The High Court has dismissed the main appeal against the decision of Full Court of the Federal Court of Australia in Apotex Pty Ltd v Sanofi-Aventis Australia Pty Ltd [No 2]. The case involved a copyright and patents dispute over a drug called leflunomide, which is used to treat the skin disorder psoriasis. Sanofi-Aventis and affiliated companies supply leflunomide and are the registered owners of its patent. Apotex registered its generic brand leflunomide (called Apo-Leflunomide and used to treat both psoriasis and rheumatoid arthritis) on the Australian Register of Therapeutic Goods to supply its own product in Australia. Sanofi-Aventis brought proceedings in the Federal Court against Apotex, claiming that Apotex had infringed copyright by substantially reproducing Sanofi-Aventis’ product. The trial judge upheld Sanofi-Aventis’ claim, and held that Apotex had not shown that it had a claim to a licence implied by custom and usage. The FCAFC dismissed Apotex’s appeal against the trial judge’s decision, agreeing that no implied licence by custom or usage existed. The central question before the High Court was whether a method of medical treatment could be a patentable invention within the meaning of s 18(1) of the Patents Act 1990 (Cth). A majority of the High Court agreed that it was, and dismissed Apotex’s application for a revocation of Sanofi-Aventis’ patent. Crennan and Kiefel JJ (with whom French CJ and Gageler J agreed) offered seven reasons in support of that conclusion. Hayne J would have allowed the appeal. By majority the High Court also allowed Apotex’s appeal against Sanofi’s claim of infringement under s 117 of the Patents Act 1990 (Cth), and has set aside the orders of the FCAFC and remitted the matter to the FCAFC to determine costs relating to that claim.