Utility (patentability requirement)

In United States patent law, utility is a patentability requirement.^[1] As provided by 35 U.S.C. § 101, an invention is "useful" if it provides some identifiable benefit and is capable of use and "useless" otherwise.^[2] The majority of inventions are usually not challenged as lacking utility,^[3] but the doctrine prevents the patenting of fantastic or hypothetical devices such as perpetual motion machines.^[4]

The patent examiners guidelines require that a patent application expresses a specific, credible, and substantial utility.^[5] Rejection by an examiner usually requires documentary evidence establishing a prima facie showing that there is no specific, substantial, and credible utility.

The main reason for having the utility requirement is to prevent issuing patents on things which are speculative and may block useful inventions in the future.^{[citation needed]} In a pharmaceutical context, the utility problem usually arises when there is a patent claim on a new drug, but the patent disclosure does not specify (or does not prove) what disease this drug treats.^{[citation needed]} Notably, a full FDA approval of the drug is not required before a patent application is filed. It suffices to demonstrate that this drug candidate passes some established in vitro test (see below).^{[citation needed]}

One commentator explained in 1853 the rationale against useless inventions as:

A patent for a useless invention is thought by some to be void at common law by others by force of the Statute of Monopolies which renders void grants of privileges which tend to the hurt of trade or are generally inconvenient. Now if a monopoly were allowed in a useless invention other persons would be prevented from improving it or turning it to any account whatever so that combinations of utility might be impeded. It would stand in the way of real inventors and hence be mischievous to the public generally.^[6]

European patent law and Patent Cooperation Treaty instead of utility use the term industrial applicability.^[7] Although it serves a similar purpose as the US utility and patentable subject matter requirements, it is more narrow in practice.^{[citation needed]}