Objective:

We evaluated the utilization, efficacy, and safety of cladribine in RMS patients in a western US healthcare system.  

Background:

In 2019, the FDA approved cladribine for relapsing MS after additional follow-up data revealed a low incidence of cancer among patients using cladribine. Recent trends show a growing prescription rate for MS patients, which provides an opportunity to closely examine cladribine’s efficacy and safety profile in a real-world cohort. 

Design/Methods:

Retrospective chart review was performed for RMS patients > 18 years old and had taken one course of cladribine between March 2019 and April 2024.  Demographic and clinical characteristics, cladribine utilization, safety, tolerability, and efficacy data were collected through review of the electronic medical record.

Results:

Of the 267 patient charts reviewed, 107 were 55 and older with a median age of 50.8 [42.8, 60.6]. In this cohort, 71.5% were female. The ARR 12 months prior to cladribine initiation was 0.17 (0.43) with a median baseline EDSS of 2.5 [1.5, 4.0]. The three most common DMTs prior to switching were anti-CD20 agents 22.8%, fumarates 18.7%, and glatiramer acetate 12.7%.  Roughly 10% of patients were treatment naïve.  During the study period (median 19.0 [9.0, 31.0) months), the ARR while on cladribine was 0.08 (0.6); the median EDSS at year 2 (n=122) was 2.5 [1.5, 3.5]. Median time to first MRI after starting cladribine was 8.0 [5.0, 11.0] months; 93.6% of the patients were radiographically stable.  New T2 lesions were seen in 14 patients, and one patient had an enhancing lesion.  Three cancers were reported, 2 breast cancers and one B-cell lymphoma.  

Conclusions:

There was rare clinical and radiographic progression in patients who were either started or  transitioned to cladribine in this relatively large real-world cohort.  Patients who had disease activity were either treatment naïve or younger than 55.  No additional safety signals were observed.