Can product-by-process claims be rejoined in a patent application?

Yes, product-by-process claims can be rejoined in a patent application under certain circumstances. The treatment of product-by-process claims for rejoinder purposes is outlined in the MPEP 821.04(b):

“Where product and process claims drawn to independent and distinct inventions are presented in the same application, applicant may be called upon under 35 U.S.C. 121 to elect claims to either the product or process. The practice of restricting between product and process claims depends on the product. Where the product as claimed can be made by materially different processes, an election of claims to a specific process or processes and the product made thereby may be proper.”

For rejoinder:

• If the product claims are found allowable, the process claims that depend from or otherwise require all the limitations of the allowable product claim will be considered for rejoinder.
• Product-by-process claims that are limited to the specific process steps recited in the product claims may be eligible for rejoinder.
• The examiner must ensure that the process steps do not materially change the product or result in a materially different product.

To learn more:

• Rejoinder
• Product-by-Process Claims
• Patent Application
• Claim Eligibility