Actavis UK Ltd. v Merck & Co. Inc Rev 1

A Swiss-form second medical use claim must involve a new and inventive therapeutic application. Novelty cannot reside merely in a different dosage regimen for treating the same condition. Applying [2001] RPC 1, the low-dose finasteride claims lacked novelty and were invalid.

Obviousness is assessed by the structured Windsurfing approach, but the ultimate question remains whether the invention was obvious. An “obvious to try” argument is only one factor. Serious doubt created by the relevant technical literature may prevent a proposed trial from being obvious, even where the investigation is rational and potentially worthwhile.

Actavis sought revocation of Merck’s European Patent (UK) 0724 444 concerning the oral use of low-dose finasteride to treat androgenic alopecia, including male pattern baldness. The patent claimed a dosage of about 0.05 to 1.0 mg.

The principal issues were whether the claims were invalid because the claimed use lacked novelty or amounted to an impermissible method of medical treatment, and whether the invention was obvious in light of the prior art and common general knowledge concerning 5α-reductase isozymes. The court also considered whether oral finasteride trials would have been obvious despite contemporary doubts about the relevant enzyme in the scalp.

1. Second medical use. The claim was in Swiss form. The binding decision in Bristol-Myers Squibb v Baker Norton [2001] RPC 1 required novelty to reside in a new therapeutic application, not merely in the method or dosage by which an already known treatment was administered. The earlier patent disclosed finasteride as a possible treatment for androgenic alopecia. The claimed low dosage was therefore only a different dosing regime. Claims 1 to 3 lacked novelty and were invalid.
2. Obviousness framework. The court adopted the structured approach in Windsurfing International v Tabur Marine [1985] RPC 59: identify the inventive concept; identify the skilled person and common general knowledge; identify the differences from the prior art; and ask whether those differences were obvious without hindsight. The approach was useful but not compulsory.
3. Obvious to try. Whether a trial was obvious depended on the ultimate question of obviousness and on the circumstances of the invention. The formulation was not itself determinative. Although Sudduth and Diani gave rational grounds for investigating finasteride, Harris and Thigpen created a serious doubt that a type 2 inhibitor would treat male pattern baldness, since type 1 appeared to be the relevant scalp enzyme. It was therefore not obvious to trial oral finasteride, whether at 5 mg or at the lower claimed doses.
4. Other obviousness points. The skilled addressee was a non-inventive team including relevant scientific and clinical expertise. Public availability did not by itself make detailed information common general knowledge. The court rejected the argument that topical administration was necessarily preferred, and rejected reliance on Merck’s own rationale as proving obviousness.
5. Actavis succeeded on lack of novelty and obtained revocation of the Patent. Its obviousness case failed, but that did not affect the result.