Astellas, Pfizer Settle Patent Suit Over Sun’s Copies of Xtandi

Astellas Pharma Inc. and Pfizer Inc. have settled their lawsuit with Sun Pharmaceutical Industries Ltd. over copies of the multibillion-dollar prostate cancer drug Xtandi, court filings show.

The co-plaintiffs and Sun agreed to drop all claims regarding US Patent No. 7,709,517, but they left the door open to renew their respective allegations, according to their proposed dismissal order filed Oct. 20 in the US District Court for the District of New Jersey.

The deal hasn’t yet been approved, but Magistrate Judge Jessica S. Allen earlier this week granted the parties’ request to unseal their joint status update filed Sept. 29, according to a letter order docketed Tuesday. After updating Allen on the status of tasks related to claim construction and fact discovery, the parties asked to delay by two weeks a status conference to allow time for further negotiations in settlement talks.

Astellas, Pfizer’s Medivation unit, and the University of California sued Sun last December alleging Sun’s proposed generic versions of Xtandi’s 40- and 80-milligram tablets infringe the ’517 patent, which covers the drug’s active ingredient, enzalutamide, and pharmaceutical compositions of it.

Enzalutamide was developed by the university, which owns the patent, according to the suit. The university licenses the patent to Medivation and Medivation Prostate Therapeutics. The Pfizer units exclusively sublicense the patent to Astellas. Medivation and Astellas jointly market enzalutamide in the US, and Astellas markets it outside the US.

Pharmaceutical industry watchers are split on whether Xtandi will continue to be targeted by attempts to reduce drug prices following the treatment’s absence from the Biden administration’s list of drugs subject to Medicare negotiations.

Lawmakers and other critics of drug industry behavior say the US price of the drug is too high—without insurance, the retail price can total more than $13,000 a month, according to data compiled by Bloomberg LP—and that the government should take steps to bring the cost more in line with what patients in other countries pay. They point out that grants provided by the US government helped fund University of California researchers’ development of innovations behind several patents on the drug.

Bloomberg Intelligence analyst Duane Wright wrote in an Oct. 20 note that “we expect Xtandi will be on a future list of drugs subject to Medicare price cuts beginning Jan. 1, 2027, making administrative action that would be subject to legal challenge, and possible delays, unnecessary”—a reference to the National Institutes of Health’s potential, if unlikely, granting of march-in rights.

The ’517 patent is one of three listed for Xtandi in the US Food and Drug Administration’s registry of approved drugs, the Orange Book. Its August 2027 expiration is the latest of the three.

Astellas reported Xtandi had US sales of $2.5 billion in the 12 months ended March 31, 29.5% of revenue, according to Bloomberg data.

Pfizer reported “Xtandi alliance” US revenue of $1.2 billion in 2022, 1.2% of overall revenue, according to Bloomberg data.

Venable LLP and Walsh Pizzi O’Reilly Falanga LLP represent Astellas, Medivation, and UC. Katten Muchin Rosenman LLP and Rivkin Radler LLP represent Sun.

The case is Astellas Pharma Inc. v. Sun Pharm. Indus. Inc., D.N.J., No. 3:22-cv-7357, order granting request to unseal Sept. 29 letter issued 10/23/23.