The PD-1 inhibitor patent battle raging between Merck & Co. ($MRK) and Bristol-Myers Squibb ($BMY) in the U.S., Europe and Australia has now reached Japan.
The original developer of Opdivo (nivolumab), Ono Pharmaceutical, has filed a patent infringement lawsuit against Merck's Japanese subsidiary MSD K.K. over its plans to launch Keytruda (pembrolizumab). The Merck med was approved by Japan's medicines regulator on September 28.
Ono wants MSD to pay royalties on sales of Keytruda in Japan, but, as in its other lawsuits, is not seeking to have the drug blocked from sale. Keeping Keytruda off the market wouldn't be in patients' best interests, the company says.
Opdivo was first approved in Japan in July 2014 for malignant melanoma and has transformed Ono's fortunes. The Japan-based drugmaker had gone years without a novel drug approval and suffered patent expiries that exposed many of its top-selling products to generic competition.
Opdivo racked up Japanese sales of more than 25 billion yen ($240 million) for the drug in the three months ending June 30, and Ono now expects sales to reach 126 billion yen for the full fiscal year, thanks to a new approval in non-small cell lung cancer.
The Japanese patent cited in the case--co-owned by Ono and eminent immunologist Tasuku Honjo of Kyoto University--has a broad claim, covering the use of anti-PD-1 antibodies as a treatment for cancer.
"We will take appropriate and immediate measures against any infringement or action that will be likely to infringe our intellectual property rights," said Ono in a statement.
The ongoing litigation outside Japan is between Merck and BMS, which licensed the rights to Opdivo. Ono and BMS also filed suit against Merck last year in the U.K. and claimed an initial victory when a court upheld the validity of Ono's patent covering antibodies to the PD-1 receptor for the treatment of all cancers.
Then in March this year, a judge presiding in the U.S. District Court for the District of Delaware turned down an attempt by Merck to dismiss patents awarded to BMS on Opdivo's use as a cancer treatment, although Merck is still pressing its claim in follow-up litigation.
In the US lawsuit BMS is claiming "substantial" injury and damages from the sales of Keytruda, leading some to speculate that Merck could face a claim for royalties of 10% or more on sales of its drug if it loses the case. Given that EvaluatePharma is predicting Keytruda will make $6.5 billion in global sales in 2022, that could equate to billions of dollars over the course of the patents.
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