FDA Deals Blow To Pfizer By Limiting Drug Linked To Liver Failures
June 09, 1999 8:35 PM
WASHINGTON -(Dow Jones)- The Food and Drug Administration
Wednesday issued stronger-than-expected restrictions on Pfizer Inc.'s
antibiotic Trovan, saying the drug should be used only by the sickest of
patients in hospitals or other inpatient facilities, and never for longer than
two weeks.
In addition, the FDA said treatment should be discontinued sooner if any
liver-failure symptoms are noticed.
Analysts said the action would kill outpatient use of the drug, which was
linked to some 140 liver failures that led to six deaths and four liver
transplants.
Pfizer was unhappy about the labeling change, and news of the
restrictions surprised investors, prompting Pfizer shares (PFE) to close
down $6.063, or 5.5%, to $104.938.
"We have a difference of opinion with the agency over the interpretation of
these data and the regulatory action being taken," said Joe Feczko,
Pfizer's senior vice president of world-wide medical operations and
regulatory affairs. "Pfizer believes that this risk assessment requires
additional scientific evaluation and analysis in order to provide physicians
with the proper clinical guidance to use Trovan safely and effectively."
Pfizer said more than 2.5 million prescriptions have been written for
Trovan, which was introduced in February 1998.
A consumer advocacy group had urged the FDA to ban the drug.
Americans can buy eight other antibiotics from the same drug class,
called quinolones, that are equally effective but less dangerous to the
liver, Dr. Sidney Wolfe of the consumer advocacy group Public Citizen
said last week.
Every drug causes side effects, and the FDA often approves drugs with
liver risks as long as doctors are warned to monitor patients carefully so
they can stop the treatment if a problem arises. Trovan's current label
tells doctors that monitoring patients' livers is advisable, but Wolfe had
said that wasn't enough.
The problems with Trovan are a setback for Pfizer, which has been
hoping the drug would generate blockbuster sales. Trovan had sales of
$160 million last year.
"This represents a doomsday scenario for future significant sales of
Trovan," said Neil Sweig, analyst at Southeast Research Partners. In
addition to its impact on U.S. sales, he said the move would jeopardize
approval in several foreign countries where the drug is not yet on the
market.
Because of the risk of liver damage, federal regulators said that the drug
should be restricted to patients with severe infections in hospitals or
other long-term care facilities. The drug should no longer be used for
patients with less-serious outpatient infections, and the drug will no
longer be sold in retail pharmacies, the agency said. In addition, therapy
shouldn't continue longer than 14 days, the FDA said.
Analysts were expecting some sort of label change for the drug, following
an announcement by Pfizer last week that it was in discussions with the
FDA regarding the liver problems. But the restrictions on the drug were
stronger than many on Wall Street anticipated, and will essentially end
outpatient use of Trovan. Outpatient use has represented about
two-thirds of the 2.5 million prescriptions for Trovan to date, according to
Pfizer.
Feczko said the first clear indication of the potential for serious liver
damage came in May, when the company received reports of three
patients needing liver transplants after taking Trovan.
Pfizer had wanted to modify the drug's label to warn of the potential for
liver damage, but still allow for outpatient use in some cases. The FDA
insisted on the more severe restrictions.
"To have a toxicity relative to the liver is not uncommon," said Murray
Lumpkin, deputy director for the FDA's Center for Drug Evaluation and
Research. "To have a toxicity of this magnitude is uncommon."
Still, Lumpkin noted, liver toxicity was rare enough that it wasn't picked
up in tests of the drug prior to approval, tests involving 7,000 patients.
The problems showed up in the FDA's post-approval reporting system,
after doctors had prescribed Trovan to millions of patients.
Pfizer said it will fully comply with the restrictions. Feczko acknowledged
some evidence of liver damage, but said, "when you take all things into
account, (the overall risk-benefit) doesn't seem to be drastically different
than other antibiotics." Trovan, he added, has some unique benefits,
including activity against certain drug-resistant bacteria. He said the
company was in discussion with European regulators over what
additional changes need to be made to the Trovan label in Europe.
Copyright (c) 1999 Dow Jones & Company, Inc.
All Rights Reserved.
smartmoney.com
|
