DMT58
Real-World Findings in Oral Cladribine Cohort Study in Patients with Multiple Sclerosis
Cladribine is an oral synthetic purine nucleoside analog approved for the treatment of patients with relapsing-remitting multiple sclerosis (RRMS). The most commonly reported adverse events (AE) are upper respiratory tract infection, headache, and lymphopenia. Cladribine may increase risk of malignancy based on clinical trial data, although follow up studies have not confirmed this increased risk. In this single-center study, we report on 50 patients treated with oral cladribine.
Objectives:
To monitor patients with RRMS on oral cladribine therapy and obtain real-world data on medication efficacy and safety
Methods:
A cohort of 50 cladribine-treated patients were evaluated at a single MS center. Clinical data included annualized relapse rate (ARR), AE, serum lymphocyte counts, serum immunoglobulin levels, and other disease-modifying therapy (DMT) administered before cladribine treatment.
Results:
Mean age and disease duration at time of starting treatment were 48.0 and 9.7 years, respectively. Patients were followed for a median of 490.5 days. Thirty-six (72%) of the patients were female. The ARR prior to starting cladribine was 0.3. Forty-seven (94%) of the patients were on a DMT prior to starting cladribine, with natalizumab (27/50, 54%), ocrelizumab (5/50, 10%), and glatiramer acetate (5/50, 10%) most commonly used. The ARR of patients on cladribine was 0.06 with three patients having a single clinical relapse each over the course of the study. One patient discontinued therapy due to AE. One patient required rescue therapy. Forty-four of the remaining forty-nine patients (88%) developed grade 0-2 lymphopenia, six patients (12%) developed grade 3 lymphopenia, and no patients developed grade 4 lymphopenia. No malignancies were reported during the course of this study.
Conclusions:
This cohort study provides real-world data demonstrating the efficacy and safety of cladribine in patients with RRMS. The study is unique in that the majority of patients (64%) had been on high efficacy DMT (natalizumab or ocrelizumab) prior to initiating cladribine. Despite this, the ARR in this cohort went from 0.3 to 0.06. It should be noted that this study was not designed to determine statistical significance in the change in ARR. Overall, the AE were relatively mild with no malignancies reported. In addition, only six patients (12%) developed severe lymphopenia with no cases of grade 4 lymphopenia and no severe infections reported. These findings are similar to previous clinical trial data.