That some experimentation might be required to make and use the full scope of a claimed invention does not necessarily mean that a patent is invalid due to lack of enablement; enablement is a matter of degree.  Cephalon, Inc. v. Watson Pharms., Inc., No. 2011-1325 (Fed. Cir. Feb. 14, 2013).  A determination that a patent is invalid for lack of enablement because of undue experimentation requires a fact-specific analysis and clear and convincing evidence.

The Cephalon case centers on an appeal from a district court ruling that Cephalon’s Khankari patents were invalid for lack of enablement.  The patents-at-issue are directed to a method of administering tablets (or other dosage forms) via the mucous membrane lining or mucosa in the oral cavity.  Such tablets include effervescent agents used as penetration enhancers, which influence drug absorption.  Because the effervescent reaction occurring in the mouth affects the pH level of the saliva, the patents also disclose the use of an additional pH adjusting substance in combination with the effervescent agent to promote the absorption of the drugs.  While both parties in the case agreed that the Khankari patents are enabled as to an effervescent “couple” (i.e., a soluble acid source plus a source for carbon dioxide) for generating the claimed effervescent reaction, the parties disputed whether the Khankari patents contain an enabling disclosure illustrating a dosage form having only a single compound effervescent agent.

Section 112, paragraph one, of the Patent Act requires an enabling specification to teach those ordinarily skilled in the art to make and use the full scope of the claimed invention without undue experimentation.  See Ortho-McNeil Pharm., Inc. v. Mylan Labs., Inc., 520 F.3d 1358, 1365 (Fed. Cir. 2008).  The Court in Cephalon emphasized that the question of undue experimentation is a matter of degree, pointing out that varying levels of experimentation are acceptable, depending on the circumstances.  What is required is that the amount of experimentation not be “unduly extensive.”  Based on these guidelines, if a reasonable amount of routine experimentation is required to practice a claimed invention, the enablement requirement is not violated.  For example, the Federal Circuit held that experimentation involving the repetition of known or commonly known techniques, even if extensive, is not necessarily categorized as undue experimentation.  See Johns Hopkins Univ. v. CellPro, Inc., 152 F.3d 1342, 1360 (Fed. Cir. 1988).  Further, the mere fact that a clinician’s involvement may be necessary to determine effective amounts of a single-compound effervescent agent and a separate, companion soluble acid source does not itself constitute undue experimentation.  See Ortho-McNeil Pharm., 520 F.3d at 1365-66.   Therefore, the inquiry regarding undue experimentation is not a simple quantitative analysis.  A considerable amount of experimentation is permissible as long as the experimentation is routine or if the specification provides sufficient guidance.  See PPG Indus., Inc. v. Guardian Indus. Corp., 75 F.3d 1558, 1564 (Fed. Cir. 1996); In re Wands, 858 F.2d 731, 736-37 (Fed. Cir. 1988).

Even though this analysis seems somewhat vague and open-ended, the Federal Circuit has suggested some boundaries on the levels of reasonable experimentation.  For example, in one case, the court found eighteen months to two years of experimentation to practice the patented invention unreasonable.  See, e.g., White Consol. Indus., Inc. v. Vega Servo-Control, Inc., 713 F.2d 788, 791 (Fed. Cir. 1983).  Additionally, the court has provided some general guidelines, noting that the amount of experimentation may be undue where (1) the specification lacks guidance by teaching away from the subject matter that was eventually claimed; and (2) there is evidence of the patentee’s own failures to make and use the later claimed invention at the time of the application.  See, e.g., AK Steel Corp. v. Sollac, 344 F.3d 1234, 1244 (Fed. Cir. 2003).

After analyzing the facts in Cephalon, the Federal Circuit found that the defendant failed to present sufficient testimony or documentary evidence showing the amount of experimentation that would be necessary to carry out the claimed invention.  Specifically, the court found that the defendant did not present any evidence showing that the embodiment disclosed in the specification would not enable a person of ordinary skill to practice other permutations of the invention, or any evidence showing that the resulting experimentation would involve testing for an unreasonable length of time.  Instead, the defendant solely relied on unsupported testimony from its expert that experimentation would be “difficult” and “complicated.”

The Federal Circuit found the expert’s testimony insufficient to constitute clear and convincing evidence of a lack of enablement.  Further, the Federal Circuit found that the district court’s emphasis on the inventor’s testimony that some experimentation may be necessary was misplaced.  The court pointed out that because the question of undue experimentation is a matter of degree, the fact that some experimentation may be necessary does not necessarily render the experiments unduly extensive, especially when the experiments involve repetition of known or commonly used techniques.  See Cephalon, slip op. at 14 (citing Johns Hopkins Univ., 152 F.3d at 1360).  As explained above, the Federal Circuit has previously held that the potential need for clinical work, without more, is not dispositive on the issue of undue experimentation.  See AK Steel, 344 F.3d at 1244.  Therefore, the Federal Circuit reversed the district court’s nonenablement determination.

Based on this renewed look at enablement, patent drafters should examine patent specifications prior to filing applications to ensure that all embodiments are fully enabled.  While it is not necessary to explain in the specification how every embodiment of the claimed invention works, patent drafters should be careful to include enough instruction to make sure that all embodiments intended to be covered by the claims are fully enabled, particularly novel embodiments for which there is no guidance in the existing art.