HIV infection in vaccinated volunteers.
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Biomedical subjects
Publications and source records attributed to R Dolin.
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OBJECTIVE: To evaluate the safety and immunogenicity of the MN strain of recombinant gp120 (MN rgp120) as a vaccine prototype to prevent human immunodeficiency virus (HIV). DESIGN: Double-blind, randomized, placebo-controlled study with subjects vaccinated at 0, 4, 24, and 48 weeks and followed up through 64 weeks. SETTING: The AIDS Vaccine Evaluation Units in St Louis, Mo, Nashville, Tenn, and Rochester, NY, conducted the clinical study. Laboratory studies were conducted at Duke University, Raleigh, NC; data analysis was done by the Data Coordinating and Analysis Center at the EMMES Corporation, Potomac, Md. PARTICIPANTS: Fifty-seven persons seronegative for HIV, at low risk for acquiring HIV infection, and 18 to 60 years of age. INTERVENTIONS: The MN rgp120 vaccine was administered to 12 volunteers each in doses of 100 micrograms, 300 micrograms, or 600 micrograms, and 12 volunteers received a combination of 300 micrograms of MN rgp120 vaccine and 300 micrograms of vaccine from rgp120 of strain IIIB. Nine volunteers received alum adjuvant alone (control). MAIN OUTCOME MEASURES: Safety was assessed by monitoring lymphocyte subsets, serum creatinine, and liver enzymes. Immunogenicity was measured by enzyme-linked immunosorbent assay using the immunogen and synthetic peptide corresponding to the variable region 3 domain of gp120. Functional antibody assays included CD4 binding blocking; antibody-dependent, cell-mediated cytotoxicity; and neutralization of homologous and heterologous HIV strains. RESULTS: No severe adverse reactions occurred. In 33 of 48 volunteers, two doses of vaccine induced antibodies that neutralized the homologous strain HIV-1/MN. Three doses of vaccine induced antibodies that neutralized MN (in 46 of 48 volunteers), SF-2 (in 45 of 48 volunteers), or IIIB strains of HIV-1 (in 30 of 48 volunteers). CONCLUSION: The vaccines were safe and immunogenic. Multiple injections of vaccine broadened and increased the neutralizing antibody response.
Phase I dose-escalating trials of didanosine revealed dose-limiting toxicities, including pancreatitis, and established a total daily dose of 12.5 mg/kg/day as the maximum tolerated dose. Clinical and pharmacokinetic data of 61 patients from two trials were analyzed to further evaluate the risk of pancreatitis: 1 (6.3%) of 16 patients who received < 500 mg/day didanosine, 2 (13.3%) of 15 who received 500-750 mg/day, and 15 (50%) of 30 who received > 750 mg/day developed pancreatitis (P < .001). A relationship between risk of pancreatitis and steady-state plasma concentrations of didanosine and age was also observed, suggesting that knowledge of didanosine pharmacokinetics provided additional information regarding risk of toxicity. Further confirmation of these findings will be necessary to determine if the risk factors for pancreatitis remain the same at lower doses currently used.
Priming with a live recombinant vector followed by subunit boosting is a promising strategy for human immunodeficiency virus (HIV) immunization. Twenty-nine vaccinia-naive volunteers were primed with gp160-recombinant vaccinia virus (HIVAC-1e) and boosted with recombinant (r) gp160 to define factors associated with the magnitude and specificity of antibody response after booster immunization. A longer interval between inoculation and boost, two inoculations of HIVAC-1e with lesion formation occurring after the first, and Western blot-detectable antibody to gp160 after inoculation were significantly associated with higher neutralizing antibody titers and fusion-inhibiting activity after boosting. HIVAC-1e-primed vaccinees were more likely to have antibody to V3- and CD4-binding regions of gp120 and less likely to have antibody to constant regions 2 and 3 than vaccinees immunized with rgp160 alone. Priming volunteers with HIVAC-1e was a key determinant of the epitope specificity and magnitude of functional antibody responses induced by rgp160 boosting.
Thirty HIV isolates, obtained from 15 patients before and after receiving single drug therapy with didanosine (ddI), were examined for sensitivity to ddI and zidovudine (ZDV) using a peripheral blood mononuclear leukocyte (PBML)-based assay. Fourteen of the patients had ARC, one had AIDS and 12 had received previous therapy with ZDV. After a median of 1 year of ddI therapy, isolates were significantly less sensitive to ddI than were isolates obtained prior to therapy (P = 0.03). A decrease in ddI sensitivity was observed in ten of the 15 isolate pairs. In contrast to ddI susceptibilities, sensitivity to ZDV increased over the same period of time (P = 0.03). Additional isolates were obtained from four patients who received ddI monotherapy for 2 years. Three of these isolates demonstrated no change in ddI sensitivity compared to baseline. No correlation could be made in this study between development of decreased ddI sensitivity and serum p24 levels, CD4 counts, or clinical outcome. Decreased ddI sensitivity occurs frequently among HIV isolates obtained from long-term recipients of ddI. This decreased sensitivity is modest in degree and is of unknown clinical significance.
The relation between the average steady-state plasma concentration (Cpss) of didanosine and selected measures of efficacy, such as CD4 cell count, p24 antigenemia, and weight gain, was evaluated in patients participating in a phase 1 safety and pharmacokinetics study. All patients were diagnosed as having AIDS or severe AIDS-related complex. These individuals first received intravenous didanosine for 2 weeks at doses of 0.8-33 mg/(kg.d) and then took the drug orally at twice the intravenous dose. Cpss values were calculated on the basis of apparent oral clearance after 4 weeks of oral administration and average daily dose over the first 12 weeks of the study. These data were available for 61 patients enrolled at three clinical sites. High values for Cpss were strongly correlated with an increase in CD4 count (P = .006), a decrease in serum levels of p24 antigen (P = .006), and weight gain (P = .0001) at week 12. Logistic regression analysis was used to assess the influence of Cpss on response (as judged by the three criteria just mentioned) after adjustment for other potential factors related to infection with human immunodeficiency virus. The baseline CD4 cell count and the status with regard to prior zidovudine therapy were related to the CD4 response. However, the odds that a response would include all three parameters were nearly twice as high when the Cpss value increased by twofold.(ABSTRACT TRUNCATED AT 250 WORDS)
The effect on immunologic and virological parameters of up to 24 weeks of therapy with didanosine at daily oral doses of < or = 12.5 mg/(kg.d) was studied retrospectively in 69 patients with advanced disease due to human immunodeficiency virus--i.e., AIDS or advanced AIDS-related complex--who had previously been treated with zidovudine. Patients entered the study with a low CD4 cell count (median, 39/microL) and with evidence of an ongoing depression of bone marrow function. Didanosine therapy was associated with a significant increase in CD4 counts and a prolonged decrease in serum levels of p24 antigen relative to baseline. These changes were more pronounced in the population with baseline CD4 counts of > or = 100/microL. A beneficial effect of didanosine therapy on hematologic parameters was observed in these patients, with increases during therapy of hemoglobin levels as well as white blood cell, granulocyte, and platelet counts. These responses were maximal at weeks 16-20. Further investigations are needed to establish the clinical correlates of these observations.
Long-term follow-up of 44 patients with AIDS or AIDS-related complex (ARC) in a phase 1 trial of didanosine is reported. These patients were monitored for as long as 72 weeks (mean, 34 weeks) for toxicity and activity of didanosine. Pancreatitis and neuropathy, the major clinical toxicities, developed infrequently at the doses of didanosine (250-750 mg/d) employed during the latter part of the study. Consistent hematologic toxicity was not encountered; moreover, mean values for hematologic parameters such as hemoglobin concentration, white blood cell count, neutrophil count, lymphocyte count, and platelet count improved for up to 20-60 weeks. CD4 counts increased significantly through 10 weeks of therapy and in some patients remained at or above counts at enrollment for as long as 60 weeks. Serum concentrations of p24 antigen decreased significantly and remained at the decreased level for up to 48 weeks. An initial diagnosis of ARC (as opposed to AIDS), an initial CD4 count of > 100/mm3, and an increase in CD4 counts during the first 10 weeks of therapy were associated with a higher rate of survival and with lower rates of development of opportunistic infections and of other clinical manifestations of disease progression.
Twelve vaccinia-naive volunteers were inoculated with recombinant vaccinia virus expressing the human immunodeficiency virus type 1 (HIV-1) strain IIIB (HIV-1IIIB) envelope glycoprotein gp160 and subsequently immunized with 640 micrograms of recombinant (r) gp160 protein produced in baculovirus. After booster immunization with rgp160, the sera of all vaccinees showed strong antibody responses detected by Western blot and ELISA; 8 had neutralizing activity and 5 had fusion inhibition activity against the homologous strain; 5 blocked binding of CD4 cells to gp120. Cross-reactive neutralization of HIV-1MN was detected in 3 of 8 sera that neutralized HIV-1IIIB. The combination of live recombinant vaccinia followed by subunit booster immunization was more immunogenic than either product alone and represents a promising approach for HIV-1 immunoprophylaxis. Further definition of recombinant vaccinia safety and augmentation of immune responses to geographically prevalent HIV-1 strains will be necessary before expanding clinical trials to high-risk groups.
Mononuclear leukocytes (MNL) were obtained from vaccina-naive, non-human immunodeficiency virus (HIV) infected subjects who were vaccinated with HIV-1-derived recombinant (r) live vaccina-gp160, 4 of whom were boosted 1-2 years later with purified rgp160. MNL obtained after receipt of the vaccinia-gp160 alone showed persisting (> or = 1 year) gp160-specific lymphocyte proliferative responses and production of immune-specific interferon (IFN)-gamma. All 4 subjects who were boosted with rgp160 responded to the boost, including 2 whose cellular responses had waned prior to the boost. MNL from these 4 exhibited gp160-specific proliferative responses, IFN-gamma production, and cytotoxic T lymphocyte activity. The gp160-specific cytolysis was severely reduced or abolished by depletion of CD8+ cells and was not detected using HLA class I-mismatched target cells. Persisting (> or = 15 months after boost) HIV gp160-specific T cell recognition and functional responses can be induced by HIV-derived envelope vaccines.
Recombinant gp160 derived from human immunodeficiency virus type 1 (HIV-1)IIIB and produced in mammalian tissue culture cells using a vaccinia virus expression system (rgp160-mam) was evaluated as a vaccine in combination with alum and deoxycholate adjuvant. Sixty low-risk, uninfected subjects received 12.5 micrograms, 50.0 micrograms, or adjuvant control at 0, 1, 6, and 12 months in a randomized, double-blind dose-escalation study. A single injection of 200 micrograms of vaccine was given at 18 months in an open study to 9 vaccines who had received 50 micrograms. The vaccine was safe. Six of 16 subjects receiving 50 micrograms developed neutralizing antibody to HIV-1IIIB. Seven of the 9 boosted with 200 micrograms of vaccine at 18 months developed neutralizing antibodies. Lymphocyte proliferation to rgp160-mam and baculovirus-derived rgp160 and rgp120 was induced in both groups (12.5 and 50.0 micrograms) and appeared after the first dose. Further studies with higher doses of rgp160-mam and vaccines derived from other strains of HIV-1 are warranted.
Myelosuppression is associated with human immunodeficiency virus (HIV) infection and may also be produced by agents used for the treatment of the disease or the treatment of its complications. Didanosine (ddl; 2',3'-dideoxyinosine) is a newer purine nucleoside that has recently become available for therapy for HIV infection. The effects of didanosine on peripheral blood counts have been retrospectively evaluated in the first 170 patients treated with this new agent in four phase I trials. Patients treated with didanosine showed statistically significant improvements in hemoglobin levels, white cell counts, and granulocyte and platelet numbers as compared with baseline values. These changes were seen with or without prior therapy with zidovudine, were somewhat more pronounced at higher doses of didanosine, and persisted for up to 1 year. Reported adverse events included peripheral neuropathy, diarrhea, and most notably, pancreatitis. It is concluded that, while some toxic side effects occur, didanosine therapy in HIV infection is associated with an amelioration of HIV-induced myelosuppression.
OBJECTIVE: To evaluate the efficacy of adding intranasal live attenuated cold-adapted influenza A vaccine to inactivated influenza vaccine to prevent influenza A in elderly residents of long-term-care institutions. DESIGN: Randomized, double-blind, placebo-controlled study conducted over 3 years. SETTING: Three large nursing homes. PARTICIPANTS: A total of 523 residents of nursing homes (mean age, 84.2 years). INTERVENTIONS: All participants received trivalent inactivated influenza vaccine parenterally and were randomly assigned to receive either live attenuated influenza A (H3N2) virus vaccine or placebo intranasally. MEASUREMENTS: Laboratory-documented influenza A was defined as a respiratory illness plus isolation of influenza A virus from nasal secretions, significant serologic response, or both. Participants were considered to have been exposed to influenza A if they resided in an institution in which cases of influenza A were documented. Outbreak-associated illnesses were defined as those occurring between the first and last isolation of influenza virus from within the institution, +/- 3 days. RESULTS: Participants who received intranasal vaccine and were subsequently exposed to influenza A had significantly lower rates of laboratory-documented influenza A (9 of 162 vaccine recipients compared with 24 of 169 placebo recipients; vaccine protective efficacy, 60.6%; 95% CI, 18% to 82%), outbreak-associated respiratory illnesses (13 of 162 vaccine recipients compared with 34 of 169 placebo recipients; vaccine protective efficacy, 56.8%; CI 23% to 76%), and outbreak-associated influenza-like illnesses (6 of 162 vaccine recipients compared with 18 of 169 placebo recipients; vaccine protective efficacy, 65.0%; CI 17% to 86%). CONCLUSIONS: Intranasal immunization with live attenuated influenza A virus vaccine provided additional protection against influenza A when added to parenteral trivalent inactivated influenza vaccine among elderly nursing home residents.
OBJECTIVE: To determine the relation between exposure to dideoxyinosine (ddl) and increased CD4 cell counts and suppression of serum p24 antigen in patients infected with the human immunodeficiency virus (HIV). DESIGN: Open-label, phase I study. SETTING: Two university hospitals. Patients were studied in both inpatient and outpatient settings. PATIENTS: Of 36 HIV-infected patients enrolled, 18 had adequate pharmacokinetic information for analysis. INTERVENTION: Dideoxyinosine was administered intravenously every 12 hours for 2 weeks. Patients were switched to oral administration at twice the intravenous dose. Pharmacokinetic profiles were obtained twice during each period. A 40-fold range of dose was examined. MEASUREMENTS: CD4-positive T-lymphocyte counts and serum p24 antigen levels were determined. Plasma area under the ddl concentration-time curve was determined for a single dose and at steady state. RESULTS: Increases in CD4-positive T-lymphocyte counts were independent of ddl exposure and were proportional to the starting CD4 count. Suppression of circulating p24 antigen was influenced by cumulative exposure to ddl and was statistically significant. CONCLUSIONS: The CD4-positive T-lymphocyte count increased at low ddl concentrations or exposures; the extent of this increase was directly proportional to the patient's CD4 count at the start of therapy. Suppression of p24 antigen was related to cumulative exposure to ddl. Therapeutic responses can probably be obtained with ddl, while minimizing long-term toxicity, using daily doses of 10 mg/kg body weight, or less.
Plasma didanosine concentration data from 36 patients receiving once-a-day therapy and from 33 patients receiving twice-a-day therapy were subject to population pharmacokinetic analysis with the computer program NONMEM. Once- or twice-a-day regimens of didanosine were administered intravenously (i.v.) (dose: 0.8-33 mg/kg) during the first 2 weeks of therapy, and orally (dose: 1.6-66 mg/kg) for the remaining 4 weeks of therapy. Plasma pharmacokinetics were determined after the first and last (steady-state) i.v. and oral doses. Population pharmacokinetic parameters for the combined i.v. and oral steady-state data were (mean [%CV]): systemic clearance, CL, 0.70 (5.2) L/h/kg; central compartment volume, Vc, 0.18 (32) L/kg; steady-state distribution volume, Vdss, 0.84 (6.8) L/kg; first-order absorption rate constant, Ka, 1.3 (9.5) hr-1; and bioavailable fraction, F, 0.34 (8.5). Interindividual variability (omega) was (%CV) 22.3 and 71.0 for CL and Vc, respectively. Intraindividual (residual) variability (sigma) in plasma concentrations (%CV) was 50.2. Body weight, sex, and age did not account for the variability in either CL or Vc, and the use of alternate pharmacokinetic models did not reduce the value of intraindividual variability. Population parameters for the combined i.v. and oral first-dose data were generally similar to those for the steady-state data. The parameters can be used to design dosing regimens in patients using the Bayesian feedback approach.
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Orally administered live rhesus monkey rotavirus vaccine (RRV, VP7 serotype 3) and human-rhesus reassortant rotavirus vaccine (DxRRV, VP7 serotype 1) were evaluated in a placebo-controlled field trial of 223 infants 2-4 months old. Both vaccines were mildly reactogenic but were generally well tolerated in the 10 days after vaccination. RRV and DxRRV were immunogenic, inducing serum antibody responses in 78% and 71% of the vaccines, respectively. Efficacy of RRV vaccine was 66% (P = .01) and of DxRRV vaccine 77% (P = .002) against rotavirus-associated illness in the first season after vaccination. Efficacy of RRV vaccine against rotavirus-associated illness over three rotavirus seasons was 51.2% (P = .045) and of DxRRV vaccine was 67.3% (P = .006). RRV vaccine provided heterotypic protection of 58.5% (P = .041) and DxRRV vaccine provided homotypic protection of 72.8% (P = .005) over three seasons against the predominant serotype 1 rotavirus.
The safety and immunogenicity of a human immunodeficiency virus type 1 (HIV-1) gp160 recombinant vaccinia virus (HIVAC-1e) vaccine was evaluated in vaccinia-naive, healthy adults at low risk for acquiring HIV-1 infection. Volunteers (n = 36) were randomized to receive HIVAC-1e or control vaccinia virus at two dosages by bifurcated needle puncture at 0 and 2 months; 12 HIVAC-1e and 6 control vaccinia virus recipients received either 10(6) or 10(7) pfu/mL at each inoculation. There was no significant difference in lesion size, level of viral replication, or systemic symptoms after vaccination with HIVAC-1e or control vaccinia virus. Of 22 HIVAC-1e recipients with lesion formation, 16 developed low-titer gp160-specific antibody responses detectable by Western blot. The peak response occurred between days 70 and 120 and was still detectable at day 365 in 9 of 18 vaccinees. gp160-specific lymphoproliferative responses were detected in 5 of 10 vaccinees. Vaccination with HIVAC-1e was safe in vaccinia-naive, healthy adults and could induce both humoral and cell-mediated gp160-specific immune responses.