| Washington, July 30
Washington, July 30 Advisors to the U.S. Food
and Drug Administration will meet on Thursday to discuss the
relative risks and benefits of Baxter International Inc's
experimental treatment for certain hereditary disorders
of the immune system.
The FDA on Wednesday posted its preliminary assessment of
the data on its website. The agency is seeking guidance from a
panel of outside experts on whether the benefits of the product
outweigh the risks. The FDA is not obligated to follow the
recommendations of its advisors, but typically does so.
Baxter's therapy, HyQvia, is designed to treat primary
immunodeficiency diseases. These are genetic disorders in which
certain cells of the immune system are missing, leading to a
infections, recurrent pneumonia and abscesses of the organs.
HyQvia combines immune globulin (IG), a substance made from
human blood plasma, and one vial of 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 after some
patients in a clinical trial developed antibodies against
rHuPH20, which Baxter licensed from Halozyme Therapeutics Inc
. HyQvia was approved in Europe in 2013.
Baxter's data showed the elevated antibodies, which the
immune system produces to fight foreign bodies, had no clinical
impact on patients. However, the FDA was concerned about the
theoretical potential of long-term exposure to the product to
cause inflammation of the brain and bowel, as well as fertility
"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. The benefit of
the product is primarily one of convenience.
Eun Yang, an analyst at Jefferies LLC, said in a research
note that without therapeutic advantages in a well-supplied
market, the "FDA does not have to take risks of approving
Even if approved, Yang added, its commercial potential would
likely be very limited given the concerns about male fertility.
He estimated that peak U.S. and European sales would reach $740
million, translating into royalty revenue for Halozyme of $37
Existing immune globulin therapies are given intravenously
once every three to four weeks in a hospital, or by injection at
home once every one to two weeks. HyQvia is designed to be
injected at home once every three to four weeks.
(Reporting by Toni Clarke in Washington. Editing by Andre