First insights into the safety and effectiveness of additional courses with cladribine tablets under real-world conditions

Background

Oral cladribine for relapsing multiple sclerosis (RMS) is administered in a cumulative dose of 3.5 mg/kg body weight over the first 2 years, followed by a 2-year drug-free interval. There is a lack of evidence on resuming cladribine therapy in year 5.

Objective

To evaluate safety and effectiveness of additional cladribine courses in patients with RMS.

Methods

Adult patients with highly active RMS who completed 5 years following cladribine initiation were included in this retrospective analysis if they received one or two additional cladribine courses or remained treatment-free through year 5 (control group). Outcome parameters included lymphocyte counts, adverse events, relapse rate and EDSS.

Results

Out of 166 available patients, 48 and 13 patients received one and two additional cladribine courses, respectively, and 105 patients remained treatment-free. Administering a third and fourth course of cladribine did not trigger any serious adverse events attributable to the therapy. Elevated serum transaminase levels following additional cladribine courses did not exceed 2.5-fold the ULN. The lymphocyte profile following the third and fourth course was consistent with observations reported after the first and second course. Relapse activity remained low following redosing and in the control group. EDSS remained stable in redosed patients.

Conclusions

Administering additional cladribine courses is an effective option to maintain disease control and did not trigger any serious adverse events attributable to the therapy. Patients with elevated serum transaminase levels should be regularly monitored.