U.S. regulators on Thursday approved a new kind of cancer drug
from Merck & Co. that is designed to unleash the body's immune
system against tumors and could generate billions of dollars in
sales.
The drug, which Merck plans to sell under the brand name
Keytruda, is part of a long-anticipated wave of medicines that
could transform cancer treatment and forge a large new market for
pharmaceutical companies.
The Food and Drug Administration cleared the drug,
pembrolizumab, for the treatment of a deadly form of skin cancer,
melanoma. The approval followed a swift review of data from a
relatively early-stage human trial--an unusual move reflecting the
medical community's keen interest in pembrolizumab.
The infused drug is a new type of immunotherapy, a category of
treatments that harness the immune system to fight cancer. It was
approved for people who've failed to respond adequately to Yervoy,
a Bristol-Myers Squibb Co. immunotherapy that works in a different
fashion, and certain other drugs.
Pembrolizumab is the first so-called PD-1 inhibitor to hit the
U.S. market. The drugs block a protein called programmed death
receptor 1, or PD-1, which acts as a brake on certain immune-system
cells to prevent them from attacking healthy tissue. Cancer cells
can escape destruction by latching onto PD-1; PD1 inhibitors block
this interaction at the site of the tumor, releasing the immune
system brake and allowing it to destroy the cancer. Yervoy also
lifts a brake on the immune system but does so earlier in the
immune-cell activation process, which researchers say may cause
more collateral destruction of normal tissue than with PD-1
blockers.
Pembrolizumab and other PD-1-targeting drugs--including those
developed by Bristol-Myers and Roche Holding AG--have generated
excitement among doctors because they appear to induce relatively
high rates of tumor shrinkage and prolong average survival beyond
historical norms in clinical studies. Researchers say the side
effects associated with the drugs appear to be manageable.
"PD-1 is truly a game-changer. It's active in a way that other
drugs are not," said Lynn Schuchter, a medical oncologist who heads
the melanoma program at the Abramson Cancer Center of the
University of Pennsylvania and has assisted in clinical trials of
the Merck drug. "And what's been interesting is the activity of
PD-1 beyond melanoma. It looks to be active in bladder and renal
and lung cancer. So this is bigger than melanoma."
Some analysts believe total annual sales of cancer
immunotherapies could reach about $32 billion by 2025, if more
drugs make it to market to treat a range of cancers. Leerink Swann
estimates Merck's new drug alone could generate annual sales of
more than $6 billion by then.
A competing PD-1 inhibitor, nivolumab, hit the market in Japan
this month, at a price of $143,000 for a year's worth of treatment
for the average Japanese patient. The drug, from Bristol-Myers and
Ono Pharmaceutical Co., is expected to be reviewed by U.S.
regulators in coming months. Other PD-1 inhibitors are expected to
have similarly high price tags, which could fuel more debate about
the affordability of new drugs.
Merck didn't immediately disclose the price for Keytruda on
Thursday
Write to Peter Loftus at peter.loftus@wsj.com
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