On the one hand, I can see that companies may want to be cautious and obtain patents before starting expensive clinical trials.

On the other hand, for drugs with large commercial potentials, it seems worth it to start patent applications and clinical trials in parallel and not wait for the long patent application delay (which can easily take years). Otherwise, the useful life of patents will be reduced by that delay.

What is usually done in practice?

  • I don't know about "usually", but I have seen it happen. There are court cases about them validity of those patents (I know of one where the patent was invalid and one where the patent has so far held).
    – user18033
    Apr 5, 2021 at 17:16

1 Answer 1


In practice, how often do U.S. pharmaceutical companies start clinical trials before obtaining their patent from the USPTO?

I'm not an expert at this, but I think the answer is companies pretty much never start a clinical trial before applying for a patent. You need to disclose (publish) quite a lot of technical description about the drug to get a clinical trial approved and you need to file your patent applications before public disclosure of the compound. There is absolutely no reason to wait for the patent to be granted. A patent, when granted, provides protection from the grant date of the application forward for 20 years from the filing date. If the patent prosecution (period from filing to grant) is excessively long due to the USPTO delaying things than there may be a patent term adjustment to account for the extra processing time. As Trish points out there are other provisions in law to compensate for excessive regulatory (FDA) approval time.

Patents typically take something like three years from application to grant although this can vary quite a lot. Drug development is generally much longer on the order of 10 years or more to get to market. It would be advantageous to delay filing a patent application to obtain a longer effective protection, but then the company would be taking the risk of someone else patenting the compound first. Since patents now go to the first to file this is a real risk. I'm not sure what your concern is with "long patent application delay" is. Since any potential infringer would also have to do clinical trials and obtain FDA approval, there is no real potential for a lost sales.

  • Thanks Eric. 1) To be clear, my question is whether companies start clinical trials before their patents are granted. 2) What I mean by the "delay": suppose getting patent approval takes 3 years, and clinical trials take 5 years. If a company wait for patent granting to do clinical trials, the remaining useful patent life is only 12 years to profit from. But if the company starts both patent applications and clinical trials simultaneously, there will be 15 years of remaining patent life. Thus, for high-value drugs, it seems worthwhile to go the second route?
    – J Li
    Apr 2, 2021 at 1:29
  • As I said in my answer, a patent goes to the first to file so there is risk in delaying filing too long. A company would greatly prefer 12 years of protection to none. It would matter greatly whether other companies were working on similar drugs.
    – Eric S
    Apr 2, 2021 at 2:35
  • FDA approval time can also adjust the patent runtime.
    – Trish
    Apr 3, 2021 at 11:27
  • @Trish I didn't know that. Can you expand on it a little, or give me a reference?
    – J Li
    Apr 4, 2021 at 20:56
  • @EricS Yes, but that doesn't answer my question. Let's assume the firm always file for patent at year t. The question is whether the company waits until the patent to be granted (e.g. at year t+3) to start clinical trials --- which, let's say, will be FDA approved at year t+8). The alternative --- which seems to make economic sense of very important drugs --- is to start clinical trials ALSO in year t, concurrent with the patent application, so that after patent approval in year t+3, FDA approval comes in year t+5. This leaves the firm with 3 more years of patent runtime.
    – J Li
    Apr 4, 2021 at 20:58

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