Mavenclad, whose active ingredient is cladribine, is a medication primarily used to treat multiple sclerosis (MS), a chronic autoimmune disease where the immune system mistakenly attacks the nervous system. One of the key questions many patients and healthcare providers have is whether Mavenclad weakens the immune system, and if so, how this happens and what the implications are.
At its core, Mavenclad works by targeting certain immune cells called lymphocytes, specifically B and T lymphocytes. These cells play a crucial role in the immune system’s ability to fight infections and regulate immune responses. Cladribine, the active compound in Mavenclad, interferes with the DNA synthesis of these lymphocytes, which leads to their depletion. This reduction in lymphocyte numbers is dose-dependent, meaning the more treatment cycles a patient undergoes, the greater the decrease in lymphocyte count. The lowest lymphocyte levels typically occur about two to three months after starting each treatment cycle, and with repeated cycles, the lymphocyte count can drop further[1].
Because lymphocytes are essential components of the immune system, their depletion by Mavenclad effectively weakens the immune system temporarily. This weakening is intentional and therapeutic in the context of MS because the disease is driven by an overactive immune system attacking the body’s own nerve cells. By reducing the number of these immune cells, Mavenclad helps to calm the immune attack, reducing relapses and slowing disease progression.
However, this immune suppression comes with risks. The decrease in lymphocytes can make patients more susceptible to infections, including serious and potentially life-threatening infections. The immune system’s ability to respond to new infections or keep latent infections in check is compromised during periods of low lymphocyte counts. This is why patients on Mavenclad are closely monitored for signs of infection and lymphocyte levels throughout their treatment[3].
The lymphocyte count usually recovers after treatment cycles, but the time to recovery can be quite long—on average, it takes about 28 weeks for lymphocyte counts to rise from very low levels (below 500 cells per microliter) back to safer levels (above 800 cells per microliter). Some patients may have prolonged lymphopenia (low lymphocyte count) even after completing treatment, which requires ongoing vigilance[1].
Importantly, Mavenclad’s immune system weakening is not continuous chronic immunosuppression like some other MS treatments. Instead, it is more of a pulsed or intermittent depletion. Patients typically receive treatment in two annual cycles, and after these cycles, the immune system begins to rebuild. This approach aims to balance effective disease control with minimizing long-term immune suppression[3].
Because of this immune weakening effect, before starting Mavenclad, patients undergo thorough screening to rule out active infections and certain cancers. During treatment, doctors monitor blood counts and watch for infections or other complications. Patients are advised to report any signs of infection promptly.
In summary, Mavenclad does weaken the immune system by reducing lymphocyte counts, which is central to its therapeutic effect in multiple sclerosis. This weakening is dose-dependent and temporary but can increase the risk of infections. The immune system gradually recovers after treatment cycles, and careful monitoring is essential to manage these risks. This immune modulation is a deliberate strategy to control the autoimmune attack in MS while trying to maintain overall patient safety.
