Sarah L. George

Clinical, virologic, histologic, and biochemical outcomes after successful HCV therapy: A 5‐year follow‐up of 150 patients

One hundred fifty patients with sustained virologic response (SVR) after treatment of chronic hepatitis C were enrolled in a long‐term clinical follow‐up study; patients were followed for 5 years for liver‐related outcomes and evidence of biochemical or virologic relapse. Patients with stage 2 or greater fibrosis on pretreatment biopsy were invited to undergo a long‐term follow‐up biopsy after their fourth year of follow‐up. One hundred twenty‐eight patients (85%) were followed through their fourth year, and long‐term follow‐up biopsies were obtained from 60 patients (40%). Forty‐nine patients had paired pretreatment and long‐term follow‐up biopsies blindly rescored. Forty of these patients (82%) had a decrease in fibrosis score, and 45 (92%) had a decrease in combined inflammation score. Ten patients (20%) had normal or nearly normal livers on long‐term follow‐up biopsy. Two patients with pretreatment cirrhosis developed hepatocellular carcinoma (HCC), and one died. All the other patients with pretreatment cirrhosis or advanced fibrosis had improved fibrosis scores on long‐term follow‐up biopsy. No patient had conclusive evidence of virologic relapse. Three patients had persistently elevated alanine aminotransferase levels; two of these had new liver disease. Conclusion: In a cohort of 150 patients with SVR followed for 5 years, the majority of patients had good outcomes. Serum virologic relapse was not seen, but two patients with pretreatment cirrhosis developed HCC, and one died. In a blind rescoring of 49 paired pretreatment and long‐term follow‐up biopsies, 82% improved fibrosis scores and 92% improved at least one component of inflammation. A minority of patients had normal or nearly normal liver tissue on long‐term follow‐up biopsy. Patients with cirrhosis pretreatment are at a low but real risk of HCC after SVR. (HEPATOLOGY 2009.)

Safety and Immunogenicity of a Live Attenuated Tetravalent Dengue Vaccine Candidate in Flavivirus-Naive Adults: A Randomized, Double-Blinded Phase 1 Clinical Trial

BACKGROUND Dengue viruses (DENVs) infect >300 million people annually, causing 96 million cases of dengue disease and 22 000 deaths [1]. A safe vaccine that protects against DENV disease is a global health priority [2]. METHODS We enrolled 72 flavivirus-naive healthy adults in a phase 1 double-blinded, randomized, placebo-controlled dose-escalation trial (low and high dose) of a live attenuated recombinant tetravalent dengue vaccine candidate (TDV) given in 2 doses 90 days apart. Volunteers were followed for safety, vaccine component viremia, and development of neutralizing antibodies to the 4 DENV serotypes. RESULTS The majority of adverse events were mild, with no vaccine-related serious adverse events. Vaccinees reported injection site pain (52% vs 17%) and erythema (73% vs 25%) more frequently than placebo recipients. Low levels of TDV-serotype 2 (TDV-2), TDV-3, and TDV-4 viremia were observed after the first but not second administration of vaccine. Overall seroconversion rates and geometric mean neutralization titers after 2 doses were 84.2% and 54.1, respectively, for DENV serotype 1 (DENV-1); 92.1% and 292.8, respectively, for DENV-2; 86.8% and 32.3, respectively, for DENV-3; and 71.1% and 15.0, respectively, for DENV-4. More than 90.0% of high-dose recipients had trivalent or broader responses. CONCLUSIONS TDV was generally well tolerated, induced trivalent or broader neutralizing antibodies to DENV in most flavivirus-naive vaccinees, and is undergoing further development. CLINICAL TRIALS REGISTRATION NCT01110551.

Preliminary aggregate safety and immunogenicity results from three trials of a purified inactivated Zika virus vaccine candidate: phase 1, randomised, double-blind, placebo-controlled clinical trials

BACKGROUND A safe, effective, and rapidly scalable vaccine against Zika virus infection is needed. We developed a purified formalin-inactivated Zika virus vaccine (ZPIV) candidate that showed protection in mice and non-human primates against viraemia after Zika virus challenge. Here we present the preliminary results in human beings. METHODS We did three phase 1, placebo-controlled, double-blind trials of ZPIV with aluminium hydroxide adjuvant. In all three studies, healthy adults were randomly assigned by a computer-generated list to receive 5 μg ZPIV or saline placebo, in a ratio of 4:1 at Walter Reed Army Institute of Research, Silver Spring, MD, USA, or of 5:1 at Saint Louis University, Saint Louis, MO, USA, and Beth Israel Deaconess Medical Center, Boston, MA, USA. Vaccinations were given intramuscularly on days 1 and 29. The primary objective was safety and immunogenicity of the ZPIV candidate. We recorded adverse events and Zika virus envelope microneutralisation titres up to day 57. These trials are registered at ClinicalTrials.gov, numbers NCT02963909, NCT02952833, and NCT02937233. FINDINGS We enrolled 68 participants between Nov 7, 2016, and Jan 25, 2017. One was excluded and 67 participants received two injections of Zika vaccine (n=55) or placebo (n=12). The vaccine caused only mild to moderate adverse events. The most frequent local effects were pain (n=40 [60%]) or tenderness (n=32 [47%]) at the injection site, and the most frequent systemic reactogenic events were fatigue (29 [43%]), headache (26 [39%]), and malaise (15 [22%]). By day 57, 52 (92%) of vaccine recipients had seroconverted (microneutralisation titre ≥1:10), with peak geometric mean titres seen at day 43 and exceeding protective thresholds seen in animal studies. INTERPRETATION The ZPIV candidate was well tolerated and elicited robust neutralising antibody titres in healthy adults. FUNDING Departments of the Army and Defense and National Institute of Allergy and Infectious Diseases.

Higher Antigen Content Improves the Immune Response to 2009 H1N1 Influenza Vaccine in HIV-Infected Adults: A Randomized Clinical Trial

BACKGROUND The immunogenicity of a high hemagglutinin (HA) dose or a second dose of influenza vaccine in human immunodeficiency virus (HIV)-infected individuals has not been fully explored. METHODS One hundered ninety-two HIV-infected individuals aged 18-64 years were stratified by CD4 cell count (<200 cells/mL or ≥200 cells/mL) and randomized to receive 2 doses of 15 μg or 30 μg HA 2009 H1N1 vaccine 21 days apart. Hemagglutination inhibition (HAI) and microneutralization (MN) antibodies were measured on days 0, 10, 21, 31, 42, and 201. RESULTS Recipients of 30 μg HA had significantly higher HAI geometric mean titers (GMTs), compared with recipients of 15 μg HA on days 10 (139.0 vs 51.9; P = .01), 21 (106.7 vs 51.9; P = .001), and 31 (130.0 vs 73.7; P = .03) but not on days 42 (91.8 vs 61.6; P = .11) and 201 (43.0 vs 27.0; P = .08). When analyzed by CD4 cell count stratum, HAI GMTs were significantly higher among 30 μg HA recipients than among 15 μg HA in the CD4 cell count <200 cells/mL stratum on days 21 and 31 and the MN GMTs on days 10, 21, 31, and 42 (P < .05). In the CD4 cell count ≥200 cells/mL stratum, MN GMTs were significantly higher among recipients of 30 μg HA than among recipients of 15 μg HA on day 10 (P = .03). CONCLUSION Increasing the HA dose of the 2009 H1N1 vaccine improves the vaccines immunogenicity in HIV-infected individuals. CLINICAL TRIALS REGISTRATION NCT00992433.

Preclinical and clinical development of a dengue recombinant subunit vaccine

This review focuses on a dengue virus (DENV) vaccine candidate based on a recombinant subunit approach which targets the DENV envelope glycoprotein (E). Truncated versions of E consisting of the N-terminal portion of E (DEN-80E) have been expressed recombinantly in the Drosophila S2 expression system and shown to have native-like conformation. Preclinical studies demonstrate that formulations containing tetravalent DEN-80E adjuvanted with ISCOMATRIX™ adjuvant induce high titer virus neutralizing antibodies and IFN-γ producing T cells in flavivirus-naïve non-human primates. The preclinical data further suggest that administration of such formulations on a 0, 1, 6 month schedule may result in higher maximum virus neutralizing antibody titers and better durability of those titers compared to administration on a 0, 1, 2 month schedule. In addition, the virus neutralizing antibody titers induced by adjuvanted tetravalent DEN-80E compare favorably to the titers induced by a tetravalent live virus comparator. Furthermore, DEN-80E was demonstrated to be able to boost virus neutralizing antibody titers in macaques that have had a prior DENV exposure. A monovalent version of the vaccine candidate, DEN1-80E, was formulated with Alhydrogel™ and studied in a proof-of-principle Phase I clinical trial by Hawaii Biotech, Inc. (NCT00936429). The clinical trial results demonstrate that both the 10 μg and 50 μg formulations of DEN1-80E with 1.25 mg of elemental aluminum were immunogenic when administered in a 3-injection series (0, 1, 2 months) to healthy, flavivirus-naïve adults. The vaccine formulations induced DENV-1 neutralizing antibodies in the majority of subjects, although the titers in most subjects were modest and waned over time. Both the 10 μg DEN1-80E and the 50 μg DEN1-80E formulations with Alhydrogel™ were generally well tolerated.

CD8+ T-cell Responses in Flavivirus-Naive Individuals Following Immunization with a Live-Attenuated Tetravalent Dengue Vaccine Candidate

We are developing a live-attenuated tetravalent dengue vaccine (TDV) candidate based on an attenuated dengue 2 virus (TDV-2) and 3 chimeric viruses containing the premembrane and envelope genes of dengue viruses (DENVs) -1, -3, and -4 expressed in the context of the attenuated TDV-2 genome (TDV-1, TDV-3, and TDV-4, respectively). In this study, we analyzed and characterized the CD8(+) T-cell response in flavivirus-naive human volunteers vaccinated with 2 doses of TDV 90 days apart via the subcutaneous or intradermal routes. Using peptide arrays and intracellular cytokine staining, we demonstrated that TDV elicits CD8(+) T cells targeting the nonstructural NS1, NS3, and NS5 proteins of TDV-2. The cells were characterized by the production of interferon-γ, tumor necrosis factor-α, and to a lesser extent interleukin-2. Responses were highest on day 90 after the first dose and were still detectable on 180 days after the second dose. In addition, CD8(+) T cells were multifunctional, producing ≥2 cytokines simultaneously, and cross-reactive to NS proteins of the other 3 DENV serotypes. Overall, these findings describe the capacity of our candidate dengue vaccine to elicit cellular immune responses and support the further evaluation of T-cell responses in samples from future TDV clinical trials.

The GB Virus C (GBV-C) NS3 Serine Protease Inhibits HIV- 1 Replication in a CD4+ T Lymphocyte Cell Line without Decreasing HIV Receptor Expression

Introduction Persistent infection with GBV-C (GB Virus C), a non-pathogenic virus related to hepatitis C virus (HCV), prolongs survival in HIV infection. Two GBV-C proteins, NS5A and E2, have been shown previously to inhibit HIV replication in vitro. We investigated whether the GBV-C NS3 serine protease affects HIV replication. Results GBV-C NS3 protease expressed in a human CD4+ T lymphocyte cell line significantly inhibited HIV replication. Addition of NS4A or NS4A/4B coding sequence to GBV-C NS3 increased the effect on HIV replication. Inhibition of HIV replication was dose-dependent and was not mediated by increased cell toxicity. Mutation of the NS3 catalytic serine to alanine resulted in loss of both HIV inhibition and protease activity. GBV-C NS3 expression did not measurably decrease CD4 or CXCR4 expression. Conclusion GBV-C NS3 serine protease significantly inhibited HIV replication without decreasing HIV receptor expression. The requirement for an intact catalytic serine at the active site indicates that inhibition was mediated by proteolytic cleavage of an unidentified target(s).

Randomized clinical trial of a single versus a double dose of 13-valent pneumococcal conjugate vaccine in adults 55 through 74 years of age previously vaccinated with 23-valent pneumococcal polysaccharide vaccine

INTRODUCTION In older adults, prior administration of 23-valent pneumococcal polysaccharide vaccine (PPSV23) blunts the opsonophagocytic antibody (OPA) response to subsequent administration of 13-valent pneumococcal conjugate vaccine (PCV13). To determine whether a higher dose of PCV13 could mitigate this effect in adults 55 through 74 years of age, we compared OPA responses to a double dose of PCV13 in persons previously vaccinated with PPSV23 with responses to a single dose of PCV13 in previously vaccinated persons, and with a single dose in PPSV23 naïve persons. METHODS Subjects previously vaccinated with PPSV23 were randomly assigned to receive either a single injection or two concurrent injections of 0.5 mL PCV13. Naïve subjects received a single injection of 0.5 mL PCV13. Serotype-specific OPA responses to 12 of the PCV13 serotypes were assessed on samples collected on Day 29 and Day 181. Comparisons of the OPA titers between study groups were based on the lower bound of the 95% confidence interval of the log geometric mean ratio to define superiority (>1) and non-inferiority (>0.5). RESULTS At Day 29, the OPA responses to one dose in previously vaccinated (n = 284) versus one dose in naïve subjects (n = 311) achieved the threshold for non-inferiority for only 3 of the 12 serotypes. In previously vaccinated subjects, responses to a double dose (n = 288) versus a single dose met the threshold for superiority for 7 serotypes. The responses to a double dose in previously vaccinated subjects versus a single dose in naïve subjects met the threshold for non-inferiority for 9 serotypes. CONCLUSIONS There is a dose response to PCV13 in older adults and the higher response to a double dose in previously vaccinated adults is non-inferior to that of a single dose in naïve adults for 9 of the 12 PCV13 serotypes evaluated.

Human pegivirus (GB virus C) NS3 protease activity inhibits induction of the type I interferon response and is not inhibited by HCV NS3 protease inhibitors

We previously found that human pegivirus (HPgV; formerly GBV-C) NS3 protease activity inhibits Human Immunodeficiency Virus (HIV) replication in a CD4+ T cell line. Given the protease׳s similarity to the Hepatitis C virus (HCV) NS3 protease, we characterized HPgV protease activity and asked whether it affects the type I interferon response or is inhibited by HCV protease antagonists. We characterized the activity of proteases with mutations in the catalytic triad and demonstrated that the HCV protease inhibitors Telaprevir, Boceprevir, and Danoprevir do not affect HPgV protease activity. HPgV NS3 protease cleaved MAVS but not TRIF, and it inhibited interferon responses sufficiently to enhance growth of an interferon-sensitive virus. Therefore, HPgV׳s inhibition of the interferon response could help promote HPgV persistence, which is associated with clinical benefits in HIV-infected patients. Our results also imply that HCV protease inhibitors should not interfere with the beneficial effects of HPgV in HPgV/HCV/HIV infected patients.