Cialis U.K. Patent Claims Knocked Out as Teva Preps Generic

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By Peter Leung

Several claims in Eli Lilly & Co.’s patent on its Cialis erectile dysfunction drug are obvious in light of earlier research involving the same drug in higher dosages, a U.K. appeals court ruled Nov. 1.

The decision is a victory for Teva UK Ltd. and Mylan’s UK division, Generics (UK) Ltd., as they prepare generic versions of the drug. Cialis generated $2.46 billion in worldwide sales in 2016, according to Eli Lilly.

Earlier research discussed using tadalafil, the generic name for Cialis, in a 50 milligram dose for inhibiting a chemical relating to erectile dysfunction. It would have been obvious for a skilled person to try to arrive at the patented 5 milligram dosage in Lilly’s patent claims, the England and Wales Court of Appeal said ( Actavis Group PTC EHF v. ICOS Corp. , [2017] EWCA Civ 1671, EWCA (Civ) (U.K.), No. A3/2014/4094, 11/1/17 ).

The generic drug makers sued Eli Lilly to invalidate EP (UK) 1,173,181, which relates to tadalafil dosages to treat sexual dysfunction. The trial court invalidated two of the patent claims for lack of novelty, but rejected arguments that three other claims were obvious. The generics companies appealed the decision relating to the three claims.

Obvious to Test

Earlier research into a 50 milligram dose of tadalafi, along with several other drugs, was in a patent application the court referred to as Daugan, after the inventor list on that application.

The trial court had said that a 25 milligram dosage was obvious in light of Daugan, and it is likely, but not inevitable, that a skilled person would continue testing even smaller doses. The lower court said it’s unexpected that a 5 milligram dosage would have the same level of efficacy as the much larger 50 milligram one. It also may have taken several rounds of testing smaller doses before getting to 5 milligrams, and the skilled person may well have stopped before getting there, the trial court said.

The appeals court reversed. After reading Daugan, a skilled person in the art would test tadalafil at different dosages, and would soon see that a 25 milligram dose is as effective as 50 milligrams, and with fewer side effects, the court said. That would lead him or her to eventually try the patented 5 milligram dose, which is generally as effective as the larger dose, the court said. Also, the skilled person would notice that the 25 milligram and 50 milligram doses are equally effective, and would test smaller and smaller doses until he or she reached the point where efficacy dropped as well, the appeals court said.

Even if that result is unexpected, the 5 milligram dose is obvious because it would be part of routine testing, the court said, noting that some testing is so routine that it will be carried out regardless of the likelihood of success.

Adrian Speck, Mark Chacksfield, and Thomas Jones were the barristers for the generic companies. Bird & Bird LLP, Taylor Wessing LLP, and Pinsent Masons LLP were the solicitors. Andrew Waugh and Katherine Moggridge were the barristers for Eli Lilly. Allen & Overy LLP were the solicitors.

To contact the reporter on this story: Peter Leung in Washington at pleung@bna.com

To contact the editor responsible for this story: Mike Wilczek at mwilczek@bna.com

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