Assessing a Mitochondrial Disease Treatment via a Novel Statistical Technique for Accelerometer Data

Area of Science:

• * Mitochondrial disease research
• * Genetic disorder therapeutics
• * Clinical trial outcome measures

Background:

• * Mitochondrial diseases stem from oxidative phosphorylation defects, hindering therapeutic development due to inadequate outcome measures.
• * Thymidine kinase 2 deficiency is an ultra-rare, autosomal recessive mitochondrial disorder.
• * Current outcome measures are unsatisfactory for assessing therapeutic efficacy in rare genetic disorders.

Purpose of the Study:

• * To introduce and clinically apply a novel, bias-adjusted outcome measure for assessing nucleoside therapy.
• * To evaluate the efficacy of nucleoside therapy in patients with thymidine kinase 2 deficiency.
• * To demonstrate the utility of an accelerometer-based measure for tracking activity changes in clinical trials.

Main Methods:

• * A phase 2 clinical trial utilizing a within-subject design where patients served as their own controls.
• * Functional data analysis and longitudinal mixed-effects linear regression were employed.
• * Data were adjusted for age, gender, circadian rhythms, and other potential biases.

Main Results:

• * A significant overall improvement in time-in-activity was observed in 14 patients with at least two assessments 6 months apart.
• * Statistically significant improvements were noted at specific activity levels (0.14 g and 2 g).
• * Longitudinal analysis of 19 subjects confirmed the highly significant effect of treatment length on time-in-activity at both 0.14 g and 2 g.

Conclusions:

• * The novel accelerometer-based activity measure effectively captures treatment effects in a small patient cohort.
• * Nucleoside therapy shows promise in increasing activity levels for individuals with thymidine kinase 2 deficiency.
• * This study highlights the potential of bias-adjusted outcome measures in rare disease clinical trials.