Naldemedine For Opioid-Induced Constipation In Patients Receiving Palliative Care:A Real-World Registry Study (Phase-R Oic Study).

11582 Background: Although naldemedine, a new peripherally-acting mu-opioid receptor antagonist, was approved for the management of opioid-induced constipation (OIC), its safety and effectiveness in real world clinical practice is unknown. Methods: We conducted a real world registry study in 14 hospital palliative care teams and inpatient palliative care units in Japan between April and December 2018. Consecutive cancer patients who received naldemedine for OIC were enrolled in a 7-day observational study. All treatment and assessment procedures were performed according to the accepted clinical practice. The primary outcome of the study was the proportion of patients who experienced spontaneous bowel movement within 24 hours after the initial administration of naldemedine. Adverse events, which indicated a possible or stronger causal relationship with naldemedine treatment, were reported according to the Common Terminology Criteria for Adverse Events (CTCAE) ver 4.0. Results: Overall, 204 patients were enrolled in the study. The mean age of the patients was 63±14 years, and 103 (50.5%) were male. The most common primary cancer site was lung (23.5%), followed by gastrointestinal (13.7%), and urological organs (9.3%). The proportion of patients undergoing active cancer treatment was 59.9%. Oxycodone was the most frequently used regular opioid (n = 115, 56.4%), and the median oral morphine-equivalent daily dose of opioids was 30 mg (interquartile range: 20-60 mg). Magnesium oxide (64.2%) and Senna (17.2%) were used as concomitant laxatives. All patients received 0.2 mg of naldemedine orally once daily. Most patients (90.2%) completed the 7-day observation. In 146 patients, spontaneous bowel movement was observed within 24 hour after the first administration of naldemedine (71.6%, 95% confidence interval 65.4-77.8%). Nearly two-thirds of the patients experienced increased frequency of spontaneous bowel movement in the week after naldemedine administration. The most prevalent adverse events were diarrhea (CTCAE grade 1-2, 35 cases; grade 3, 1 case) and abdominal pain (CTCAE grade 1-2, 10 cases; grade 3, 1 case). No serious adverse events including gastrointestinal perforation were reported. Conclusions: Naldemedine for opioid-induced constipation is safe and effective in the real world oncology and palliative care settings. Clinical trial information: UMIN000031381.