Blood Monitoring for Kesimpta (Ofatumumab)
Kesimpta does not require routine hematologic or hepatic laboratory monitoring during maintenance therapy, but specific pre-treatment screening and immunoglobulin monitoring are essential. 1, 2
Pre-Treatment Required Screening
Before initiating Kesimpta, you must obtain:
- Hepatitis B virus (HBV) screening - mandatory before the first dose 2
- Quantitative serum immunoglobulins (IgG, IgM, IgA) - baseline measurement required before starting therapy 2
Ongoing Monitoring Requirements
Immunoglobulin Monitoring
Monitor immunoglobulin levels at the beginning of treatment, during therapy, and after discontinuation until B-cell repletion occurs. 3, 2 The specific monitoring schedule should include:
- Regular immunoglobulin level checks with particular attention to IgM and IgG levels throughout treatment 3, 4
- Monthly monitoring if immunoglobulin replacement therapy becomes necessary 3
- Continued monitoring after discontinuation until B-cell recovery occurs (median time to B-cell recovery is approximately 24.6 weeks post-treatment) 2
Clinical Significance of Low Immunoglobulins
Low IgM levels increase infection risk, particularly from encapsulated bacteria. 3, 4 Consider the following management approach:
- Immunoglobulin replacement therapy should be considered for patients who experience ≥2 severe recurrent infections by encapsulated bacteria, regardless of IgG level 3
- Monthly IVIG treatment is recommended for the duration of immunoparesis until immunoglobulin levels recover 3
- Consider discontinuing Kesimpta if a patient with low immunoglobulins develops a serious opportunistic infection or recurrent infections 2
What Monitoring is NOT Required
Unlike traditional immunosuppressive agents that require frequent CBC and liver function monitoring every 2-4 weeks initially, then every 8-12 weeks, Kesimpta does not require routine hematologic or hepatic laboratory monitoring during maintenance therapy. 1 This represents a significant practical advantage over other disease-modifying therapies.
Important Caveats
IgG and IgM serology tests for viral infection diagnosis should be interpreted with caution in patients on Kesimpta, as they may have false-negative results due to failure to mount antibody responses to pathogens. 3
If immunoglobulin replacement therapy is initiated, continue Kesimpta dosing - do not discontinue the medication solely due to low immunoglobulin levels unless serious infections develop. 3
Active infections require delaying Kesimpta administration until the infection resolves, but this does not change the underlying monitoring requirements. 2