Background

The emergence of a new coronavirus (COVID-19) and the subsequent pandemic present a unique challenge to neurologists managing patients with multiple sclerosis (MS). Preliminary reports do not support an increased risk of severe outcome associated with disease modifying therapies (DMTs) but real-world evidence is lacking.

Objectives

To describe our experience in 14 patients with MS who have been affected by SARS-CoV-2 (with a clinical, RT-PCR, or serological diagnosis) and who were being treated with cladribine in Spain.

Methods

We conducted a consecutive clinical series study including cases occurred in Spain since January 31, 2020 when the first COVID-19 patient was detected in Spain until the end of June 2020.

Results

Patients were mostly female (64%), with an average age of 40.1 (± 12.0) years and a disease duration of 9.7 (± 8.9) years. Median EDSS was 1 (IQR 0–2.5), and the average time on treatment with cladribine was 7.7 (±5.77) months. Two patients had grade 1 lymphopenia, five patients had grade 2 lymphopenia, one patient had grade 3 lymphopenia and six patients were in normal range. Only 1 patient required hospitalization. None required ICU care, or intubation. 93% of the patients improved without any specific treatment. 2 patients (14%) were asymptomatic, 11 (79%) were mild and 1 (7%) was moderate. All recovered without sequelae. 7 of the patients (50%) had a serology test done that showed presence of anti-viral antibodies of IgG and IgM type in all cases.

In our series the patients had a favorable evolution, and all recovered. Factors that could have influenced those results could be the age of the patients, the lack of other risk factors and the mechanism of action of cladribine. It is known that the limited activity of cladribine on cells of the innate immune system and its relatively minor impact on CD8 T cells and plasma cells may have implications for maintained protection from bacterial and viral infections. Importantly, cladribine CD4+ T cell and B cells depletion is partial and transient. The short-term dosing regimen of oral cladribine, potentially reduces depleting effects on the innate immune system.

Conclusions

From this limited number of patients our observations suggest that cladribine treatment does not appear to worsen COVID-19 disease prognosis. MS is a debilitating disease and discontinuing effective treatments might have adverse consequences, benefit/risk assessment is crucial in the current context. Our patients treated with cladribine had an adequate resolution of COVID-19 and mounted an immune response, however more studies are necessary to confirm and extend our preliminary findings.