Patent A was filed formally, March-13-2010, published Nov-2011

Patent B was filed provisional, March-14-2010, then formal-filed Mar-2011

The patents covered some similar areas, but Patent B spec was much more complete, covering the areas of Patent A and much more.

This might have been a straight forward case, but there's a couple of twists.

  • Patent A was abandoned after years of failing to overcome office actions.

  • Patent B issued on the basis of simpler broad claims

  • In continuations Patent B ultimately succeeded with claims that overlap, but failed to issue, in Patent A

Since the publication date of A was after B was filed, how does that matter in this case ?

Could the owners of Patent B (successfully) pursue the owners of Patent A, for example in infringement actions B vs A ?

Could Patent A be used to invalidate Patent B e.g. in IPR ? in litigation of B vs C ?

Can Patent B cite Patent A as prior art ?

Many interesting questions - am sure there's more twists haven't thought of ... point out the best ones ?

1 Answer 1


Interesting question. I would say that the burden had fallen on Patent Application A to pursue an examiner switch etc. and somehow push it through the patent office to grant. Because they failed to do that yet Patent B was able to do that, I don't think Patent B holders should be penalized. If it's true that Patent A should not have been granted and the office actions were correct, then it would stand to reason that the same arguments may be made in invalidating Patent B. That is to say though, that Patent A's prosecution history should have no direct bearing on Patent B except for similar arguments being made at trial for invalidation of Patent B.

So I would say that: No, Patent A cannot be used to invalidate directly. No, Patent B cannot cite Patent A as prior art because it was not yet a patent, nor can it cite the application because it is not prior art, as publication date was after the filing date of Patent B. Yes, Patent B owners can successfully sue Patent A users if there is infringement because Patent B owns the patent. - Again it would have been up to Patent A holders to pursue a more aggressive stance at the PTO to get another examiner or come up with better arguments etc. to get it passed. Or Patent A users should have a fairly good argument to invalidate Patent B. So in the end, it seems to me that Patent A owners either dropped the ball or no patent should have issued at all with the broad claims that the question is asking about. Either way it is fair for Patent A and for Patent B owners.

But what's also interesting I think is that this shows another valuable aspect of keeping prosecution open and not abandoning within a reasonable amount of time.

I should add though that as far as I know it, none of what I have said above is the law. These are just my reasonable thoughts on the matter and potentially one way that it is resolved.

  • 1
    An generally good answer but you can't get a new examiner. You can get the examiner's SPE involved, you can appeal. Keeping a prosecution going (by fling RCE's or continuations) in the hope that someone else will get similar claims through and then you can do - what? is not logical.
    – George White
    Dec 28, 2020 at 2:03
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    Speaking of logical, the patent prosecution process is not science. What one examiner may continually reject another examiner might allow. It might be better arguments, they might have stumbled on different art, or most likely are just different people with different attributes. There might be subtle differences in the claims that the OP doesn't appreciate. If art was found by examiner A that examiner B didn't find their might be fodder for invalidating B. But B might be fine, and examiner A might be an "I allow nothing" person.
    – George White
    Dec 28, 2020 at 2:05
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    And the question says spec. of B was more complete. Possibly A's claims were not enabled. A 112 rejection is just as rejected as a 102 or 103.
    – George White
    Dec 28, 2020 at 4:53
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    And in the scenario there is no “Patent A”since it didn’t issue. Also patent application A would not have more or less weight if it had issued.
    – George White
    Jan 24, 2022 at 20:08

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