Abstract
INTRODUCTION: The primary analysis of the MiroTAS study in patients with lumbar spinal stenosis (LSS) taking non-steroidal anti-inflammatory drugs showed that mirogabalin add-on therapy further improved pain and quality of life (QOL) without new safety concerns. METHODS: This post hoc analysis of the MiroTAS study examined the timing of onset of mirogabalin-related adverse drug reactions (mrADRs) (composite of somnolence, dizziness, edema, and peripheral edema), factors affecting safety and efficacy, and the relationships between baseline numbness severity (by spine painDETECT questionnaire [SPDQ] score), EQ-5D-5L scores, leg pain improvement (by visual analogue scale [VAS]), and patient satisfaction (by Patient Global Impression of Change [PGIC] scores). RESULTS: Among 110 patients, there were no significant differences in the incidence rates of mrADRs by patient characteristics. The mrADRs occurred mainly after the first administration and uptitration period of mirogabalin. EQ-5D-5L scores significantly improved from baseline to week 12 in patients with mrADRs vs those without (difference 0.0767; p = 0.0304 by t test). The proportion of patients with PGIC scores ≤ 3 at week 12 was numerically higher in patients with mrADRs vs those without. There were no differences in the percentage of patients with reduced leg pain by VAS score (improvement ≥ 20 mm) at week 12 by patient characteristics except for spondylolysis/spondylolisthesis as a complication. Baseline SPDQ numbness scores were positively correlated with improvement in EQ-5D-5L at week 12 (Spearman's rank correlation coefficient 0.2811, p = 0.0092). CONCLUSIONS: Mirogabalin was not related to specific patient characteristics regarding the onset of mrADRs and was effective for LSS regardless of patient characteristics. Caution is needed regarding the onset of mrADRs after first administration and uptitration of mirogabalin, but these may not reduce QOL or patient satisfaction. Patients with high numbness scores may be more likely to benefit from treatment with mirogabalin in terms of QOL. TRIAL REGISTRATION: Japan Registry of Clinical Trials (jRCTs021200007).