Lilly loses UK patent challenge

A UK court has ruled that Allergan (formerly Actavis) is not infringing Eli Lilly’s patents on cancer chemotherapy drug Alimta (pemetrexed) by marketing an alternative salt form.

Lilly’s European patent on the drug molecule itself expired in December 2015, but the company also holds patents around a vitamin regimen to prevent side effects. The UK Court of Appeal had previously ruled that Allergan’s alternative form would infringe these patents if marketed with instructions to dilute it in saline before use (presumably because this would effectively generate Lilly’s patent-protected disodium salt in situ). However, Allergan now intends to market the drug with instructions to dilute it in dextrose solution, avoiding that issue.

In early 2015, an appeals court in Germany ruled that a generic version marketed as the dipotassium salt would not infringe Lilly’s patents.

Lilly is attempting to appeal both these decisions. In the US, a court has fully upheld Lilly’s vitamin regimen patent, and the central European Patent Office holds that the patent is valid, but it can still be challenged in individual EU member states.