Johnson & Johnson will have to carry out additional clinical testing of its painkiller product AP-77 if it wants to secure US approval, according to the Food and Drug Administration.

The FDA told J&J’s Alza subsidiary that it will need another trial to supplement the existing clinical data for the product, also known as OROS hydromorphone, before it will accept a marketing submission for the product.

In a statement, Alza said it would ‘modify’ its clinical programme for AP-77, but stopped short of saying how long the development of the product in the USA would be delayed. AP-77’s development in Europe is proceeding as planned, said the firm, and it still expects to launch the product in the European Union next year.

AP-77 is designed to provide 24-hour control of chronic pain from single oral dose, unlike other opioid painkillers which usually require patients to take several doses a day to maintain pain relief.