Prior to this Court of Appeal decision, case law in the UK had maintained that a new dosage regime could not impart novelty upon a claim. The opposite was true in Europe. This created the situation where dosage regime claims granted by the EPO were unlikely to be enforceable in the UK. This decision now brings the UK into line with the EPO on dosage regime patents, although the legal situation is still not fully settled.

Until recently, UK and EPO law had differed on the question of whether novelty could reside in a second medical use claim, where the drug is not novel and the indication is not novel, but the dosage regime for that use is novel. It has been settled for some time in Europe that the novelty of such claims can reside in the dosage regime. In contrast, case law in the UK had maintained that such claims were not valid. Accordingly, dosage regime claims granted by the EPO were unlikely to be enforceable in the UK.

In the UK, the Court of Appeal recently held in Actavis UK v Merck2 that in second medical use claims novelty can reside in a new dosage regime of a known substance for a known indication. Whilst this decision goes against established UK case law — such as Bristol-Myers Squibb v Baker Norton — it was distinguished on the basis that this earlier decision did not contain a clear rationale that a second medical use claim lacked novelty if the only difference between it and the prior art was a new dosage regime for a known medical condition.

European Patent Office Technical Board of Appeal decision T1020/03 held that there is nothing in the EPC which prevents Swiss-style claims being granted for novel and inventive dosage regimes of an existing medicament.3 This was the first decision from the EPO in which a pure dosage regime was recognized as not being excluded from patentability. This decision is widely followed by the EPO. More recently, decision T1319/04 concerned a dosage regime patent covered by Article 54(5) EPC 2000 under the transitional provisions. The Board of Appeal did not rule directly on whether whether to grant the patent under the provisions of EPC2000, but instead referred (as Case G2/08) the following questions to the Enlarged Board of Appeal:

  1. Where it is already known to use a particular medicament to treat a particular illness, can this known medicament be patented under the provisions of Articles 53(c) and 54(5) of the EPC 2000 for use in a different, new and inventive treatment by therapy of the same illness?
  2. If the answer to question 1 is yes, is such patenting also possible where the only novel feature of the treatment is a new and inventive dosage regime?
  3. Are any special considerations applicable when interpreting and applying Articles 53(c) and 54(5) of the EPC 2000?

Whilst the Court of Appeal decision brings the UK into line with the EPO on dosage regime patents, some uncertainty still remains. In the UK, Actavis have the possibility to appeal to the House of Lords. In Europe, the decision in G2/08 is awaited with interest.