Obviousness-type double patenting analysis should focus on the entire claims, not just the differences between the two claims; disclosure of later-claimed use in an earlier patent is only invalidating if the compounds in the two patents are identical.

The district court found asserted claims for a therapeutic compound were not invalid due to obviousness-type double patenting over two earlier-issued claims. The Federal Circuit affirmed, finding the asserted claims patentably distinct from the earlier-issued claims.

In analyzing claims from the first earlier-issued patent, the panel acknowledged that the only difference between the two claimed compounds was the number of members in one ring. But the panel rejected the notion that only the differences should be analyzed—instead “the claims must be considered as a whole.” The proper analysis “requires identifying some reason that would have led a chemist to modify the earlier compound to make the later compound with a reasonable expectation of success.” The panel found no clear error in the district court’s factual findings that the prior art never suggested or provided a reason to expect success in making the necessary modification.

The second earlier-issued claim claimed a chemical intermediary that could be used to produce the compound in the asserted claim. Although the use of the final product was disclosed in the specification of the earlier-issued patent, a court may not rely on the specification of the supposedly invalidating patent in deciding obviousness-type double patenting; only the claims are compared. Earlier cases involving disclosure of uses of products in earlier-issued patents were distinguished because each earlier-issued patent claimed the same compound as was later patented. The claimed intermediary, though, could be used to make a variety of final compounds. Further, the compound of the asserted claim could be made using a different intermediary. Therefore, the intermediary and the final claimed compound were found to be “separate and independent chemical compounds.” 

Finally, the Federal Circuit again noted that secondary indicia of nonobviousness should be analyzed when evaluating claims of invalidity based on obviousness-type double patenting. 

A copy of the opinion can be found here.