Multiple sclerosis symptom recrudescence at the end of the natalizumab dosing cycle

Background: This study was undertaken to determine how frequently patients receiving natalizumab for multiple sclerosis (MS) experience recrudescence of their MS symptoms at the end of the dosing cycle. Methods: One hundred consecutive MS patients receiving natalizumab completed a survey evaluating changes in symptoms during the natalizumab dosing cycle. Ninety-one patients also completed questionnaires at two time points: the first week after natalizumab infusion and the last week of the dosing cycle. These included the Multiple Sclerosis Quality of Life-54 (MSQOL-54), Fatigue Visual Analog Scale (VAS), Fatigue Severity Scale (FSS), and Beck Depression Inventory-II (BDI-II). Results: End of dosing interval (EDI) symptoms were reported as currently being experienced by 57% of respondents. An additional 10% reported that they previously experienced that phenomenon, but not currently, and 33% reported never experiencing this. In those with EDI symptoms, they began to occur a median of 21 days after infusion and improved again a median of 1 day after infusion. The most common symptoms reported were fatigue, weakness, walking impairment, and cognitive difficulties. No specific demographic or disease characteristics were associated with this phenomenon. In the subgroup with EDI symptoms, the MSQOL-54, Fatigue VAS, FSS, and BDI-II scores were all significantly worse in the last week of the dosing cycle when compared with the first week. No difference was seen in these scores between first and last week in the subgroup not experiencing symptom recrudescence. Conclusions: Recrudescence of fatigue, weakness, walking impairment, or cognitive difficulties at the end of the dosing cycle occurs in about two-thirds of MS patients receiving natalizumab