Does Kevzara Cause Low White Blood Cells?
Yes, Kevzara (sarilumab) can cause low white blood cells, known as leukopenia or neutropenia. This is a common side effect, occurring in up to 15-20% of patients in clinical trials, with severe cases (absolute neutrophil count below 500 cells/mm³) in about 1-3%.[1][2] The drug suppresses immune activity by blocking IL-6 receptors, which can reduce white blood cell production.
How Common Is Neutropenia with Kevzara?
Neutropenia develops early, often within weeks of starting treatment. In rheumatoid arthritis trials:
- Grade 3-4 neutropenia (severe) hit 12% of patients on 200 mg every two weeks.
- It was dose-dependent and reversible upon stopping or dose reduction.[1][3]
Monitoring blood counts monthly is standard, especially in the first 3-6 months.
Why Does It Happen and What Increases Risk?
Kevzara inhibits IL-6 signaling, which regulates neutrophil production in bone marrow. Risk rises with higher doses, concurrent immunosuppressants like methotrexate, or infections. Elderly patients or those with liver/kidney issues face higher odds.[2][4]
What Happens If White Blood Counts Drop?
Mild drops often need no action. Severe neutropenia prompts holding doses until recovery, then resuming at lower strength. Infections risk increases, so doctors watch for fever or symptoms.[1][5] FDA labeling warns of potential sepsis.
How Does This Compare to Other RA Drugs?
Kevzara's neutropenia rate exceeds Humira (adalimumab, ~5-10%) but matches Actemra (tocilizumab, another IL-6 blocker, ~10-15%). Unlike TNF inhibitors, IL-6 drugs like Kevzara demand stricter neutrophil monitoring.[3][6]
When Does Patent Expire for Kevzara?
U.S. patents on sarilumab expire around 2032, with pediatric exclusivity possibly extending to 2033. No biosimilars approved yet.[7]
[1]: Kevzara Prescribing Information (FDA)
[2]: Kevzara Safety Data (Sanofi)
[3]: ClinicalTrials.gov - MOBILITY Study (NCT01061736)
[4]: Drugs.com - Kevzara Side Effects
[5]: Medscape - Sarilumab Dosing
[6]: Actemra Prescribing Information (FDA)
[7]: DrugPatentWatch.com - Kevzara Patents