Objective We analyzed the longitudinal profile of Alzheimer's disease (AD) cerebrospinal fluid (CSF) biomarkers in early Parkinson's disease (PD) compared with healthy controls (HCs) and tested baseline CSF biomarkers for prediction of clinical decline in PD. Methods Amyloid‐β 1 to 42 (Aβ42), total tau (t‐tau) and phosphorylated tau (p‐tau) at the threonine 181 position were measured using the high‐precision Roche Elecsys electrochemiluminescence immunoassay in all available CSF samples from longitudinally studied patients with PD (n = 416) and HCs (n = 192) followed for up to 3 years in the Parkinson's Progression Markers Initiative (PPMI). Longitudinal CSF and clinical data were analyzed with linear‐mixed effects models. Results We found patients with PD had lower CSF t‐tau (median = 157.7 pg/mL; range = 80.9–467.0); p‐tau (median = 13.4 pg/mL; range = 8.0–40.1), and Aβ42 (median = 846.2 pg/mL; range = 238.8–3,707.0) than HCs at baseline (CSF t‐tau median = 173.5 pg/mL; range = 82.0–580.8; p‐tau median = 15.4 pg/mL; range = 8.1–73.6; and Aβ42 median = 926.5 pg/mL; range = 239.1–3,297.0; p < 0.05–0.001) and a moderate‐to‐strong correlation among these biomarkers in both patients with PD and HCs (Rho = 0.50–0.97; p < 0.001). Of the patients with PD, 31.5% had pathologically low levels of CSF Aβ42 at baseline and these patients with PD had lower p‐tau levels (median = 10.8 pg/mL; range = 8.0–32.8) compared with 27.7% of HCs with pathologically low CSF Aβ42 (CSF p‐tau median = 12.8 pg/mL; range 8.2–73.6; p < 0.03). In longitudinal CSF analysis, we found patients with PD had greater decline in CSF Aβ42 (mean difference = −41.83 pg/mL; p = 0.03) and CSF p‐tau (mean difference = −0.38 pg/mL; p = 0.03) at year 3 compared with HCs. Baseline CSF Aβ42 values predicted small but measurable decline on cognitive, autonomic, and motor function in early PD. Interpretation Our data suggest baseline CSF AD biomarkers may have prognostic value in early PD and that the dynamic change of these markers, although modest over a 3‐year period, suggest biomarker profiles in PD may deviate from healthy aging. ANN NEUROL 2020;88:574–587

OBJECTIVE:For progressive forms of multiple sclerosis, determine whether ibudilast has an effect on brain volume and new lesions.METHODS:A randomized, placebo controlled, blinded study evaluated ibudilast at a dose of up to 100 mg over 96 weeks in primary and secondary progressive multiple sclerosis. In this secondary analysis of a previously reported trial, secondary and tertiary endpoints included gray matter atrophy, new or enlarging T2 lesions as measured every 24 weeks, and new T1 hypointensities at 96 weeks. Whole brain atrophy measured by SIENA was a sensitivity analysis.RESULTS:129 participants were assigned to ibudilast and 126 to placebo. New or enlarging T2 lesions were observed in 37.2% on ibudilast and 29.0% on placebo (p=0.82). New T1 hypointense lesions at 96 weeks were observed in 33.3% on ibudilast and 23.5% on placebo (p=0.11). Gray matter atrophy was reduced by 35% for those on ibudilast vs. placebo (p=0.038). Progression of whole brain atrophy by SIENA was slowed by 20% in the ibudilast group compared with placebo (p=0.08).CONCLUSIONS:Ibudilast treatment was associated with a reduction in gray matter atrophy. Ibudilast treatment was not associated with a reduction in new or enlarging T2 lesions, or new T1 lesions. An effect on brain volume contributes to prior data that ibudilast appears to impact markers associated with neurodegenerative processes, but not inflammatory processes.Classification of Evidence:This study provides Class II evidence that for people with MS, ibudilast does not significantly reduce new or enlarging T2 lesions, or new T1 lesions.