Authors: Lian Liu, Yue Zhang, Jia Wei, Zhaoxin Chen, and Jing Yu (2019)
Liu and colleagues have adapted the N-of-1 design to investigate the effect of amino acid supplementation on immune response and inflammation in patients receiving chemotherapy for unresectable non-small-cell lung cancer (NSCLC). For this vulnerable population, the study covered just one period, rather than the recommended two or more. Only quantitative outcome measures were employed and captured parameters of inflammation including C-reactive protein and various indices of immune function. The effect on each patient was not described, but data was combined and a Bayesian modelling technique used to estimate treatment effectiveness for a population. Inclusion criteria focused on the staging of the cancer and the stability of other treatments, while exclusion criteria were designed to control for additional sources of inflammation, allowing the enrolment of 26 individuals with a range of NSCLC tumours and treatments into a series of N-of-1 trials. Each patient was exposed to both an individually prescribed cycle of chemotherapy associated with an injectable amino acid supplement and a cycle involving an isocalorific injectable glucose supplement (the placebo) allowing each participant to act as their own control. The two cycles of chemotherapy were separated by a wash-out and the order of placebo and amino acid supplementation was randomised. The authors conclude that amino acids may improve immune function and reduce inflammation in patients with NSCLC, however the small numbers in the series was reported as a limitation.
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Full Citation: Liu, L., Zhang, Y., Wei, J., Chen, Z., & Yu, J. (2019). A pilot study of amino acids in unresectable non-small-cell lung cancer patients during chemotherapy: a randomized serial N-of-1 trials design. Nutrition and Cancer, 71(3), 399-408. https://doi.org/10.1080/01635581.2018.1515962