To assess visual acuity (VA) endpoints according to time of idebenone treatment initiation from symptom onset (T_i) in patients with Leber hereditary optic neuropathy (LHON) in the LEROS study.

It is not yet established whether T_i impacts the clinical outcome of patients with LHON. LEROS, a Phase IV, open-label, international, natural-history controlled study (NCT02774005), assessed the long-term efficacy of idebenone in the treatment of LHON.

In this post-hoc analysis, VA at last visit of the LEROS study was assessed in the eyes of idebenone-treated patients with the m.11778G>A mitochondrial DNA mutation with an observation time of 12–24 months (m). Eyes were stratified by T_i.

Median [range, n] age (years [y]) at baseline was similar regardless of T_i (0–3m: 32.2y [12.6–49.6, 10]; 3–6m: 36.2y [12.6–62.5, 21]; 6–9m: 37.4y [12.6–64.5, 20]; 9–12m: 33.0y [19.5–49.6, 19]; 12–24m: 32.4y [12.1–60.2, 44]; >24m: 34.7y [12.4–62.4, 61]). Regardless of T_i, VA endpoints at last visit were similar, with minor differences observed. Eyes that were 3–6m from symptom onset at treatment initiation had the best median [interquartile range (IQR)] VA (in logMAR) at last visit (0–3m: 1.27 [0.40–1.68]; 3–6m: 1.22 [0.30–1.80]; 6–9m: 1.40 [1.02–1.56]; 9–12m: 1.52 [0.98–1.60]; 12–24m: 1.39 [0.58–1.74]; >24m: 1.32 [0.90–1.62]) and the best median [IQR] VA change from last visit to baseline (0–3m: 0.08 [-0.20–0.62]; 3–6m: -0.20 [-0.46–0.10]; 6–9m: -0.11 [-0.19–0.00]; 9–12m: -0.10 [-0.48– -0.04]; 12–24m: -0.09 [-0.47–0.00]; >24m: -0.06 [-0.18–0.00]).

This post-hoc analysis of the LEROS study offers valuable insights into the impact of treatment initiation timing on VA, despite the small sample size and large variability of the data.