Erin Quirk

Safety and Immunogenicity of a Replication-Incompetent Adenovirus Type 5 HIV-1 Clade B gag/pol/nef Vaccine in Healthy Adults

BACKGROUND The safety and immunogenicity of the MRK adenovirus type 5 human immunodeficiency virus type 1 clade B gag/pol/nef vaccine, a replication-incompetent adenovirus type 5-vectored vaccine designed to elicit cell-mediated immunity against conserved human immunodeficiency virus proteins, was assessed in a phase 1 trial. METHODS Healthy adults not infected with human immunodeficiency virus were enrolled in a multicenter, dose-escalating, blind, placebo-controlled study to evaluate a 3-dose homologous prime-boost regimen of the trivalent MRK adenovirus type 5 human immunodeficiency virus type 1 vaccine containing from 3 x 10(6) to 1 x 10(11) viral particles per 1-mL dose administered on day 1, during week 4 and during week 26. Adverse events were recorded for 29 days after each intradeltoid injection. The primary immunogenicity end point was the proportion of study participants with a positive unfractionated Gag-, Pol-, or Nef-specific interferon-gamma enzyme-linked immunosorbent spot response measured 4 weeks after administration of the last dose. RESULTS Of 259 randomized individuals, 257 (99%) received > or = 1 dose of vaccine or placebo and were included in the safety analyses. Enzyme-linked immunosorbent spot results were available for 217 study participants (84%) at week 30. No serious vaccine-related adverse events occurred. No study participant discontinued participation because of vaccine-related adverse events. The frequency of injection-site reactions was dose dependent. Vaccine doses of > or = 3 x 10(9) viral particles elicited positive enzyme-linked immunosorbent spot responses to > or = 1 vaccine component in > 60% of recipients. High baseline antibody titers against adenovirus type 5 diminished enzyme-linked immunosorbent spot responses at all doses except the 3 x 10(10) viral particle dose. CONCLUSIONS The vaccine was generally well tolerated and induced cell-mediated immune responses against human immunodeficiency virus type 1 peptides in most healthy adults. Despite these findings, vaccination in a proof-of-concept trial with use of this vaccine was discontinued because of lack of efficacy.

Comparative Cell-Mediated Immunogenicity of DNA/DNA, DNA/Adenovirus Type 5 (Ad5), or Ad5/Ad5 HIV-1 Clade B gag Vaccine Prime-Boost Regimens

BACKGROUND We report composite results from the Merck phase I program of near-consensus clade B human immunodeficiency virus (HIV) type 1 gag vaccines. METHODS Healthy HIV-uninfected adults were enrolled in 6 blinded placebo-controlled studies evaluating the immunogenicity of (1) a 4-dose regimen of a DNA vaccine, (2) a 3-dose priming regimen of the DNA vaccine with a booster dose of an adenovirus type 5 (Ad5)-vectored vaccine, or (3) a 3-dose regimen of the Ad5 vaccine. The DNA plasmid was provided with or without an aluminum phosphate or CRL1005 adjuvant. The primary end point was the unfractionated HIV-1 gag-specific interferon gamma enzyme-linked immunospot (ELISpot) response 4 weeks after the final dose. RESULTS Overall, 254 (83%) of 307 subjects randomized to the vaccine groups were evaluable. Adjuvants did not enhance immunogenicity of the DNA vaccine. Postboost ELISpot responder frequencies were higher for Ad5-containing regimens than for the DNA/DNA regimen (33%) but were similar for DNA/Ad5 (55%) and Ad5/Ad5 (50%). DNA/DNA elicited mainly a CD4 response, whereas Ad5/Ad5 elicited mainly a CD8 response; DNA/Ad5 generated CD4 and CD8 responses comparable to those of DNA/DNA and Ad5/Ad5, respectively. CONCLUSIONS The DNA vaccine alone or as a priming regimen for the Ad5 vaccine did not increase unfractionated ELISpot responses compared with the Ad5 vaccine alone. Qualitative T cell responses to different vaccine regimens deserve further study.

Safety and Immunogenicity of the Merck Adenovirus Serotype 5 (MRKAd5) and MRKAd6 Human Immunodeficiency Virus Type 1 Trigene Vaccines Alone and in Combination in Healthy Adults

ABSTRACT Preexisting immunity to adenovirus serotype 5 (Ad5) diminishes immune responses to vaccines using Ad5 as a vector. Alternate Ad serotypes as vaccine vectors might overcome Ad5-specific neutralizing antibodies and enhance immune responses in populations with a high prevalence of Ad5 immunity. To test this hypothesis, healthy human immunodeficiency virus (HIV)-seronegative adults were enrolled in a blinded, randomized, dose-escalating, placebo-controlled study. In part A, subjects with baseline Ad6 titers of ≤18 received the Merck Ad6 (MRKAd6) HIV type 1 (HIV-1) trigene vaccine at weeks 0, 4, and 26. In part B, subjects stratified by Ad5 titers (≤200 or >200) and Ad6 titers (≤18 or >18) received the MRKAd5-plus-MRKAd6 (MRKAd5+6) HIV-1 trigene vaccine at weeks 0, 4, and 26. Immunogenicity was assessed by an enzyme-linked immunospot (ELISPOT) assay at week 30. No serious adverse events occurred. MRKAd6 trigene vaccine recipients responded more often to Nef than to Gag or Pol. In part A, ELISPOT response rates to ≥2 vaccine antigens were 14%, 63%, and 71% at 109, 1010, and 1011 viral genomes (vg)/dose, respectively. All responders had positive Nef-specific ELISPOT results. In part B, Nef-ELISPOT response rates at 1010 vg/dose of the MRKAd5+6 trigene vaccine were 50% in the low-Ad5/low-Ad6 stratum (n = 8), 78% in the low-Ad5/high-Ad6 stratum (n = 9), 75% in the high-Ad5/low-Ad6 stratum (n = 8), and 44% in the high-Ad5/high-Ad6 stratum (n = 9). The MRKAd6 and MRKAd5+6 trigene vaccines elicited dose-dependent responses predominantly to Nef and were generally well tolerated, indicating that Ad6 should be considered a candidate vector for future vaccines. Although small sample sizes limit the conclusions that can be drawn from this exploratory study, combining two Ad vectors may be a useful vaccine strategy for circumventing isolated immunity to a single Ad serotype.

Characterization of vaniprevir, a hepatitis C virus NS3/4A protease inhibitor, in patients with HCV genotype 1 infection: Safety, antiviral activity, resistance, and pharmacokinetics

Vaniprevir is a competitive inhibitor of the hepatitis C virus (HCV) NS3/4A protease that has potent anti-HCV activity in preclinical models. This placebo-controlled dose-ranging study assessed the safety, tolerability, and antiviral efficacy of vaniprevir monotherapy in patients with genotype 1 chronic HCV infection. Treatment-naive and treatment-experienced non-cirrhotic adult patients with baseline HCV RNA >10(6)IU/ml were randomized to receive placebo or vaniprevir at doses of 125 mg qd, 600 mg qd, 25mg bid, 75 mg bid, 250 mg bid, 500 mg bid, and 700 mg bid for 8 days. Forty patients (82.5% male, 75% genotype 1a) received at least one dose of placebo or vaniprevir. After 1 week of vaniprevir, the decrease in HCV RNA from baseline ranged from 1.8 to 4.6 log₁₀IU/ml across all treatment groups, and there was a greater than dose-proportional increase in vaniprevir exposure at doses above 75 mg bid. The most commonly reported drug-related adverse events (AEs) were diarrhea (n=5) and nausea (n=5). No pattern of laboratory or ECG abnormalities was observed, all AEs resolved during the study, and there were no discontinuations due to AEs. No serious AEs were reported. Resistance-associated amino acid variants were identified at positions R155 and D168 in patients infected with genotype 1a virus. Vaniprevir monotherapy demonstrated potent antiviral activity in patients with chronic genotype 1 HCV infection, and was generally well tolerated with no serious AEs or discontinuations due to AEs. Further development of vaniprevir, including studies in combination with other anti-HCV agents, is ongoing.

HIV Seroconversion without Infection after Receipt of Adenovirus-Vectored HIV Type 1 Vaccine

BACKGROUND We analyzed human immunodeficiency virus (HIV) seroresponses from 3 phase I HIV-1 vaccine trials to assess the frequency of vaccine-induced seroconversion. METHODS HIV-1 and HIV-2 enzyme-linked immunosorbent assay (ELISA) was performed during trials of adenovirus type 5 (Ad5)-vectored clade B HIV-1 monovalent gag and trivalent gag/pol/nef vaccines given to HIV-seronegative adults. Doses were administered at day 1, week 4, and week 26. Results were analyzed by vaccine formulation and dose and were stratified by baseline Ad5 titer. ELISA-positive samples were reflexively tested by Western blotting. RESULTS Overall, 165 (41%) of 406 evaluable vaccine recipients had positive ELISA results but negative PCR results by week 78. Seroconversion rates were directly related to vaccine dose, were inversely related to baseline Ad5 titer, and were unaffected by vaccine valency. One hundred (89%) of 113 evaluable patients with low baseline Ad5 antibody titers (<or=200) who were given >or=1 dose of vaccine with >or=1 x 10(10) gag-containing Ad5 particles per dose experienced seroconversion. Of 163 vaccine recipients who had positive ELISA results and available Western blot results, 150 (92%) had indeterminate results of Western blot, typically involving bands at p24, p40, and/or p55. Thirteen uninfected patients (8%) had equivocally positive Western blot results, usually because of an additional weak glycoprotein 41 band. Env-specific enzyme immunoassay results were falsely positive for 2 uninfected vaccine recipients. CONCLUSIONS Positive ELISA results were similarly common for monovalent and trivalent vaccine recipients. Vaccine dose and baseline Ad5 immunity were major determinants of vaccine-induced seroconversion rates. Corresponding Western blots characteristically showed bands directed only at Gag proteins, which helped to distinguish HIV-uninfected vaccine recipients who experienced seroconversion from true HIV-infected patients. If available, an enzyme immunoassay exclusively targeting proteins not expressed by the vaccine should be the screening test of first choice for vaccine recipients.

1056 MK-7009 SIGNIFICANTLY IMPROVES RAPID VIRAL RESPONSE (RVR) IN COMBINATION WITH PEGYLATED INTERFERON ALFA-2A AND RIBAVIRIN IN PATIENTS WITH CHRONIC HEPATITIS C (CHC) GENOTYPE 1 INFECTION

MK-7009 Significantly Improves Rapid Viral Response (RVR) in Combination with Pegylated Interferon Alfa-2a and Ribavirin in Patients with Chronic Hepatitis C (CHC) Genotype 1 Infection Michael P. Manns,1 Edward Gane,2 Maribel Rodriguez-Torres,3 Albrecht Stoehr,4 Chau-Ting Yeh,5 Richard T. Wiedmann,6 Peggy M. Hwang,7 Erin Quirk,6 Jeffrey Silber,6 and Andrew W. Lee6* 1Medical School of Hannover, Hannover, Germany, 2Auckland Clinical Studies, Auckland, New Zealand, 3Fundacion de Investigacion de Diego, San Juan, and Ponce School of Medicine, Ponce, Puerto Rico, 4ifi-institute for interdisciplinary medicine, Hamburg, Germany, 5Liver Research Unit, Chang Gung Medical Center, Taipei, Taiwan, 6ID/Vaccines Clinical Research, Merck Research Laboratories, West Point, PA, USA, 7Biostatistics, Merck Research Laboratories, West Point, PA, USA *for the MK-7009 Protocol 007 Study Group

Antiviral Activity, Safety, and Pharmacokinetics of Bictegravir as 10-day Monotherapy in Hiv-1-infected Adults.

Objective: To evaluate antiviral activity, safety, and pharmacokinetics of short-term monotherapy with bictegravir (BIC), a novel, potent HIV integrase strand transfer inhibitor (INSTI). Design: Phase 1b, randomized, double-blinded, adaptive, sequential cohort, placebo-controlled study. Methods: HIV-infected adults not taking antiretroviral therapy were randomized to receive BIC (5, 25, 50, or 100 mg) or placebo once daily for 10 days. Primary endpoint was time-weighted average change from baseline to day 11 (DAVG11) for plasma HIV-1 RNA. HIV-1 RNA, adverse events (AEs), and laboratory assessments were evaluated through day 17. Results: Twenty participants were enrolled (n = 4/group). Mean DAVG11 ranged from −0.92 to −1.61 across BIC doses versus −0.01 for placebo. Significant reductions in plasma HIV-1 RNA from baseline at day 11 were observed for all BIC doses compared with placebo (P < 0.001); mean decreases were 1.45–2.43 log10 copies/mL. Increased BIC exposures correlated with increased reduction in plasma HIV-1 RNA from baseline on day 11. Three participants on BIC (50 or 100 mg) achieved plasma HIV-1 RNA <50 copies/mL by end of study. Median Tmax ranged from 1.0 to 1.8 hours (day 1, postdose) and 1.3–2.7 hours (day 10), with median t1/2 ranging from 15.9 to 20.9 hours. No participant developed primary INSTI-R substitution through day 17. BIC was well tolerated, with no discontinuations because of adverse events. Conclusions: BIC is a novel, potent, unboosted INSTI that demonstrated rapid, dose-dependent declines in HIV-1 RNA after 10 days of monotherapy. BIC was well tolerated, and displayed rapid absorption and a half-life supportive of once-daily therapy in HIV-infected subjects.

Efficacy and safety of switching to fixed-dose bictegravir, emtricitabine, and tenofovir alafenamide from boosted protease inhibitor-based regimens in virologically suppressed adults with HIV-1: 48 week results of a randomised, open-label, multicentre, phase 3, non-inferiority trial

BACKGROUND Switching from therapy based on a boosted protease inhibitor to bictegravir, emtricitabine, and tenofovir alafenamide could avoid drug interactions and unwanted side-effects in virologically suppressed adults with HIV-1 infection, while maintaining a high barrier to resistance and providing a simplified once-daily, single-tablet regimen. Here, we report 48 week results of a phase 3 study investigating this switch. METHODS In this multicentre, randomised, open-label, active-controlled, non-inferiority, phase 3 trial, adults with HIV-1 infection were enrolled at 121 outpatient centres in ten countries. Eligible participants were aged 18 years or older, had an estimated glomerular filtration rate of 50 mL per min or higher, had been virologically suppressed (plasma HIV-1 RNA <50 copies per mL) for 6 months or more before screening, and were on a regimen consisting of boosted atazanavir or darunavir plus either emtricitabine and tenofovir disoproxil fumarate or abacavir and lamivudine. We randomly assigned participants (1:1), using a computer-generated randomisation sequence, to switch to co-formulated once-daily bictegravir (50 mg), emtricitabine (200 mg), and tenofovir alafenamide (25 mg), herein known as the bictegravir group, or to remain on their baseline boosted protease inhibitor regimen, herein known as the boosted protease inhibitor group, for 48 weeks. Randomisation was stratified by use of tenofovir disoproxil fumarate or abacavir at screening. The primary endpoint was the proportion of participants with plasma HIV-1 RNA of 50 copies per mL or higher at week 48 (by US Food and Drug Administration snapshot algorithm), with a prespecified non-inferiority margin of 4%. Efficacy and safety analyses included all participants who received at least one dose of study drug. This study is ongoing but not actively recruiting patients and is registered with ClinicalTrials.gov, number NCT02603107. FINDINGS Between Dec 2, 2015, and July 15, 2016, 578 participants were randomly assigned and 577 were treated (290 in the bictegravir group and 287 in the boosted protease inhibitor group). At week 48, five participants (2%) in the bictegravir group and five (2%) in the boosted protease inhibitor group had plasma HIV-1 RNA of 50 copies per mL or higher (difference 0·0%, 95·002% CI -2·5 to 2·5), thus switching to the bictegravir regimen was non-inferior to continued boosted protease inhibitor therapy. The overall incidence and severity of adverse events was similar between groups, although headache occurred more frequently in the bictegravir group than in the boosted protease inhibitor group. 233 (80%) participants in the bictegravir group and 226 (79%) in the boosted protease inhibitor group had an adverse event. Only two (1%) participants in the bictegravir group and one (<1%) in the boosted protease inhibitor group discontinued treatment because of adverse events. 54 participants (19%) in the bictegravir group had drug-related adverse events compared with six (2%) in the protease inhibitor group. INTERPRETATION Fixed-dose bictegravir, emtricitabine, and tenofovir alafenamide might be a safe and efficacious alternative to continued boosted protease inhibitor therapy in adults with HIV-1 infection. FUNDING Gilead Sciences.

Switching to fixed-dose bictegravir, emtricitabine, and tenofovir alafenamide from dolutegravir plus abacavir and lamivudine in virologically suppressed adults with HIV-1: 48 week results of a randomised, double-blind, multicentre, active-controlled, phase 3, non-inferiority trial

BACKGROUND Bictegravir, co-formulated with emtricitabine and tenofovir alafenamide, has shown good efficacy and tolerability, and similar bone, renal, and lipid profiles to dolutegravir, abacavir, and lamivudine, in treatment-naive adults with HIV-1 infection, without development of treatment-emergent resistance. Here, we report 48-week results of a phase 3 study investigating switching to bictegravir, emtricitabine, and tenofovir alafenamide from dolutegravir, abacavir, and lamivudine in virologically suppressed adults with HIV-1 infection. METHODS In this multicentre, randomised, double-blind, active-controlled, non-inferiority, phase 3 trial, HIV-1-infected adults were enrolled at 96 outpatient centres in nine countries. Eligible participants were aged 18 years or older and on a regimen of 50 mg dolutegravir, 600 mg abacavir, and 300 mg lamivudine (fixed-dose combination or multi-tablet regimen); had an estimated glomerular filtration rate of 50 mL/min or higher; and had been virologically suppressed (plasma HIV-1 RNA <50 copies per mL) for 3 months or more before screening. We randomly assigned participants (1:1), using a computer-generated randomisation sequence, to switch to co-formulated bictegravir (50 mg), emtricitabine (200 mg), and tenofovir alafenamide (25 mg; herein known as the bictegravir group), or to remain on dolutegravir, abacavir, and lamivudine (herein known as the dolutegravir group), once daily for 48 weeks. The investigators, participants, study staff, and individuals assessing outcomes were masked to treatment assignment. The primary endpoint was the proportion of participants with plasma HIV-1 RNA of 50 copies per mL or higher at week 48 (according to the US Food and Drug Administration snapshot algorithm); the prespecified non-inferiority margin was 4%. The primary efficacy and safety analyses included all participants who received at least one dose of study drug. This study is ongoing but not actively recruiting participants and is in the open-label extension phase, wherein participants are given the option to receive bictegravir, emtricitabine, and tenofovir alafenamide for an additional 96 weeks. This trial is registered with ClinicalTrials.gov, number NCT02603120. FINDINGS Between Nov 11, 2015, and July 6, 2016, 567 participants were randomly assigned and 563 were treated (282 received bictegravir, emtricitabine, and tenofovir alafenamide, and 281 received dolutegravir, abacavir, and lamivudine). Switching to the bictegravir regimen was non-inferior to remaining on dolutegravir, abacavir, and lamivudine for the primary outcome: three (1%) of 282 in the bictegravir group had HIV-1 RNA of 50 copies per mL or higher at week 48 versus one (<1%) of 281 participants in the dolutegravir group (difference 0·7%, 95·002% CI -1·0 to 2·8; p=0·62). Treatment-related adverse events were recorded in 23 (8%) participants in the bictegravir group and 44 (16%) in the dolutegravir group. Treatment was discontinued because of adverse events in six (2%) participants in the bictegravir group and in two (1%) participants in the dolutegravir group. INTERPRETATION The fixed-dose combination of bictegravir, emtricitabine, and tenofovir alafenamide might provide a safe and efficacious option for ongoing treatment of HIV-1 infection. FUNDING Gilead Sciences.

Safety Profile of the Merck Human Immunodeficiency Virus-1 Clade B gag DNA Plasmid Vaccine With and Without Adjuvants

The immunogenicity results from 3 phase I trials of the Merck DNA human immunodeficiency virus (HIV) vaccine have previously been reported. Because preventive DNA vaccine strategies continue to be leveraged for diverse infections, the safety and tolerability results from these studies can inform the field moving forward, particularly regarding adverse reactions and adjuvants. No serious vaccine-related adverse events were reported during the 3-dose priming phase. Pain at the injection site was more common with adjuvanted formulations than with the phosphate-buffered saline diluent alone. Febrile reactions were usually low grade. Although the AlPO4 or CRL1005 adjuvants used in these studies did not significantly enhance the immunogenicity of the DNA vaccine, adverse events were numerically more common with adjuvanted formulations than without adjuvants.