Shares of Bristol, which closed at $55.49 on the New York Stock
Exchange, were down 6.2 percent at $52.08 after hours.
The pharmaceutical company cited "a review of data available at this
time" for the decision to hold off on filing for Food and Drug
Administration approval of the combination of its cancer drugs
Opdivo and Yervoy.
Jefferies analyst Jeffrey Holford said in a research note that he
still expects the Bristol immunotherapy combination to be approved
in the second half of 2018 and sees "no real change to valuation or
estimates as a result of this update."
But the move helps secure Merck & Co Inc's current lead in the
development of combination lung cancer treatments.
Merck last week said U.S. regulators had agreed to an accelerated
review of its application to combine immune system-boosting drug
Keytruda with chemotherapy as an initial therapy for advanced lung
Merck said the FDA would decide by May 10 whether to approve its
Keytruda and Opdivo, which both block a protein called PD-1 to boost
the ability of the body's own immune system to kill cancer cells,
are already approved to treat a range of cancers, but their biggest
market would be first-line lung cancer. Yervoy targets a different
protein called CTLA-4.
Immunotherapy is revolutionizing some areas of cancer care but
giving it on its own only seems to work better than chemotherapy in
previously untreated lung cancer patients who have high levels of a
protein called PD-L1. Merck's Keytruda is already approved for such
[to top of second column]
Since just a quarter to a third of non-small cell lung cancer (NSCLC)
patients have tumors with at least 50 percent of cells producing
PD-L1, around 70 percent of the market is still up for grabs for
successful combination products.
Jefferies' Holford said he still expects the front line, or initial,
treatment of NSCLC patients to evolve toward combinations of
immunotherapy drugs without chemotherapy, where Bristol-Myers and
AstraZeneca Plc have super positions.
(Reporting by Deena Beasley; Editing by G Crosse and Gopakumar
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