Exploratory study investigating the efficacy and safety of olanzapine prophylaxis for opioid-induced nausea and vomiting (JORTC-PAL20).

Abstract

TPS12151 Background: In opioid therapy for cancer pain, it is essential to manage opioid-related adverse effects. Opioid-induced nausea and vomiting (OINV) is common, occurring in 20–40% of patients during initial opioid treatment or after opioid doses are increased. Tolerance to OINV develops within a few days to a week. In patients with cancer, OINV results in decreased quality of life as well as failure to relieve pain due to poor opioid adherence, thus increasing the psychological barriers to opioid use. Therefore, antiemetics are used for OINV prophylaxis, but their efficacy and safety in this context have not yet been fully elucidated. Olanzapine is a promising antiemetic for prophylaxis against nausea and vomiting induced by highly emetogenic chemotherapy, and it is less likely to cause extrapyramidal symptoms than haloperidol and prochlorperazine. We are conducting this exploratory study to evaluate the efficacy and safety of olanzapine prophylaxis against OINV. Methods: This single-arm, single-center exploratory study will evaluate the prophylactic antiemetic efficacy and safety of olanzapine (5 mg PO once a day for 5 days) in patients with cancer pain reserving initial regular opioid therapy. Thirty-five patients will be enrolled. This study was designed to provide preliminary efficacy data, with a primary objective of assessing the proportion of patients who achieved complete control (CC) of OINV during 120 hours of opioid treatment. CC was defined as the absence of emetic episodes, the lack of a need for rescue medication to treat nausea, and minimal or no nausea (3 or less on an 11-point categorical scale). Secondary endpoints include the following: the complete response (CR) rate, defined as the percentage of patients with no emetic episodes and no rescue medication use; the total control (TC) rate, defined as the percentage of patients with no emetic episodes, no rescue medication use, and no nausea during the 120 hours of opioid treatment; the time from opioid initiation to the first emetic episode; the time from opioid initiation to the first administration of a rescue antiemetic; the time to treatment failure, defined as the time from opioid initiation to the first emetic episode or to the administration of a rescue antiemetic; the number of emetic episodes; the levels of nausea, anorexia, sleepiness, pain, and fatigue, all determined using a numerical rating scale (0–10); the impact of antiemetic therapy on daily life severity and patient satisfaction, determined using a 7-grade categorical scale; and adverse events graded by PRO-CTCAE ver.1.0 and CTCAE ver. 5.0. The study is currently open, and 25 patients have been enrolled at time of abstract submission. Clinical trial information: jRCTs031220008 .