Hernan Valdez

Durable efficacy of tipranavir-ritonavir in combination with an optimised background regimen of antiretroviral drugs for treatment-experienced HIV-1-infected patients at 48 weeks in the Randomized Evaluation of Strategic Intervention in multi-drug reSistant patients with Tipranavir (RESIST) studies: an analysis of combined data from two randomised open-label trials

BACKGROUND Treatment options for HIV-1 infected individuals who have received extensive previous antiretroviral therapy are limited. We compared efficacy and safety of the novel non-peptidic protease inhibitor tipranavir co-administered with ritonavir plus an optimised background regimen with that of an investigator-selected ritonavir-boosted comparator protease inhibitor (CPI-ritonavir) in such patients. METHODS We did a combined analysis of 48-week data from two ongoing, randomised, open-label, multinational, phase III, RESIST studies. HIV-1-infected adults with 3 months or longer previous triple antiretroviral class experience, two or more previous protease inhibitor regimens, HIV-1 RNA 1000 copies per mL or greater, and genotypically demonstrated primary resistance to protease inhibitor, were eligible. Primary endpoints were proportion of treatment responders (with reduction in viral load of 1 log(10) copies per mL or greater below baseline without treatment change) at 48 weeks and time to treatment failure through 48 weeks (intention-to-treat analysis). The RESIST studies are registered with ClinicalTrials.gov, numbers NCT00054717 (RESIST-1) and NCT00144170 (RESIST-2). FINDINGS 3324 patients were screened; 746 received tipranavir-ritonavir and 737 CPI-ritonavir. 486 (65.1%) patients on tipranavir-ritonavir and 192 (26.1%) on CPI-ritonavir remained on assigned treatment until week 48. At week 48, more patients achieved and maintained treatment response in the tipranavir-ritonavir group than in the CPI-ritonavir group (251 [33.6%] vs 113 [15.3%]; p<0.0001). Median time to treatment failure was significantly longer in the tipranavir-ritonavir group than in the CPI-ritonavir group (113 days vs 0 days; p<0.0001). Gastrointestinal system disorders and raised transaminase, cholesterol, and triglycerides were more frequent in the tipranavir-ritonavir group than in the CPI-ritonavir group. INTERPRETATION Compared with CPI-ritonavir, tipranavir-ritonavir with an optimised background regimen provides better virological and immunological responses over 48 weeks in patients who have received extensive previous antiretroviral treatment.

Poor CD4 T cell restoration after suppression of HIV-1 replication may reflect lower thymic function.

ObjectiveTo characterize immune phenotype and thymic function in HIV-1-infected adults with excellent virologic and poor immunologic responses to highly active antiretroviral therapy (HAART). MethodsCross-sectional study of patients with CD4 T cell rises of ⩾ 200 × 106 cells/l (CD4 responders; n = 10) or < 100 × 106 cells/l (poor responders; n = 12) in the first year of therapy. ResultsPoor responders were older than CD4 responders (46 versus 38 years;P < 0.01) and, before HAART, had higher CD4 cell counts (170 versus 35 × 106 cells/l;P = 0.11) and CD8 cell counts (780 versus 536 × 106 cells/l ; P = 0.02). After a median of 160 weeks of therapy, CD4 responders had more circulating naive phenotype (CD45+CD62L+) CD4 cells (227 versus 44 × 106 cells/l ; P = 0.001) and naive phenotype CD8 cells (487 versus 174 × 106 cells/l ; P = 0.004) than did poor responders (after 130 weeks). Computed tomographic scans showed minimal thymic tissue in 11/12 poor responders and abundant tissue in 7/10 responders (P = 0.006). Poor responders had fewer CD4 cells containing T cell receptor excision circles (TREC) compared with CD4 responders (2.12 versus 27.5 × 106 cells/l ; P = 0.004) and had shorter telomeres in CD4 cells (3.8 versus 5.3 kb ; P = 0.05). Metabolic labeling studies with deuterated glucose indicated that the lower frequency of TREC-containing lymphocytes in poor responders was not caused by accelerated proliferation kinetics. ConclusionPoor CD4 T cell increases observed in some patients with good virologic response to HAART may be caused by failure of thymic T cell production.

Continued CD4 cell count increases in HIV-infected adults experiencing 4 years of viral suppression on antiretroviral therapy

Objective: To determine the extent to which HIV-infected patients, including those with advanced immunodeficiency, can reverse peripheral CD4 T-cell depletion while maintaining long-term viral suppression on highly active antiretroviral therapy. Design: Cohort study. Participants: Four-hundred and twenty-three HIV-infected patients who initiated HAART prior to 1998 and achieved a viral load ⩽ 1000 copies/ml by 48 weeks were evaluated for up to 4 years or until plasma HIV RNA levels increased to > 1000 copies/ml. Main outcome measure: CD4 count changes. Results: Among patients who maintained plasma HIV RNA levels ⩽ 1000 copies/ml, CD4 counts continued to increase through year 4 of HAART. In the last year examined, from year 3 to 4 of HAART, mean CD4 count gains were +89 × 106, +86 × 106, +95 × 106, and +88 × 106/l in patients with pre-therapy CD4 counts of < 50 × 106, 50 × 106–199 × 106, 200 × 106–349 × 106, and ⩾ 350 × 106/l, respectively (all gains were significantly greater than zero; P < 0.05). Among those with a pre-therapy CD4 count of < 50 × 106/l, 88% achieved a CD4 cell count of ⩾ 200 × 106/l and 59% achieved a count of ⩾ 350 × 106/l by year 4. Factors associated with increased CD4 cell count gains from month 3 to year 4 included lower pre-therapy CD4 cell count, younger age, female sex, and infrequent low-level viremia (versus sustained undetectable viremia). Conclusions: Most patients who achieve and maintain viral suppression on HAART continue to experience CD4 T-cell gains through 4 years of therapy. The immune systems capacity for CD4 T lymphocyte restoration is not limited by low pre-therapy CD4 counts.

Limited immune restoration after 3 years' suppression of HIV-1 replication in patients with moderately advanced disease.

Objective: To describe the magnitude of immune restoration after long-term control of HIV-1 replication. Design: Prospective study of immune restoration in patients starting highly active antiretroviral therapy (HAART). Methods: Patients with moderately advanced HIV-1 infection (CD4 cells between 100 × 106 and 300 × 106/l) who enrolled in a trial of HAART and who had suppression of HIV-1 replication during 3 years of therapy were evaluated for phenotypic and functional indices of immune restoration. Results: Almost all immune restoration achieved occurred during the first year. The median CD4 lymphocyte count increased by 159 × 106 cells/l during the first year (P < 0.001); CD4 lymphocyte rises during the second and third years were not significant. Most decreases in activation antigen expression (CD38/HLA-DR) on CD4 and CD8 lymphocytes occurred during the first year, and after 3 years, patient lymphocytes were still abnormally activated. The proportion of CD4 lymphocytes expressing CD28 increased during the first and second years, but even after 3 years, CD28 expression on CD4 cells remained abnormally low. Lymphocyte proliferative responses to Candida normalized during the first 12 weeks of HAART while responses to tetanus increased only after immunization and enhanced responses to HIV-1 p24 antigen were not observed. Conclusions: Immune restoration was incomplete in patients who started HAART with moderately advanced HIV-1 disease and most changes occurred during the first year. These data suggest that this degree of suppression of HIV-1 replication alone will not suffice to restore immune competence. The clinical significance of incomplete reconstitution of CD4 lymphocyte number, phenotype, and proliferative function in HIV-1 infection remains to be determined.

Nadir CD4+ T-cell count and numbers of CD28+ CD4+ T-cells predict functional responses to immunizations in chronic HIV-1 infection.

Objective: To ascertain whether delaying the initiation of highly active antiretroviral therapy (HAART) compromises functional immune reconstitution in HIV-1 infection in persons who regain ‘normal’ CD4 T-cell counts after suppressive antiretroviral therapies. Design: Prospective open-label study carried out at two University-affiliated HIV-outpatient clinics in the USA. Subjects and methods: Response to immunization was used as a model for in vivo functional immune competence in 29 HIV-1 infected patients with CD4 T-cell counts > 450 × 106cells/l and HIV-RNA < 400 copies/ml for > 12 months after HAART and nine HIV-1 seronegative controls. After immunization with tetanus toxoid, diphtheria-toxoid, and keyhole limpet hemocyanin, immune response scores (IRS) were calculated using postimmunization antibody concentrations, lymphocyte proliferation, and delayed-type hypersensitivity responses to vaccine antigens. Results: Despite normal numbers of circulating CD4 T-cells, the CD4 T-cell nadir before HAART initiation predicted the immune response to immunization (ρ = 0.5; P < 0.005) while current CD4 T-cell count did not. Likewise, CD4 T-lymphocyte expression of the co-stimulatory molecule CD28 was also an independent predictor of response to immunization (ρ = 0.5; P < 0.005). Conclusions: Even among persons who controlled HIV replication and normalized CD4 T-cell counts with HAART, pretreatment CD4 T-cell count and numbers of circulating CD4+CD28+ T-cells at immunization, but not current CD4 T-cell count, predict the ability to respond to vaccination. Delaying the initiation of HAART in chronic HIV-1 infection results in impaired functional immune restoration despite normalization of circulating CD4 T-cell numbers.

Selective Impairments in Dendritic Cell-Associated Function Distinguish Hepatitis C Virus and HIV Infection

Impaired APC functions may play important roles in chronicity of hepatitis C virus (HCV) and HIV infections. To investigate the separate and combined effects of HCV and HIV infection on immature dendritic cells (DCs), we evaluated myeloid-derived DC (MDC) and plasmacytoid-derived DC (PDC) frequencies and functions, measured by Toll-like receptor ligand-induced IFN-α and IL-12, in healthy controls and subjects with chronic HCV, HIV, and HCV-HIV infection. To evaluate the relation between innate and adaptive immunity, we measured HCV-specific IFN-γ-producing T cell frequency. MDC frequencies tended to be reduced in HIV infection (1.8-fold), while PDC frequencies were minimally reduced in HCV infection (1.4-fold). In contrast, a striking reduction in non-PDC-associated IFN-α production was observed in HIV-infected subjects (17-fold), while PDC-associated IFN-α production was markedly reduced in HCV-infected subjects (20-fold). Both non-PDC and PDC functions were impaired in HCV-HIV coinfection. MDC-associated IL-12 production was markedly reduced in both HCV and HIV-infected subjects (over 10-fold). Functional defects were attenuated with slowly progressive HIV infection. The proportion of subjects with HCV-specific T cell responses, and the number of Ags recognized were reduced in HCV-HIV subjects as compared with HCV singly infected subjects. A positive association was observed between MDC-associated IL-12 production and HCV-specific T cell frequency in HCV-infected subjects. These results indicate that immature DC function is dysregulated in HIV and HCV infections, but differentially, and that these defects are attenuated in slowly progressive HIV infection. These selectively different impairments may contribute to the reduced adaptive immune response to HCV in HCV-HIV coinfection.

Thymic Size and Lymphocyte Restoration in Patients with Human Immunodeficiency Virus Infection after 48 Weeks of Zidovudine, Lamivudine, and Ritonavir Therapy

Human immunodeficiency virus (HIV) infection is associated with progressive loss of circulating CD4+ lymphocytes. Treatment with highly active antiretroviral therapy (HAART) has led to increases in CD4+ T lymphocytes of naive (CD45RA+62L+) and memory (CD45R0+RA-) phenotypes. Thymic computerized tomography scans were obtained on 30 individuals with HIV disease to investigate the role of the thymus in cellular restoration after 48 weeks of HAART. Individuals with abundant thymic tissue had higher naive CD4+ T lymphocyte counts at weeks 2-24 after therapy than individuals with minimal thymic tissue. Individuals with abundant thymic tissue had significantly larger increases in naive CD4+ cells during the first 4 weeks of therapy. These individuals were also more likely to experience viral rebound despite comparable initial declines in plasma HIV-1 RNA. These findings suggest that there is a complex relationship among the thymus, viral replication, and lymphocyte restoration after application of HAART in HIV disease.

Immune recovery is associated with persistent rise in hepatitis C virus RNA, infrequent liver test flares, and is not impaired by hepatitis C virus in co-infected subjects.

Objectives: The impact of highly active antiretroviral therapy (HAART) on hepatitis C virus (HCV) is unknown. We analysed changes in HCV RNA and the frequency of hepatotoxicity in co-infected patient enrolling in AIDS Clinical Trials Group trials, and determined whether HCV impairs successful immune reconstitution in these populations. Design/methods: In a prospective analysis of co-infected patients completing at least 16 weeks of HAART in four trials, and co-infected patients with available stored plasma from two other completed HAART trials, HCV RNA was measured at baseline and to week 48. A retrospective analysis of immune recovery in 40 HCV-RNA-positive and 129 HCV-RNA-negative patients from a single trial was performed. Results: Prospective analysis: 60 patients completed at least 16 weeks of HAART. The mean HCV-RNA level increased 0.35 log10 IU/ml at week 16 and 0.43 log10 IU/ml at week 48. When stratified by baseline CD4 cell count, subjects’ HCV-RNA levels increased 0.43 and 0.59 log10 IU/ml at weeks 16 and 48 for entry CD4 cell counts < 350 cells/mm3, but only 0.26 and 0.1 log10 IU/ml at weeks 16 and 48 for entry CD4 cell counts > 350 cells/mm3. Severe alanine aminotransferase elevations occurred in only 3.3%. Retrospective analysis: HCV co-infection had no effect on the overall mean CD4 cell increase at weeks 16 or 48 compared with uninfected controls. Conclusion: In HCV-co-infected patients undergoing HAART, immune recovery is associated with a persistent increase in HCV RNA, especially with baseline CD4 cell counts < 350 cells/mm3. HCV co-infection did not antagonize the CD4 cell response to HAART.

Response to immunization with recall and neoantigens after prolonged administration of an HIV-1 protease inhibitor-containing regimen

ObjectivesTo ascertain if immunization results in the restoration of responses to recall antigens, in the development of responses to presumed neoantigens, and to identify the virologic and immunologic correlates of these responses in persons with HIV-1 infection. Design and settingOpen-label study carried out at three university-affiliated AIDS Clinical Trials Units in the United States. Subjects and methodsThirty-one subjects participating in AIDS Clinical Trials Group Protocol 375 who had received zidovudine, lamivudine, and ritonavir for at least 48 weeks. Subjects were immunized with tetanus toxoid (TT) at entry and with inactivated hepatitis A vaccine (hep A) and keyhole limpet hemocyanin (KLH) at entry and 6 weeks. The development of antibody, lymphocyte proliferative assay (LPA), and delayed-type hypersensitivity (DTH) responses after immunization were monitored. ResultsThe LPA and DTH responses to TT improved in 57 and 68% of participants, respectively; 73 and 65% developed enhanced LPA and DTH responses to KLH. Forty-eight percent of patients developed a four-fold increase in antibody concentration to tetanus. Seventy-three percent of patients without detectable hepatitis A antibodies at baseline developed antibodies after immunization. Eighty-three percent of patients experienced at least a four-fold rise in KLH antibody concentration. Immune activation and viral load predicted poor recall responses and the number of memory CD4+ T-cells predicted good responses to recall antigens. Naïve CD4+ T-cell numbers, decrease in viral load, increases in CD4+ and CD28+ cells, and decreases in immune activation were associated with responses to presumed neoantigens. ConclusionsMost HIV-infected patients treated with potent combination antiretrovirals develop responses to recall and presumed neoantigens after immunization. Functional immune restoration in response to immunization is related to control of viral replication, decreased immune activation as well as to both quantitative and qualitative restoration of circulating T- lymphocyte subpopulations.

Deep sequencing to infer HIV-1 co-receptor usage: application to three clinical trials of maraviroc in treatment-experienced patients.

BACKGROUND The Maraviroc versus Optimized Therapy in Viremic Antiretroviral Treatment-Experienced Patients (MOTIVATE) studies compared maraviroc versus placebo in treatment-experienced patients with CCR5-using (R5) human immunodeficiency virus type 1 (HIV-1), screened using the original Trofile assay. A subset with non-R5 HIV infection entered the A4001029 trial. We retrospectively examined the performance of a genotypic tropism assay based on deep sequencing of the HIV env V3 loop in predicting virologic response to maraviroc in these trials. METHODS V3 amplicons were prepared from 1827 screening plasma samples and sequenced on a Roche/454 GS-FLX to a depth of >3000 sequences/sample. Samples were considered non-R5 if ≥2% of their viral population scored greater than or equal to -4.75 or ≤3.5 using the PSSM(x4/R5) or geno2pheno algorithms, respectively. RESULTS Deep sequencing identified more than twice as many maraviroc recipients as having non-R5 HIV, compared with the original Trofile. With use of genotyping, we determined that 49% of maraviroc recipients with R5 HIV at screening had a week 48 viral load <50 copies/mL versus 26% of recipients with non-R5. Corresponding percentages were 46% and 23% with screening by Trofile. In cases in which screening assays differed, median week 8 log₁₀ copies/mL viral load decrease favored 454. Other parameters predicted by genotyping included likelihood of changing to non-R5 tropism. CONCLUSIONS This large study establishes deep V3 sequencing as a promising tool for identifying treatment-experienced individuals who could benefit from CCR5-antagonist-containing regimens.