The DIANA Study: Continued Access to Darunavir/Ritonavir (DRV/r) and Long-Term Safety Follow-Up in HIV-1-Infected Pediatric Patients Aged 3 to < 18 Years.

INTRODUCTION: Darunavir is a human immunodeficiency virus type 1 (HIV-1) protease inhibitor boosted with ritonavir (DRV/r) or cobicistat. OBJECTIVE: This study provided continued access to DRV/r and assessed long-term safety in patients aged 3 to < 18 years. METHODS: Patients who had completed treatment in the DELPHI (TMC114-C212), DIONE (TMC114-TiDP29-C230), or ARIEL (TMC114-TiDP29-C228) studies were eligible to participate if they derived benefit from using DRV/r in countries where it was not available to them. DRV/r dosing was continued based on original study protocols. Only safety data were collected. Reportable adverse events (AEs) included AEs considered at least possibly related to treatment with DRV/r, AEs leading to discontinuation or treatment interruption, and serious AEs (SAEs). RESULTS: Forty-six patients rolled over to this study and received at least one dose of DRV/r. Median duration of DRV/r intake was 4.2 years. Overall, 15/46 patients experienced one or more reportable AEs, 10/46 patients experienced one or more grade 3 or 4 AEs, and 12/46 patients experienced one or more SAEs. The most common grade 3 or 4 and SAEs were pneumonia (3/46) and asthma (2/46). Only one AE (grade 1 lipoatrophy) was considered probably related to DRV/r (DIONE, n = 1). Overall, 3/46 patients experienced an HIV-related AE (grade 3 pneumonia SAE; grade 2 tuberculosis SAE, and grade 2 lipoatrophy AE), none of which were considered related to DRV/r or led to study discontinuation. Two AEs leading to discontinuation were pregnancies. CONCLUSION: These long-term safety results continue to support DRV/r as a valuable therapeutic option for the treatment of HIV-1 infection in pediatric patients aged ≥ 3 years. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01138605/EudraCT number: 2009-017013-29; first submitted 8 April 2010.

Differential immunogenicity of HIV-1 clade C proteins in eliciting CD8+ and CD4+ cell responses.

BACKGROUND: The relative immunogenicity of human immunodeficiency virus type 1 (HIV-1) proteins for CD8+ and CD4+ cell responses has not been defined. METHODS: HIV-1-specific T cell responses were evaluated in 65 chronically HIV-1-infected untreated subjects by interferon- gamma flow cytometry with peptides spanning the clade C consensus sequence. RESULTS: The magnitude of HIV-1-specific CD8+ T cell responses correlated significantly with CD4+ cell responses, but the percentage of CD8+ T cells directed against HIV-1 (median, 2.76%) was always greater than that of CD4+ cells (median, 0.24%). Although CD8+ T cell responses were equally distributed among Gag, Pol, and the regulatory and accessory proteins, Gag was the dominant target for CD4+ cell responses. There was no consistent relationship between virus-specific CD8+ or CD4+ cell response and viral load. However, the median viral load in subjects in whom Gag was the dominant CD8+ T cell target was significantly lower than that in subjects in whom non-Gag proteins were the main target (P=.007). CONCLUSIONS: Gag-specific responses dominate the CD4+ T cell response to HIV, whereas CD8+ T cell responses are broadly distributed, which indicates differential immunogenicity of these cells against HIV-1. The preferential targeting of Gag by CD8+ T cells is associated with enhanced control of viral load.

Immune selection for altered antigen processing leads to cytotoxic T lymphocyte escape in chronic HIV-1 infection.

Mutations within cytotoxic T lymphocyte (CTL) epitopes impair T cell recognition, but escape mutations arising in flanking regions that alter antigen processing have not been defined in natural human infections. In human histocompatibility leukocyte antigen (HLA)-B57+ HIV-infected persons, immune selection pressure leads to a mutation from alanine to proline at Gag residue 146 immediately preceding the NH2 terminus of a dominant HLA-B57-restricted epitope, ISPRTLNAW. Although N-extended wild-type or mutant peptides remained well-recognized, mutant virus-infected CD4 T cells failed to be recognized by the same CTL clones. The A146P mutation prevented NH2-terminal trimming of the optimal epitope by the endoplasmic reticulum aminopeptidase I. These results demonstrate that allele-associated sequence variation within the flanking region of CTL epitopes can alter antigen processing. Identifying such mutations is of major relevance in the construction of vaccine sequences.