Breaking the PROMISE: poor association between brain volume loss and clinical disability worsening over 2 years of follow-up in primary progressive multiple sclerosis

The association of the investigated volumetric MRI measures and clinical disability outcomes was noticeably weak and inconsistent. Our findings question the suitability of brain volume loss and lesion burden accumulation as functionally relevant trial endpoints in PPMS and inform the design and interpretation of clinical trials in PPMS.