# A Berlin Neurologist's Last-Resort Drug Is Keeping Six Children Alive - Date: 2026-04-01 - Category: Biotech & Life Sciences A teenager in Berlin was near palliative care. After seven years on sildenafil — the active ingredient in Viagra — he is still alive. Six patients with Leigh syndrome, a fatal mitochondrial disease, have now been treated off-label, with mixed but striking results. A larger trial is coming. ---