Comparison of Three Hepatitis B Vaccination Regimens in HIV-Positive Youth

• Sero-response to Hepatitis B Surface Antigen [ Time Frame: Week 28 ]
  The primary outcome, percentage positive sero-response, was compared between Arm 1 and each of the two alternative strategy arms (Arm 2 and Arm 3) and measured 4 weeks after the third vaccination at Week 28. Response is defined as greater than or equal to 10 IU/mL of serum being present; non-response is defined as less than 10 IU/mL.
  
  

• Safety of 3 Hepatitis B Vaccine Regimens in HIV+ Youth - ADVERSE EVENTS BY INTERVENTION ARM ON STUDY - POSSIBLY OR PROBABLY RELATED [ Time Frame: Baseline through Week 72 ]
  The number of adverse events (AE) was described by study arm. The proportion of subjects with clinical adverse events in Arms 1 and each of the two alternative strategy arms (Arm 2 and Arm 3) were compared to assess whether or not there is a difference in patients with any grade toxicity.
  
  
• Safety of 3 Hepatitis B Vaccine Regimens in HIV+ Youth - ADVERSE EVENTS BY INTERVENTION ARM ON STUDY - DEFINITELY RELATED [ Time Frame: Baseline through Week 72 ]
  The number of AEs was described by study arm. The proportion of subjects with clinical AEs in Arms 1 and each of the two alternative strategy arms (Arm 2 and Arm 3)were compared to assess whether or not there is a difference in subjects with any grade toxicity.
  
  
• Safety of 3 Hepatitis B Vaccine Regimens in HIV+ Youth - ABNORMAL LABORATORY VALUES GRADE 2 OR ABOVE BY INTERVENTION ARM ON STUDY [ Time Frame: Baseline through Week 72 ]
  The number of adverse events and subjects with the events were described by study arm. The proportion of subjects with abnormal labs in Arms 1 and each of the two alternative strategy arms (Arm 2 and Arm 3) were compared to assess whether or not there is a difference in subjects with grade 3 or 4 toxicity. The laboratory events included are AEs classified as probably, possibly, or definitely related to study drug as classified by the Site Investigator.
  
  
• Response Rates in HIV+ Youth Within Each Study Arm by Study Duration [ Time Frame: Entry through Week 72 ]
  Within each arm, the duration of response in HIV-infected youth was analyzed for all subjects who were responders at 28 weeks. The possible values for response duration could be 20 weeks or less (responder at 28 weeks but not at 48 weeks), 20 to 44 weeks (responder at 28 and 48 weeks but not at 72 weeks), or greater than 44 weeks (responder at 28, 48, and 72 weeks). A response of greater than 20 weeks includes those who responded after 20 weeks, but whose exact response duration was unknown.
  
  
• Sero-Response to Hepatitis B Surface Antigen; Predictor: STUDY ARM [ Time Frame: Week 28 ]
  Response rate associated with the participant's study arm, baseline CD4 count, and interaction term that reflects how subjects in Arm 2 responded differently depending on their CD4 count. Response is defined as greater than or equal to 10 IU/mL of serum being present; non-response is defined as less than 10 IU/mL.
  
  

Suboptimal response to hepatitis B vaccination in HIV+ adults and children has been well documented in the literature. Given the importance of preventing hepatitis B virus (HBV) co-infection in HIV+ youth and the poor response rates in this population, this study will attempt to improve the immediate and long-term sero-response rates by undertaking a randomized, open-label trial of three hepatitis B vaccination schemas, as follows:

1. standard adult dosing of HBV-only vaccine: Engerix-B 20 mcg at Entry, Week 4 and Week 24
2. increased adult dosing of HBV-only vaccine: Engerix-B 40 mcg at Entry, Week 4 and Week 24
3. standard adult dosing of combined HBV/hepatitis A virus (HAV) vaccine: Twinrix 720 enzyme immunoassay (EIA) HAV Ag plus 20 mcg HBsAg at Entry, Week 4 and Week 24.

This study will also describe the safety of administration of an increased dose of the hepatitis B vaccine in this population. In general, patients undergoing dialysis who have received the dosing regimen recommended for immunocompromised individuals have tolerated the vaccine series well.

Design: This is a stratified, block-randomized, open-label trial of three hepatitis B vaccination schemas in HIV-infected and HBV-uninfected youth. Once randomized, there will be a total of 6 study visits in a 72 week period. Vaccination will occur at Entry, Week 4 and Week 24. Primary sero-response will be evaluated at Week 28 and sustainability of response will be evaluated at Weeks 48 and 72 for those who achieve a primary antibody response of >= 10 IU/ml. Primary non-responders (antibody response of < 10 IU/ml) will be provided with a booster vaccine using the increased-dose Engerix-B vaccine at Week 48 and evaluated for responsiveness at Week 72.