Effect of patients' expectations on clinical response to fampridine treatment

Patient expectation of treatment outcome is one of the primary mechanisms underlying the placebo effect. In multiple sclerosis trials with symptomatic treatments, a robust placebo effect is observed, which might be related to patient expectations. The aim of this study was to evaluate whether patient expectations regarding fampridine treatment influence the clinical response after 4 weeks and 6 months of treatment.

We designed and carried out a prospective study from June 2015 to August 2017. Before treatment, patients completed a questionnaire including a scale evaluating their expectations regarding the treatment. The effect of baseline positive expectancy on the response status after 4 weeks and 6 months of treatment was analyzed through univariable and, when applicable, multivariable analysis.

A total of 47 consecutive patients were included in the study. At week 4, 37 (78.7%) patients were classified as responders; a one-point increase in the positive expectancy questionnaire was significantly associated with a fourfold increase in the likelihood of being a responder [OR = 4.020 (95% CI 1.082-14.933); p = 0.038]. At 6 months, 43 patients completed follow-up. The number of responders decreased to 28; at this point, positive expectancy at baseline was no longer associated with response status.

Baseline positive expectancy regarding fampridine was determinant of the clinical response after 4 weeks of treatment. However, in the long term, fampridine efficacy was not dependent on expectations prior to treatment.