Importance Currently there is no standard therapy to improve cancer-related anorexia, hampering survival. Mirtazapine has been suggested as a feasible option in this context.

Objectives:

To assess the effect of mirtazapine on appetite and energy consumption in patients with advanced non-small cell lung cancer (NSCLC). Design, Setting, and

Participants:

This randomized, double-blind, placebo-controlled clinical trial including adults was performed in a tertiary cancer care center from August 2018 to May 2022 with a follow-up of 8 weeks. Overall, 134 patients were screened; 114 were assessed for eligibility and 28 were excluded.

Interventions:

Patients were randomized in a 11 ratio to receive mirtazapine, 15 mg, or placebo for 2 weeks followed by a dose escalation to 30 mg until week 8 or placebo. Both groups received nutritional assessment and dietary advice. Main outcomes and

measures:

Appetite was assessed by the Anorexia Cachexia Scale and energy intake. Dietary parameters were evaluated at baseline, 4 weeks, and 8 weeks, with a 24-hour dietary recall, and energy quantification based on the Mexican system of nutritional equivalents.

Results:

A total of 86 patients met the inclusion criteria and were randomized to the placebo (n = 43) or the mirtazapine group (n = 43). The mean (SD) age was 63.5 (11.2) years, 41 were women (57.7%) and had adenocarcinoma, Eastern Cooperative Oncology Group performance status scale score of 1, stage IV NSCLC, and were receiving first-line treatment. Baseline characteristics were similar between groups. There was no difference in appetite scores in patients who received mirtazapine or placebo after 4 and 8 weeks. After 4 weeks, mirtazapine significantly increased energy intake (379.3 kcal; 95% CI, 1382.6-576.1; P < .001) including proteins (22.5 g; 95% CI, 11.5-33.4; P = .001), carbohydrates (43.4 g; 95% CI, 13.1-73.8; P = .006), and fats (13.2 g; 95% CI, 6.0-20.4; P = .006). Fats intake was significantly higher in patients in the mirtazapine group (14.5 g vs 0.7 g; P = .02) after 8 weeks. The mirtazapine group significantly decreased the proportion of patients with sarcopenia (82.8% vs 57.1%, P = .03) at 8 weeks. Patients on mirtazapine tolerated the treatment well, but reported a higher perception of nightmares at 2 weeks based on a 10 cm VAS score (0 [25th-75th percentile, 0-1] vs 0 [25th-75th percentile, 0-0] in the control group; P = .009) but this finding was nonsignificant after 4 and 8 weeks. Conclusion and Relevance In this randomized clinical trial of patients with advanced NSCLC, there was no difference in appetite scores in all patients who received mirtazapine or placebo, but the mirtazapine group had a significant increase in energy intake through the 4- and 8-week follow-up, mainly in fat intake, which is a better and crucial source of energy. The addition of mirtazapine in the treatment of patients with advanced NSCLC and anorexia may help these patients achieve their energy requirements and improve health-related quality of life, specifically emotional and cognitive functioning. Trial Registration ClinicalTrials.gov Identifier NCT04748523.