LB749. High HBsAb Seroprotection Achieved 4 Weeks after 3 doses of HepB-CpG Vaccine in People Living with HIV (PLWH) without Prior HBV Vaccination (ACTG A5379 Group B Preliminary Results)

Abstract Background Three-dose series of conventional alum-adjuvanted Hepatitis B surface antigen (HBsAg)-based vaccines achieve seroprotection rates (SPRs) 35-70% in PLWH. HepB-CpG, a HBsAg vaccine adjuvanted with TLR-9 agonist, achieves high SPR immunocompetent adults 2-dose regimen, but limited data exist Methods A5379 is an ongoing prospective, open-label study to evaluate immunogenicity the HBV HepB-CpG The vaccine-naïve group consisted PLWH without past infection on antiretroviral therapy CD4 ≥100 cells/mm3 and HIV-1 RNA < 1000 copies/mL. Participants received 0.5 mL intramuscularly (20 mcg recombinant 3000 CpG 1018® adjuvant) at Wks 0, 4, 24. Primary objectives were determine proportion participants who (HBsAb≥10 mIU/mL) Wk 28 assess safety. This was designed conclude >55%, up 10% loss follow-up prior wks. Results Of 74 eligible enrolled 13 global sites: 46% male, 66% Asian, 16% Black,15% White median age 47 years (range 23-68). 27% US, 65% Thailand. Median 625 cells/mm3, 96% had 60 copies/mL, 9% diabetes. analysis set per plan 68 (excluded: 3 missed visit, out visit window). All completed doses achieved (100% [95% CI: 94.7%, 100%]). 88% HBsAb >1000 mIU/mL (assay upper limit). also 100% [CI: 94.2%,100%] protocol 62 participants. At 8 wks after 2nd dose, 94.4% followed by 98.5% 24, 3rd dose. increased from 27.9% 24 83.8% 28. One or more AEs related treatment experienced 61% (39% Grade 1, 20% 2, malaise one participant). Vaccination site pain (40%), (26%), fatigue (23%), myalgia (22%) headache most frequent AEs. Seroprotection week. Percentage achieving over first weeks. administered Entry, Week Conclusion In this no history vaccination evidence exposure, 4 weeks HepB-CpG. No unexpected safety issues observed. Disclosures Kristen Marks, MD, MS, Gilead Sciences: Grant/Research Support Andrea L. Cox, M.D. Ph.D., Janssen: Advisor/Consultant Jennifer C. Price, PhD, AbbVie: Support|Gilead Honoraria|Merck: Support|Theratechnologies: Kelvin McKoy, M.D., M.B.A., Dynavax Technologies: Employee|Dynavax Ownership Interest|Dynavax Stocks/Bonds Kenneth E. Sherman, Support|Gilead: Advisor/Consultant|Gilead: Support|Helio: Support|Inovio: DSMB|Intercept: Support|MedPace: DSMB|Theratechnologies: Advisor/Consultant|Zydus: Support.