I know that chemical compounds are usually first patented right after discovery, long before they are clinically tested. Is there, however, any requirement on the application for proof of its intended therapeutic benefit?

  • If the answer to this question is no, why wouldn't an applicant claim use for a plethora of diseases?
  • If yes, what kind of evidence is required?

Thanks in advance for your time.

2 Answers 2


Pharmaceutical patents are not my area, and it's very specialized in that patent attorneys in working in the field tend to have related PhDs. Therefore, this answer will be evolving as I learn more. At a high-level, my understanding is that what is being patented are methods of production, delivery, or chemical composition of medicines, but absolute proof of efficacy seems not a requirement.

I'd highly recommend looking up some famous drug patents and reviewing the claims, and seeking out review articles on the subject from sites like ipwatchdog and The National Law Review, among others. Certain financial publications may also have relevant articles, such as this recent article on Forbes.

You may also want to look at USPTO guidelines for the US. It's fairly complicated.

  • Utility of a drug or therapeutic technique is a requirement

An invention that is “inoperative” (i.e., it does not operate to produce the results claimed by the patent applicant) is not a “useful” invention in the meaning of the patent law ...


...the defense of non-utility cannot be sustained without proof of total incapacity.” If an invention is only partially successful in achieving a useful result, a rejection of the claimed invention as a whole based on a lack of utility is not appropriate.

Actual therapeutic efficacy seems not to be a requirement:

Courts have repeatedly found that the mere identification of a pharmacological activity of a compound that is relevant to an asserted pharmacological use provides an “immediate benefit to the public” and thus satisfies the utility requirement. As the Court of Customs and Patent Appeals held in Nelsonv.Bowler: "Knowledge of the pharmacological activity of any compound is obviously beneficial to the public."

It's a lot more complex than these two excerpts convey, but the cited source goes into much greater detail, with the relevant precedents.

  • An examiner may request proof of utility

In appropriate situations the Office may require an applicant to substantiate an asserted utility for a claimed invention... (“When the operativeness of any process would be deemed unlikely by one of ordinary skill in the art, it is not improper for the examiner to call for evidence of operativeness.”)

Again, the cited document goes into much greater detail. You'll probably also want to review 2112 Requirements of Rejection Based on Inherency; Burden of Proof [R-07.2015]

I also found this interesting article that discusses patent protections for new uses of known drugs.

  • What about the second part of the question? My guess is that you would need a separate patent for each disease treated but I'm not sure of this.
    – Eric S
    Sep 8, 2017 at 2:05
  • 2
    Thanks a lot for these comments. So I had a look at several of the patents on Abacavir, an AIDS drug. I noticed that even the process-patents mention its anti-viral use (without proof). If a competitor comes up with a different use, this seems patentable (see ruttlermills.com/Blog/2012/8/patenting-new-us), although I don't know whether this relates to new diseases or more to different ways of administering the drug.
    – buzzie13
    Sep 8, 2017 at 9:10
  • @buzzie13 Thanks. Again, this is not my area, and I didn't have a lot of time to research it, but I figured some information was better than no information. chempatent1981's answer is sound, especially in that it links to the EPO guidelines. That was helpful in that I was then able to search for USPTO guidelines (answer amended.)
    – DukeZhou
    Sep 8, 2017 at 16:12
  • 2
    Thanks DukeZhou, this is excellent. It seems the answer is neither that there is no proof necessary, nor that full proof of clinical efficacy is required. But it to put it simply, there is some minimal therapeutic proof necessary. The pharmacological quote seems to me this would be for example preclinical lab results. Thanks again, really cleared things up!
    – buzzie13
    Sep 8, 2017 at 18:43

I am European-based so I will talk only for Europe. But I do know that US is more free than Europe, so most likely the same goes for US, perhaps with different claim formulation.

In Europe (EPO proceedings) the applicants actually often claim use for a plethora of diseases. There are claims like "Use of compound X as a medicament". If the compound is new and depending on the disclosure, this might be patentable. Otherwise you go for a claim like "Use of compound X as a medicament for...". Now, if in future you discover a new use for this drug (and this is not obvious of course) you may also claim that use. So if you had the use of compound X for diabetes and then you find out that it may be used for e.g. Parkinson, you can claim it. Independently of the above, you may also claim stuff like dosage strength of a pill (if for some reason it proves non-obvious), the type of the drug formulation (transdermal patch, double-layered pill, syrup, etc). Those are all actual cases. For the disease-related types of claims you can have further reading here: http://www.epo.org/law-practice/legal-texts/html/guidelines/e/g_vi_7_1.htm

  • 1
    Thanks a lot for this info. This clears up the second part of my question.
    – buzzie13
    Sep 8, 2017 at 18:30

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