(P-491) Real- world Utilization of Octreotide Immediate Releasing Use with Octreotide Long-acting Releasing

Background: Octreotide is a somatostatin analogue prescribed for the control of carcinoid syndrome in patients with neuroendocrine tumors. Octreotide long-acting releasing (LAR) is commonly used in long-term therapy, while octreotide short-acting immediate-release (IR) is needed for ‘rescue’ therapy to control the breakthrough symptoms. Based on a RCT, we hypothesize 30-40% of patients would require rescue IR doses. The maximum LAR dosage according to the prescribing information is 30 mg/ 4 weeks. However, the optimal LAR dosage remains unclear, a recent study found that 30% of patients received higher than the maximum recommended dose to better control symptoms or tumor progression. The real-world utilization pattern of IR and LAR is unclear.

Objectives: To evaluate the utilization of octreotide IR with octreotide LAR.

Methods: A retrospective cohort study included patients (≥ 18 years) if they had ≥1 outpatient pharmacy claim of LAR (first fill date as index date) between 7/1/ 2009 to 10/1/2018, had ≥180 days continuous enrollment before the index date and ≥90 days after the index date in IBM MarketScan database. We excluded patients who had ≥ 1 diagnosis of acromegaly during the baseline or follow-up period. Patients were followed from the index date until the end of LAR use, the study period, or enrollment. For the prescription-level analysis, we calculated the normalized LAR dose per 4 weeks for each prescription (Rx) and categorized into 7 dose groups. We calculated the average IR daily dose within the 4 weeks period prior to each LAR Rx (stratified by LAR normalized dose groups). For the patient-level analysis, we estimated the daily IR dose prior to LAR dose escalation.

Results: We included 952 patients; with the most frequently dose of LAR being 31-40 mg/4 weeks (n of Rx =1271), followed by 51-60 mg/4 weeks (n of Rx =606). Eighty percent of patients did not receive an IR prescription. There were more IR prescriptions in patients with a low LAR dose compared to the high dose (LAR ≤30 mg/4 weeks, n of IR Rx =625; LAR >30 mg/4 weeks, n of IR Rx =332). No IR use prior to 80% of dose escalation of LAR; prescriptions were more common with a smaller LAR dose escalation compared to larger dose escalation. The daily dose was low (≤ 0.5 dose/day, 33%; 0.5-1 dose/day: 16%; 1-2 dose/day: 26%; >2 dose/day: 25%) for patients who used IR prior to LAR.

Conclusions: Octreotide LAR dosing in excess of the prescribing information (>30 mg/4 weeks) is common in real-world practice. Compared to the RCT study, IR rescue dosing appears to be underutilized. However, since LAR has tumor control properties, future studies are needed to evaluate the reason of LAR dose escalation and associated octreotide IR rescue dosing.