Long-term cladribine experience in relapsing-remitting multiple sclerosis

We present the case of a 40-year-old male patient who was diagnosed with multiple sclerosis (MS) at age 16. Initially, he was treated with glatiramer acetate, but he later received cladribine due to high disease activity. After participating in the CLARITY study in 2007, he achieved 10 years of clinical and radiological stability (NEDA-3) with a single cladribine treatment. In 2019, relapse symptoms of optic neuritis and a new enhancing lesion on an MRI scan prompted the initiation of a second cladribine treatment cycle. Despite the appearance of a new asymptomatic lesion prior to the second-year dose, therapy was continued without modification. The patient remained free of relapses, disability progression, and radiological activity for the following three years. This case illustrates cladribine's potential for long-term efficacy, even with intermittent disease activity, and supports its use as a viable option for sustained disease control in relapsing MS.