Trial also included interim analysis for the efficacy of B cell depletion from the intrathecal compartment with pre-defined stopping criteria for futility: if less than 50% of intrathecal B cells were depleted by active treatment (measured by <25% decrease in CSF CXCL13 and <50% increase in CSF BAFF), then trial was deemed to be underpowered to demonstrate efficacy on clinical or MRI outcomes and would be stopped.