Merck is planning to sell a subcutaneous version of its blockbuster Keytruda that can be injected rather than administered intravenously.  Yet, standing in the way of that is a growing portfolio of patents recently acquired by Halozyme Therapeutics.  In 2024, Halozyme was awarded numerous patents covering modified PH20 hyaluronidase polypeptides.  Merck immediately went to the Patent Office and filed petitions for the patents to be cancelled.  What is the likelihood Merck’s patent challenges will succeed?  Or Merck will be compelled to sign a license for Halozyme’s patents. 

In February 2023, United States Senator Elizabeth Warren penned a letter to Kathi Vidal, Director of the USPTO, asking what the Patent Office can do to blunt Merck’s use of patents to stall entry of lower-cost alternatives for Keytruda.  Unfortunately for consumers, the answer may be, not that much.

Senator Warran recently asked what the Patent Office can do about patent thickets. Yet, the courts are in the unique position of having to contend with scores of patents asserted within a single suit.  When a brand pharmaceutical company shows up with 20, 60 or 100 patents in a single suit, those challenges can be exacerbated by orders of magnitude. So, how have courts face this challenge?  Regeneron’s pending patent suit against Mylan over its prospective biosimilar for Eyelea® is an interesting example.