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Cytomegalovirus (CMV) antigens have been reported in over 90% of GBMs. CD4+ and CD8+ T cells are most frequently directed against the gB and pp65 antigens, respectively, which are immunogenic targets in a CMV-based GBM immunotherapeutic. First-recurrent GBM patients were enrolled, with Karnofsky Performance Status of at least 70, to receive VBI-1901 (a gB/pp65 enveloped virus-like particle [eVLP]) adjuvanted with GM-CSF and given intradermally (NCT03382977). Patients were vaccinated with VBI-1901 every 4 weeks, with serologic immune-monitoring 2 weeks after each vaccination and surveillance brain MRI scans every 6 weeks. Sixteen patients (8 women, 8 men) with a median age of 55 (33-67 yrs) were enrolled into the GM-CSF arm. Seven tumor responses, including two durable partial responses, were observed which led to an 18-month OS rate of 25% and mOS of 56 weeks. Detailed immunological testing was performed to identify potential correlations at baseline and after treatment between biomarkers and tumor responses. Analyses included class I and II HLA typing, modulation of plasma cytokine and chemokine responses, boosting of CMV-specific antibody and IFN-g ELISPOT responses, and modulation of CMV-specific CD4 Tem cells, of which only differential trafficking of the CD4 Tem cells appears to distinguish patients with tumor responses from those with tumor progression. Single cell, RNAseq is underway in an attempt to understand mechanistic differences in these immune cell populations in Tumor Responders vs. Non-Responders. The U.S. FDA granted Fast Track Designation to VBI-1901 adjuvanted with GM-CSF in first-recurrent GBM patients, and an expansion of the ongoing trial with this formulation in this patient population, with the addition of randomization with a contemporaneous control arm, is anticipated to begin in Q3 2022.

Rapid emergence of SARS-CoV-2 variants is a constant threat and a major hurdle to reach heard immunity. We produced VBI-2905a, an enveloped virus-like particle (eVLP)-based vaccine candidate expressing prefusion spike protein from the Beta variant that contains several escape mutations. VBI-2905a protected hamsters against infection with a Beta variant virus and induced high levels of neutralizing antibodies against Beta RBD. In a heterologous vaccination regimen, a single injection of VBI-2905a in animals previously immunized with VBI-2902, a vaccine candidate expressing S from ancestral SARS-CoV-2, hamsters were equally protected against Beta variant infection. As an alternate strategy to broaden immunity, we produced a trivalent vaccine expressing the prefusion spike protein from SARS-CoV-2 together with unmodifed S from SARS-CoV-1 and MERS-CoV. Relative to immunity induced against the ancestral strain, the trivalent vaccine VBI-2901a induced higher and more consistent antibody binding and neutralizing responses against a panel of variants including Beta, Delta, Kappa, and Lambda, with evidence for broadening of immunity rather than just boosting cross-reactive antibodies.

We evaluated enveloped virus-like particles (eVLPs) expressing various forms of the Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike protein and several adjuvants in an effort to identify a highly potent Coronavirus disease 2019 (COVID-19) vaccine candidate. eVLPs expressing a modified prefusion form of SARS-CoV-2 spike protein were selected as they induced high antibody binding titers and neutralizing activity after a single injection in mice. Formulation of SARS-CoV-2 S eVLPs with aluminum phosphate resulted in balanced induction of IgG2 and IgG1 isotypes and antibody binding and neutralization titers were undiminished for more than 3 months after a single immunization. A single dose of this candidate, named VBI-2902a, protected Syrian golden hamsters from challenge with SARS-CoV-2 and supports the on-going clinical evaluation of VBI-2902a as a highly potent vaccine against COVID-19.

Diabetes mellitus (DM), older age (≥45 years) and obesity (BMI >30 kg/m2) are associated with lower response to immunizations and worse outcomes of chronic hepatitis B infection. Therefore, there is a need to enhance immunogenicity of HBV vaccine for adults, especially those with DM, older age, and obesity. PROTECT study compared the immunogenicity and safety of 3-doses of 3-antigen / 3A-HBV (Sci-B-Vac) and 1-antigen / 1A-HBV (Engerix-B) HBV vaccines administered at months 0, 1 and 6. The study enrolled 1607 adults age ≥18 years in the US (42.3%), Europe (41.6%) and Canada (16.1%). Immunogenicity, measured as rate of non-response (% not achieving anti-HBs levels ≥10 mIU/mL), anti-HBs geometric mean concentration (GMC), and safety were evaluated in all adults and key subgroups of interest. Of 1607 study participants, 7.5% (3A-HBV arm) and 8.0% (1A-HBV arm) had a stable and well controlled DM (HbA1c 30 kg/m2. Overall non-response rates were 23.5% (1A-HBV) and 8.6% (3A-HBV). For diabetics, non-response rates were 41.7% (1A-HBV) and 16.7% (3A-HBV), for those age ≥45 years, 34.3% (1A-HBV) and 16.4% (3A-HBV) and for BMI >30 kg/m2, 31.9% (1A-HBV) and 10.8% (3A-HBV). Mean GMC of anti-HBs was higher for 3A-HBV compared to 1A-HBV (1424.5 vs. 235.4 mIU/mL) and consistently higher across key subgroups, including those with DM, age ≥45 years and BMI >30 kg/m2. Safety of 3A-HBV was comparable to 1A-HBV except for higher rates of injection site pain, tenderness and myalgia of mild to moderate severity and mean duration of 1-2 days. Completion rate of all 3 vaccine doses was high at 96.8% (1A-HBV) and 95.2% (3A-HBV). Immunization with 3A-HBV achieved lower rates of non-response compared to 1A-HBV in all adults, including those with diabetes, older age, and obesity. Disclosure F. Diaz-mitoma: Consultant; Self; VBI Vaccines. Protect study group: n/a. T. Vesikari: Research Support; Self; VBI Vaccines. J. M. Langley: Research Support; Self; GlaxoSmithKline plc., Medicago, VIDO, Entos, Merck & Co., Inc., Pfizer Inc., Sanofi. A. Hossain: None. N. Machluf: Employee; Self; VBI Vaccines. J. Spaans: Employee; Self; VBI Vaccines Inc. B. Yassin-rajkumar: None. D. E. Anderson: Employee; Self; VBI Vaccines, Inc., Stock/Shareholder; Self; VBI Vaccines, Inc. V. Popovic: Employee; Self; VBI Vaccines.

Development of efficacious single dose vaccines would substantially aid efforts to stop the uncontrolled spread of the COVID-19 pandemic. We evaluated enveloped virus-like particles (eVLPs) expressing various forms of the SARS-CoV-2 spike protein and several adjuvants in an effort to identify a COVID-19 vaccine candidate efficacious after a single dose. The eVLPs expressing a modified prefusion form of SARS-CoV-2 spike protein were selected as they induced the highest antibody binding titers and neutralizing activity after a single injection in mice. Formulation of SARS-CoV-2 S eVLPs with aluminum phosphate resulted in balanced induction of IgG2 and IgG1 isotypes and antibody binding and neutralization titers were undiminished for more than 3 months after a single immunization. A single dose of this candidate, VBI-2902a (prefusion S eVLPs formulated with aluminum phosphate), protected Syrian golden hamsters from challenge with SARS-CoV-2 and supports the on-going clinical evaluation of VBI-2902a as a potential single dose vaccine against COVID-19.HighlightsVBI-2902a is a VLP-based vaccine candidate against SARS-COV-2VBI-2902a contains VLPs pseudotyped with a modified prefusion SARS-COV-2 S in Alum.VBI-2902a induces robust neutralization antibody response against SARS-COV-2 SVBI-2902a protects hamsters from SARS-CoV-2 induced lung inflammationA single dose of VBI-2902a provides protective benefit in hamsters

Background Sci-B-Vac®, a 3-antigen hepatitis B vaccine (3A-HBV), contains all three recombinant hepatitis B virus (HBV) envelope proteins (S, pre-S1, and pre-S2). In 2005, 3A-HBV manufacturing transferred facilities (A to B), where it continues to be manufactured. Methods This phase 3, single-blind, randomized study, conducted at one site in Vietnam, compared efficacy and safety among two 3A-HBV lots, lot A and lot B, and a single-antigen hepatitis B vaccine (1A-HBV), Engerix-B®. Primary objective was to demonstrate equivalence at day 210 of two 3A-HBV lots in seroprotection rate (SPR; defined as percentage of participants achieving hepatitis B surface antigen antibody [anti-HBs] titers ≥ 10 mIU/mL). Secondary objectives were assessing immunogenicity at days 180, 210, and 360, and safety of 3A-HBV. Results 3A-HBV SPR equivalence was demonstrated at day 210 (lot A: 97.3% [95% CI: 92.4%, 99.4%] vs. lot B: 100.0% [97.0%, 100.0%]). Compared to 1A-HBV, lot B SPR was higher at day 180 (98.3% vs. 81.2%; difference: 17.1% [9.7%, 24.6%]) and non-inferior at day 210 (100% vs. 98.3%; difference: 1.7% [-0.6%, 4.1%]). 3A-HBV lot B showed the same SPR after 2 doses (98.3%) as 1A-HBV after 3 doses (98.3%). Adverse events (AEs) were comparable with both 3A-HBV lots (lot A: 68.7% vs. lot B: 54.2%), but higher than 1A-HBV (35.3%). Vaccination-related AEs included transient injection site pain (38.9%), myalgia (9.3%), and fatigue (7.5%). Eight serious AEs were reported (lot A: 3/134 [2.2%]; lot B: 1/134 [0.8%]; 1A-HBV: 4/133 [2.3%]). One serious AE, syncope, was noted as probably related to study vaccine, lot B. Conclusions The two 3A-HBV lots had equivalent immunogenicity, but lot B elicited faster onset of seroprotection and higher anti-HBs titers than both lot A and 1A-HBV in an Asian population. This supports 3A-HBV lot B as an effective choice for HBV vaccination, with a favorable safety profile. ClinicalTrials.gov: NCT04531098.

Importance There is a need for improved immunogenicity of hepatitis B virus (HBV) vaccines among young adults with risk of infection. Objectives To demonstrate manufacturing equivalence of a 3-antigen (3A) HBV vaccine, evaluate noninferiority of seroprotection rate (SPR) of 3A-HBV vs single-antigen (1A) HBV after 2 and 3 vaccine doses, and compare safety and reactogenicity between 3A-HBV and 1A-HBV vaccines. Design, Setting, and Participants This phase 3, double-blinded, randomized clinical trial included healthy adults aged 18 to 45 years randomized to 1 of three 3A-HBV groups or 1 control group receiving 1A-HBV. The trial was conducted at 37 community clinics and academic hospitals in Canada, Europe, the United Kingdom, and the United States between December 2017 and October 2019. Participants were followed up for 48 weeks after the first vaccination. Interventions Intramuscular administration of 3A-HBV (10 μg) or 1A-HBV (20 μg) on days 0, 28, and 168. Main Outcomes and Measures Geometric mean concentration (GMC) of serum hepatitis B surface antibodies (anti-HBs) and proportion of participants achieving seroprotection. Results Of 2838 participants, 1638 (57.8%) were women, 2595 (91.5%) were White, and 161 (5.7%) were Black or African American. A total of 712 participants (25.1%) were randomized to the 1A-HBV group and 2126 (74.9%) to 3A-HBV. The mean (SD) age at informed consent was 33.5 (8.0) years. The study demonstrated 3A-HBV lot-to-lot consistency, as the 2-sided 95% CIs for each pairwise comparison for the anti-HBs GMC ratios were within 0.67 and 1.50 (eg, adjusted GMC ratio, lot A vs lot B: 0.82; 95% CI, 0.67-1.00; lot A vs lot C: 0.95; 95% CI, 0.78-1.15; lot B vs lot C: 1.16; 95% CI, 0.95-1.41). The SPR of the pooled 3A-HBV was noninferior to 1A-HBV and higher than 1A-HBV after 2 vaccinations at day 168 (90.4% [95% CI, 89.0%-91.8%] vs 51.6% [95% CI, 47.5%-55.6%]) and 3 vaccinations at day 196 (99.3% [95% CI, 98.7%-99.6%] vs 94.8% [95% CI, 92.7%-96.4%]). The mean GMC of anti-HBs with 3A-HBV was 7.9 times higher after 2 vaccinations at day 168 and 3.5 times higher after 3 vaccinations at day 196 compared with 1A-HBV (after 2 vaccinations, 3A-HBV: GMC, 118.7 mIU/mL; 95% CI, 108.0-129.0 mIU/mL; SE, 1.0 mIU/mL; 1A-HBV: GMC, 15.0 mIU/mL; 95% CI, 12.9-17.5 mIU/mL; SE, 1.0 mIU/mL; after 3 vaccinations, 3A-HBV: GMC, 5442.4 mIU/mL; 95% CI, 4967.0-5963.0 mIU/mL; SE, 1.0 mIU/mL; 1A-HBV: 1567.2 mIU/mL; 95% CI, 1338.0-1834.0 mIU/mL; SE, 1.0 mIU/mL). Rates of local and systemic reactogenicities were higher with 3A-HBV compared with 1A-HBV (local: 1805 of 2124 [85.0%] vs 469 of 712 [65.9%]; systemic: 1445 [68.0%] vs 428 [60.1%]). Vaccine discontinuation due to adverse events (AE) was uncommon, and serious AEs were infrequent, reported in 42 participants (2.0%) and 3 participants (0.4%) in the 3A-HBV and 1A-HBV groups, respectively. Conclusions and Relevance In this study, consistently higher antibody concentrations and SPRs were found with 3A-HBV after 2 and 3 doses vs 1A-HBV in adults aged 18 to 45 years old. The safety and efficacy of 3A-HBV shows its usefulness for the prevention of hepatitis B in young healthy adults. Trial Registration Clinicaltrials.gov Identifier: NCT03408730; EU Clinical Trials Number: 2017-001820-22

2014 Background: Cytomegalovirus (CMV) antigens have been reported in over 90% of GBMs. CD4+ and CD8+ T cells are most frequently directed against the gB and pp65 antigens, respectively, which are immunogenic targets in a CMV-based GBM immunotherapeutic. Methods: A total of 20 first-recurrent GBM patients were enrolled, with Karnofsky Performance Status of at least 70, across 2 arms of the Phase IIa extension phase to receive VBI-1901 (a gB/pp65 enveloped virus-like particle [eVLP]) adjuvanted with either GM-CSF (given intradermally) or AS01B (given intramuscularly) (NCT03382977). Patients were vaccinated with VBI-1901 every 4 weeks, with serologic immune-monitoring 2 weeks after each vaccination and surveillance brain MRI scans every 6 weeks. Results: 10 patients (6 women, 4 men) with a median age of 58 (33-67 yrs) were enrolled into the GM-CSF arm and 10 patients (3 women, 7 men) with a median age of 65 (40-67) enrolled into the AS01B arm. The 12-month OS rates for the GM-CSF and AS01B arms were 60% and 70%, respectively; the 18-month OS rate for the GM-CSF arm was 30%, and for the AS01B arm is expected to be 30%-40% (data has not yet matured). Two durable partial responses (locally determined by RANO) have been observed in the GM-CSF arm, with one patient progression-free and on protocol after 2 years with a tumor size reduction of 93% relative to start of treatment. Immunological analyses demonstrate that prolonged, monthly dosing with VBI-1901 does not lead to immunological tolerance. Dynamic boosting and loss in the peripheral blood of CMV-specific CD4 Tem cells after treatment with VBI-1901 formulated with GM-CSF may correlate with tumor responses. Conclusions: The U.S. FDA granted Fast Track Designation to VBI-1901 adjuvanted with GM-CSF in first-recurrent GBM patients, and an expansion of the ongoing trial with this formulation in this patient population, with the addition of randomization with a contemporaneous control arm, is anticipated to begin in H1 2022. Acknowledgement: GlaxoSmithKline Biologicals SA provided the AS01B adjuvant used in this study. Clinical trial information: NCT03382977.

Tobacco smoking continues to be a global epidemic and the leading preventable cause of cancer and cardiovascular disease. Nicotine vaccines have been investigated as an alternative to currently available smoking cessation strategies as a means to increase rates of success and long-term abstinence. Recently, we demonstrated that a mucosal nicotine vaccine was able to induce robust mucosal and systemic antibodies when delivered heterologously using intranasal and intramuscular routes. Herein, we investigated the neutralization ability of the anti-nicotine antibodies using both intranasal and intracardiac nicotine challenges. Combining the extraction of lyophilized organ samples with RP-HPLC methods, we were able to recover between 47% and 56% of the nicotine administered from the blood, brain, heart, and lungs up to 10 min after challenge, suggesting that the interaction of the antibodies with nicotine forms a stable complex independently of the route of vaccination or challenge. Although both challenge routes can be used for assessing systemic antibodies, only the intranasal administration of nicotine, which is more physiologically similar to the inhalation of nicotine, permitted the crucial interaction of nicotine with the mucosal antibodies generated using the heterologous vaccination route. Notably, these results were obtained 6 months after the final vaccination, demonstrating stable mucosal and systemic antibody responses.

Background This study compares the immunogenicity and safety of a 3-antigen (S/pre-S1/pre-S2) hepatitis B (HepB) vaccine (3AV), to a single antigen vaccine (1AV) in adults to support the registration of 3AV in Russia. Methods We conducted a randomized, double-blind, comparative study of 3-dose regimens of 3AV (10 μg) and 1AV (20 µg) in adults aged 18–45 years. We evaluated immunogenicity based on hepatitis B surface (HBs) antibody titers at days 1, 28, 90, 180, and 210, adverse and serious adverse events (SAEs) to study day 210. The primary outcome was based on the difference in rates of seroconversion at day 210 (lower bound 95% confidence interval [CI]: > − 4%). Secondary outcomes were seroprotection rates (SPR), defined as anti-HBs ≥10 mIU/mL and anti-HBs geometric mean concentration (GMC). Results Rate of seroconversion in 3AV (100%) was noninferior to 1AV (97.9%) at study day 210 (difference: 2.1%, 95% CI: −2.0, 6.3%]) but significantly higher at study day 28. SPR at study day 210 was >97% in both arms. Anti-HBs titers were significantly higher at study days 90 (P = .001) and 180 (P = .0001) with 3AV. Sex, age, and body mass index (BMI) had no impact on anti-HBs titers. The rates of local reactions related to vaccination were similar between vaccine arms (3AV vs 1AV) after the first (30% vs 18.8%, P = .15), second (20.0% vs 14.6%, P = .33), and third vaccination (14.9% vs 23.4%, P = .22). No SAEs were reported. Conclusions 3AV was noninferior to 1AV. 3AV induced high SPR, and there were no safety concerns. Clinical Trials Registration. NCT04209400., The findings of this study demonstrate the noninferiority of seroconversion rates of Sci-B-Vac® compared to Engerix-B®, and similar rates of vaccination-related local reactogenicities between vaccine arms.

Summary Background The seroprotection rate (SPR) of hepatitis B vaccination in adults is suboptimal. The aim of this study was to compare the SPR of a tri-antigenic hepatitis B vaccine (TAV), with a mono-antigenic vaccine (MAV) in adults of all ages. Methods This was a multicentre, double-blind, phase 3, randomised controlled trial (PROTECT) comparing the immunogenicity and safety of TAV with MAV in 28 community and hospital sites in the USA, Finland, Canada, and Belgium. Adults (aged ≥18 years) seronegative for hepatitis B virus (HBV), including those with well-controlled common chronic conditions, were randomly assigned (1:1) and stratified by study centre and age according to a web-based permuted blocked randomisation. Participants received either TAV or MAV which were administered as an intramuscular dose (1 mL) of TAV (10 μg; Sci-B-Vac, VBI Vaccines [SciVac, Rehovot, Israel]) or MAV (20 μg; Engerix-B [GlaxoSmithKline Biologicals, Rixensart, Belgium]) on days 0, 28, and 168 with six study visits and 24 weeks of follow-up after the third vaccination. Participants, investigators, and those assessing outcomes were masked to group assignment. The co-primary outcomes were to show non-inferiority of the SPRs 4 weeks after the third vaccination with TAV versus MAV in adults aged 18 years and older, as well as superiority in adults aged 45 years and older. SPR was defined as the percentage of participants attaining anti-HBs titres of 10 mIU/mL or higher. Non-inferiority of TAV to MAV was concluded if the lower limit of the 95% CI for the between-group difference was greater than −5%. Non-inferiority was assessed in the per-protocol set of participants (aged ≥18 years) and superiority was assessed in all participants (aged ≥45 years) who received at least one vaccination and had at least one evaluable immunogenicity sample after baseline (full analysis set). Safety analyses were a secondary outcome and included all participants who received at least one injection. This trial is registered at Clinicaltrials.gov ( NCT03393754 ) and EudraCT (2017–001819–36) and is closed to new participants. Findings Between Dec 13, 2017, and April 8, 2019, 1607 participants (796 allocated to TAV and 811 allocated to MAV) were randomly assigned and distributed across age cohorts of 18–44 years (299 of 1607; 18·6%), 45–64 years (716 of 1607; 44·6%), and 65 years and older (592 of 1607; 36·8%). In participants aged 18 years and older, SPR was 91·4% (656 of 718) in the TAV group versus 76·5% (553 of 723) in the MAV group (difference 14·9%, 95% CI 11·2–18·6), showing non-inferiority in the per-protocol set. In participants aged 45 years and older, SPR was 89·4% (559 of 625) in the TAV group versus 73·1% (458 of 627) in the MAV group (difference 16·4%, 95% CI 12·2–20·7), showing superiority in the full analysis set. TAV was associated with higher rates of mild or moderate injection site pain (63·2% [503 of 796] in TAV vs 36·3% [294 of 811] in MAV), tenderness (60·8% [484 of 796] in TAV vs 34·8% [282 of 811] in MAV), and myalgia (34·7% [276 of 796] vs 24·3% [197 of 811] in MAV). Otherwise, the safety profile of TAV was similar to that of MAV. Interpretation The safety and efficacy of TAV shows its usefulness for the prevention of HBV infection in adults, including those with stable and controlled chronic conditions. Funding VBI Vaccines.

BACKGROUND: Many Clostridium difficile infection (CDI) cases are classified as health care–associated (HA)-CDI using standard definitions. However, this classification may not be accurate and may lead to the declaration of outbreaks when the acquisition of C. difficile is not HA, and the source of infection or strain type are unknown. OBJECTIVE: To characterize C. difficile ribotypes to establish the relationship between CDI cases involved in two outbreaks at a Canadian hospital, and to determine whether there was a common source of infection between the outbreaks. METHODS: C. difficile isolates from infected patients involved in two CDI outbreaks affecting two wards (A and B) were analyzed using ribotyping and mutlilocus sequence typing (MLST) techniques. Antibiotic use and length of hospital stay for the CDI cases during the outbreaks were also analyzed by reviewing patient charts. RESULTS: C. difficile was isolated from 19 of 22 CDI patients. Twelve patients in ward A carried 10 different ribotypes, of which eight were isolated once. Similarly, seven patients in ward B carried five different ribotypes, of which four were isolated once. Only three ribotypes – 027, 056, and 106 – were isolated in both wards, of which at least two isolates of ribotype 027 and ribotype 056 belonged to different MLST groups, indicating genetic diversity, even among the shared ribotypes between the two wards. All CDI patients were isolated throughout their hospital stay. The CDI cases did not show an association with the length of hospital stay. Antibiotic use was also documented before and after the onset of HA-CDI. A common pattern of exposure to multiple antibiotics and proton pump inhibitors was noticed before the onset of CDI that continued afterward. CONCLUSION: Two concurrent CDI outbreaks in two separate wards involving 22 patients admitted to a Canadian acute health care facility in 2012 are reported. On examining these two outbreaks, there was no evidence to support ongoing nosocomial transmission of C. difficile among these patients. The genetic diversity of recovered C. difficile isolates suggested that the outbreaks could not be attributed to a common source or sustained transmission of an outbreak strain.

Background More than 2 billion individuals worldwide have evidence of past or current hepatitis B virus (HBV) infection, emphasizing the importance of awareness and need for elimination of HBV infection. Effective vaccination, defined as the induction of protective anti-HBs titres, is a key component of those elimination plans. Magnitude of the immune response to HBV vaccines can be measured by serum levels of anti-HBs, whose persistence and durability is believed to be dependent upon the peak antibody levels reached after completion of vaccinations. CONSTANT and PROTECT: High Hepatitis B antibody titres after vaccination Methods In two phase 3, head-to-head studies of immunogenicity and safety of a tri-antigenic HBV vaccine (TAV) containing 10 µg of full-length HBs (pre-S1 + pre-S2 + S antigens) and a mono-antigenic HBV vaccine (MAV) containing 20 µg of small HBs antigen, subjects were vaccinated at months 0, 1 and 6 with safety follow-up for at least 6 months after the 3rd vaccination. PROTECT, which enrolled 1607 adults age ≥18, demonstrated non-inferiority of seroprotection rates (SPR, defined as the % of participants achieving anti-HBs titres ≥10 mIU/mL) of TAV vs. MAV in adults age ≥ 18 and superiority of SPR in adults age ≥ 45. CONSTANT, which enrolled 2838 adults age 18–45 demonstrated manufacturing equivalence of 3 lots of TAV. In both studies, anti-HBs titres were measured across timepoints and safety was assessed. Results In CONSTANT, at day 168 after two doses, mean anti-HBs titers (mIU/mL) induced across the 3 lots of TAV were > 7.5x those induced with MAV [113–124 vs. 15]. At day 196, after the 3rd dose, mean anti-HBs titers induced with TAV remained substantially higher than those induced with MAV [4855–5979 vs. 1526] (Fig A). In PROTECT, anti-HBs titers were 6x higher in all subjects ≥ 18 year at day 196 [1148 vs. 193] with TAV and 5-8x higher in key subgroups compared to MAV, regardless of age, BMI, or diabetic status (Fig B). Adverse events were well-balanced and consistent with known vaccine safety profiles. Conclusion In the two pivotal phase 3 studies, TAV demonstrated its ability to rapidly elicit higher anti-HBs titres compared to MAV, in all study subject populations, reflecting the very strong immune response to TAV, which may be an important predictor of the persistence and durability of seroprotection. Disclosures Joanne M. Langley, MD, GSK group of companies (Research Grant or Support)Immunivaccines Inc (Scientific Research Study Investigator, Research Grant or Support)Janssen (Research Grant or Support)Pfizer (Research Grant or Support)Symvivo (Scientific Research Study Investigator, Research Grant or Support)VBI Vaccines (Research Grant or Support) Nathalie Machluf, PhD, VBI Vaccines Inc. (Employee) Johanna Spaans, BSc, MSc, VBI Vaccines Inc (Employee) Dave Anderson, PhD, VBI Vaccines (Employee, Shareholder) Vlad Popovic, MD, VBI Vaccines, Inc. (Employee, Shareholder) Francisco Diaz-Mitoma, MD, VBI Vaccines, Inc. (Shareholder, Independent Contractor)

While Zika virus (ZIKV) infection induces mild disease in the majority of cases, it has been identified as responsible for microcephaly and severe neurological disorders in recent 2015-2016 outbreaks in South America and the Caribbean. Since then, several prophylactic vaccine strategies have been studied. Here, we describe the development of a ZIKV candidate vaccine consisting of bivalent enveloped virus-like particles (eVLPs) expressing a modified form of E and truncated NS1 (EG/NS1) proteins. In EG/NS1, the E transmembrane/cytoplasmic tail has been replaced with those domains from the VSV G protein and a β-domain of NS1 was fused in-frame to Gag from Moloney murine leukemia virus (MLV). Immunization of BALB/C mice demonstrated that bivalent EG/NS1 and monovalent EG eVLPs induced comparable levels of antibody (Ab) titers but that EG/NS1 induced much higher neutralizing activity, comparable to naturally acquired anti-ZIKV immunity. In contrast, monovalent NS1 eVLPs did not induce a significant anti-NS1 Ab response but promoted strong T cell immunity that was also elicited with EG/NS1 eVLPs. ZIKV challenge studies in C57BL/6-IFNαR−/−mice demonstrated that EG/NS1 eVLPs conferred 100% protection against clinical disease after ZIKV challenge compared to 80% protection after EG eVLP vaccination, with protection against challenge correlating with neutralizing antibody titers and overt signs of infection.Author SummaryZika virus has caused rapidly spreading epidemics with potentially severe neurological symptoms including microcephaly in new born babies. Rapid progress has been made with several candidate vaccines under clinical evaluation but no vaccine or treatment is yet available. In this context, we have produced and tested recombinant virus-like particles that incorporate one or two Zika virus proteins, E and NS1 that have been modified for optimal efficacy. Our immunogenicity studies in mice showed a synergistic effect of both proteins in the bivalent vaccine. NS1 induced a strong T cell response enhancing the neutralizing antibody production induced by the E protein. In challenge experiments, the bivalent vaccine protected 100% of mice from clinical signs of Zika virus infection. These products could be further used to explore Zika virus correlates of protection and evaluated as vaccine candidates.

2047 Background: Cytomegalovirus (CMV) antigens have been reported in over 90% of GBMs. CD4+ and CD8+ T cells are most frequently directed against the gB and pp65 antigens, respectively, and are immunogenic targets in a CMV-based GBM vaccine. Methods: We enrolled a total of 20 patients with KPS at least 70 and first recurrence of GBM into 2 arms of the Phase IIa extension of gB/pp65 enveloped virus-like particles (eVLPs) adjuvanted with either GM-CSF given intradermally or with AS01B given intramuscularly (NCT03382977). Patients were vaccinated with VBI-1901 every 4 weeks, with serologic immune-monitoring 2 weeks after each vaccination and surveillance brain MRI scans every 6 weeks. Results: 10 patients (6 women, 4 men) with a median age of 58 (33-67 yrs) were enrolled into the GM-CSF arm and 10 patients (3 women, 7 men) with a median age of 65 (40-67) enrolled into the AS01B arm. Disease control rates of 40% and 50% were observed in the GM-CSF and AS01B arms, respectively, with 2 sustained PRs in the GM-CSF arm. The 6-month OS rate for the GM-CSF arm is 80% and is estimated to be comparable for the AS01B arm. CMV-specific CD4+ effector memory T cells may correlate with tumor responses in both arms of the study, with AS01B boosting higher frequencies of these cells regardless of baseline CD4/CD8 ratio. Conclusions: These encouraging results from both arms of the trial justify further clinical evaluation in a randomized, controlled trial expected to begin later in 2021. Clinical trial information: NCT03382977.

Our long-term goal is to discover the combination of host parameters that help some HIV-infected individuals to resist progression to AIDS. In this study, we examined antibody responses using multiple samples obtained from a cohort of Long-Term Non-Progressors (LTNPs). Our hypothesis is that antibody responses to variable regions of the HIV-1 envelope glycoprotein are involved in reducing the viral load associated with LTNPs and that these specific immune responses influence susceptibility to disease progression. Multiple plasma samples were obtained from patients identified as LTNPs with the objective of characterizing humoral immune response directed to the five hypervariable regions of the envelope glycoprotein. Antibody binding was tested against peptides representing the five hypervariable regions of gp120, as well as against analog peptides representing different isolates of HIV-1 and against recombinant envelope glycoprotein. LTNPs have specific antibodies to the hypervariable regions of the envelope glycoprotein and develop different patterns of antibody recognition to variable epitopes of envelope glycoprotein. These antibodies can be detected using HIV peptides as capture antigens.

Cytomegalovirus (CMV) antigens have been reported in over 90% of GBM tumors. CD4+ and CD8+ T cells are most frequently directed against the gB and pp65 antigens, respectively, and are immunogenic targets in a CMV-based GBM vaccine. We enrolled 10 patients (6 women, 4 men) with KPS at least 70 and first recurrence of GBM to a trial (Phase IIa extension) of gB/pp65 enveloped virus-like particles (eVLPs) with GM-CSF. Intradermal vaccination was administered every 4 weeks, with serologic immune-monitoring 2 weeks after each vaccination and surveillance brain MRI scans every 6 weeks. Median age was 59 years (range 33–67). Among 8 response-evaluable patients, we observed 1 SD and 1 PR. Among all patients treated on phase I and II (n=26), a normal baseline ratio of CD4/CD8 T cells in peripheral blood predicted response (n=6). Other baseline peripheral blood markers did not correlate with efficacy, including total white blood cell, lymphocyte percentage, and absolute lymphocyte count. During treatment, the peripheral blood of responders demonstrated dynamic losses followed by subsequent reappearance and expansion of CMV-specific CD4+ effector memory T cells. Based on these encouraging results, a new arm is enrolling subjects combining gB/pp65 eVLPs (at the same dose) formulated with adjuvant intramuscular AS01B and results will be presented.

Background Hepatitis B (HBV) remains a significant public health risk with an estimated 240-350 million people chronically-infected with HBV worldwide. In the US, rates of new HBV infections are highest among individuals aged 30-39 years, highlighting the elevated risk in adults. Moreover, CDC reported that in 2017 only 34.3% of US adults aged 19-49 years were vaccinated against HBV. Younger adults who are at-risk of HBV infection, through exposure in the workplace or home (e.g. healthcare workers, public service sector workers, those living with HBsAb-positive individuals), through travel to countries with high HBV prevalence, or through exposure as a result of high-risk behavior (e.g. injection drug use, risk through sexual transmission), need a highly effective and safe HBV vaccine with a rapid onset of seroprotection. Seroprotection Rates from Phase 3 Studies Methods Four phase 3 studies assessing kinetics of seroprotection rates (SPR; anti-HBs ≥ 10 mIU/mL) in adults aged 18-45 years, vaccinated at months 0, 1 and 6 with 10 µg of tri-antigenic HBV vaccine (TAV) vs. 20 µg of a mono-antigenic HBV vaccine (MAV) were completed between 2008 & 2020: (1) PROTECT study in US, Europe, and Canada, n = 299; (2) CONSTANT study in US, Europe and Canada, n = 2,838; (3) SG-005-05 study in Vietnam, n = 349; (4) 38-13-040 study in Russia, n = 99. One phase 4, single-arm study was conducted with 10 µg of TAV in adults aged 20-40 years: SciB018 study in Israel, n = 83. Results In all five studies, vaccination with TAV achieved SPRs of 87.2-100.0% at month 6 after 2 doses and 99.2-100.0% at month 7 after 3 doses, compared to 39.0-89.4% and 91.1-98.3% achieved with MAV at months 6 and 7, respectively (Fig 1). Moreover, as demonstrated with the data available from two of the controlled studies, TAV induced SPRs of 76.0%-95.9% at month 3 after 2 doses compared to 37.2%-87.2% with MAV. No major safety signals were observed, and adverse events were well-balanced and consistent with the known vaccine safety profiles. Conclusion Tri-antigenic HBV vaccine (TAV) has demonstrated its ability to rapidly, consistently, and safely elicit high SPRs in younger adults across different regions of the world. Disclosures Joanne M. Langley, MD, GSK group of companies (Research Grant or Support)Immunivaccines Inc (Scientific Research Study Investigator, Research Grant or Support)Janssen (Research Grant or Support)Pfizer (Research Grant or Support)Symvivo (Scientific Research Study Investigator, Research Grant or Support)VBI Vaccines (Research Grant or Support) Nathalie Machluf, PhD, VBI Vaccines Inc. (Employee) Johanna Spaans, BSc, MSc, VBI Vaccines Inc (Employee) Dave Anderson, PhD, VBI Vaccines (Employee, Shareholder) Vlad Popovic, MD, VBI Vaccines, Inc. (Employee, Shareholder) Francisco Diaz-Mitoma, MD, VBI Vaccines, Inc. (Shareholder, Independent Contractor)

Numerous independent laboratories using several techniques have demonstrated cytomegalovirus (CMV) antigens in over 90% of glioblastoma (GBM) tumors. We initiated a phase I/IIA multicenter study designed to demonstrate safety and determine the most immunogenic dose of an enveloped virus-like particle (eVLP) vaccine expressing the CMV gB and pp65 antigens for treatment of recurrent GBM patients. In Part A of the trial, 6 patients in each of 3 different antigen dose cohorts were vaccinated monthly and followed until tumor progression, with PBMCs collected 2 weeks after each vaccination. Surprisingly, only 7/18 patients enrolled in Part A of the trial had baseline CMV-specific antibody (Ab) titers. This was unexpected given the documented high prevalence of CMV antigens in GBM tumor samples as well as epidemiological data demonstrating much higher CMV Ab seropositive rates in otherwise healthy individuals of a comparable age. In the low dose cohort, 4/6 patients had baseline CMV Ab titers. Of these 4 patients,vaccination boosted strong T cell responses in 2 patients (based on IFN-γ ELISPOT against CMV gB and pp65 antigens). Vaccination did not boost T-cell responses in the CMV Ab-negative patients. In the intermediate dose cohort, among 4 evaluable patients, T cell responses were robustly boosted in the only patient with a baseline CMV Ab titer. In marked contrast, the T-cell responses in the high dose cohort were boosted in 3/5 evaluable patients, all of which were CMV Ab seronegative at baseline. Moreover, the T-cell responses correlated with tumor responses (stable disease based on 2 or more stable MRI scans) as well as improved PFS and 6 month OS relative to vaccine non-responders. To further understand the apparent disconnect between baseline CMV Ab titers and vaccine-mediated impact on tumor and clinical responses, we developed a more sensitive flow cytometry-based assay which evaluated proliferating (Ki-67-positive) gB- and pp65-specific T cells within naïve, central memory (CD45RA-CCR7+) or effector memory (CD45RA-CCR7-) subsets. Among 2/3 tested vaccine responders evaluated thus far in the high dose cohort that were CMV Ab negative at baseline, high frequencies of effector memory cells (~2% total CD3+CD4+ T cells) against both the CMV pp65 and gB antigens were detected at baseline. Collectively, these data suggest that CMV-specific immune dysregulation exists in a substantial number of rGBM patients, which can be overcome with the appropriate dose of a CMV vaccine immunotherapeutic. Importantly, vaccine-mediated boosting of CMV immunity correlates with improved tumor response and clinical outcomes and warrants further confirmation. Citation Format: Tamara Berthoud, Felicia Deonarine, Spenser Ng Cheong Chung, Catalina Soare, Francisco Diaz-Mitoma, David E. Anderson. CMV-specific immuno-dysregulation in recurrent glioblastoma patients can be overcome with therapeutic vaccination which is associated with tumor response and overall survival benefits in a Phase I/IIA study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6538.

Objective:The goals of the research were to determine if a foamy effect on macrophages was due to human endogenous retrovirus K102 (HERV-K102) replication, and to further address its potential significance in HIV-1 infection.Methods:An RT-PCR HERV-K HML-2 pol method was used to screen the unknown HERV, and isolated bands were sent for sequencing. Confirmation of RNA expression was performed by a real time quantitative PCR (qPCR) pol ddCt method. Rabbit antibodies to Env peptides were used to assess expression by immunohistology and processing of Env by western blots. A qPCR pol ddCt method to ascertain genomic copy number was performed on genomic DNA isolated from plasma comparing HIV-1 exposed seronegative (HESN) commercial sex workers (CSW) to normal controls and contrasted with HIV-1 patients.Results:HERV-K102 expression, particle production and replication were associated with foamy macrophage generation in the cultures of cord blood mononuclear cells under permissive conditions. A five-fold increased HERV-K102 pol genomic copy number was found in the HESN cohort over normal which was not found in HIV-1 positive patients (p=0.0005).Conclusions:This work extends the evidence that HERV-K102 has foamy virus attributes, is replication competent, and is capable of high replication rate in vivo and in vitro. This may be the first characterization of a replication-competent, foamy-like virus of humans. High particle production inferred by increased integration in the HESN cohort over HIV-1 patients raises the issue of the clinical importance of HERV-K102 particle production as an early protective innate immune response against HIV-1 replication.

Atherosclerotic cardiovascular disease (ASCVD) events, including coronary heart disease and stroke, are the most frequent cause of death and major disability in the world. Current American College of Cardiology/American Heart Association primary prevention guidelines are mainly on the basis of randomized controlled trials of statin-based low-density lipoprotein cholesterol (LDL-C)-lowering therapy for primary prevention of ASCVD events. Despite the clear demonstration of statin-based LDL-C lowering, substantial 10-year and lifetime risks of incident ASCVD continue. Although the 10-year risk is low in young and middle-aged adults who would not be treated according to current guidelines, they ultimately account for most incident ASCVD. If statin-based LDL-C lowering were initiated in them at an age before complex coronary plaques are common in the population, a substantial reduction in lifetime risk of incident coronary heart disease might be achieved. We examine this hypothesis and introduce the design of a currently recruiting trial to address it. (Eliminate Coronary Artery Disease [ECAD]; NCT02245087).

Summary Background There is some evidence to suggest that one or two doses of the HPV vaccine provides similar protection to the three-dose regimen. The main aim of the study was to ascertain HPV-16/18 vaccine efficacy in both full and naive cohorts and to explore protection conferred against non-vaccine HPV types, by number of doses received. Methods Summary data from the Costa Rica Vaccine Trial (CVT; NCT00128661) and ~the PATRICIA trial (NCT001226810), two phase 3, double-blind, randomised controlled clinical trials of the HPV-16/18 AS04-adjuvanted vaccine in young women, were combined in a post-hoc analysis (GlaxoSmithKline [GSK] e-track number 202142) to investigate the efficacy of fewer than three doses of the HPV-16/18 vaccine after 4 years of follow-up. Women were randomly assigned to receive three doses of the HPV-16/18 vaccine or to a control vaccine; yet, some received fewer doses. After exclusion of women with less than 12 months of follow-up or those who were HPV-16/18 DNA-positive at enrolment (for the HPV-16/18 endpoint), we calculated vaccine efficacy against one-time detection of incident HPV infections after three, two, and one dose(s). The primary study endpoint was one-time detection of first incident HPV-16/18 infections accumulated during the follow-up phase. Findings We assessed vaccine efficacy against incident HPV-16/18 infection in the modified total vaccinated cohort (22 327 received three doses, 1185 two doses, 543 one dose). Vaccine efficacy against incident HPV-16/18 infections for three doses was 77·0% (95% CI 74·7–79·1), two doses was 76·0% (62·0–85·3), and one dose was 85·7% (70·7–93·7). Vaccine efficacy against incident HPV-31/33/45 infections for three doses was 59·7% (56·0–63·0), two doses was 37·7% (12·4–55·9), and one dose was 36·6% (–5·4 to 62·2). Vaccine efficacy against incident HPV-16/18 infection for two-dose women who received their second dose at 1 month was 75·3% (54·2–87·5) and 82·6% (42·3–96·1) for those who received the second dose at 6 months (CVT data only). Vaccine efficacy against HPV-31/33/45 for two-dose women who received their second dose at 6 months (68·1%, 27·0–87·0; CVT data only), but not those receiving it at one month (10·1%, −42·0 to 43·3), was similar to the three-dose group. Interpretation 4 years after vaccination of women aged 15–25 years, one and two doses of the HPV-16/18 vaccine seem to protect against cervical HPV-16/18 infections, similar to the protection provided by the three-dose schedule. Two doses separated by 6 months additionally provided some cross-protection. These data argue for a direct assessment of one-dose efficacy of the HPV-16/18 vaccine. Funding US National Cancer Institute, National Institutes of Health Office of Research on Women's Health, and Ministry of Health of Costa Rica (CVT); GlaxoSmithKline Biologicals SA (PATRICIA).

The efficacy of the human papillomavirus type 16 (HPV-16)/HPV-18 AS04-adjuvanted vaccine against cervical infections with HPV in the Pa pilloma Tri al against C ancer i n Young A dults (PATRICIA) was evaluated using a combination of the broad-spectrum L1-based SPF 10 PCR-DNA enzyme immunoassay (DEIA)/line probe assay (LiPA 25 ) system with type-specific PCRs for HPV-16 and -18. Broad-spectrum PCR assays may underestimate the presence of HPV genotypes present at relatively low concentrations in multiple infections, due to competition between genotypes. Therefore, samples were retrospectively reanalyzed using a testing algorithm incorporating the SPF 10 PCR-DEIA/LiPA 25 plus a novel E6-based multiplex type-specific PCR and reverse hybridization assay (MPTS12 RHA), which permits detection of a panel of nine oncogenic HPV genotypes (types 16, 18, 31, 33, 35, 45, 52, 58, and 59). For the vaccine against HPV types 16 and 18, there was no major impact on estimates of vaccine efficacy (VE) for incident or 6-month or 12-month persistent infections when the MPTS12 RHA was included in the testing algorithm versus estimates with the protocol-specified algorithm. However, the alternative testing algorithm showed greater sensitivity than the protocol-specified algorithm for detection of some nonvaccine oncogenic HPV types. More cases were gained in the control group than in the vaccine group, leading to higher point estimates of VE for 6-month and 12-month persistent infections for the nonvaccine oncogenic types included in the MPTS12 RHA assay (types 31, 33, 35, 45, 52, 58, and 59). This post hoc analysis indicates that the per-protocol testing algorithm used in PATRICIA underestimated the VE against some nonvaccine oncogenic HPV types and that the choice of the HPV DNA testing methodology is important for the evaluation of VE in clinical trials. (This study has been registered at ClinicalTrials.gov under registration no. NCT00122681.)

The high incidence of Campylobacter jejuni-associated diarrhoea, the increase in the frequency of drug resistance, and the correlation between infection and Guillain-Barré syndrome, has heightened the need to develop effective anti-Campylobacter vaccines. Due to the risk of auto-immunity, vaccinations using whole-cells or attenuated cells are not clinical candidates. Subunit vaccines are viable alternatives and have been shown to be effective against other enteric pathogens. This research tested the efficacy of the catalase (KatA) from C. jejuni as a potential vaccine candidate against the pathogen. The protein was found to be immunogenic following an intramuscular murine immunization. A balanced IgG1/IgG2a response was generated when KatA was co-administered with monophosphoryl lipid A and alum. The antibodies elicited reduced the adhesion and invasion of C. jejuni to human epithelial cells (IECs) in vitro. The next phase of testing will be in combination with a proteoliposome (PL) derived from the outer membrane of V. cholerae. PL nano-vesicles were generated with an average size of ≈70nm and had a zeta potential of ≈-40mV.

Colonization of the stomach with Helicobacter pylori can contribute to the development of gastric ulcers and stomach cancer. The typical treatment course for H pylori infection is a proton pump inhibitor in addition to at least two antibiotics. Increasing resistance to these antibiotics has led to a considerable decline in the eradication rate following treatment over the past several years. The purpose of this study was to assess the rates of resistance to several of the antibiotics commonly used to treat H pylori infection, by investigating a population of patients presenting to a single health care facility in Sudbury, Ontario. Multiple methods were used to assess antibiotic resistance., BACKGROUND: Helicobacter pylori plays a significant role in gastritis and ulcers. It is a carcinogen as defined by the WHO, and infection can result in adenocarcinomas and mucosa-associated lymphoid tissue lymphomas. In Canada, rates of antimicrobial resistance are relatively unknown, with very few studies conducted in the past 15 years. OBJECTIVE: To examine rates of resistance in Sudbury, Ontario, compare antimicrobial susceptibility methods and attempt to determine the molecular basis of antibiotic resistance. METHODS: Patients attending scheduled visits at Health Sciences North (Sudbury, Ontario) provided gastric biopsy samples on a volunteer basis. In total, 20 H pylori isolates were collected, and antimicrobial susceptibility testing (on amoxicillin, tetracycline, metronidazole, ciprofloxacin, levofloxacin and clarithromycin) was conducted using disk diffusion and E-test methods. Subsequently, genomic DNA from these isolates was sequenced to detect mutations associated with antimicrobial resistance. RESULTS: Sixty-five percent of the isolates were found to be resistant to at least one of the listed antibiotics according to E-test. Three isolates were found to be resistant to ≥3 of the above-mentioned antibiotics. Notably, 25% of the isolates were found to be resistant to both metronidazole and clarithromycin, two antibiotics that are normally prescribed as part of first-line regimens in the treatment of H pylori infections in Canada and most of the world. Among the resistant strains, the sequences of 23S ribosomal RNA and gyrA, which are linked to clarithromycin and ciprofloxacin/levofloxacin resistance, respectively, revealed the presence of known point mutations associated with antimicrobial resistance. CONCLUSIONS: In general, resistance to metronidazole, ciprofloxacin/levofloxacin and clarithromycin has increased since the studies in the early 2000s. These results suggest that surveillance programs of H pylori antibiotic resistance may need to be revisited or improved to prevent antimicrobial therapy failure.

We report here the first complete circularly closed genome sequence of Enterococcus thailandicus strain a523 isolated from raw urban sewage. This genome contains 2,646,250 bp with a G+C content of 36.8%, 2,499 genes, 2,370 protein-coding sequences, 6 rRNA operons, 65 tRNAs, and 6 clustered regularly interspaced short palindromic repeat arrays.

Background Combination diphtheria-tetanus-5 component acellular pertussis-inactivated poliovirus-Haemophilus influenzae b conjugate-hepatitis B vaccine (DTaP5-IPV-Hib-HepB) administered either concurrently with 7-valent pneumococcal conjugate vaccine (PCV7) or 1 month apart was generally safe and immunogenic at 2, 4 and 6 months of age. This study examined the effects of a booster dose at age 15 months. Methods Participants were randomized to DTaP5-IPV-Hib-HepB plus PCV7, DTaP5-IPV-Hib-HepB with PCV7 administered 1 month later or a pentavalent DTaP5-IPV/Hib plus HepB plus PCV7 at 15 months of age in a randomized, open-label, phase IIb clinical trial. Immunogenicity endpoints were rates of seroresponse to pertussis toxoid, filamentous hemagglutinin, pertactin and fimbriae types 2 and 3; rates of seroprotection against (Hib) polyribosylribitol phosphate capsular polysaccharide, hepatitis B surface antigen, diphtheria toxoid, tetanus toxoid and poliovirus types 1, 2 and 3; and geometric mean titers to all vaccine antigens. Safety endpoints included solicited injection-site reactions and systemic and serious adverse events. Results Seroresponse/seroprotection rates for all antigens exceeded prespecified criteria in both groups that received the hexavalent DTaP5-IPV-Hib-HepB; in the group that received the currently licensed pentavalent vaccine, seroresponse/seroprotection rates exceeded the criteria for all antigens except filamentous hemagglutinin. Seroresponse rates were ≥88.9% for pertussis antigens and seroprotection rates against polyribosylribitol phosphate capsular polysaccharide, hepatitis B surface antigen, diphtheria toxoid, tetanus toxoid and poliovirus antigens were ≥95.1% in recipients of DTaP5-IPV-Hib-HepB. Conclusions DTaP5-IPV-Hib-HepB administered concomitantly with PCV7 or 1 month apart at 15 months of age following the infant series was well-tolerated and elicited antibody responses to all vaccine antigens, with no significant interference from concomitant PCV7 administration (clinicaltrials.gov registration number NCT00362427).

Cytomegalovirus (CMV) antigens have been reported in over 90% of GBM tumors. CD4+and CD8+T cells are most frequently directed against the gB and pp65 antigens, respectively, and are immunogenic targets in a CMV-based GBM vaccine. We have initiated a phase I/IIa clinical trial for patients with recurrent GBM using gB/pp65 enveloped virus-like particles (eVLPs) formulated with GM-CSF and administered intradermally. In phase I, eligible patients were age 18–70 with Karnofsky Performance Status at least 70, normal end-organ function, on stable or decreasing corticosteroids of at most 4mg dexamethasone (or equivalent), with recurrent GBM following any standard initial therapy and any number of recurrences of any size. Patients were vaccinated monthly until tumor progression, with immune-monitoring performed 2 weeks after each vaccination and MRI exams every 6 weeks. The primary endpoint was safety/tolerability and secondarily to assess immunogenicity. Three vaccine doses (0.4µg, 2µg, and 10µg pp65) were evaluated with 6 patients in each cohort, and the DSMB identified no DLTs or safety concerns with any of the doses. The highest 10µg dose was chosen for the Phase IIa extension phase of the trial based on stable disease (3 months or longer) observed in 3/6 patients, which correlated with vaccine-induced IFN-γ-secreting T cell responses against CMV. Enrollment in phase IIa of the trial, which is designed to explore initial potential efficacy signals in an additional 10 patients that receive the optimal 10µg dose of vaccine, is expected in June 2019 and includes the additional requirements of unifocal, measurable enhancing tumor 1–3 cm across at first recurrence and no prior immunotherapy. Patients will be vaccinated monthly until clinical progression. Tumor responses and associated immunological biomarkers will be presented, and are expected to include initial data for all 10 patients.

Background Many adults fail to achieve seroprotection after receiving 3 doses of monovalent HepB vaccines such as Engerix-B® and the response decreases with age and with common co-morbidities. Sci-B-Vac™ is a trivalent HepB vaccine produced in mammalian cells, adjuvanted with aluminum hydroxide, which in addition to small S antigen, contains preS1 and preS2 antigens expressing highly immunogenic T- and B-cell epitopes that may enhance seroprotection rates (SPR) in adults. Methods In a multicentre study, the immunogenicity of 10 µg dose of Sci-B-Vac™ was compared with a 20-µg dose of Engerix-B® given at days 0, 28, and 168 (NCT03393754). Randomization was stratified by study center and age (18–44, 45–64, ≥65 years). Immunogenicity, including SPR (% subjects with anti-HBs levels ≥10 mIU/mL), and safety outcomes were followed to Day 336. The co-primary objectives were (1) non-inferiority in adults ≥18 years and (2) superiority in adults ≥45 years of SPR, 4 weeks after the third dose. Results Of 1,607 randomized subjects, 42.3% were from United States, 41.6% EU, and 16.1% Canada. Males (38.5%) and females (61.5%) were enrolled to 18–44 (18.6%), 45–64 (44.6%), and ≥ 65 year (36.8%) age groups. Both co-primary endpoints were met. In the non-inferiority analysis, SPR in Sci-B-Vac™ recipients aged ≥18 years was 91.4% vs. 76.5% for Engerix-B®; SPR difference: 14.9%; 95% confidence interval (CI) [11.2%, 18.6%]. Superiority analysis showed that SPR in Sci-B-Vac™ recipients aged ≥45 years was 89.4% vs. 73.1% for Engerix-B®—SPR difference: 16.4%; 95% CI [12.2%, 20.7%] (figure). Significantly higher SPR for Sci-B-Vac™ vs. Engerix-B® was noted in subgroups (gender, BMI, diabetes, smoking and particularly age—SPR difference for 45–64 (14.7% [9.8–19.8%]) and ≥ 65 (18.9% [11.6–26.1%]) years. No major safety signals were observed; solicited and unsolicited adverse events were consistent with the known vaccine safety profiles. Conclusion Sci-B-Vac™ met immunogenicity endpoints for non-inferiority in adults aged ≥ 8 years and was superior in adults aged ≥45 years, compared with the monovalent vaccine, Engerix-B®. Sci-B-Vac™ SPR was higher compared with Engerix-B® in key subgroups. No safety signals were observed and safety and tolerability were consistent with the known profile of Sci-B-Vac™. Disclosures Timo Vesikari, MD, VBI (Grant/Research Support, I have received funding from VBI to carry out the reported clinical trial in Finland), Joanne M. Langley, MD, VBI Vaccines (Grant/Research Support), Johanna Spaans, BSc, MSc, VBI Vaccines (Employee), Nathalie Machluf, PhD, SciVac Ltd. (Employee), Dave Anderson, PhD, VBI Vaccines, Inc. (Employee, Shareholder), Vlad Popovic, MD, VBI Vaccines (Employee), Francisco Diaz-Mitoma, MD, VBI Vaccines, Inc. (Consultant, Shareholder, Independent Contractor). Other Authors: No reported disclosures.

2048 Background: Cytomegalovirus (CMV) antigens have been reported in over 90% of GBM tumors. CD4+and CD8+T cells are most frequently directed against the gB and pp65 antigens, respectively, and are immunogenic targets in a CMV-based GBM vaccine. Methods: We have initiated a phase I/IIa clinical trial for patients with recurrent GBM using gB/pp65 enveloped virus-like particles (eVLPs) formulated with GM-CSF and administered intradermally. Subjects are vaccinated monthly until tumor progression, with immunomonitoring performed 2 weeks after each vaccination and MRI exams every 6 weeks. In phase I, eligible patients were age 18-70 with Karnofsky Performance Status at least 70, normal end-organ function, on stable or decreasing corticosteroids of at most 4mg dexamethasone (or equivalent), with recurrent GBM following any standard initial therapy and any number of recurrences. The primary endpoint was safety/tolerability and secondarily to assess immunogenicity. Three vaccine doses (0.4µg, 2µg, and 10µg pp65) were evaluated with 6 subjects in each cohort and DSMB safety review of the first 3 subjects in each cohort prior to enrolling additional subjects. Results: The DSMB identified no DLTs or safety concerns with any of the doses. Grade 2, 3 or 4 AEs occurred in 66%, 22% and 11% of participants, respectively, but were not related to vaccine administration. Twelve men and 6 women were enrolled with a median age 54 (range 39-66). Prior therapies included radiotherapy, temozolomide, and nivolumab. Immunological analyses demonstrate robust boosting of CMV-specific antibody titers and T cell responses against both gB and pp65 antigens in some but not all subjects, across all dose cohorts. Boosting of IFN-gsecreting T cells (measured by ELISPOT) exceeded the assay threshold for several subjects. Stable disease by MRI of 3 months or greater has been observed in 2 subjects in the high dose cohort and 1 subject in the low dose cohort and may correlate with vaccine response. Conclusions: The phase IIa extension phase of the trial planned to begin in Q2 2019 is designed to explore efficacy in an additional 10 subjects that will receive the optimal vaccine dose and includes the additional requirements of unifocal, measurable enhancing tumor 1-3 cm across at first recurrence and no prior immunotherapy. Clinical trial information: NCT03382977.

Hepatitis B (HBV) virus infects the liver, and upon chronic infection, can cause liver cirrhosis and hepatocellular carcinoma. Despite universal vaccination programs against the virus, HBV still affects over 2 billion people worldwide, with over 240 million developing a chronic infection. While current alum-adjuvanted vaccines have shown efficacy in promoting seroprotection in healthy adults, 5-10% of immune-competent populations fail to achieve long-lasting seroprotection from these formulations. Furthermore, a large proportion of immunocompromised patients fail to achieve seroprotective antibody titers after receiving these vaccines. A novel vaccine candidate, HEPLISAV™, uses immunostimulatory sequences (ISS), in its formulation that helps induce a robust humoral and cell mediated immunity against HBV. In Phase III clinical trials, HEPLISAV™ has been shown to elicit seroprotective antibody titers with fewer immunizations. Similar safety profiles are demonstrated when compared with current HBV vaccines. For these reasons, HEPLISAV™ is an attractive vaccine to combat this global disease.

BACKGROUND DTaP₅-IPV-Hib-HepB, an investigational hexavalent combination vaccine, was evaluated for safety and immunogenicity, when administered to infants with heptavalent pneumococcal conjugate vaccine (PCV7). METHODS Infants were randomized to receive DTaP₅-IPV-Hib-HepB plus PCV7, DTaP₅-IPV-Hib-HepB with PCV7 administered 1 month later or DTaP₅-IPV/Hib plus HepB plus PCV7 at 2, 4 and 6 months of age in an open-label, phase IIb trial. Vaccine responses were assessed by pertussis toxoid, filamentous hemagglutinin, pertactin and fimbriae types 2/3 seroconversion rates, Haemophilus influenzae type b polyribosylribitol phosphate capsular polysaccharide, hepatitis B surface antigen, diphtheria toxoid, tetanus toxoid and poliovirus types 1, 2 and 3 seroprotection rates and geometric mean titers. Solicited injection site and systemic reactions, serious adverse events, and other safety outcomes were reported. RESULTS Seroprotection rates to polyribosylribitol phosphate, hepatitis B surface antigen, diphtheria toxoid, tetanus toxoid and poliovirus antigens across all groups met or exceeded predetermined acceptability criteria. Seroconversion rates to pertussis toxoid, pertactin and fimbriae types 2/3, but not filamentous hemagglutinin, met such criteria. Antidiphtheria antibodies were significantly lower when PCV7 was coadministered. Geometric mean titers to the other antigens of the hexavalent and PCV7 vaccines were all high and similar in the 2 groups. No safety signals were noted. CONCLUSIONS DTaP₅-IPV-Hib-HepB administered at 2, 4 and 6 months of age concomitantly with PCV7 was well tolerated and elicited robust antibody responses to all but the antidiphtheria antigens for which there may be evidence of immune interference. Only filamentous hemagglutinin did not meet seroconversion rate acceptability criteria.

Tobacco smoking is recognized as a global pandemic resulting in 6 million deaths per year. Despite a variety of anti-smoking products available to aid with tobacco cessation, the majority of people who attempt to quit smoking relapse within 6 months due to the addictive nature of nicotine. An immunotherapy approach could offer a promising treatment option by inducing a potent selective antibody response against nicotine in order to block its distribution to the brain and its addictive effects in the central nervous system. Our nicotine vaccine candidate was administered intranasally using the Neisseria meningitidis serogroup B Adjuvant Finlay Proteoliposome 1 (AFPL1) as a part of the delivery system. This system was designed to generate a robust immune response by stimulating IL-1β production through Toll-like receptor 4 (TLR4), a potent mechanism for mucosal immunity. The vaccine induced high antibody titers in mice sera in addition to inducing mucosal antibodies. The efficacy of our vaccine was demonstrated using in vivo challenge experiments with radioactive [3H]-nicotine, followed by an analysis of nicotine distribution in the lung, liver, blood and brain. Our results were encouraging as the nicotine concentration in the brain tissue of mice vaccinated with our candidate vaccine was four times lower than in non-vaccinated controls; suggesting that the anti-nicotine antibodies were able to block nicotine from crossing the blood brain barrier. In summary, we have developed a novel nicotine vaccine for the treatment of tobacco addiction by intranasal administration and also demonstrated that the AFPL1 can be used as a potential adjuvant for this vaccine design.