Common Side Effects of Kesimpta
Kesimpta (ofatumumab), used for relapsing multiple sclerosis, most often causes upper respiratory tract infections (about 40% of patients), injection-related reactions like pain or redness at the site (20-39%), headache (18-23%), urinary tract infections (11-13%), and fatigue (10%). These typically occur early in treatment and decrease over time.[1][2]
Serious Side Effects and Risks
Serious risks include infections such as hepatitis B reactivation, progressive multifocal leukoencephalopathy (PML, a rare brain infection), and decreased immunoglobulins leading to higher infection rates. Other concerns are allergic reactions (swelling, rash, breathing issues), liver problems (elevated enzymes), and low blood cell counts. Patients with active infections should avoid starting treatment.[1][2][3]
Injection Site Reactions
Redness, swelling, itching, or pain at the injection site affects up to 20% initially, often mild and resolving within days. Pre-injection steps like rotating sites and room-temperature storage reduce severity.[1][2]
Long-Term Side Effects Patients Report
Over 2-3 years, persistent issues include ongoing infections (e.g., sinusitis, bronchitis) and fatigue. Immunoglobulin levels drop in some, increasing infection risk; monitoring is recommended. Breastfeeding patients face unknown infant risks, so alternatives are advised.[1][3]
How Kesimpta Side Effects Compare to Other MS Drugs
Unlike injectables like Avonex (flu-like symptoms more common), Kesimpta has fewer systemic reactions but similar infection risks to Ocrevus (also anti-CD20). Oral options like Tecfidera often cause more GI upset.[2][3]
Managing and Reporting Side Effects
Use over-the-counter pain relief for mild reactions; contact a doctor for fever, persistent infections, or neurological changes. FDA requires reporting via MedWatch. Regular blood tests track risks like low immunoglobulins.[1][2]
[1]: Kesimpta Prescribing Information (Novartis)
[2]: FDA Label for Kesimpta
[3]: Drugs.com - Kesimpta Side Effects