Relevance of Lesion Volume as an Outcome in Cerebral Cavernous Malformation Drug Trial: Exploratory Analyses in Atorvastatin Treatment of Cavernous Angiomas with Symptomatic Hemorrhage Exploratory Proof of Concept

BACKGROUND AND OBJECTIVES: It is not clear whether changes in lesion volume might represent a clinically relevant and statistically advantageous outcome parameter in early phase trials aimed at preventing bleeding in cerebral cavernous malformations (CCM). METHODS: We examined prospective changes in CCM lesion volume in the double-blinded AT CASH EPOC trial (clinicaltrials.gov NCT02603328). We correlated these with symptomatic hemorrhage (SH) events, contemporaneously assessed changes in lesional iron content by quantitative susceptibility mapping (QSM) on MRI, and objective (modified Rankin Scale (mRS)) and subjective (Euro-QoL Visual Analog Scale [EQ-VAS]) functional status. We also simulated sample sizes needed to detect potential effects on lesion volume. RESULTS: There was excellent correlation between independently assessed maximum lesion diameter and CCM lesion volume (R 2 = 0.68, P < .0001). The mean (SD) percentage change in lesion volume per year was +6 (65) and +18 (94) in atorvastatin and placebo patients, respectively ( P = .43). All cases with SH had increases in lesion volume and increases in mean lesional iron content by QSM, and most had declines in functional status on mRS and EQ-VAS, but there were no overall meaningful correlations of changes in lesion volume with concomitant changes in mean lesional QSM, mRS, or EQ-VAS (all R/R 2 < 0.5 and Bonferroni corrected P > .05), including in brainstem lesions analyzed separately. Sample size simulations indicate larger case numbers needed to demonstrate an effect on change in lesion volume than those needed to detect an effect on QSM change with α = 0.05 and β = 0.8, and even larger samples to detect effects on the number of cases with increased or decreased lesion volume. CONCLUSION: Changes in lesion volume occur frequently in CCM lesions after recent SH, but do not correlate with biomarkers of lesional bleeding, nor reflect functional changes, and are not statistically advantageous compared with QSM measures in detecting potential drug effects.