Maintenance Lab Monitoring for Kesimpta (Ofatumumab)
Required Baseline Screening
Before initiating Kesimpta, hepatitis B virus (HBV) screening and quantitative serum immunoglobulin levels are mandatory. 1
Ongoing Laboratory Monitoring
Monitor quantitative serum immunoglobulin levels (IgG, IgM, IgA) at the beginning of treatment, during treatment, and after discontinuation until B-cell repletion occurs. 1 This is the primary laboratory monitoring requirement for Kesimpta maintenance therapy.
Immunoglobulin Monitoring Rationale
- Mean IgG levels remain stable during ofatumumab treatment, while mean IgM levels decrease but typically remain above the lower limit of normal in most patients 2
- Decreased immunoglobulin levels have not been associated with increased serious infections in clinical trials 2
- If a patient develops serious opportunistic infections or recurrent infections with evidence of immune compromise based on immunoglobulin levels, consider discontinuing Kesimpta 1
Infection Surveillance
- Delay Kesimpta administration in patients with active infection until the infection resolves 1
- No routine complete blood count (CBC) or liver function test (LFT) monitoring is specified in the FDA label for Kesimpta, unlike other disease-modifying therapies 1
- The overall infection rate with ofatumumab (51.6%) is similar to teriflunomide (52.7%), with serious infections occurring in only 2.5% of patients 3
B-Cell Monitoring
- Ofatumumab achieves rapid and sustained near-complete B-cell depletion with the approved dosing regimen (20 mg at weeks 0,1,2, then monthly) 3
- B-cell depletion is largely independent of body weight, race, and other factors 3
- Monitor for B-cell repletion after discontinuation to guide timing of live vaccine administration 1
Key Monitoring Differences from Other Immunosuppressants
Unlike traditional disease-modifying antirheumatic drugs that require frequent CBC and LFT monitoring every 2-4 weeks initially, then every 8-12 weeks 4, Kesimpta does not require routine hematologic or hepatic laboratory monitoring 1. This represents a significant practical advantage for patients on long-term therapy.
Safety Profile Over Extended Treatment
- Up to 3.5 years of continuous ofatumumab treatment shows no new safety risks 2
- No cases of progressive multifocal leukoencephalopathy have been identified 2
- Malignancy risk remains low with extended exposure 2
- Only 2 of 914 patients (0.2%) developed anti-drug antibodies in pivotal trials, indicating minimal immunogenicity 3