In Warner Chilcott v. Teva, the Federal Circuit used the appellant’s claim limitation, as defined in the specification, to uphold the district court’s finding that the claims of two patents were invalid as obvious.1 The claims at issue covered the osteoporosis drug Atelvia®. Warner Chilcott, the holder of the patents, filed suit in November 2011 following Teva’s ANDA application to make and sell a generic version of the drug.

Warner Chilcott owns the ’459 and ’460 patents, which are directed to oral dosage forms comprising risedronate (a bisphosphonate) and disodium ethylenediaminetetraacetic acid (“EDTA”), and methods of treating diseases characterized by abnormal calcium and phosphate metabolism, e.g., osteoporosis. Warner Chilcott’s commercial product, Atelvia®, is an oral formulation for treating osteoporosis comprising 35 mg risedronate and 100 mg EDTA. According to Warner Chilcott, Atelvia® solved the problem of prior osteoporosis drugs that were rendered ineffective when taken with or soon after a meal by utilizing a chelating agent to prevent calcium binding.2 The active ingredient, a bisphosphonate, forms an undesirable complex with calcium ions present in food that inhibits absorption of the drug.3 By using a chelating agent, the bisphosphonate can be freed for absorption, however, the chelating agent can also cause undesirable effects when used in a fasted state.4

During prosecution, the claims were rejected as obvious over a prior art patent application.5 The drugmaker overcame the rejection by amending the claims, adding the limitation, “pharmaceutically effective absorption.”6

The district court found the claims invalid, stating that a person of ordinary skill in the art would have recognized the problem caused by interacting bisphosphonate with food and the solution of using chelators to bind a metal ion, because it had been well explored in literature.7 The district court believed that although Warner Chilcott defined the limitation, “pharmaceutically effective absorption” such that it is not equivalent to merely overcoming the food effect, “the pharmaceutically effective absorption would have been a logical and obtainable goal for a drug with bioavailability that is significantly affected by co-administration with food.”8

Warner Chilcott appealed, arguing that the district court misinterpreted the meaning of “pharmaceutically effective absorption,” and that the limitation wasn’t applicable only to food consumption while taking the drug.9 Warner Chilcott argued,

the district court misinterpreted “pharmaceutically effective absorption” and erroneously equated the invention with overcoming the food effect. . . the limitation requires similar fed and fasted absorption of the drug, not merely absorption of an effective amount in either fed or fasted state. . . the specific amounts of risedronate and EDTA are critical, as only the claimed formulation has been shown to achieve such absorption.10

The Federal Circuit affirmed the district court’s obviousness holding. According to the Federal Circuit, the broad disclosure of [the prior art] nearly anticipates, and the only claim limitation it lacks is “pharmaceutically effective absorption.” According to the Federal Circuit,

Although common sense tells us that any pharmaceutical composition entitled to a patent would have to be pharmaceutically effective, as would any such formulation approved by the FDA, the fact is that, without that limitation specifically referring to the fed/fasted absorption defined in the specification, the asserted claims would not have issued from the original prosecution.”11

The Federal Circuit affirmed the district court’s obviousness holding stating, “it would have been obvious in view of the prior art to use a chelating agent to bind calcium ions to mitigate the food effect for risedronate and thereby achieve similar fed/fasted absorption.”12