Nabi Biopharmaceuticals Announces Positive Results Of Phase IIb Trial Of NicVAX
Biopharmaceuticals (Nasdaq: NABI) today announced that a statistically
significant number of patients with a high anti-nicotine antibody response
met the primary endpoint of eight weeks of continuous abstinence between
weeks 19-26 in its ongo
Data from the drug-treated population was divided into those who quit
and those who continued to smoke and then analyzed for antibody levels
throughout the trial. In an analysis of completers, patients who showed
continuous abstinence between weeks 19-26 had significantly higher antibody
levels than those who did not quit (p=0.03 and p=0.02 at the beginning and
end of the eight-week assessment period, respectively). In an analysis of
the intent to treat population, patients who quit smoking had a median
total antibody level that was significantly greater than patients who
continued smoking (p=0.002).
To further examine the relationship between antibody and quit rate, the
top 30% of antibody responders (61 of the total 201 patients receiving
drug) were examined in detail. A statistically significant number of these
patients, (24.6%; p=0.04) showed continuous abstinence between weeks 19-26
compared to only 13.0% for the 100 patients receiving placebo. The quit
rate of those patients who did not have a high antibody response was not
statistically significant from placebo. The trial enrolled a total of 301
heavy smokers who smoked an average of 24 cigarettes per day prior to
enrollment. In no case did any of these patients smoke less than 15
cigarettes per day prior to enrollment.
Current drugs for smoking cessation were approved using a four-week
continuous quit rate at the end of the treatment period. NicVAX high
antibody responder patients showed a high rate of continuous abstinence
(31.1%; p=0.006) when assessed for an analogous four-week period between
23-26 weeks after their first vaccination.
This double-blind, placebo-controlled and dose-ranging study tested two
antigen doses, 200 mcg and 400 mcg per injection, and two different
regimens of administration. The efficacy data trends were both vaccine
dose- proportional and antibody level-dependent. In the responder group,
antibody levels increased with time and number of doses. Individual
patients were tracked on a continual basis and were seen to be more likely
to abstain from smoking as their antibody levels rose after vaccination;
thus definitively providing proof of concept.
NicVAX was well-tolerated throughout the six months of dosing to date,
and showed a favorable adverse events profile with no difference between
placebo and each dose group. The most common local reactogenicity events
were minor ache and tenderness. Systemic reactogenicity events - such as
general discomfort, headache and muscle ache - were mild to moderate in
severity, resolved quickly and did not increase with number of injections.
Fever and nausea were seen in less than 10% of all patients.
The Phase IIb trial is continuing after all patients received a booster
at six months. The study will assess a series of secondary endpoints at 12
months, including abstinence rate, total cigarette consumption, antibody
concentration, safety and the degree of nicotine dependency.
"We are very encouraged by the results of this Phase IIb trial of
NicVAX. In responders, the study met its primary endpoint and achieved
statistical significance - two key milestones in the development of a
vaccine for nicotine addiction," said Dr. Paul Kessler, senior vice
president, clinical, medical and regulatory affairs. "With these data, we
have clearly established proof of concept for NicVAX and can identify the
optimal dose and design for our planned Phase III program."
"These results definitively enable us to move our NicVAX clinical
development program forward and support our ongoing efforts to secure the
most suitable clinical and commercial partner," said Dr. Leslie Hudson,
interim president and chief executive officer. "We believe NicVAX is now
well positioned to enter Phase III pivotal trials and to secure a strategic
Phase IIb Trial Data
Nabi will present further data from this trial at the Phacilitate
Vaccine Forum on May 30-June 1, 2007 in Munich, Germany and will submit
data for the European Society of Cardiology Congress, September 1-5, 2007
in Vienna, Austria. Nabi also will submit this trial's full 12-month data
for scientific presentation at the American Heart Association's Scientific
Sessions on November 4-7, 2007 in Orlando, Florida. More information about
Nabi presentations is available at http://www.nabi.com.
About the Phase IIb Study
The Phase IIb study is a double-blinded, placebo-controlled and dose-
ranging study comprised of 301 patients and is designed to establish proof
of concept and the optimal dose for the Phase III program. This study was
designed in collaboration with the U.S. Food and Drug Administration and
other global regulatory agencies and incorporates the most current clinical
trial standards and prevailing protocol design for smoking cessation
The trial's primary endpoint is the rate of carbon monoxide (CO)-
confirmed, continuous abstinence from smoking during weeks 19-26 after
first vaccination. Full evaluation of abstinence at the six month primary
endpoint will include reported cigarette consumption, chemical markers of
nicotine in the bloodstream, and behavioral assessment. Secondary endpoints
include the abstinence rate at 12 months, total cigarette consumption,
antibody levels, safety and nicotine dependency. The efficacy rates in this
study incorporate the benefits of other elements of standard of care in
smoking cessation programs, including counseling and behavior modification.
How NicVAX is Designed to Work
NicVAX is an innovative and proprietary investigational vaccine being
developed by Nabi to treat nicotine addiction and prevent smoking relapse.
NicVAX is designed to stimulate the immune system to produce antibodies
that bind to nicotine. A nicotine molecule attached to an antibody is too
large to cross the blood-brain barrier. Therefore, NicVAX blocks nicotine
from reaching its receptors in the brain and prevents the highly-addictive
pleasure sensation experienced by smokers and users of nicotine products.
Pre-clinical and previous clinical data, as well as the study reported
here, show that NicVAX's ability to block nicotine from reaching the brain
could help people quit smoking. Because the body's immune system can be
boosted to produce long-lasting antibodies, Nabi believes NicVAX also could
be effective in preventing smoking relapse. Relapse is a significant
challenge facing smokers and, with currently-available smoking cessation
therapies, relapse rates can be as high as 90% in the first year after a
Development Progress to Date
In September 2005, the company announced that it received a $4.1
million grant from the National Institute of Drug Abuse (NIDA) which is
part of the National Institutes of Health. NIDA has also funded, in part,
the costs for toxicology testing and earlier clinical trials in the U.S.
and contributed scientific and clinical expertise to the program overall.
In March 2006, Nabi Biopharmaceuticals announced that NicVAX had received
Fast Track Designation from the FDA, which facilitates the development of
products that treat serious diseases where an unmet medical need exists.
Nabi Biopharmaceuticals' intellectual property portfolio for technology
related to NicVAX includes both issued and pending patents in the U.S. In
addition, the company holds granted patents in 18 European countries, plus
patents and pending patent applications in numerous other countries around
Cigarette Smoking: A Growing Global Health Challenge
Smoking is a global healthcare problem. The World Health Organization
(WHO) estimates that there are 1.3 billion smokers worldwide with nearly
five million tobacco-related deaths each year. WHO estimates that
approximately 70 - 80 percent of smokers in the U.S. want to quit, but less
than five percent of those who try to quit remain free of the habit after
one year. It is estimated that smoking accounts for $167 billion in
healthcare expenditures and productivity losses each year.(1)
Nabi will host a live webcast today at 4:30 p.m. EDT to discuss the
results of its Phase IIb NicVAX trial as well as the company's first
quarter 2007 financial results, which will be announced today after market
close. Presentation slides - outlining the trial's preliminary data
analysis - will be available as part of the webcast.
An archived version of the webcast will be available at the same
Internet address through May 9, 2007. The audio replay also will be
available through May 9, 2007. The press release will be available on the
company's Web site: