Table 1.

Data collection for trial participants.

Event		Baseline	Phase 1					Washout period		Phase 2					Follow-up
		Month 0	Month 1	Month 2	Month 3	Month 4	Month 5		Month 6		Month 7	Month 8	Month 9	Month 10
Informed consent		✓a	N/Ab	N/A	N/A	N/A	N/A		N/A		N/A	N/A	N/A	N/A
Height and weight		✓	N/A	N/A	N/A	✓	N/A		N/A		N/A	N/A	✓	N/A
Medical history		✓	N/A	N/A	N/A	N/A	N/A		N/A		N/A	N/A	N/A	N/A
Clinical examinationc		✓	N/A	N/A	N/A	✓	N/A		N/A		N/A	N/A	✓	N/A
Bicycle ergometry (exercise bike test)
	Peak oxygen consumption	✓	N/A	N/A	N/A	✓	N/A		N/A		N/A	N/A	✓	N/A
	Tissue Doppler studies	✓	N/A	N/A	N/A	✓	N/A		N/A		N/A	N/A	✓	N/A
Echocardiogram (at rest and during exercise)d		✓	N/A	N/A	N/A	✓	N/A		N/A		N/A	N/A	✓	N/A
12-lead ECGe at rest and during exercise (during echo)		✓	N/A	N/A	N/A	✓	N/A		N/A		N/A	N/A	✓	N/A
Blood sample (20-30 mL total)f
	Transformed lymphoblast line for in vitro incubation with bezafibrate and resveratrol	✓	N/A	N/A	N/A	N/A	N/A		N/A		N/A	N/A	N/A	N/A
	FBCg, absolute neutrophil count, urea/electrolytes, LFTh, CKi, plasma arginine/cysteine, full lipid profile (total cholesterol, high-density lipoprotein, and triglycerides), and brain natriuretic peptide	✓	N/A	N/A	N/A	✓	N/A		N/A		N/A	N/A	✓	N/A
	Mitochondrial assessment	✓	N/A	N/A	N/A	✓	N/A		N/A		N/A	N/A	✓	N/A
Blood sample (safety assessment) done locally to the patient
	FBC including absolute neutrophil count, routine renal and LFT, plasma triglyceride/total cholesterol/LDLj-cholesterol and creatine kinase, and creatinine	N/A	✓	✓	✓	N/A	✓		✓		✓	✓	N/A	N/A
Cardiac/skeletal muscle MRIk,l/MRSm,n scan		✓	N/A	N/A	N/A	✓	N/A		N/A		N/A	N/A	✓	N/A
PedsQLo		✓	N/A	N/A	N/A	✓	N/A		N/A		N/A	N/A	✓	N/A
Adverse events		N/A	✓	✓	✓	✓	✓		✓		✓	✓	✓	✓
Drug prescribing		✓	N/A	N/A	N/A	✓	N/A		N/A		N/A	N/A	N/A	N/A
Qualitative interview		N/A	N/A	N/A	N/A	✓	N/A		N/A		N/A	N/A	✓	N/A

^aData was collected (or event took place) at this time.

^bN/A: not applicable.

^cIncluding resting blood pressure, heart rate, and oxygen saturation.

^dCardiac status: left ventricular ejection fraction and 2D strain.

^eECG: electrocardiogram.

^fSamples for detailed cardiolipin profiling and calculation of MLCL/L4-CL ratio; examination of mitochondria of the blood cells by electron microscopy; measurements of size, number, and shape recorded; and the analysis of mitochondrial function studies including the analysis of respiratory chain enzyme complexes.

^gFBC: full blood count.

^hLFT: liver function test.

ⁱCK: creatine kinase.

^jLDL: low-density lipoprotein

^kMRI: magnetic resonance imaging.

^lCardiac magnetic resonance imaging will be used to assess right and left ventricular functions and volumetrics.

^mMRS: magnetic resonance spectroscopy.

ⁿMagnetic resonance spectroscopy will be used to assess phosphocreatine to adenosine triphosphate ratio and oxidative function (phosphocreatine recovery kinetics) in cardiac and skeletal muscles.

^oPedsQL: Pediatric Quality of Life Inventory.