Is Hepatitis B vaccination required before starting treatment with Kesimpta (ofatumumab)?

Hepatitis B Vaccination Requirements for Kesimpta (Ofatumumab) Treatment

Yes, hepatitis B screening is required before starting Kesimpta, and vaccination is recommended for those who are not immune to hepatitis B.

Hepatitis B Screening Requirements

According to the FDA label for Kesimpta (ofatumumab), hepatitis B virus (HBV) screening is mandatory before initiating treatment 1:

• Required screening tests:

  • Hepatitis B surface antigen (HBsAg)
  • Anti-hepatitis B core antibody (anti-HBc)

• Contraindications:

  • Kesimpta is contraindicated in patients with active HBV infection confirmed by positive results for HBsAg and anti-HBV tests 1

Vaccination Recommendations

For patients who test negative for both HBsAg and anti-HBc (indicating no immunity to hepatitis B):

• Hepatitis B vaccination should be completed at least 4 weeks prior to starting Kesimpta if using live or live-attenuated vaccines, and at least 2 weeks prior if using inactivated vaccines 1
• The standard hepatitis B vaccination schedule consists of doses at 0,1-2, and 4-6 months 2
• Protective antibody levels develop in approximately 50% of adults after one dose, 85% after two doses, and >90% after three doses 2

Management Based on HBV Screening Results

1. If HBsAg positive and/or HBV DNA positive (active infection):

   • Kesimpta is contraindicated 1

2. If HBsAg negative but anti-HBc positive (past infection):

   • Consult liver disease experts before starting and during treatment with Kesimpta 1
   • Monitor for HBV reactivation during treatment
   • Consider antiviral prophylaxis based on risk assessment

3. If HBsAg and anti-HBc negative (no immunity):

   • Complete hepatitis B vaccination before starting Kesimpta 1

Risk of HBV Reactivation with B-Cell Depleting Therapies

B-cell depleting therapies like ofatumumab (Kesimpta) carry a high risk (>10%) of HBV reactivation 2. This can lead to:

• Severe hepatic injury
• Acute exacerbation of chronic HBV infection in HBsAg-positive patients
• Relapse of past HBV infection in HBsAg-negative/anti-HBc-positive patients

Clinical Considerations

• Patients with multiple sclerosis often receive long-term immunosuppressive therapy, making hepatitis B vaccination particularly important 2
• Vaccination should ideally be completed before immunosuppressive treatment begins, as response rates are lower once immunosuppression has started 2
• For patients who cannot delay Kesimpta treatment, antiviral prophylaxis may be necessary if there's evidence of past HBV infection

Common Pitfalls to Avoid

1. Skipping HBV screening: Failure to screen for HBV before starting Kesimpta can lead to serious complications including fulminant hepatitis and death

2. Inadequate vaccination timing: Ensure complete vaccination at least 4 weeks before starting Kesimpta for optimal protection

3. Ignoring anti-HBc positive results: Patients who are HBsAg-negative but anti-HBc-positive require expert consultation and close monitoring

4. Incomplete vaccination series: All three doses of the hepatitis B vaccine should be completed for optimal protection

5. Lack of post-vaccination testing: In immunocompromised patients, testing for anti-HBs after vaccination is recommended to confirm immunity

In conclusion, hepatitis B screening is mandatory before starting Kesimpta, and vaccination is strongly recommended for non-immune patients to prevent potentially life-threatening HBV reactivation during treatment.