Friday, March 3, 2017

PTAB: No Reasonable Expectation of Success Despite Prior Art Suggesting Naproxen/Esomeprazole Tablet

In a final written decision (IPR2015-01773), the Patent Trial and Appeal Board (PTAB) found claims of U.S. Patent No. 8,858,996 (the ‘996 Patent) directed to a tablet of naproxen and esomeprazole to be valid (non-obvious).  Claim 1 of the '996 Patent states:

1. A pharmaceutical composition in unit dosage form in the form of a tablet, said composition comprising: naproxen in an amount of 200–600 mg per unit dosage form;
and esomeprazole in an amount of from 5 to 100 mg per unit dosage form,
wherein upon introduction of said unit dosage form into a medium, at least a portion of said esomeprazole is released regardless of the pH of the medium, and release of at least a portion of said naproxen is inhibited unless the pH of said medium is 3.5 or higher.

Petitioner contended that the claims of the ‘996 patent were obvious over the combination of U.S. Patent 5,698,225 and WO 00/26185.  Despite the PTAB finding that there was teaching/suggestion/motivation in the prior art, the PTAB found the claims of the '996 patent to be non-obvious because a person of ordinary skill would not have had a reasonable expectation of success.  Below are relevant excerpts from PTAB’s decision:

Teaching/Suggestion/Motivation

[W]e find that an ordinarily skilled artisan, seeking to avoid the significant disadvantages associated with misoprostol, and to create a combination acid inhibitor-NSAID pharmaceutical composition that could be prescribed to women of childbearing potential, would have been motivated to seek a replacement acid inhibitor for misoprostol and would have turned to the PPIs omeprazole and its (-)-enantiomer, esomeprazole. Indeed, as Petitioner further points out, WO ’185 expressly teaches that omeprazole possesses “a very good safety profile,” , and is a “‘logical choice’” for stress ulcer prophylaxis.

Reasonable Expectation of Success

Petitioner has not adequately rebutted Patent Owner’s argument that the skilled artisan would have expected, based on the teachings of WO ’185, that the sodium bicarbonate would completely break down the enteric coating protecting the naproxen core of the ’225 patent in a medium. In this scenario, Patent Owner reasonably explains, no portion of naproxen would remain to release only after pH reached 3.5.   Again, challenged claim 1 recites a tablet where release of “at least a portion of said naproxen is inhibited unless the pH of said medium is 3.5 or higher.”  Thus, although claim 1 allows for release of at least some naproxen immediately (i.e., at any pH), claim 1 also requires that at least some naproxen releases only when pH is 3.5 or higher.

No comments:

Post a Comment