Contradicting rulings of the US patent office on double patenting jeopardize the generic and biosimilar drugs

Obviousness-type double patenting is allowed only in the US, but only if a terminal disclaimer and the same ownership are made for the expiry of the patent. Historically, this provision has hampered the entry of generic and biosimilar drugs due to the legal complexity and cost burden of resolving patent thickets accumulated by the originator companies. The United States Patent and Trademark Office (USPTO) proposed a change in the ruling in March 2024 to avoid double patenting if the patent to which it is tied in terminal disclaimer has any claims that have been invalidated as anticipated or obvious. This rule change aimed to promote innovation and competition by deterring strategies that leverage multiple patents for obvious variants to obstruct competitors. However, after receiving 349 comments on the proposed rule change, the USPTO withdrew its plan in December 2024 despite most comments favoring it. In a contrary move, the USPTO secured a court ruling that the terminal disclaimers do not apply to extended patent expiry due to the failure of the USPTO to prosecute a patent on a timely basis. The double patenting must end to enable more affordable generic and biosimilar drugs.