The long-term clinical outcomes and associated prognostic factors in contactin-associated protein-like 2 (CASPR2)-antibody diseases are unknown. A total of 75 participants with CASPR2 antibodies were longitudinally assessed for disability, quality-of-life, and chronic pain. Although most symptoms improved within 6 months of treatment, neuropathic pain and fatigue were the most immunotherapy refractory, and persisted for up to 6 years. Furthermore, these two factors-but not CASPR2 antibody levels or subclasses-independently predicted worse disability and quality-of-life at 24 months. Quality-of-life varied widely for any given modified Rankin Scale score, indicating a divergence between patient and clinician assessed outcomes. Further work should study the relative importance of these measures, and the immunopathogenesis underlying intractable symptoms. ANN NEUROL 2025
97:521-528.