Kesimpta and Ocrevus are both medications used to treat multiple sclerosis (MS), specifically targeting B-cells, a type of immune cell involved in the disease process. When comparing their safety profiles, it is important to understand how each drug works, their side effects, and the risks they carry.
Kesimpta (ofatumumab) is a self-administered injection given monthly, designed to selectively deplete CD20-positive B-cells. Ocrevus (ocrelizumab), on the other hand, is administered by intravenous infusion every six months and also targets CD20-positive B-cells but with a different dosing schedule and delivery method. Both drugs aim to reduce the immune system’s attack on the nervous system by lowering the number of B-cells that contribute to inflammation and damage.
In terms of safety, both medications share some common risks due to their immune-suppressing effects. These include increased susceptibility to infections, such as respiratory infections and herpes-virus-related infections. Ocrevus has been associated with infusion reactions during administration, which can range from mild to severe, requiring monitoring by healthcare providers during and after the infusion. Kesimpta, being a subcutaneous injection, generally avoids infusion-related reactions but can cause injection site reactions like redness or swelling.
A notable safety concern with Ocrevus is the rare but serious risk of progressive multifocal leukoencephalopathy (PML), a potentially fatal brain infection caused by the JC virus. Most reported cases of PML in Ocrevus users occurred in patients who had previously taken other immunosuppressive MS drugs. Kesimpta, while also an anti-CD20 therapy, has not been prominently linked to PML cases, but long-term data is still accumulating.
Both drugs can reduce the effectiveness of vaccines, especially live or live-attenuated vaccines. It is recommended that patients complete all necessary vaccinations before starting treatment with either medication. Ocrevus requires live vaccines to be administered at least four weeks prior to initiation, while non-live vaccines should be given at least two weeks before treatment begins.
Regarding cancer risk, Ocrevus has been reported to slightly increase the risk of certain cancers, such as breast cancer, necessitating adherence to standard cancer screening guidelines. There is less evidence about Kesimpta’s impact on cancer risk, but as both drugs modulate the immune system, ongoing monitoring is prudent.
From a mechanistic perspective, studies show that Ocrevus rapidly depletes B-cells and gradually alters T-cell pathways over months, potentially reprogramming regulatory T-cells to sustain long-term immunomodulation. Kesimpta also depletes B-cells effectively, but detailed comparative data on long-term immune system changes between the two drugs is still emerging.
Patient convenience and lifestyle factors also influence safety considerations. Kesimpta’s monthly self-injection may offer more flexibility and reduce hospital visits compared to Ocrevus’s biannual infusions, which require clinical supervision and carry risks of infusion-related side effects.
In summary, neither Kesimpta nor Ocrevus is unequivocally safer than the other; both have distinct safety profiles shaped by their administration routes, dosing schedules, and immune effects. Ocrevus carries a small but serious risk of PML and infusion reactions, while Kesimpta may have fewer infusion-related risks but requires monthly injections and monitoring for injection site reactions. Both increase infection risk and affect vaccine responses. The choice between them often depends on individual patient factors, prior treatments, lifestyle preferences, and close consultation with healthcare providers to balance efficacy and safety.
