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TOPLINE:

Adding olanzapine to a standard antiemetic substantially reduced nausea and vomiting among patients receiving abdominal-pelvic radiotherapy in a phase 3 trial. Over 85% of patients receiving the drug had complete nausea control.

METHODOLOGY:

• Nausea and vomiting are distressing symptoms of abdominal and pelvic radiation therapy, with up to 80% of patients needing supportive care. Standard antiemetics reduce, but don’t eliminate, these symptoms. Olanzapine is an antipsychotic medication that acts on neurotransmitters linked to nausea, and it’s guideline recommended for symptoms induced by chemotherapy. Proof of effectiveness for radiation-induced nausea has been lacking.
• Researchers conducted a double-blind, placebo-controlled, phase 3 randomized trial at a tertiary care teaching hospital in India. A total of 301 patients receiving 15 or more fractions of abdominal or pelvic radiation therapy were enrolled. All received standard ondansetron 4 mg twice daily and were randomly assigned to either placebo (n = 153) or olanzapine 5 mg once daily (n = 148), administered 30 minutes before radiotherapy.
• The primary endpoint was complete control of nausea (no nausea and no rescue therapy during radiation therapy). Secondary endpoints included complete control of emesis, rescue medication use, adverse drug events, anxiety, depression, and quality of life.
• Nausea and vomiting were assessed daily using a patient-maintained symptom diary, with weekly evaluations corresponding to treatment weeks throughout the radiation therapy course.

TAKEAWAY:

• Overall, 85.8% of patients in the olanzapine arm had no or minimal nausea during treatment compared with 16.3% in the placebo arm (P < .001). Just under 96% had no or minimal vomiting vs 74.5% of patients in the placebo group (P < .001).
• Adding olanzapine also reduced symptom severity: 7.4% of patients receiving olanzapine had grade 2 or worse nausea vs 67.3% of those in the placebo arm (P = .001). Grade 2 or worse vomiting occurred in 1.4% vs 7.8% of patients (P = .001).
• Among patients receiving concurrent chemoradiation, nausea was significantly more common in the placebo arm (94.3%) compared with the olanzapine arm (12.6%; P < .001) — as was vomiting, at 32.2% and 6.3%, respectively (P < .001).
• Anxiety and depression scores were significantly reduced with olanzapine compared with placebo (P < .001 for both), while mean sleep duration was higher (8.45 hours vs 5.29 hours with placebo). The most common side effects from the drug were grade 1 drowsiness (10%), orthostatic hypotension (8%), and dysarthria (6.75%). There were no grade 3 or 4 adverse events.

IN PRACTICE:

“This prospective, placebo-controlled, randomized study with high-level evidence (Level IB) suggests that adding olanzapine to standard antiemetics in abdominal-pelvic radiation therapy with chemotherapy reduces [radiotherapy-induced nausea and vomiting] and helps in improving quality of life during treatment,” the study authors concluded.

SOURCE:

This study, led by Meenu Vijayan, MPharm, of AIMS Health Sciences Campus in Kochi, India, was published in Radiotherapy & Oncology.

LIMITATIONS:

Long-term effects were not analyzed. About half of patients had rectal cancer, while only small numbers had certain other cancer types, particularly stomach and pancreatic cancers. Subgroup analysis based on radiotherapy technique was not performed due to limited sample size in the three-dimensional conformal radiation therapy subgroup, and the study was not specifically designed or powered to evaluate technique-based differences.

DISCLOSURES:

This study received funding from the Indian Council of Medical Research. The authors reported having no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.