Pfizer's 'Trovan' Antibiotic
Tied To Sudden Death,
Liver Damage
By Ransdell Pierson
NEW YORK - The European Union agency that monitors prescription drugs said it has received reports that eight patients who took Pfizer Inc.'s antibiotic Trovan have suddenly died or needed liver transplants since February 1998.
Analysts said the incidents had cast a shadow over Trovan, a fast-growing antibiotic with blockbuster sales potential, although it was too soon to determine whether Trovan itself caused the liver problems. The European Union Agency for the Evaluation of Medicinal Products, in a May 25 report, said the deaths were among 140 documented cases of serious liver injuries seen in Trovan users since Pfizer launched the drug in the United States in February 1998. "These data suggest that the onset and severity of these liver injuries are unpredictable," the European agency said, adding it would need to reassess whether the benefit of taking the drug outweighed the risk.
Trovan (trovafloxacin), a member of the quinolone family of antibiotics which is effective against a wide range of bacteria, was approved by European Union regulators in July 1998 and is sold in eight member nations. It had global sales of $159 million in 1998, including $154 million in the United States. An estimated 2.5 million prescriptions have been written for the antibiotic worldwide, including 200,000 in Europe. Pfizer, the New York drug maker best known for its anti-impotence pill Viagra, said Wednesday it was "strengthening" the Trovan package insert label on its European product to warn of potential liver-related side effects. In addition, Pfizer said it was in "advanced discussions" with the U.S. Food and Drug Administration to revise the Trovan product label in the United States. The European Union advisory, released to Reuters by Pfizer, said about 35 percent of the patients with liver problems also had hypersensitivity (allergic) reactions.
Trovan's current label warns patients to stop using the antibiotic if they develop such reactions, which include skin rash, hives or joint pain.
The agency said it intended to inform patients and doctors about the "unpredictability and potential severity of liver injuries" from taking Trovan, stressing that doctors had to decide on a "case by case" basis whether to prescribe it.
It said patients should be informed to immediately stop the treatment and consult their doctors if they develop signs of liver or pancreatic injury, including fatigue, yellowing of the skin and eyes, severe stomach pain, nausea or vomiting.
"It's a setback for Pfizer," Hambrecht & Quist analyst Alex Zisson said of the liver-damage reports, predicting it could take European and U.S. regulators months to determine Trovan's exact role.
"It may turn out to be a ripple in the pond or it might turn out to be more serious" for Trovan, Zisson said.
He noted that patients on antibiotics are often very ill and take several medications at the same time. "So it could be difficult to trace liver problems to one drug."
Lehman Brothers analyst Anthony Butler said Trovan's European label cautions that rare cases of liver dysfunction have been reported in patients.
In a research report to clients, Butler said the liver problems are reversible upon discontinuation of Trovan and might be attributable in some cases to concurrent use of other medications or to other underlying disease.
"With changes to Trovan's European and possibly U.S. labels, risk has entered one of Pfizer's primary growth drivers," said Butler.
Pfizer shares fell $1.12 to $101 in heavy trade on the New York Stock Exchange.