4th UPDATE:FDA Panel Backs Denosumab As Osteoporosis Treatment
14 August 2009 - 12:51AM
Dow Jones News
WASHINGTON--(Dow Jones) A Food and Drug Administration panel on
Thursday unanimously backed a potential Amgen Inc. (AMGN)
blockbuster drug for fragile bones, but suggested limits on its use
that could slow adoption of the drug.
The expert panel said the drug denosumab should be used to treat
osteoporosis but not to prevent the disease in women who are at
risk of developing it. The FDA usually follows the advice of its
expert panels but isn't required to.
Amgen, the biggest U.S. biotechnology company by sales, is
placing a big bet on denosumab, hoping to grab a share of the
roughly $7 billion market for osteoporosis drugs. Hopes for FDA
approval have helped boost Amgen's stock price by about 30% in
recent months.
About 10 million Americans have osteoporosis, or bone weakness
that places people at high risk of suffering bone fractures, while
an additional 34 million have low bone mass that puts them at risk
for developing osteoporosis.
The panel said treatment with denosumab should be limited to
women who have a history of fracture or are at high risk for
fracture. Panel members also said women should try other treatments
first until more long-term safety data is available for denosumab,
in particular about whether the new drug raises risks for serious
infections and cancer.
The FDA has a deadline to make a decision on denosumab by
mid-October, but that timetable could be delayed, especially if the
agency decides it needs a stringent safety monitoring plan for the
drug after it goes on the market. The panel called for such a
plan.
If approved, the drug would be sold under the brand name Prolia.
It is injected twice yearly, which Amgen says represents an
advantage over other drugs that have to be taken more often.
The FDA said denosumab was effective at increasing bone-mineral
density and reducing the risk of spine fractures by nearly 70% and
hip fractures by 40% over three years compared to women not taking
the drug. However, the agency raised concerns about its impact on
the immune system.
To treat or prevent osteoporosis, denosumab is designed to
inhibit a protein known as RANK Ligand that is involved with bone
destruction. The same protein also plays a role in the body's
immune system.
The agency said clinical trials involving denosumab showed a
slightly higher rate of serious infections and the development of
certain types of cancer. However, the data didn't reach statistical
significance, meaning the differences could be a chance
finding.
Amgen officials said there was no evidence seen in clinical
trials that denosumab suppresses the immune system and increases
risks for infections and cancer.
Catherine Stehman-Breen, Amgen's vice president of global
development, told the panel that denosumab has a "favorable safety
profile," with most adverse events being "mild-to-moderate."
Amgen officials said they already have long-term studies in
progress that can be used to track safety issues. They said they
plan additional studies if denosumab is approved.
Denosumab is the first type of drug in its class and acts in a
different manner than many other osteoporosis drugs, such as
Boniva, Fosamax and Reclast, which are known as bisphosphonates.
These drugs, which are delivered orally or through an infusion,
have their own side effects, including a risk of a rare jaw decay
problem.
The panel was asked whether there are women with low bone
mineral density who would benefit from taking denosumab as a
preventive step. A yes vote would have expanded the potential
market, but the the panel voted no by a 13-2 margin.
The panel backed use of the drug for certain prostate-cancer
patients but rejected it for women with breast cancer being treated
with aromatase inhibitors.
Amgen said it was too early to discuss the pricing of denosumab,
but like other sophisticated biotechnology drugs it is expected to
cost thousands of dollars a year.
Reclast, made by Novartis AG (NVS), is an infusion that is given
once a year and would be the most direct competitor to denosumab,
if approved. That drug has a wholesale cost of $1,000. Generic
versions of Merck & Co.'s (MRK) Fosamax cost less than $20 a
month.