Background: Opioid-induced constipation is a frequent side-effect of opioid treatment, and standard interventions have limited or inconsistent efficacy. This study assessed the efficacy and safety of naldemedine, a peripherally acting μ-opioid receptor antagonist, for the treatment of opioid-induced constipation in patients with chronic non-cancer pain.
Methods: We report two double-blind, randomised, placebo-controlled trials in adults with chronic non-cancer pain and opioid-induced constipation. The first (COMPOSE-1) was done in 68 outpatient sites in seven countries and the second (COMPOSE-2) at 69 outpatient sites in six countries; both studies were done in Europe and the USA. Eligible patients were aged 18-80 years, did not use laxatives, and had a stable opioid regimen for treatment of chronic non-cancer pain with a total daily dose averaging at least 30 mg (morphine equivalent) for at least 1 month before screening. Patients were randomly assigned (1:1) to receive either oral naldemedine 0·2 mg or matching placebo once a day for 12 weeks. Randomisation was stratified by average total daily opioid dose (30-100 mg and >100 mg equivalents of oral morphine sulphate). The primary endpoint was proportion of responders. A responder had at least three spontaneous bowel movements (SBMs) per week with an increase from baseline of at least one SBM per week for at least 9 weeks of the 12-week treatment period including at least three of the last 4 weeks. Efficacy endpoints were analysed by intention to treat and the safety population included all patients who received at least one dose of study drug. These trials have both been completed and are registered with ClinicalTrials.gov, numbers NCT01965158 and NCT01993940.
Findings: In COMPOSE-1, 547 patients were recruited between Aug 29, 2013, and Jan 22, 2015, and were randomly assigned to receive naldemedine (n=274) or placebo (n=273). Patients for COMPOSE-2 were recruited between Nov 4, 2013, and June 9, 2015; 553 patients were randomly assigned to receive naldemedine (n=277) or placebo (n=276). Five patients were enrolled at more than one site, so were excluded from the intention-to-treat population (COMPOSE-1: one per group; COMPOSE-2: one in the naldemedine group, two from the placebo group), with intention-to-treat group sizes of 273 in the naldemedine group and 272 in the placebo group in COMPOSE-1, and 276 in the naldemedine group and 274 in the placebo group in COMPOSE-2. The proportion of responders in both trials was significantly higher with naldemedine than with placebo in COMPOSE-1 (130 responders [47·6%] of 273 in the naldemedine group vs 94 responders [34·6%] of 272 in the placebo group, difference 13·0% [95% CI 4·8-21·3]; p=0·002) and in COMPOSE-2 (145 [52·5%] of 276 vs 92 [33·6%] of 274, difference 18·9% [10·8-27·0]; p<0·0001). Incidence of adverse events with naldemedine was similar to placebo (COMPOSE-1: 132 [49%] of 271 in the naldemedine group vs 123 [45%] of 272 in the placebo group; COMPOSE-2: 136 [50%] of 271 vs 132 [48%] of 274). Treatment-related adverse events were noted in 59 (22%) of 271 patients in the naldemedine group and 45 (17%) of 272 in the placebo group in COMOPOSE-1, and in 54 (20%) of 271 patients in the naldemedine group and 31 (11%) of 274 in the placebo group of COMPOSE-2; the between-group differences were largely due to gastrointestinal disorders, which were more common with naldemedine than placebo (COMPOSE-1: 40 [15%] patients in the naldemedine group vs 18 [7%] in the placebo group; COMPOSE-2: 42 [16%] vs 20 [7%]).
Interpretation: Naldemedine treatment led to a significantly higher responder rate than did placebo and was generally well tolerated. These results support that naldemedine could be a new option for the treatment of opioid-induced constipation in patients with chronic non-cancer pain.
Funding: Shionogi & Co, Ltd.
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