The majority of disease-modifying drugs (DMDs) available for the management of multiple sclerosis (MS) depend on continuous drug intake for maintained efficacy, with escalation to a more active drug when an unacceptable level of disease activity returns.

Immune reconstitution therapy (IRT) provides efficacy that outlasts a short course of treatment.

Pharmacological IRT, currently Cladribine Tablets 3.5 mg/kg or alemtuzumab, can provide long-term suppression of MS disease activity, without need for continuous treatment.

Cladribine Tablets 3.5 mg/kg shows some selectivity in targeting adaptive immunity with a lesser effect on innate immunity.

The introduction of IRT-like disease-modifying drugs challenges the traditional maintenance/escalation mode of treatment and raises new questions about how disease activity is measured.