(Adds analyst comment)
By Toni Clarke
WASHINGTON, July 31 The benefit of Baxter
International Inc's experimental immune deficiency
therapy, HyQvia, outweighs the risks, an advisory committee to
the U.S. Food and Drug Administration concluded on Thursday.
The panel voted 15-1 that the available data shows a
favorable benefit-to-risk ratio for the drug, which is designed
to treat primary immunodeficiency diseases. These are genetic
disorders in which certain cells of the immune system are
missing, leading to infections, recurrent pneumonia and
abscesses of the organs.
The FDA is not obliged to follow the advice of its advisory
panels but typically does so.
The agency had raised concerns that some patients developed
high levels of antibodies to a component of the treatment.
Antibodies are used by the immune system to fight off viruses
and other foreign substances in the blood.
Baxter's data showed the elevated antibodies had no clinical
impact on patients. The FDA said there is, nonetheless, a
possibility that long-term exposure to the product could cause
inflammation of the brain and bowel, as well as fertility
Panelists said the risk remains theoretical, and they voted
against requiring routine monitoring of antibody levels. They
also voted against restricting availability of the product. The
FDA had asked whether certain subgroups of patients, such as
pregnant women, male children and patients with certain
inflammatory conditions, should be excluded.
The votes follow a far more cautious assessment of HyQvia by
FDA reviewers on Tuesday.
Michael Weinstein, an analyst at J.P. Morgan, lowered his
earnings estimate for Baxter on Thursday, before the panel
meeting, to reflect the company's divestiture of its vaccines
business and an assumption that HyQvia "fails to reach the US
market following our negative read of the FDA panel documents."
Baxter's shares were down 1.3 percent at $75.08 in afternoon
trading following the vote.
HyQvia, which was approved in Europe in 2013, combines
immune globulin (IG), a substance made from human blood plasma,
and recombinant human hyaluronidase, or rHuPH20, a genetically
engineered enzyme that increases absorption of the IG and allows
it to be used less frequently than traditional products.
The FDA declined to approve the product in 2012, and asked
for more information about its possible impact on fertility
after some patients in a clinical trial developed antibodies
against rHuPH20, which Baxter licensed from Halozyme
Halozyme's shares rose 7.25 percent to $9.89 in afternoon
trading following the vote.
"The risk-benefit considerations are very different for
HyQvia compared to other IG products because the main
immunogenetic component of concern (rHuPH20) is not a
life-saving therapeutic," the FDA's report noted.
FDA scientists reiterated their concerns on Thursday, saying
it could take years to fully understand the risks.
Existing IG therapies are given intravenously every three to
four weeks in a hospital, or by injection at home every one to
two weeks. HyQvia is designed to be injected at home every three
to four weeks.
Derrick Sung, an analyst at Sanford Bernstein, said he
believes HyQvia will be a "significant growth driver" for
Baxter. He expects the product to be approved by the end of the
year and estimates it could generate peak sales of $800 million.
(Reporting by Toni Clarke; Editing by Eric Beech and Leslie