--Partial hold follows heart failure in patient taking
competitor's hepatitis C drug
--Echocardiograms planned for 67 patients treated in Idenix
study
--No timeline given for potential lift on hold
(Updates with analyst, company commentary beginning with the
fourth paragraph.)
By Drew FitzGerald and Melodie Warner
Regulators dealt Idenix Pharmaceuticals Inc. (IDIX) a new
setback, placing a partial hold on further trials of its hepatitis
C drug after a similar compound from rival Bristol-Myers Squibb Co.
(BMY) raised concerns about the treatments' heart safety.
Idenix said the U.S. Food and Drug Administration informed it
about the hold verbally late Wednesday, citing a patient taking
Bristol's experimental hepatitis C treatment who suffered heart
failure. Bristol earlier this month voluntarily suspended Phase II
testing of its version of the drug, though it is unclear whether
the treatment caused the reported heart failure.
Nevertheless, Idenix is seeking echocardiograms on all 67
patients recently treated with the compound, called IDX184. None of
those patients are currently taking that drug, though they remain
enrolled in a study that combines IDX184 with pegylated interferon
and ribavirin, another hepatitis C regimen.
"The FDA appears to be reluctant to allow expansion into more
patients without assurance that the drug is safe," Bernstein
Research analyst Geoffrey Porges wrote in a note to clients, adding
the event will likely raise concerns about the risks to the
spectrum of programs testing nucleotide polymerase inhibitors, the
class of drugs Bristol, Idenix and others are pushing to improve
hepatitis C treatment.
Idenix shares dropped 29% to $5.89 Thursday, while rival Gilead
Sciences Inc. (GILD), which is developing a rival nucleotide
treatment, fell 1.7% to $57.
Idenix said it expects to submit additional data to the FDA in
the coming weeks.
Test results show Idenix's compound delivers more of its active
ingredient to the liver, for which the treatment is intended, while
Bristol's drug demonstrated toxic properties in other types of
cells, Idenix Chief Medical Officer Douglas Mayers told Dow Jones
Newswires.
A Bristol spokeswoman said researchers found some indications of
safety concerns in preclinical trials on animals, though those
tests featured higher dosages than those used on human
patients.
Both drug makers still use the same active ingredient to treat
the liver-damaging virus, however. Idenix's review of its trial
patients faces an added complication from the combination regimen
patients took after treatment with IDX184, Dr. Mayers said.
"There's more that we don't know than what we do know," Idenix
President and Chief Executive Ronald C. Renaud told analysts on a
conference call Thursday. "Unfortunately, we can't give any kind of
concrete answer on the impact on the timeline" other than to say
the company will move as quickly as possible.
Idenix, which focuses on drugs to treat human viral diseases, is
developing IDX184 as its lead hepatitis C drug. Current treatments
for the serious liver disease generate about $5 billion of
sales.
The latest order represents at least the second setback in as
many years to the Cambridge, Mass., company's hepatitis-C treatment
efforts. The FDA halted a testing candidate in September 2010 on
concerns about potential side effects to the liver. The agency
lifted another hold on Idenix's current hepatitis C drug candidate
in February.
-Jonathan D. Rockoff contributed to this article.
Write to Drew FitzGerald at andrew.fitzgerald@dowjones.com and
Melodie Warner at melodie.warner@dowjones.com
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