Patent Law FAQ

This FAQ answers all your questions about patent law, patent procedure, and the patent examination process.

In product-by-process claim rejections, the burden of proof is initially on the patent examiner, but it’s lower than for conventional product claims. According to MPEP 2113:

“The Patent Office bears a lesser burden of proof in making out a case of prima facie obviousness for product-by-process claims because of their peculiar nature” than when a product is claimed in the conventional fashion.

Once the examiner provides a rationale showing that the claimed product appears to be the same or similar to a prior art product, the burden shifts to the applicant. The applicant must then provide evidence establishing a nonobvious difference between the claimed product and the prior art product.

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