Pietro Vernazza

Clinical progression and virological failure on highly active antiretroviral therapy in HIV-1 patients: a prospective cohort study

BACKGROUND The efficacy of highly active antiretroviral therapy (HAART) in suppression of HIV-1 is well documented. We investigated virological and clinical outcomes of HAART in routine practice. METHODS We analysed prospective data from the Swiss HIV Cohort Study on suppression of viral load and progression to AIDS or death in 2674 outpatients (median age 36 years, 27.3% women) who started HAART in 1995-98. Viral rebound was defined as two consecutive HIV-1-RNA measurements of more than 400 copies/mL. We analysed separately outcomes in patients with a history of antiretroviral treatment and in treatment-naïve patients. FINDINGS An estimated 90.7% of treatment-naïve patients reached undetectable viral load (<400 copies/mL) by 12 months. Among pretreated patients, estimates ranged from 70.3% treated with one new drug to 78.7% on three new drugs. 2 years after reaching undetectable concentrations, an estimated 20.1% of treatment-naïve patients and 35.7-40.1% of pretreated patients had viral rebound. At 30 months, an estimated 6.6% (95% CI 4.6-8.6) of patients who had maintained undetectable concentrations, 9.0% (5.5-12.5) who had viral rebound, and 20.1% (15.3-24.9) who had never reached undetectable concentrations developed AIDS or died. Compared with patients who maintained undetectable viral load, the adjusted relative hazard of AIDS or death was 1.00 (0.66-1.55) for patients with viral rebound, and 2.40 (1.72-3.33) for patients who failed to reach undetectable concentrations. INTERPRETATION The rate of virological failure of HAART was high among these patients, but the probability of clinical progression was low even in patients with viral rebound.

Reduction of concentration of HIV-1 in semen after treatment of urethritis: implications for prevention of sexual transmission of HIV-1

BACKGROUND Transmission of HIV-1 is predominantly by heterosexual contact in sub-Saharan Africa, where sexually transmitted diseases (STDs) are also common. Epidemiological studies suggest that STDs facilitate transmission of HIV-1, but the biological mechanism remains unclear. We investigated the hypothesis that STDs increase the likelihood of transmission of HIV-1 through increased concentration of the virus in semen. METHODS HIV-1 RNA concentrations were measured in seminal and blood plasma from 135 HIV-1-seropositive men in Malawi; 86 had urethritis and 49 controls did not have urethritis. Men with urethritis received antibiotic treatment according to the guidelines of the Malawian STD Advisory Committee. Samples were analysed at baseline and at week 1 and week 2 after antibiotic therapy in urethritis patients, and at baseline and week 2 in the control group. FINDINGS HIV-1-seropositive men with urethritis had HIV-1 RNA concentrations in seminal plasma eight times higher than those in seropositive men without urethritis (12.4 vs 1.51 x 10(4) copies/mL, p = 0.035), despite similar CD4 counts and concentrations of blood plasma viral RNA. Gonorrhoea was associated with the greatest concentration of HIV-1 in semen (15.8 x 10(4) copies/mL). After the urethritis patients received antimicrobial therapy directed against STDs, the concentration of HIV-1 RNA in semen decreased significantly (from 12.4 x 10(4) copies/mL to 8.91 x 10(4) copies/mL at 1 week [p = 0.03] and 4.12 x 10(4) copies/mL at 2 weeks [p = 0.0001]). Blood plasma viral RNA concentrations did not change. There was no significant change in seminal plasma HIV-1 RNA concentrations during the 2-week period in the control group (p = 0.421). INTERPRETATION These results suggest that urethritis increases the infectiousness of men with HIV-1 infection. HIV-1-control programmes, which include detection and treatment of STDs in patients already infected with HIV-1, may help to curb the epidemic. Targeting of gonococcal urethritis may be a particularly effective strategy.

Response to antiretroviral treatment in HIV-1-infected individuals with allelic variants of the multidrug resistance transporter 1: a pharmacogenetics study

BACKGROUND HIV-1-infected patients vary considerably by their response to antiretroviral treatment, drug concentrations in plasma, toxic events, and rate of immune recovery. This variability could have a genetic basis. We did a pharmacogenetics study to analyse the association between response to antiretroviral treatment and allelic variants of several genes. METHODS In 123 patients, we did PCR analyses of the gene for the multidrug-resistance transporter (MDR1), which codes for P-glycoprotein, of genes coding for isoenzymes of cytochrome P450, CYP3A4, CYP3A5, CYP2D6, and CYP2C19, and of the gene for the chemokine receptor CCR5. We measured concentrations in plasma of the antiretroviral agents efavirenz and nelfinavir by high-performance liquid-chromatography, and measured levels of P-glycoprotein expression, CD4-cell count, and HIV-1 viraemia. FINDINGS Median drug concentrations in patients with the MDR1 3435 TT, CT, and CC genotypes were at the 30th, 50th, and 75th percentiles, respectively (p=0.0001). In patients with CYP2D6 extensive-metaboliser or poor-metaboliser alleles, median drug concentrations were at percentiles 45 and 62.5, respectively (p=0.04). Patients with the MDR1 TT genotype 6 months after starting treatment had a greater rise in CD4-cell count (257 cells/microL) than patients with the CT (165 cells/microL) and CC (121 cells/microL) genotype (p=0.0048), and the best recovery of naïve CD4-cells. INTERPRETATION The polymorphism MDR1 3435 C/T predicts immune recovery after initiation of antiretroviral treatment. This finding suggests that P-glycoprotein has an important role in admittance of antiretroviral drugs to restricted compartments in vivo.

Brief but Efficient: Acute HIV Infection and the Sexual Transmission of HIV

BACKGROUND We examined whether viral dynamics in the genital tract during the natural history of acute human immunodeficiency virus type 1 (HIV-1) infection could explain efficient heterosexual transmission of HIV. METHODS We measured HIV-1 concentration in blood and semen samples from patients with acute and long-term HIV-1 infection. We explored the effect of changes in viral dynamics in semen on the probability of transmission per coital act, using a probabilistic model published elsewhere. RESULTS Considered over time from infection, semen HIV-1 concentrations, in men with acute infection, increase and decrease in approximate parallel with changes occurring in blood. Modeling suggests that these acute dynamics alone are sufficient to increase probability of heterosexual transmission by 8-10-fold between peak (day 20 after infection, based on the model) and virologic set points (day 54 and later after infection). Depending on the frequency of coitus, men with average semen HIV-1 loads and without sexually transmitted diseases (STDs) would be expected to infect 7%-24% of susceptible female sex partners during the first 2 months of infection. The predicted infection rate would be much higher when either partner has an STD. CONCLUSIONS Empirical biological data strongly support the hypothesis that sexual transmission by acutely infected individuals has a disproportionate effect on the spread of HIV-1 infection. Acute hyperinfectiousness may, in part, explain the current pandemic in heterosexual individuals.

Impact of new antiretroviral combination therapies in HIV infected patients in Switzerland: prospective multicentre study. Swiss HIV Cohort Study.

Abstract Objectives: To examine trends in disease progression and survival among patients enrolled in the Swiss HIV cohort study during 1988–96 and to assess the influence of new antiretroviral combination therapies. Design: Prospective multicentre study, with follow up visits planned at six monthly intervals. Setting: Seven HIV units at university centres and cantonal hospitals in Switzerland. Patients: 3785 men (mean age 35.0 years) and 1391 women (30.3 years) infected with HIV. 2023 participants had a history of intravenous drug misuse; 1764 were men who had sex with men; 1261 were infected heterosexually; and 164 had other or unknown modes of transmission. 601 participants had had an AIDS defining illness. Results: During more than 15 000 years of follow up, there were 1456 first AIDS defining diagnoses and 1903 deaths. Compared with those enrolled during 1988-90, the risk of progression to a first AIDS diagnosis was reduced by 18% (relative risk 0.82 (95% confidence interval 0.73 to 0.93)) among participants enrolled in 1991-2, by 23% (0.77 (0.65 to 0.91)) among those enrolled in 1993-4, and by 73% (0.27 (0.18 to 0.39)) among those enrolled in 1995-6. Mortality was reduced by 19% (0.81 (0.73 to 0.90)), 26% (0.74 (0.63 to 0.87)), and 62% (0.38 (0.25 to 0.97)) respectively. Compared with no antiretroviral treatment, the risk of an initial AIDS diagnosis after CD4 lymphocyte counts fell to <200 cellsx106/l was reduced by 16% (0.84 (0.73 to 0.97)) with monotherapy, 24% (0.76 (0.63 to 0.91)) with dual therapy, and 42% (0.58 (0.37 to 0.92)) with triple therapy. Mortality was reduced by 23% (0.77 (0.68 to 0.88)), 31% (0.69 (0.60 to 0.80)), and 65% (0.35 (0.20 to 0.60)) respectively. Conclusions: The introduction of antiretroviral combination therapies outside the selected patient groups included in clinical trials has led to comparable reductions in disease progression and mortality. Key messages The Swiss HIV cohort study is an ongoing prospective study that includes a large proportion of the patients infected with HIV in Switzerland Antiretroviral combination therapy with two nucleoside analogues was introduced in 1995, and triple therapy with protease inhibitors was introduced in 1996 The risk of AIDS and death was substantially lower among patients enrolling in 1995 and 1996 than among those enrolled in earlier years Reductions in disease progression were similar among men and women and among patients from different transmission groups In Switzerland the introduction of antiretroviral combination therapies outside selected patient groups included in clinical trials has led to similar reductions in disease progression

Prevalence of adverse events associated with potent antiretroviral treatment: Swiss HIV Cohort Study

BACKGROUND Data on adverse events to antiretroviral treatment have been recorded in clinical trials, post-marketing analyses, and anecdotal reports. Such data might not be an up-to-date or comprehensive assessment of all possible treatment combinations defined as potent antiretroviral treatment. METHODS Using a standard clinical and laboratory method, we assessed prevalence of adverse events in 1160 patients who were receiving antiretroviral treatment. We measured the toxic effects associated with the drug regimen (protease inhibitor [PI], non-nucleoside and nucleoside analogue reverse transcriptase inhibitor) and specific compounds using multivariate analyses. FINDINGS 47% (545 of 1160) of patients presented with clinical and 27% (194 of 712) with laboratory adverse events probably or definitely attributed to antiretroviral treatment. Among these, 9% (47 of 545) and 16% (30 of 194), respectively, were graded as serious or severe. Single-PI and PI-sparing-antiretroviral treatment were associated with a comparable prevalence of adverse events. Compared with single-PI treatment, use of dual-PI-antiretroviral treatment and three-class-antiretroviral treatment was associated with higher prevalence of adverse events (odds ratio [OR] 2.0 [95% CI 1.0-4.0], and 3.9 [1.2-12.9], respectively). Compound specific associations were identified for zidovudine, lamivudine, stavudine, didanosine, abacavir, ritonavir, saquinavir, indinavir, nelfinavir, efavirenz, and nevirapine. INTERPRETATION We recorded a high prevalence of toxic effects attributed to antiretroviral treatment for HIV-1. Such data provides a reference for regimen-specific and compound-specific adverse events and could be useful in postmarketing analyses of toxic effects.

Viral burden in genital secretions determines male-to-female sexual transmission of HIV-1: a probabilistic empiric model.

ObjectiveTo develop a model to predict transmission of HIV-1 from men to women. DesignHIV-1 in seminal plasma, and endocervical CCR5 receptors were correlated with epidemiological studies of HIV-1 transmission to develop a probabilistic model. SettingsSemen samples were collected from patient subjects in Seattle Washington, Chapel Hill, North Carolina, and St. Gallen, Switzerland. Endocervical biopsy specimens were obtained from women in Chicago, Illinois. ParticipantsEighty-six men (not receiving antireroviral therapy) in whom CD4 cell count and semen volume were available, and 24 women in whom the number of endocervical CCR5 receptors were determined. Main outcome measuresPrediction of transmission of HIV-1 from men to women per episode of vaginal intercourse based on the absolute burden of HIV (volume × HIV RNA copies/ml seminal plasma). ResultsThe model suggests efficient heterosexual transmission of HIV-1 when semen viral burden is high. When semen contains 100 000 copies of non-syncytium-inducing (NSI) HIV RNA the probability of HIV-1 transmission is 1 per 100 episodes of intercourse; conversely, with 1000 copies NSI HIV RNA in semen, transmission probability is 3 per 10 000 episodes of intercourse. ConclusionsThis model links biological and epidemiological data related to heterosexual HIV-1 transmission. The model can be used to estimate transmission of HIV from men with high semen viral burden from inflammation, or reduced burden after antiretroviral therapy. The results offer a biological explanation for the magnitude of the HIV epidemic in places where earlier studies have shown men have high semen viral burden, such as in sub-Saharan Africa. The model can be used to develop and test HIV-1 prevention strategies.

Discontinuation of Primary Prophylaxis against Pneumocystis carinii Pneumonia in HIV-1–Infected Adults Treated with Combination Antiretroviral Therapy

BACKGROUND It is unclear whether primary prophylaxis against Pneumocystis carinii pneumonia can be discontinued in patients infected with the human immunodeficiency virus (HIV) who are successfully treated with combination antiretroviral therapy. We prospectively studied the safety of stopping prophylaxis among patients in the Swiss HIV Cohort Study. METHODS Patients were eligible for our study if their CD4 counts had increased to at least 200 cells per cubic millimeter and 14 percent of total lymphocytes while they were receiving combination antiretroviral therapy, with these levels sustained for at least 12 weeks. Prophylaxis was stopped at study entry, and patients were examined every three months thereafter. The development of P. carinii pneumonia was the primary end point, and the development of toxoplasmic encephalitis the secondary end point. RESULTS Of the 262 patients included in our analysis, 121 (46.2 percent) were positive for IgG antibodies to Toxoplasma gondii at base line. The median CD4 count at study entry was 325 per cubic millimeter (range, 210 to 806); the median nadir CD4 count was 110 per cubic millimeter (range, 0 to 240). During a median follow-up of 11.3 months (range, 3.0 to 18.8), prophylaxis was resumed in nine patients, and two patients died. There were no cases of P. carinii pneumonia or toxoplasmic encephalitis. The one-sided upper 99 percent confidence limit for the incidence of P. carinii pneumonia was 1.9 cases per 100 patient-years (based on 238 patient-years of follow-up). The corresponding figure for toxoplasmic encephalitis was 4.2 per 100 patient-years (based on 110 patient-years of follow-up). CONCLUSIONS Stopping primary prophylaxis against P. carinii pneumonia appears to be safe in HIV-infected patients who are receiving combination antiretroviral treatment and who have had a sustained increase in their CD4 counts to at least 200 cells per cubic millimeter and to at least 14 percent of total lymphocytes.

Potent antiretroviral treatment of HIV-infection results in suppression of the seminal shedding of HIV

ObjectiveThe amount of HIV in semen likely influences infectiousness. Antiretroviral therapy decreases HIV-RNA in semen, but data on HIV concentrations in semen in a large cohort of men with suppressed HIV-RNA in blood is unavailable. MethodsMale patients with a treatment-induced reduction of HIV-RNA load in plasma below 400 copies/ml were asked to donate a semen and blood sample. Blood and seminal plasma were tested for the presence of HIV-RNA by the NucliSens method (detection limit 400 copies/ml). Seminal cell samples from 67 patients were further analysed for the presence of HIV-DNA using a nested DNA-polymerase chain reaction. Results of RNA and DNA testing in semen were compared with 55 HIV-positive antiretroviral therapy-naive men. ResultsA total of 114 patients participated in the study. Seminal plasma HIV-RNA was detectable in only two patients [1.8%, 95% confidence ratio (CI), 0–4.2%] compared with a detection frequency of 67% in untreated controls [Odds ratio (OR), 0.01; 95% CI, 0–0.03]. Detection of cell-associated HIV-DNA in semen was significantly less frequent (16 versus 38%) in patients receiving suppressive therapy compared with untreated controls (OR, 0.32; 95% CI, 0.12–0.80). ConclusionIn patients with treatment-induced suppression of blood viral load the likelihood of having detectable HIV in semen is very low (< 4%). In addition, seminal shedding of cell-free and cell-associated HIV is significantly lower than in an untreated population of HIV-infected asymptomatic men. On a population basis, this effect of therapy may help to reduce sexual transmission of HIV. However, individual patients may still be infected as evidenced by continued shedding of cells harbouring the HIV provirus.

CD4-guided scheduled treatment interruptions compared with continuous therapy for patients infected with HIV-1: results of the Staccato randomised trial.

BACKGROUND Stopping antiretroviral therapy in patients with HIV-1 infection can reduce costs and side-effects, but carries the risk of increased immune suppression and emergence of resistance. METHODS 430 patients with CD4-positive T-lymphocyte (CD4) counts greater than 350 cells per muL, and viral load less than 50 copies per mL were randomised to continued therapy (n=146) or scheduled treatment interruptions (n=284). Median time on randomised treatment was 21.9 months (range 16.4-25.3). Primary endpoints were proportion of patients with viral load less than 50 copies per mL at the end of the trial, and amount of drugs used. Analysis was intention-to-treat. This study is registered at ClinicalTrials.gov with the identifier NCT00113126. FINDINGS Drug savings in the scheduled treatment interruption group, compared with continuous treatment, amounted to 61.5%. 257 of 284 (90.5%) patients in the scheduled treatment interruption group reached a viral load less than 50 copies per mL, compared with 134 of 146 (91.8%) in the continued treatment group (difference 1.3%, 95% CI-4.3 to 6.9, p=0.90). No AIDS-defining events occurred. Diarrhoea and neuropathy were more frequent with continuous treatment; candidiasis was more frequent with scheduled treatment interruption. Ten patients (2.3%) had resistance mutations, with no significant differences between groups. INTERPRETATION Drug savings with scheduled treatment interruption were substantial, and no evidence of increased treatment resistance emerged. Treatment-related adverse events were more frequent with continuous treatment, but low CD4 counts and minor manifestations of HIV infection were more frequent with scheduled treatment interruption.