By Andrew Williams --
Last week, in ALZA Corp. v. Andrx Pharms., LLC, the Federal Circuit affirmed the U.S. District Court for the District of Delaware's decision that ALZA's patent related to treating Attention Deficit and Hyperactivity Disorder ("ADHD") was invalid for lack of enablement. ALZA markets the drug Concerta® for the treatment of ADHD, which releases methylphenidate after ingestion at an ascending rate over an extended period of time. Methylphenidate is the same active ingredient as found in Ritalin®. However, because Ritalin® is an immediate-release formulation, it had to be administered two to three times a day. And, as many of the patients that took Ritalin® were children, at least one of these doses had to be administered during the school day. As a result, there was a desire to create a once-a-day method of treating ADHD by developing a sustained or controlled-release dosage form, also known as an extended-release formulation.
ALZA undertook to create such a dosage form. It discovered after a series of clinical trials that MPH plasma concentrations that had ascending patterns had greater efficacy than when concentrations were constant. ALZA was able to use this information to develop a safe and effective once-a-day extended release oral dosage form. Subsequently, ALZA obtained U.S. Patent No. 6,919,373 ("the '373 patent"), whose only independent claim reads: "A method for treating ADD or ADHD comprising administering a dosage form comprising methylphenidate that provides a release of methylphenidate at an ascending release rate over an extending period of time." ALZA spent most of its effort developing an osmotic dosage form, and therefore the '373 patent specification focused on adapting osmotic systems to create ascending release dosage forms. However, the '373 patent did mention non-osmotic dosage forms.
Andrx filed an Abbreviated New Drug Application ("ANDA") to sell a generic version of Concerta®. However, Andrx asserted that its product did not infringe the '373 patent. It is likely that Andrx believed that its ANDA product was a non-osmotic dosage form, because it attempted to limit the scope of the claims to osmotic dosage forms. Nevertheless, the District Court construed the claims to include both osmotic and non-osmotic dosage forms. ALZA successfully argued for the broader claim interpretation, but ultimately it was because the claims were construed broadly that they were found to be invalid. The District Court held that the asserted claims were invalid for lack of enablement because the specification did not enable the full scope of the claims, namely non-osmotic dosages forms.
The issue presented to the Federal Circuit was whether the specification would have enabled a person of ordinary skill in the art to create non-osmotic oral dosage forms (such as tablets and capsules) with ascending release rates without undue experimentation at the time of filing. As with all cases dealing with undue experimentation, the Court looked at the Wands factors, and agreed with the District Court that seven of the eight factors weighed in favor of undue experimentation. One of the most significant reasons identified by the Federal Circuit was that the specification did not contain "such full, clear, concise, and exact terms as to enable any person skilled in the art" to make and use such non-osmotic oral dosage forms. ALZA pointed to the specification that contained a ten-line disclosure of various non-osmotic forms with a reference to a textbook that discusses how to make and use these forms. The problem, however, was not that the claims encompassed non-osmotic forms themselves, but that the claims included a functional limitation -- the non-osmotic oral dosage forms were required to have ascending release rates. And, ALZA was trying to rely on the knowledge of a person of ordinary skill to serve as a substitute for missing information in the specification. Interestingly, ALZA argued that a person skilled in the art could derive this functional limitation if they engaged in an iterative, trial-and-error process. Apparently, however, according to the Federal Circuit, iterative, trial-and-error is undue experimentation.
ALZA also challenged the District Court's reliance on the testimony of the fact and expert witnesses. ALZA's expert witness, Dr. Martyn Davies, testified that the experimentation required to obtain non-osmotic dosage forms was routine. However, the level of skill upon which his analysis was based was at a level higher than the one the District Court adopted. In addition, ALZA challenged the testimony of its own employees, who explained that ALZA had been unable to develop these "routine" non-osmotic dosage forms. Specifically, ALZA argued that at least one of these employees was not skilled in the art. However, the Federal Circuit found the level of the employees' knowledge to be irrelevant, because their testimony related to ALZA's difficulty in creating a non-osmotic form, not to the knowledge of one skilled in the art.
The Federal Circuit commented on the irony that it was precisely because ALZA argued for broader claim construction that its claims were found to be invalid. The Court failed, however, to mention that ALZA may have been required to argue for the broader construction in order for the claims to cover Andrx's ANDA product. Nevertheless, one lesson to be learned from this case is that you better be careful what you ask for, because you might not like what you get.
ALZA Corp. v. Andrx Pharmaceuticals, LLC (Fed. Cir. 2010)
Panel: Circuit Judges Dyk, Schall, and Prost
Opinion by Circuit Judge Prost