Dear Readers,

It is with great pleasure that we present to you the latest issue of MS Report, this time focusing on high-efficacy therapy (HET). In the first article, Professor Anna Jamroz-Wiśniewska of the Chair and Department of Neurology of the Medical University of Lublin shares her insights on early use of HET in the initial stages of multiple sclerosis. Later in the article, she offers an in-depth look at the mechanism of action of natalizumab, which is relevant not only to the pathophysiology of multiple sclerosis but also to that of other comorbidities.

In the next paper, Marzena Maciągowska-Terela, MD, of the Neurology Clinic of the Military Institute of Medicine, headed by prof. Adam Stępień, discusses the first natalizumab biosimilar among biological medications. She describes the systemic and individual benefits associated with access to biosimilars and bioequivalents and refers to the experience of various centers with the use of biosimilar natalizumab.

The third article, written by Marcelina Jeziorko, MD, and Stanisław Rusek, MD, PhD, of the Department of Neurology and Cerebral Stroke with a Cerebral Stroke Sub-Department of the Ludwik Rydygier Specialist Hospital in Krakow, analyses the stratification of risk of progressive multifocal leukoencephalopathy in multiple sclerosis patients treated with natalizumab. The authors present several profiles of patients treated with natalizumab who required various management approaches depending on the clinical and MRI activity of their disease and their anti-JCV antibody index.

Addressing the latter, Kamila Żur-Wyrozumska, MD, PhD, of the Centre for Innovative Medical Education of the Jagiellonian University Medical College in Krakow, explains the basics of using the ImmunoWell JCV IgG assay as a tool for the assessment of risk of progressive multifocal leukoencephalopathy. Detection of antibodies against the JC virus remains a key element of risk stratification in the safety monitoring of natalizumab. However, the STRATIFY JC assay, commonly used to date, was developed for the first formulation of natalizumab, and the introduction of its biosimilar made it necessary to develop an appropriate new assay. The author discusses the significance of differences between the results obtained via both assays and, in conclusion, formulates recommendations regarding their interpretation.

The final article by Przemysław Puz, MD, PhD, of the Neurology Chair and Clinic of the Department of Health Sciences of the Silesian Medical University in Katowice presents a review of current knowledge about fampridine used as a symptomatic treatment for patients with gait disorders. The author discusses the relevance of the drug, its mechanism of action and safety profile, and, even more importantly, real-world evidence to support its efficacy and limitations.

Enjoy the read!

prof. Dagmara Mirowska-Guzel, MD, PhD
Agnieszka Piechal, MD, PhD