Bristol-Myers Squibb Co. and partner Ono
Pharmaceutical Co. 4528.TO +2.32% have sued Merck & Co., alleging that its
new cancer drug violates their patent for a method of harnessing the body's
immune system to fight cancer. Bristol and Ono filed suit in federal court in
Delaware on Thursday, the same day that Merck received U.S. Food and Drug
Administrationapproval to market Keytruda as a treatment for the deadly skin
cancer melanoma.
The dispute represents another front in a
multicompany battle in the emerging market for so-called immunotherapy cancer
drugs, which some analysts predict will reach more than $30 billion in annual
sales in the next decade. The drugs have generated promising results in
clinical trials, particularly for melanoma but also for other types of cancer.
Keytruda, the generic name of which is
pembrolizumab, works by blocking a component of immune-system cells known as
programmed death receptor 1. The mechanism helps take a brake off the immune
system, enhancing its ability to destroy cancer cells with what doctors say are
manageable side effects.
Bristol and Ono have developed a competing PD-1
blocker known as nivolumab. The drug went on sale in Japan last week under the
brand Opdivo for melanoma. Bristol has said it expects to file by Sept. 30 for
FDA approval of nivolumab as a melanoma treatment, and by year-end to complete
an application for FDA clearance of nivolumab to treat a form of lung cancer.
Bristol and Ono's lawsuit says Merck's Keytruda
infringes a U.S. patent that was issued to Ono in May on methods of treating
cancer with an anti-PD-1 compound. Bristol has an exclusive license to Ono's
patent.
Bristol and Ono allege that Merck started
developing pembrolizumab after the partners created nivolumab and that Merck
has been aware of their U.S. patent.
"Merck is threatening to exploit that
invention with a later-developed anti-PD-1 antibody," the lawsuit says.
The plaintiffs ask the court to declare that Merck infringes the patent and to
award damages to compensate Bristol and Ono for the infringement.
Merck said the lawsuit was without merit and
that the company was confident it wouldn't be prevented from marketing
pembrolizumab. Similar patent litigation among the companies is under way in
Europe. Merck said in an August filing to the U.S. Securities and Exchange
Commission that the Ono patent was invalid.
The stakes are high. Merck is selling its drug
for about $12,500 a month per patient in the U.S., or $150,000 for a full year
of treatment. Ono's drug in Japan costs about $143,000 a patient for a full
year. The cost of the drugs vary with patient weight and treatment duration.