Did Pfizer get punked by a nonprofit? The U.S. Patent and Trademark Office (USPTO) issued a ruling on one of several patents that Pfizer holds on Lipitor (atorvastatin), its top-selling cholesterol drug. In the reexamination proceeding initiated last year by the Public Patent Foundation ("PUBPAT"), the USPTO rejected all 44 of the claims of U.S. patent 5,969,156 when it ruled that Pfizer's arguments for securing the patent in 1999 were invalid. Each of the 44 claims of the '156 patent claim crystalline atorvastatin, known by the chemical name [R-(R*,R*)]-2-(4-fluorophenyl)-beta,delta-dihydroxy-5-(l-methylethyl)- 3-phenyl-4-[(phenylamino)carbonyl]-1 H-pyrrole-1-heptanoic acid hemi calcium salt. The claims of the '156 patent differ only in having limitations regarding either (a) X-ray powder diffraction values, (b) solid-state 13C nuclear magnetic resonance chemical shift differences, or (c) moles of water. PUBPAT's Request for Re-examination alleged that the claims of the '156 patent are anticipated by U.S. patents 5,273,995 and 5,686,104 as having disclosed crystalline atorvastatin. The USPTO has now rejected the claims as unpatentable under 35 U.S.C. 103(a) over US 5,273,995 (‘995) and/or US 5,686,104 (‘104). The Examiner contends that the ‘995 patent teaches a specific enantiomer of the racemic atorvastatin although admitting that it is not absolutely clear if the compound disclosed in the ‘995 patent is amorphous or crystalline. However, in col. 15, line 51, the word "recrystallized" is recited, which the USPTO says implies that the compound was initially crystallized. On this basis, the Examiner assumed that the compound in the ‘995 patent existed in a crystalline form unless Pfizer can show otherwise.