Bristol-Myers Squibb Challenges Patent on Merck's Pembrolizumab

Bristol-Myers Squibb has filed a lawsuit over Merck’s newly approved immunotherapy drug pembrolizumab (Keytruda), contending that the much-heralded PD-1 inhibitor will infringe upon patents that Bristol-Myers holds on the groundbreaking technology.

The lawsuit was filed in US District Court in Delaware Thursday on the same day that the FDA approved pembrolizumab as a treatment for patients with advanced or unresectable melanoma following progression on prior therapies. Bristol-Myers’ marketing partner Ono Pharmaceuticals also is a plaintiff in the suit.

Although pembrolizumab represents the first PD-1 inhibitor to gain approval in the United States, Bristol-Myers maintains the PD-1 inhibitor it developed—nivolumab—was approved in Japan for patients with unresectable melanoma under the trade name Opdivo in July.

“The invention at issue here covers using antibodies that bind to PD-1 (“anti-PD-1 antibodies”) in a method for treating cancer,” the company said in the suit. “By binding to PD-1 and blocking the PD-1 checkpoint pathway, the anti-PD-1 antibodies allow a patient’s immune system to resume its ability to recognize, attack, and destroy cancer cells.”

Bristol-Myers said the approach “has the potential to revolutionize cancer treatment.”

In a written statement, Merck said it was aware of the legal action and expressed confidence that the pending lawsuit would not prevent pembrolizumab from getting to patients.

“Merck is confident that it will be able to market Keytruda (pembrolizumab) in any country in which it is approved and that it is will not be prevented from doing so by the Ono/BMS patents,” the statement reads. “We believe the suit is without merit.”

Specifically, Bristol-Myers and Ono contend they obtained a patent on nivolumab on May 20, 2014, from the US Patent & Trademark Office. The suit seeks unspecified damages.

“We will appropriately pursue and vigorously defend our intellectual property rights, while always mindful of the best interests of patients,” Bristol-Myers said in a statement.

The two companies have been the leading contenders in a race to develop the first anti-PD-1 agents for the US market since nivolumab generated excitement at the American Society of Clinical Oncology annual meeting two years ago with impressive early-phase results in melanoma.

Since then, Bristol-Myers Squibb has advanced development of the compound as monotherapy and in combinations across various tumor types in clinical trials that have enrolled an estimated 7000 patients. The FDA has designated nivolumab as a breakthrough therapy in lymphoma and has granted the compound fast track status in non-small cell lung cancer, melanoma, and renal cell carcinoma. The company has said it plans to submit an application to the FDA for nivolumab in melanoma during the third quarter of this year.

The FDA evaluated pembrolizumab in advanced melanoma under its Breakthrough Therapy program and granted accelerated approval based upon clinical trial results showing an overall response rate of 24%.

Multiple clinical trials are currently under way exploring pembrolizumab across a variety of tumor types, including a phase II and III study investigating the agent for advanced melanoma. At this point, over 30 studies are exploring the drug.