N | Pretrial period | Evaluation period† | P value | Statistical analysis | |

Annual relapse rate of focal neurological deficits | 10 | 2.22±0.73 | 0.72±0.62 | 0.001* | t-test |

Frequency of intravenous formulation with L-arginine | 10 | 6.94±10.54 | 1.09±2.39 | 0.1405 | t-test |

JMDRS | Wilcoxon signed-rank test | ||||

Section 1 | 10 | 5.5 (1–11) | 6 (1–12) | 0.7969 | |

Section 2 | 10 | 3.5 (0–13) | 4.5 (0–13) | 0.8125 | |

Section 3 | 10 | 3 (0–4) | 3 (0–7) | 0.5 | |

Section 4 | 10 | 0 (0–1) | 0 (0–2) | 1 | |

Section 5 | 10 | 0.5 (0–1) | 1 (0–1) | 1 | |

Section 6 | 10 | 0 (0–1) | 0 (0–1) | 1 | |

Section 7 | 10 | 1.5 (0–5) | 2.5 (0–6) | 0.375 | |

Total scores | 10 | 15 (2–28) | 18 (1–32) | 0.5625 | |

Taurine | t-test | ||||

Plasma taurine (nmol/mL) | 10 | 57.57±20.29 | 945.67±406.18 | 0.0001* | |

CSF taurine (nmol/mL) | 7 | 11.24±2.88 | 42.11±13.77 | 0.0007* | |

Lactate and pyruvate | t-test | ||||

Serum lactate (mg/dL) | 10 | 32.49±12.97 | 35.76±12.64 | 0.4079 | |

CSF lactate (mg/dL) | 7 | 40.54±15.31 | 45.73±17.87 | 0.4742 | |

Serum pyruvate (mg/dL) | 10 | 1.26±0.39 | 1.42±0.51 | 0.395 | |

CSF pyruvate (mg/dL) | 7 | 1.39±0.39 | 1.72±0.52 | 0.1672 | |

Serum lactate:pyruvate ratio | 10 | 26.14±5.92 | 25.51±4.89 | 0.7048 | |

CSF lactate:pyruvate ratio | 7 | 28.47±4.93 | 26.03±4.68 | 0.0521 |

Data are expressed as mean±SD, except JMDRS being expressed as median (range).

*P<0.05.

†The first 8 weeks after the start of the study drug administration were not included in the evaluation period.

CSF, cerebrospinal fluid; JMDRS, Japanese Mitochondrial Disease Rating Scale.