e24155 Background: Naloxegol is a peripherally acting, µ-opioid receptor antagonist for treatment of opioid-induced constipation (OIC). The main objective of this study was to analyze the efficacy and safety of naloxegol in patients with cancer in a real-world 12-month follow-up study. Methods: An observational prospective study was conducted in 16 Spanish centers. Patients older than 18 years, with active oncological disease who were under treatment with opioids for pain control and Karnofsky ≥ 50 were selected. OIC with inadequate response to treatment with laxative (s) was the main diagnostic. All the patients received treatment with naloxegol according to clinical criteria. Efficacy was measured by the response rate and symptoms evolution measured by means of PAC-SYM questionnaire. Intensity of pain was measured by a 0-10-point visual analogue scale (VAS). Intent to treat last observation carried forward was applied. Results: A total of 126 patients were included in the study. About 58.7% were men, with a mean age of 61.5 years (34-89). Lung cancer was observed in 35.7%, breast cancer in 16.7%, 10.3% digestive cancer and 8.7% had prostate cancer. About 67.5% had metastases. Naloxegol at doses of 25 mg/day was administered to 88.1% and with concomitant laxatives in 48.4%. At 12 months, 77.8% of the patients were responders to naloxegol treatment: 78.6% at doses of 12.5 mg/day, and 78.4% with 25 mg/day. Furthermore, response was observed in 78.5% of patients without concomitant laxative treatment and 77% of patients with any concomitant laxative. PAC-SYM total score and all the dimensions improved from baseline (p < 0.0001). VAS pain intensity was reduced and controlled from baseline onwards (Baseline-12 months: 4.6 to 3.6, p < 0.001). A total of 28 adverse reactions mainly gastrointestinal were observed in 15.1% of the patients (19/126), 75% (21) mild, 17.9% (5) moderate and 7.1% (2) severe. Most adverse reactions (67.9%) were observed the first 15 days of treatment with naloxegol. Conclusions: The results of this first real-world-data study in patients with cancer confirm the long-term efficacy of naloxegol for the treatment of OIC in this group of patients. Naloxegol is safe and well tolerated in patients with cancer while maintaining pain control.