Chris Tsoukas

Parallel decline of Cd8+/cd38++ T cells and viraemia in response to quadruple highly active antiretroviral therapy in primary Hiv infection

Objectives To monitor changes in the numbers of CD8 lymphocytes expressing the activated CD38++ phenotype in peripheral blood samples from patients with primary HIV infection (PHI) treated with highly active antiretroviral therapy (HAART). Methods Zidovudine, lamivudine, abacavir and amprenavir were initiated during PHI as part of the Quest study. Absolute numbers of CD8+/CD38++ T cells were determined using three-colour flow cytometry, and plasma viral load (VL) was measured using the Roche Amplicor method. Results The median, pre-therapy CD8+/CD38++ T cell count was 461/mm3 (interquartile range 216, 974) in 131 patients compared with normal control values of less than 20 cells/mm3. Levels fell markedly in parallel with VL within the first 2 weeks of HAART initiation, to a median of 47 cells/mm3at 28 weeks (median 436 cell decline;P < 0.001). At that time, 80% of patients had a VL less than 50 copies/ml, and 16.3% of all patients had less than 20 CD8+/CD38++ T cells/mm3. A continued decrease in CD8+/CD38++ T cell count occurred in 67.2% of patients whose VL was maintained below 50 copies/ml (median change from first to last value −18 cells/mm3;P < 0.001). Conclusion After the initiation of HAART in PHI, CD8+/CD38++ lymphocytes declined rapidly in parallel with VL, and allowed for a normalization of CD8+/CD38++ T cell numbers in a subset of patients at week 28. Cell numbers continued to decline in patients who maintained VL below 50 copies/ml, indicating that the CD8+/CD38++ T cell count may represent a marker of residual viral replication when VL falls below detectable levels after HAART intervention.

Lamivudine Plus Zidovudine Compared with Zalcitabine Plus Zidovudine in Patients with HIV Infection: A Randomized, Double-Blind, Placebo-Controlled Trial

For the treatment of human immunodeficiency virus (HIV) type 1 infection, five nucleoside reverse transcriptase inhibitors are currently available: zidovudine, didanosine, zalcitabine, stavudine, and lamivudine. The results of clinical trials to date [1-7] suggest that the effectiveness of monotherapy with these agents is time limited. This may be because the regimens incompletely suppress viral burden and allow the emergence of drug-resistant virus populations and because of the dynamic nature of HIV infection. Combinations of anti-HIV agents in vitro provide more thorough viral suppression and may limit the emergence of drug resistance [8]. Numerous clinical trials of zidovudine plus zalcitabine or zidovudine plus didanosine [9-13] have suggested that suppression of HIV replication and increases in absolute CD4+ cell counts are greater with combination therapy than with monotherapy. Several recent trials [3, 14] have shown improved clinical outcomes for patients receiving combination therapy, including those who had previously received zidovudine monotherapy. These results have encouraged further evaluation of antiretroviral drug combinations for the treatment of HIV infection. Lamivudine ([minus]-2,3-dideoxy-3-thiacytidine; 3TC) is a nucleoside reverse transcriptase inhibitor and a potent, relatively nontoxic, selective inhibitor of HIV replication [15, 16]. It is active against zidovudine-resistant HIV isolates and is synergistic with zidovudine in vitro [17, 18]. Lamivudine is well tolerated and effectively improves prognostic virologic and immunologic markers during the treatment of HIV-infected patients [19-21]. Lamivudine-resistant HIV isolates have been identified both in vitro and in vivo during therapy in association with the development of a mutation at codon 184 in the HIV pol gene [22-27]. In vitro studies have shown that inserting the lamivudine resistance-conferring codon 184 mutation into zidovudine-resistant viruses restores phenotypic zidovudine sensitivity in tissue culture [22, 27]. Despite the rapid appearance of lamivudine-resistant viruses in clinical trials of lamivudine monotherapy or therapy with lamivudine-containing drug combinations, sustained reductions in viral burden have been seen [26, 27]. Therefore, the combination of lamivudine and zidovudinebecause of its in vitro synergy; its potential reversal of zidovudine resistance; its antiretroviral activity, seen in vivo despite the emergence of lamivudine resistance; and its favorable safety profilemay be particularly promising as therapy for HIV-infected patients previously treated with zidovudine. This NUCA 3002 study was designed to compare the safety and activity of two doses of lamivudine plus zidovudine with the safety and activity of zalcitabine plus zidovudine in patients with moderately advanced HIV infection who had previously received zidovudine. Methods Study Sample To be eligible for the study, patients had to meet all of the following criteria: age at least 18 years; documented HIV infection; absolute CD4+ cell count between 100 and 300 cells/mm3; at least 6 months of previous zidovudine therapy, including current zidovudine use at time of study entry; either no experience with didanosine, zalcitabine, or investigational antiretroviral drugs or a maximum of 4 weeks of previous treatment with didanosine; Karnofsky score of at least 60; hemoglobin concentration of at least 92 g/L for men and 88 g/L for women; absolute neutrophil count of at least 1000 cells/mm3; platelet count of at least 5 107/L; hepatic aminotransferase and alkaline phosphatase levels no greater than five times the upper limit of normal; serum bilirubin level less than 25.65 mg/L; serum creatinine concentration less than 132.6 mg/L; and total serum amylase level no greater than 1.5 times the upper limit of normal. Patients receiving chemoprophylaxis for Pneumocystis carinii pneumonia, candidiasis, or herpes simplex infections and those receiving erythropoietin or granulocyte colony-stimulating factor were eligible for inclusion. Exclusion criteria were evidence of active acquired immunodeficiency syndrome (AIDS)-defining opportunistic infections for which therapy had not been completed; current peripheral neuropathy of mild to moderate or greater severity; significant cardiac, hepatic, renal, or neurologic disease; active cancer; or intractable diarrhea or severe malabsorption. Patients were also ineligible if they were pregnant, were breastfeeding, or had childbearing potential and were not using adequate contraception. Study Design Our study was a multicenter, randomized, double-blind (the use of zidovudine was open-label) clinical trial designed to compare the safety and activity of two different doses of lamivudine plus zidovudine with the safety and activity of zalcitabine plus zidovudine. The study was originally intended to last 24 weeks, but the duration was amended during the course of the trial so that all patients who completed 24 weeks of study therapy could continue their assigned treatment in a double-blind manner through at least 52 weeks. The study was done at 21 sites in the United States, Canada, and Puerto Rico. The institutional review board at each institution approved the study, and all patients gave written consent. Glaxo Wellcome, Inc., collected and analyzed the primary study data, and the study investigators reviewed and interpreted the results. Treatment Regimens Patients were randomly assigned to receive one of three treatment regimens: 150 mg of lamivudine every 12 hours, 200 mg of zidovudine every 8 hours, and zalcitabine placebo every 8 hours (low-dose lamivudine group); 300 mg of lamivudine every 12 hours, 200 mg of zidovudine every 8 hours, and zalcitabine placebo every 8 hours (high-dose lamivudine group); or 0.75 mg of zalcitabine and 200 mg of zidovudine every 8 hours and lamivudine placebo every 12 hours (zalcitabine group). Each dose of zidovudine (Retrovir; Glaxo Wellcome, Inc., Research Triangle Park, North Carolina) was given as two 100-mg capsules; each dose of zalcitabine (Hivid; Hoffman-La Roche, Inc., Nutley, New Jersey) was given as two 0.375-mg tablets; and each dose of lamivudine (Epivir; Glaxo Wellcome, Inc.) was given as two 75-mg tablets or as one 300-mg tablet with a matching placebo. All adjustments of medications for management of adverse events were made by each study center in a standardized and blinded manner. Adverse events and abnormal laboratory results were graded according to a toxicity rating scale developed by the Division of AIDS, National Institutes of Health. Study Assessments The primary outcome measure was the change from baseline in absolute CD4+ cell counts during the first 24 weeks of the study. The secondary outcome measures were the change in log10 plasma HIV RNA levels, clinical progressions of HIV disease, percentages of cells that were CD4+ cells, serum 2-microglobulin and neopterin levels, and serum immune complex-dissociated p24 antigen levels. Each patient was evaluated within 14 days of randomization, at least 72 hours before randomization, at the time of randomization (day 1), at study weeks 2 and 4, and every 4 weeks thereafter. Safety of the study regimens was evaluated through medical histories and physical examinations, clinical laboratory tests, and the reporting of adverse events. All laboratory studies were done by the Laboratory Corporation of America (formerly Roche Biomedical Laboratories, Research Triangle Park, North Carolina, and Raritan, New Jersey). Virologic activity was evaluated through the measurement of plasma HIV RNA levels by reverse transcriptase quantitative polymerase chain reaction (PCR) (Roche Quantiplex PCR, Laboratory Corporation of America) and the measurement of serum immune complex-dissociated p24 antigen levels (Coulter Corp., Hialeah, Florida) in all patients. The lower limit of detection for the reverse transcriptase PCR assay was 200 copies of HIV RNA per mL. Human immunodeficiency virus isolates were banked for future drug-resistance studies. Immunologic activity was evaluated through the measurement of T-lymphocyte subsets, 2-microglobulin levels, and neopterin levels in all patients. T-lymphocyte subsets were determined three times before therapy with study medications was initiated, and the baseline absolute CD4+ cell count was defined as the mean of the final two values obtained at the last visit made before and at the time of randomization. Clinical progressions of HIV disease were classified according to the criteria from the Centers for Disease Control and Prevention (CDC); these criteria consist of commonly recognized AIDS-related events (class B conditions) and AIDS-defining events (class C conditions) [28]. All diagnoses were reviewed by clinical research personnel who were blinded to treatment assignments. The criteria for the discontinuation of assigned treatment included serious adverse events; a 50% decline from baseline in absolute CD4+ cell counts on two consecutive occasions at least 28 days apart or a new AIDS-indicator illness (at the discretion of the center); pregnancy; unreliable follow-up (at the discretion of the center); or noncompliance. Patients who discontinued treatment were asked to return for monitoring of CD4+ cell counts every 4 weeks until study week 52. Statistical Analysis An equal number of patients was randomly assigned to the three treatment regimens through the use of permuted blocks at each study center. A sample size of 75 participants per treatment group was chosen to allow 80% power to detect a difference of 25 CD4+ cells/mm3 between the mean CD4+ cell counts of the three groups at the 0.05 level of significance. A summary metric [29] was used to characterize the HIV disease marker profile during the first 24 weeks of the study for the analyses of primary study outcomes. The time-weighted area under the curve (trapezoidal rule) minus the baseline value (DAVGT) was used to compare the profi

Effects of Lovastatin on Natural Killer Cell Function and Other Immunological Parameters in Man

Suppression of cholesterol synthesis by 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, such as lovastatin, has been shown to inhibit mitogen stimulated proliferation of natural killer (NK) cells and other lymphocytesin vitro. This effect is only partially overcome by provision of exogenous free or lipoprotein cholesterol but is reversed by mevalonate, suggesting that proliferating lymphocytes have a specific requirement for a nonsterol isoprenoid product of mevalonate. The effect of lovastatin (20 mg bid) on a range of immune function parameters was determined in a randomized, placebo-controlled, double-blindex vivo study in 52 patients with primary hypercholesterolemia. No significant differences (P<0.05) were found between lovastatin and placebo groups for basal NK or interleukin-2 (IL-2)-induced cell-mediated cytotoxicity, PHA-stimulated lymphocyte proliferation, or relative numbers of T lymphocytes (CD3+), B lymphocytes (CD19+), total NK cells (CD3−, CD16+, CD56+) and CD57+ NK cells or in immunoglobulin levels after 4 or 8 weeks of treatment. In contrast to previousin vitro data, no statistically or clinically significant changes were observed in any parameter of lymphocyte function in patients treated with lovastatin.

Clindamycin with Primaquine vs. Trimethoprim-Sulfamethoxazole Therapy for Mild and Moderately Severe Pneumocystis carinii Pneumonia in Patients with AIDS: A Multicenter, Double-Blind, Randomized Trial (CTN 004)

This double-blind, randomized, multicenter trial compared clindamycin/primaquine (Cm/Prq) with trimethoprim-sulfamethoxazole (TMP-SMZ) as therapy for AIDS-related Pneumocystis carinii pneumonia (PCP). Forty-five patients received clindamycin (450 mg four times daily [q.i.d.]) and primaquine (15 mg of base/d); 42 received TMP-SMZ (320 mg/1,600 mg q.i.d. if weight of > or = 60 kg or 240 mg/1,200 mg q.i.d. if weight of < 60 kg) plus placebo primaquine. Overall, the efficacy of Cm/Prq was similar to that of TMP-SMZ (success rate, 76% vs. 79%, respectively); Cm/Prq was associated with fewer adverse events (P = .04), less steroid use (P = .18), and more rashes (P = .07). These differences were even greater for patients with PaO2 of > 70 mm Hg (P = .02, P = .04, and P = .02, respectively). For patients with PaO2 of < or = 70 mm Hg (23 Cm/Prq recipients and 21 TMP-SMZ recipients), the efficacy of Cm/Prq was similar to that of TMP-SMZ (success rate, 74% vs. 76%, respectively); Cm/Prq was associated with similar adverse events (P = .57), steroid use (P = .74), and rashes (P = .78). This trial confirms that Cm/Prq is a reasonable alternative therapy for mild and moderately severe PCP.

Overcoming resistance to existing therapies in HIV-infected patients: the role of new antiretroviral drugs.

Resistance to available antiretroviral (ARV) agents is of increasing concern, and development of novel agents that address this problem has been identified as a major public health priority. As ARV resistance becomes more prevalent with extended use of existing agents, individuals with HIV infection resistant to all three traditional classes of ARVs, nucleoside reverse transcriptase inhibitors (NRTIs), non‐nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs), find themselves increasingly limited with regard to effective treatment options. The need for tolerable new drug regimens that effectively suppress viral replication while being simple to adhere to is increasingly pressing. This article reviews the epidemiology of antiretroviral drug resistance, the factors that contribute to the emergence of resistance, and presents data that support the need for early detection of resistance and maximal virologic suppression in order to delay treatment failure and reduce mortality. Healthcare providers are encouraged to optimize therapy through the use of new agents from existing drug classes, which can minimize cross‐resistance, as well as agents with novel mechanisms of action, in order to realize the potential for greater viral containment and to forestall development of resistance mutations. This article evaluates several emerging therapies that are in late‐stage clinical development and promise to expand treatment options for highly treatment‐experienced patients with the goal of improving outcomes for HIV‐infected individuals whose options for sustained antiviral efficacy are increasingly limited. J. Med. Virol. 80:565–576, 2008.

HIV-associated Lipodystrophy Syndrome: A Review of Clinical Aspects

Approximately two years after the introduction of highly active antiretroviral therapy for the treatment of HIV infection, body shape changes and metabolic abnormalities were increasingly observed. Initially, these were ascribed to protease inhibitors, but it is now clear that nucleoside reverse transcriptase inhibitors also contribute to lipodystrophy syndrome. The syndrome groups together clinical conditions describing changes in body fat distribution that include lipoatrophy, lipoaccumulation or both. However, there does not appear to be a direct link between lipoatrophy and lipoaccumulation that would support a single mechanism for the redistribution of body fat. Currently, there is no clear definition of lipodystrophy, which explains the difficulty in determining its prevalence and etiology. There are no current guidelines for the treatment of fat distribution abnormalities that occur in the absence of other metabolic complications. The present article reviews the current state of knowledge of the definition, symptoms, risk factors, pathogenesis, diagnosis and treatment of the morphological changes associated with lipodystrophy syndrome.

Predictors of CD4:CD8 ratio normalization and its effect on health outcomes in the era of combination antiretroviral therapy.

Background HIV leads to CD4:CD8 ratio inversion as immune dysregulation progresses. We examined the predictors of CD4:CD8 normalization after combination antiretroviral therapy (cART) and determined whether normalization is associated with reduced progression to AIDS-defining illnesses (ADI) and death. Methods A Canadian cohort of HIV-positive adults with CD4:CD8<1.2 prior to starting cART from 2000–2010 were analyzed. Predictors of (1) reaching a CD4:CD8 ≥1.2 on two separate follow-up visits >30 days apart, and (2) ADI and death from all causes were assessed using adjusted proportional hazards models. Results 4206 patients were studied for a median of 2.77 years and 306 (7.2%) normalized their CD4:CD8 ratio. Factors associated with achieving a normal CD4:CD8 ratio were: baseline CD4+ T-cells >350 cells/mm3, baseline CD8+ T-cells <500 cells/mm3, time-updated HIV RNA suppression, and not reporting sex with other men as a risk factor. There were 213 ADIs and 214 deaths in 13476 person-years of follow-up. Achieving a normal CD4:CD8 ratio was not associated with time to ADI/death. Conclusions In our study, few individuals normalized their CD4:CD8 ratios within the first few years of initiating modern cART. This large study showed no additional short-term predictive value of the CD4:CD8 ratio for clinical outcomes after accounting for other risk factors including age and HIV RNA.

A CD4+ cell count <200 cells per cubic millimeter at 2 years after initiation of combination antiretroviral therapy is associated with increased mortality in HIV-infected individuals with viral suppression

Objective:To determine the long-term impact of immunologic discordance (viral load <50 copies/mL and CD4+ count ≤200 cells/mm3) in antiretroviral-naive patients initiating combination antiretroviral therapy (cART). Methods:Our analysis included antiretroviral-naive individuals from a population-based Canadian Observational Cohort that initiated cART after January 1, 2000, and achieved virologic suppression. Multivariable Cox proportional hazards regression was used to examine the association between 1-year and 2-year immunologic discordance and time to death from all-causes. Correlates of immunologic discordance were assessed with logistic regression. Results:Immunologic discordance was observed in 19.9% (404 of 2028) and 10.2% (176 of 1721) of individuals at 1 and 2 years after cART initiation, respectively. Two-year immunologic discordance was associated with an increased risk of death [adjusted hazard ratio = 2.69; 95% confidence interval (CI): 1.26 to 5.78]. One-year immunologic discordance was not associated with death (adjusted hazard ratio = 1.12; 95% CI: 0.54 to 2.30). Two-year immunologic discordance was associated with older age (aOR per decade = 1.23; 95% CI: 1.03 to 1.48), male gender (aOR = 1.86; 95% CI: 1.09 to 3.16), injection drug use (aOR = 2.75; 95% CI: 1.81 to 4.17), and lower baseline CD4+ count (aOR per 100 cells = 0.24; 95% CI: 0.19 to 0.31) and viral load (aOR per log10 copies/mL = 0.46; 95% CI: 0.33 to 0.65). Conclusions:Immunologic discordance after 2 years of cART in antiretroviral-naive individuals was significantly associated with an increased risk of mortality.

Didanosine Compared with Continued Zidovudine Therapy for HIV-Infected Patients with 200 to 500 CD4 Cells/mm3: A Double-Blind, Randomized, Controlled Trial

Zidovudine (3-azido-3-deoxythymidine) has been shown in placebo-controlled studies [1, 2] to prolong survival in patients with the acquired immunodeficiency syndrome (AIDS), to delay the development of AIDS in those with AIDS-related complex, and to delay the development of AIDS and AIDS-related complex in patients with asymptomatic human immunodeficiency virus (HIV) infection. The duration of the clinical benefit afforded by zidovudine monotherapy, however, appears to be limited [3-6]. The underlying mechanism or mechanisms responsible for disease progression during zidovudine therapy must still be definitively established. However, current evidence suggests that the development of viral resistance to zidovudine is at least partly responsible for the short duration of benefit [7, 8]. Didanosine (2,3-dideoxyinosine) is a newer nucleoside analog that has been shown to be effective in vitro against HIV [9]. Didanosine has in vitro activity against viral isolates that have high-level resistance to zidovudine [10]. Early clinical trials showed that didanosine can have a persistent beneficial effect on surrogate markers of HIV infection, such as CD4 counts, p24 antigen levels, and constitutional symptoms [11-14]. The investigators who did these studies found that peripheral neuropathy and pancreatitis were the dose-limiting toxicities of didanosine. More recently, controlled studies have shown that a switch to didanosine can improve clinical outcome in persons with advanced HIV disease who have received zidovudine [15, 16]. More specifically, Kahn and colleagues [15] showed such a benefit in patients with AIDS or AIDS-related complex who were clinically stable while receiving zidovudine and who had CD4 counts of 300 cells/mm3 or less and in asymptomatic HIV-infected patients with CD4 counts of 200 cells/mm3 or less. Spruance and coworkers [16] showed a similar benefit in patients with CD4 counts of 300 cells/mm3 or less and signs of clinical deterioration while receiving zidovudine therapy. No clinical data are available on the role of didanosine in stable patients in earlier stages of HIV disease who have received zidovudine. We therefore specifically compared the safety and efficacy of didanosine with that of continued zidovudine therapy in clinically stable HIV-infected persons who had CD4 counts between 200 and 500 cells/mm3 and had received zidovudine for at least 6 months. We hypothesized that a change to a second effective antiretroviral agent before the anticipated development of high-level resistance to zidovudine would prevent resistance and consequently delay the progression of HIV disease. Methods Study Design Randomization was stratified by the study center and by the CD4 cell count at study enrollment (more than or less than 300 cells/mm3). Successfully screened patients were randomly assigned using computer-generated random numbers. Randomization was done at a central location to ensure that patients, research personnel, and pharmacists remained blinded to the treatment allocation. All study participants provided informed consent. The study protocol and informed consent were approved by the review boards of the participating institutions and by the Canadian HIV Trials Network (CTN), with which our study is registered as protocol CTN-002. Patients Eligible study participants were male and nonpregnant female patients 12 years of age or older. Other entry criteria were the following: 1) HIV infection documented by enzyme-linked immunosorbent assay; 2) two sequential prerandomization CD4 counts between 200 and 500 cells/mm3 obtained at least 72 hours apart within 30 days of randomization, with the most recent measurement done within 14 days of randomization; 3) zidovudine therapy received for at least 6 months before randomization at a dose of at least 500 mg/d for the month immediately preceding study entry; 4) zidovudine therapy at 500 mg/d or greater for at least 21 of the previous 26 weeks; 5) a Karnofsky performance status of greater than 60 at study entry; 6) a hemoglobin level greater than 85 g/L or a hematocrit greater than 0.25 (in the absence of blood transfusion in the preceding 2 weeks); 7) a neutrophil count greater than 0.75 109/L; 8) a platelet count greater than 50 109/L; 9) serum aminotransferase and alkaline phosphatase levels greater than five times the upper limit of normal; 10) a serum creatinine level greater than 1.5 times the upper limit of normal; 11) a serum uric acid level less than 530 mol/L; and 12) a serum amylase level less than 2.1 times the upper limit of normal. The following are the normal values for chemical variables: aspartate aminotransferase, as high as 0.67 kat/L; alkaline phosphatase, 0.58 to 1.75 kat/L; creatinine, 40 to 120 mol/L; and amylase, 0.50 to 1.83 kat/L. Study participants were required to take adequate birth control measures during the study. The following were the exclusion criteria: 1) the presence of an uncontrolled AIDS-defining illness; 2) known or suspected pulmonary Kaposi sarcoma or Kaposi sarcoma requiring systemic cytotoxic chemotherapy; 3) grade II or greater dementia; 4) active substance abuse; 5) antiretroviral therapy other than zidovudine; 6) any use of biological-response modifiers or corticosteroids within 30 days of entry or therapy with ribavirin within 90 days of entry; 7) previous participation in studies involving didanosine or zalcitabine; 8) grade II or greater neurologic, allergic, or renal toxicities; 9) any history of pancreatitis, intractable diarrhea, or malabsorption; 10) unexplained seizures within the previous 6 months or need for anticonvulsant agents; 11] treatment with neurotoxic drugs within 30 days of entry; and 12) past or current heart disease or requirement for cardiac medication. All study participants were encouraged to use prophylaxis for Pneumocystis carinii infection according to contemporary guidelines [17]. The use of megestrol acetate, foscarnet, aspirin, acetaminophen, nonsteroidal anti-inflammatory agents, oral acidifying agents, and oral acyclovir was discouraged. Treatment of opportunistic infections was permitted. In patients developing serious symptoms or laboratory abnormalities, study medications were withheld until the symptoms or laboratory abnormalities resolved; at this point, patients were encouraged to resume the study medication, according to a prespecified dose-reduction scheme. Treatment Regimens Zidovudine (Retrovir, Burroughs-Wellcome, Research Triangle Park, North Carolina) was provided in 100-mg capsules to be taken at a dosage of 600 mg/d divided into at least three daily doses. Didanosine (Videx, Bristol-Myers Squibb, Princeton, New Jersey) was provided in sachets containing 5.2 g of citrate-phosphate buffer and sucrose adjusted to yield a final net weight of 20 g. The contents of one sachet were to be dissolved in water and swallowed. Didanosine dosage was adjusted for weight: Patients weighing at least 60 kg received 500 mg/d in two divided doses; patients weighing less than 60 kg received 334 mg/d in two divided doses. The didanosine formulation was changed in October 1991 from 500- and 334-mg/d sachet formulations to 400- and 200-mg/d tablet formulations. Study participants were instructed to chew the didanosine tablets thoroughly either together or in rapid succession and then to rinse with approximately 120 mL of room-temperature drinking water, which was also to be swallowed. Alternatively, the two tablets were to be crushed and thoroughly dispersed in at least 120 mL of drinking water; this solution was to be drunk immediately, followed by approximately 120 mL of drinking water. Study participants were instructed to always take didanosine on an empty stomach, at least 2 hours after and 1 hour before meals. To maintain the double-blind nature of the protocol, patients assigned to receive didanosine were given identical zidovudine placebo, and those assigned to receive zidovudine were given identical didanosine placebo. Follow-up After completion of the baseline evaluation, patients were seen at biweekly intervals for the first 2 months and monthly thereafter. A safety profile, including a symptom-targeted questionnaire, hematologic assessment, and chemistry panel were done at each visit. The CD4 count and viral resistance studies were done at baseline; at weeks 2, 8, and 12; and every 3 months thereafter. Formal follow-up of this cohort, as per the study protocol, was completed on 12 October 1992. Long-term, off-protocol, follow-up information on survival, AIDS-defining illnesses, and CD4 lymphocyte counts was compiled on one occasion using standardized data collection forms in December 1993. This allowed us to collect additional follow-up information on all patients after study completion and information on the complete study period for patients who dropped out of the study. Study End Points The primary clinical end point was the occurrence of a new, previously undiagnosed AIDS-defining event (according to the revised 1987 criteria of the Centers for Disease Control and Prevention) or death [18]. Clinical end points were reviewed by study monitors at each clinical site and were confirmed in a blinded manner by the clinical end points committee. Didanosine was licensed by the Food and Drug Administration in the United States and by the Health Protection Branch in North America in the fall of 1991. At that time, didanosine became the standard therapy in Canada for persons with zidovudine intolerance or disease progression despite zidovudine therapy. Thus, in late 1991, while the study remained blinded and before any data were analyzed, a 33% decline in CD4 counts from baseline was added as a primary study end point to maintain consistency with prevailing clinical practice. Sensitivity Testing Samples for testing sensitivity to the study drugs were obtained from 102 of 120 patients (85%) enrolled at five clinical sites who were preselected on the basis of logistic issues. For

Study Protocol for the Evaluation of the Potential for Durable Viral Suppression After Quadruple HAART With or Without HIV Vaccination: The QUEST Study

Abstract Purpose: By protecting and stimulating HIV-specific CD4 cell responses, treatment of primary HIV infection (PHI) with potent quadruple HAART could lead to prolonged suppression of HIV replication after cessation of antiretroviral therapy. The QUEST trial investigates this hypothesis and aims to determine whether addition of a therapeutic vaccine to HAART increases the likelihood of prolonged viral suppression compared to HAART alone. Method: 148 patients with PHI were recruited. Participants were treated with open-label HAART for at least 76 weeks. Participants with sustained viremia <50 copies/mL were randomized to one of three 5-month, double-blinded study treatment groups: HAART alone, HAART + ALVAC-HIV (vCP1452), or HAART + ALVAC-HIV (vCP1452) + RemuneTM. After a further month of HAART alone, all treatment was stopped where plasma HIV-1 RNA remained at <50 copies/mL. Intensive virologic and immunologic monitoring during a 24-week observation period followed treatment interruption. Patients who met treatment reintroduction criteria were offered HAART rescue.