Safety, Tolerability, and Immunogenicity Study of Homologous Ad26 Mosaic Vector Vaccine Regimens or Heterologous Ad26 Mosaic and MVA Mosaic Vector Vaccine Regimens With Glycoprotein 140 (gp140) for Human Immunodeficiency Virus (HIV) Prevention

Solicited local AEs (at injection site) included erythema, induration, swelling, itching and warmth were collected within 7 days after vaccination.

Solicited systemic AEs included fever (defined as body temperature of 38.0-degree celsius or higher), headache, fatigue, myalgia, nausea, vomiting were collected within 7 days after vaccination.

Unsolicited AEs were defined as events that participants experienced but were not specifically asked about.

An AE is any untoward medical occurrence in a clinical study participant administered a medicinal (investigational or non-investigational) product. An AE does not necessarily have a causal relationship with the study vaccine. An AE can be any unfavorable and unintended sign (including an abnormal finding), symptom, or disease temporally associated with the use of a medicinal (investigational or non-investigational) product, whether or not related to that medicinal (investigational or non-investigational) product. A SAE is any AE that results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect and is a suspected transmission of any infectious agent via a medicinal product.

The Env Clade A (92UG037.1), B (1990a), and C (Con C), (C97ZA.012)- specific binding antibody titer were assessed using enzyme-linked immunosorbent assay (ELISA). The response was defined as post-baseline value greater than (>) lower limit of quantification (LLOQ) if baseline less than (<) LLOQ or missing or defined as post-baseline value >3-fold increase from baseline if baseline greater than or equal to (>=) LLOQ. The lower limits of quantification (LLOQs) for this assay were 625, 156.25, 625, and 156.25 endotoxin units per milliliter (EU/mL) for Clade A (92UG037.1), Clade B (1990a), Clade C (Con C), and Clade C (C97ZA.012) respectively.

Vaccine-induced binding antibody IgG1, IgG2, IgG3 and IgG4 subclass responses were investigated using Clade C (C97ZA.012) specific ELISAs. The response was defined as post-baseline value >LLOQ if baseline <LLOQ or missing or defined as post-baseline value >3-fold increase from baseline if baseline >=LLOQ. The LLOQs for this assay were 12.3, 28.7, 12.4, and 13.2 for IgG1, IgG2, IgG3 and IgG4 respectively. Samples taken after Week 48 (W48) from PPI set, who missed 4th vaccine or deviated schedule were excluded. As planned, the data reported for this endpoint at specified time points only for each reported category.

The response was defined as post-baseline value >LLOQ if baseline <LLOQ or missing or defined as post-baseline value >3-fold increase from baseline if baseline >=LLOQ. The LLOQ for this assay is a 50 percent (%) inhibitory concentration (IC50) of 20 (fold-dilution). The lower limits of quantification (LLOQs) for this assay were 625 and 78.125 EU/mL for Clade C (Con C) and Mos1 respectively. Samples taken after W48 from PPI set, who missed 4th vaccine or deviated schedule were excluded. As planned, the data reported for this endpoint at specified time points only for each reported category.

The functionality of vaccine-induced antibody responses was investigated by the determination of ADCP. The response was defined as post-baseline value > limit of detection (LOD) if baseline <LOD or missing or defined as post-baseline value >3-fold increase from baseline if baseline >=LOD. The lower limits of detection (LODs) for this assay were 5.16, 6.43, 6.49, 4.32 and 4.28 (phagocytic score) for Clade A (92UG037.1), Clade B (1990a), Clade C (Con C), Clade C (C97ZA.012), and Mos1, respectively. Samples taken after W48 from PPI set, who missed 4th vaccine or deviated schedule were excluded. As planned, the data reported for this endpoint at specified time points only for each reported category of Clade A, B, C and Mos 1.

The functionality of vaccine-induced antibody responses was investigated by the determination of nAb activity in a virus neutralization assay (VNA) using TZM-bl cells and Env-pseudotyped viruses. The response was defined as post-baseline value >LLOQ. The LLOQ for this assay is an inhibitory concentration (IC50) of 20 (fold-dilution). Data reported for the responses against Tier 1 HIV strain Clade C (MW965.26) was reported. Samples taken after W48 from PPI set, who missed 4th vaccine or deviated schedule were excluded. As planned, the data reported for this endpoint at specified time points only for each reported category.

The human immunodeficiency virus (HIV)-1 BAMA employs flow-cytometric-based technology that also utilizes antibody and antigen interactions to test for the presence of specific antibodies in an unknown sample with the added advantage of multiplexing the antigens of interest. Positive and negative control standards were run with each assay to ensure specificity. The positivity threshold was determined per antigen based on the plus (+) 3 standard deviation (SD) on the non-specific background. Sample values had to be greater than or equal to this value and had to be 3-fold over the baseline values with a minimum median fluorescent intensities (MFI) value of 100. Samples taken after W48 from PPI set, who missed 4th vaccine or deviated schedule were excluded. As planned, the data reported for this endpoint at specified time points only for each reported category.

Frozen peripheral blood mononuclear cell (PBMCs) were analyzed by interferon-gamma (IFN-gamma) (ELISpot). The response was defined as post-baseline value >P95 if baseline <P95 or missing or defined as post-baseline value >3-fold increase from baseline if baseline >=P95. The threshold for ELISpot test was based on the 95th percentile (P95) from the baseline values of participants on that test in the study. Samples taken after W48 from PPI set, who missed 4th vaccine or deviated schedule were excluded. As planned, the data reported for this endpoint at specified time points only for each reported category.