I have a question about the prior art applicability of earlier-filed later-published applications having a common inventor or a common assignee.

Earlier filed application: Indian Patent application IN2765DEL2009 filed June 30, 2010 and published February 1, 2013.

International Application WO2013/098829 filed December 30, 2011 and published July 4, 2013 (US is a designated state).

Both applications are identical and share the same inventor and the same applicant. The Earliest application (IN2765DEL2009) was filed 18 months before the International application.

Assuming that the Applicant will enter national phase in US, does the Indian Patent application (IN2765DEL2009) qualify as "prior art” in US?

If not, how can we prevent this Applicant from obtaining two patents for the same invention?


2 Answers 2


First, there is nothing unusual or wrong with an inventor getting patents in multiple counties that cover the same subject matter. It is done all the time and is what the PCT system was set up to facilitate.

Under the Paris convention the original Indian patent that was filed longer than a year before the international application shouldn't qualify to provide priority to the international application. But the Indian patent published after the international application was filed so it did not "break novelty" of the international patent. In most places (not the US) that matters.

In the US, for the dates involved, we still had a robust 1 year grace period so if the inventors were 100% in common the Indian patent application could have published up to a year before the international application and still not have been prior art in the US.

  • Thanks you Mr. White for your quick reply. Do you think that a US national application of the international application WO2013/098829 might be provisionally rejected for same invention double patenting?
    – harpers01
    Sep 5, 2013 at 20:12
  • No, the national stage of a PCT application is technically the SAME application as the PCT aplication it came from. That's why the word "stage" is used. Any PCT application that designates the US (and the default is that all PCT applications designate all states) is a US application, and it is a UK application and if filed today would also be an Iranian application, etc. in 144 more countries. The two documents represent different phases of getting to a single US patent.
    – George White
    Sep 5, 2013 at 21:16
  • Can the PCT application claim priority on the Indian application?
    – Kevin
    Jun 3, 2014 at 17:48

For all I can see, the PCT application (WO/2013/098829) does not actually claim any priority: http://patentscope.wipo.int/search/en/WO2013098829

Its effective date therefore is in any case its own filing date, i.e., December 30, 2011.

However, according to the OP, said Indian patent application is post-published after the effective date on February 1, 2013. It will therefore normally not be considered as prior art unless in the same jurisdiction. (E.g., a post-published EP application with an earlier priority date is valid prior art for another EP application for the purpose of evaluating novelty; however, the same does not apply to post-published US applications with an earlier priority date).

Such documents, if they are cited at all, should be listed in the section "certain documents cited" (Box VI.) in the PCT IPRP / IPER, so that the national offices can evaluate them according to their own law in the national phase.

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