Pharmacometabolomics applied to low‐dose interleukin‐2 treatment in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating motor neuron disease. The immunosuppressive functions of regulatory T lymphocytes (Tregs) are impaired in ALS, and correlate to disease progression. The phase 2a IMODALS trial reported an increase in Treg number in ALS patients following the administration of low‐dose (ld) interleukin‐2 (IL‐2). We propose a pharmacometabolomics approach to decipher metabolic modifications occurring in patients treated with ld‐IL‐2 and its relationship with Treg response. Blood metabolomic profiles were determined on days D1, D64, and D85 from patients receiving 2 MIU of IL‐2 (n = 12) and patients receiving a placebo (n = 12). We discriminated the three time points for the treatment group (average error rate of 42%). Among the important metabolites, kynurenine increased between D1 and D64, followed by a reduction at D85. The percentage increase of Treg number from D1 to D64, as predicted by the metabolome at D1, was highly correlated with the observed value. This study provided a proof of concept for metabolic characterization of the effect of ld‐IL‐2 in ALS. These data could present advances toward a personalized medicine approach and present pharmacometabolomics as a key tool to complement genomic and transcriptional data for drug characterization, leading to systems pharmacology. This study provides a proof of concept for the metabolic characterization of the effect of low‐dose IL‐2 treatment for amyotrophic lateral sclerosis and reveals the role of important pathways (e.g., kynurenine pathway). The reliability of these results is supported by the upregulation of genes involved in this pathway that have been previously reported in the same cohort. This study also provides insights into metabolic modifications associated with the drug response.