Mavenclad (cladribine) is a medication primarily approved for treating **relapsing forms of multiple sclerosis (MS)**, including relapsing-remitting MS and *active secondary progressive MS*. It is not generally indicated for non-active or purely progressive forms of MS without relapses. This distinction is important because MS can present in different patterns, and treatment effectiveness varies accordingly.
Progressive MS refers to a stage where disability worsens over time, often without clear relapses or flare-ups. There are two main types relevant here: *primary progressive MS* (PPMS), where progression starts from the beginning, and *secondary progressive MS* (SPMS), which evolves from relapsing-remitting MS and may or may not have active inflammation or relapses. Mavenclad is approved for **active secondary progressive MS**, meaning it is used when there is still evidence of inflammatory activity such as relapses or new lesions on MRI scans. However, its use in non-active progressive MS, where inflammation is minimal or absent, is not established or recommended.
Mavenclad works by selectively reducing certain immune cells, particularly lymphocytes, which are involved in the autoimmune attack on the nervous system in MS. This immune modulation leads to fewer relapses and slows disability progression related to inflammatory activity. Clinical trials have shown that Mavenclad significantly reduces relapse rates and MRI lesion counts, and it also slows the progression of disability in patients with relapsing forms of MS, including active secondary progressive MS. For example, a large clinical trial demonstrated that about 81% of patients taking Mavenclad remained relapse-free over nearly two years, compared to 63% on placebo. It also reduced the worsening of disability over three months and lowered the number of new MRI lesions.
Long-term data indicate that Mavenclad’s effects can be durable, with many patients maintaining benefits for several years after the two-year treatment course. Some studies have shown that after four years, a high percentage of patients treated with Mavenclad were free from confirmed disability progression and progression independent of relapse activity (PIRA), which is a measure of worsening disability not directly linked to relapses. This suggests Mavenclad may help control both inflammatory and some non-inflammatory aspects of MS-related disability, especially when treatment starts early in the disease course.
Despite these benefits, Mavenclad is a cytotoxic drug, meaning it can suppress the immune system and carries risks such as lymphopenia (low lymphocyte count), which requires careful monitoring. It is generally recommended for patients who have not responded adequately to or cannot tolerate other MS treatments. Because of its safety profile, Mavenclad is not recommended for use in clinically isolated syndrome (CIS) or for patients without active disease.
In summary, Mavenclad **can be used for progressive MS only if the disease is active**, meaning there are relapses or MRI evidence of inflammation. It is not approved or typically used for non-active progressive MS forms. Its mechanism targets the inflammatory component of MS, which is more prominent in relapsing and active secondary progressive stages. For patients with progressive MS without active inflammation, other treatment options are usually considered. The decision to use Mavenclad involves weighing its benefits in reducing relapses and disability progression against its immunosuppressive risks, and it is often reserved for those who have not had success with other therapies.
