Form 10-K for the year ended December 31, 1997.
To receive an index and copies of recent press releases, call Aviron's
News-On-Call toll-free fax service, 800-758-5804, extension 114000.
Additional information about the company can be located at
http://www.aviron.com.
For information, please contact:
Media: Karen Gilbert, Aviron, 650-919-6578
John Bluth, Fleishman-Hillard, 212-453-2000
Investors: Lyn Christenson, Aviron, 650-919-3716
APPENDIX I
DISEASE DEFINITIONS
Influenza-like illness (ILI): at least two consecutive days of symptoms,
at least one day of fever, at least two symptoms on at least one day; possible
additional symptoms -- runny nose, sore throat, cough, headache, muscle aches,
chills, feeling tired/weak.
Severe ILI: at least three consecutive days of symptoms, at least one day
of fever, and at least two symptoms on all three days.
Febrile upper respiratory illness (FURI): at least two consecutive days
of upper respiratory symptoms (runny nose, sore throat, cough), at least one
day of fever; at least two symptoms on one day.
APPENDIX II
INVESTIGATORS:
HEALTHY WORKING ADULTS STUDY
Thirteen clinical sites were included in the trial. The principal
investigators were:
-- Jeffrey Adelglass, M.D., Research Across America, Dallas, TX
-- Stan L. Block, M.D., Kentucky Pediatric and Adult Research, Inc.,
Bardstown, KY
-- Geoffrey Gorse, M.D., St. Louis Veterans Affairs Medical Center and
Saint Louis University Health Sciences Center, St. Louis, MO
-- Lisa Jackson, M.D., Group Health Cooperative of Puget Sound, Center
for Health Studies, Seattle, WA
-- Harry Keyserling, M.D., Emory University School of Medicine,
Department of Pediatrics, Atlanta, GA
-- William Lang, M.D., ViRx, Inc., San Francisco, CA
-- James McCarty, M.D., Hill Top Research, Inc., Pharmaceutical Clinicals
Trials Division, Fresno, CA
-- Kristin Nichol, M.D., Minneapolis VA Medical Center and University of
Minnesota Medical School, Minneapolis, MN
-- Keith Reisinger, M.D., Primary Physicians Research, Pittsburgh, PA
-- Gilbert M. Schiff, M.D., Director, Gamble Program, Division of
Infectious Diseases, Children's Hospital Medical Center, Cincinnati, OH
-- Innovative Medical Research, Inc., Towson, MD and Catonsville, MD
-- Karl V. Sitz, M.D., University of Arkansas for Medical Sciences,
Division of Pulmonary and Critical Care Medicine, Little Rock, AR
-- Mark Snell, M.D., Golden Valley Memorial Hospital, Clinton, MO
INVESTIGATORS:
CHALLENGE STUDY IN CHILDREN
Eleven clinical sites were included. The principal investigators were:
-- Robert Belshe, M.D., Center for Vaccine Development at Saint Louis
University School of Medicine, St. Louis, MO
-- David Bernstein, M.D., Children's Hospital Medical Center,
Cincinnati, OH
-- Stan L. Block, M.D., Kentucky Pediatric Research Institute, Inc.,
Bardstown, KY
-- William C. Gruber, M.D., Vanderbilt University, Nashville, TN
-- Frederick Hayden, M.D., University of Virginia Health Sciences Center,
Charlottesville, VA
-- James King, M.D./Karen Kotloff, M.D., University of Maryland at
Baltimore, Baltimore, MD
-- Pedro Piedra, M.D., Influenza Research Center, Baylor University
College of Medicine, Houston, TX
-- Keith Reisinger, M.D., Primary Physicians Research, Pittsburgh, PA
-- John Treanor, M.D., University of Rochester School of Medicine and
Dentistry, Rochester, NY
-- Ken Zangwill, M.D., Harbor-UCLA Research and Education Institute,
Torrance, CA
INVESTIGATORS:
CROUP VACCINE STUDY
Four sites were included in the trial. The principal investigators were:
-- David Greenberg, M.D., Children's Hospital of Pittsburgh,
Pittsburgh, PA
-- Keith Reisinger, M.D., Primary Physicians Research, Pittsburgh, PA
-- Joel Ward, M.D./Sylvia Yeh, M.D., UCLA Center for Vaccine Development,
Torrance, CA
-- Ram Yogev, M.D., Children's Memorial Hospital, Chicago, IL
SOURCE Aviron
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CONTACT:
Media: Karen Gilbert of Aviron,
650-919-6578; or John Bluth of Fleishman-Hillard, 212-453-2000;
or Investors: Lyn Christenson of Aviron, 650-919-3716
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