AstraZeneca announced enrolment of the first patient in the Phase III clinical programme for NKTR-118, an oral peripherally-acting opioid antagonist being investigated for the treatment of opioid-induced constipation (OIC). The Phase III clinical programme is designed to investigate the safety and efficacy of NKTR-118 as a medicine to relieve opioid induced constipation, a common side effect of prescription opioids when used for chronic pain management. NKTR-118 is part of the exclusive worldwide license agreement announced on 21 September 2009, between AstraZeneca and Nektar Therapeutics. The Phase III clinical program will consist of two 12-week, randomized, placebo-controlled efficacy studies (with approximately 630 randomized patients each) and an open-label, randomized, long-term safety study with a “usual care” comparator arm. The 12-week efficacy studies will compare response rate among placebo and two different doses of NKTR-118 with primary endpoint at 4 weeks. There is a three month safety extension following one of the two 12-week studies.
The long-term safety study will include patients from the 12-week treatment in the efficacy studies, as well as new patients not previously enrolled. All patients will be randomly assigned to open-label treatment of either NKTR-118 or physician’s choice (usual care) of laxative regimen. Safety assessments will also be collected throughout the trials.