Viagra's Competitors to Disclose Data on Effectiveness, Safety
Bloomberg News
June 2, 1998, 10:01 a.m. PT
Viagra's Competitors to Disclose Data on Effectiveness, Safety
San Diego, June 2 (Bloomberg) -- Physicians and investors
will learn more today about two impotence pills aiming to compete
against Pfizer Inc.'s Viagra as researchers release data on
clinical trials of the two medications.
Schering-Plough Corp. and Zonagen Inc. will apply within the
next month for U.S. approval to market their entry, Vasomax.
Apomorphine, a tablet being developed by a joint venture of
Abbott Laboratories and Japan's Takeda Chemical Industries is
likely to be ready for consideration in about a year.
The presentations at the annual meeting of the American
Urological Association will provide information on two pills
closest to challenging Viagra, which met unprecedented demand
after its April introduction. While Viagra appears to be the most
effective of the three, Vasomax and apomorphine could be used by
men who can't take Viagra because they're on heart medication.
''Whatever drug that comes along against Viagra is going to
have to be good,'' said Ira Sharlip, a San Francisco-based
impotence expert. ''Viagra has set a standard for safety and
efficacy that has to be equaled or exceeded in other drugs.''
Viagra has been the focus of media attention during the past
month because its introduction caused millions of people to
openly discuss the issue of impotence for the first time and
created a market that drug-industry analysts say could reach $4
billion in sales annually.
Impotence is a problem for as many as an estimated 30
million men in the U.S., including more than a third of 40-year-
olds and two-thirds of 70-year-olds. While surgery, vacuum pumps,
prostheses, penile injections and drug delivery through the
urethra have been available for years, they can be painful and
awkward to use, and have left many men reluctant to discuss the
problem with their doctors.
Vasomax
Schering-Plough last year joined the battle for the
impotence market by acquiring rights to market Zonagen's Vasomax
to treat male impotence.
Investors saw that partnership as a vote of confidence in a
drug has been the subject of at least eight lawsuits by
shareholders who say Vasomax doesn't work and the company is
guilty of fraud.
Zonagen shares have doubled so far this year after plunging
more than 60 percent last year after Manuel Asensio of New York-
based Asensio & Co. issued a news release saying Vasomax has
dangerous side effects and is ineffective.
The company has declined to comment on the allegations,
except to say they are groundless.
Previous Zonagen SEC disclosures show that in a study of 435
men, 40 percent of those taking Vasomax and 34 percent in another
trial of 360 men reported positive responses from the drug,
including an erection and successful intercourse.
That was well below the response rate of as much as 80
percent in tests for Pfizer's Viagra.
Apomorphine
Apomorphine, which is being developed by the Takeda-Abbott
venture known as TAP Pharmaceuticals, is about a year behind
Vasomax.
It's a tablet placed under the tongue, which could enable it
to take effect faster than a swallowed pill like Viagra.
Investors said they're most interested in what the study
says about apomorphine's side effects because earlier trials have
shown that it can cause vomiting and nausea.
''The questions are how long did you see nausea and how long
does the drug work? The longer the better,'' said John Schroer,
manager of the $1.1 billion Invesco Strategic Health Sciences
Fund.
Concern about safety of impotence drugs was raised last
month after the Pfizer reported the deaths of six men who had
been prescribed Viagra. Yesterday, the FDA said it's only
confirmed that four of the six had used the drug.
Doctors attending the urology meeting said they're not
surprised that four of some 1 million men on the drug have died.
The bulk of men with impotence are ill or elderly and the deaths
may be unrelated to Viagra's use, they said.
Side Effects
Still, Viagra should not be taken with nitrates, common
drugs that dilate arteries in patients with chest pain. That
combination can lead to severely lowered blood pressure, a heart
attack, or death. And so far, it appears that Vasomax and
apomorphine don't present this risk.
Zonagen President and Chief Executive Joseph Podolski said
researchers will know more about Vasomax's effectiveness and
safety than they did about Viagra before its U.S. introduction.
Schering-Plough last week won approval to market it in
Mexico, a much smaller market than the U.S. The company will be
able to look for side effects that might not have shown up in
clinical trials involving only a few thousand patients.
''That means millions of doses of the drug will have been
used already before the U.S. introduction,'' Podolski said.
To be sure, Vasomax and apomorphine aren't guaranteed of
winning FDA approval, and both are yet to even submit the drugs
for such review.
''I don't think you'll get all the answers at this
meeting,'' said Schroer.
--Jim Finkle in San Diego through the Princeton newsroom (609) |
