Lot-to-lot immunogenicity consistency of the respiratory syncytial virus prefusion F protein vaccine in older adults

Background

Previous phase 3 studies showed that the AS01E-adjuvanted respiratory syncytial virus (RSV) prefusion F protein-based vaccine for older adults (RSVPreF3 OA) is well tolerated and efficacious in preventing RSV-associated lower respiratory tract disease in adults ≥ 60 years of age. This study evaluated lot-to-lot immunogenicity consistency, reactogenicity, and safety of three RSVPreF3 OA lots.

Methods

This phase 3, multicenter, double-blind study randomized (1:1:1) participants ≥ 60 years of age to receive one of three RSVPreF3 OA lots. Serum RSVPreF3-binding immunoglobulin G (IgG) concentration was assessed at baseline and 30 days post-vaccination. Lot-to-lot consistency was demonstrated if the two-sided 95 % confidence intervals (CIs) of the RSVPreF3-binding IgG geometric mean concentration (GMC) ratios between each lot pair at 30 days post-vaccination were within 0.67 and 1.50. Solicited adverse events (AEs) within four days, unsolicited AEs within 30 days, and serious AEs (SAEs) and potential immune-mediated diseases within six months post-vaccination were recorded.

Results

A total of 757 participants received RSVPreF3 OA, of whom 708 were included in the per-protocol set (234, 237, and 237 participants for each lot). Lot-to-lot consistency was demonstrated: GMC ratios were 1.06 (95 % CI: 0.94-1.21), 0.92 (0.81-1.04), and 0.87 (0.77-0.99) between the lot pairs (lot 1/2; 1/3; 2/3). For the three lots, the RSVPreF3-binding IgG concentration increased 11.84-, 11.29-, and 12.46-fold post-vaccination compared to baseline. The reporting rates of solicited and unsolicited AEs, SAEs, and potential immune-mediated diseases were balanced between lots. Twenty-one participants reported SAEs; one of these-a case of atrial fibrillation-was considered by the investigator as vaccine-related. SAEs with a fatal outcome were reported for four participants, none of which were considered by the investigator as vaccine-related.

Conclusion

This study demonstrated lot-to-lot immunogenicity consistency of three RSVPreF3 OA vaccine lots and indicated that the vaccine had an acceptable safety profile.ClinicalTrials.gov: NCT05059301.

Safety and Immunogenicity of a Revaccination With a Respiratory Syncytial Virus Prefusion F Vaccine in Older Adults: A Phase 2b Study

BACKGROUND

In the previous (parent) study, 2 doses of different formulations of an investigational vaccine against respiratory syncytial virus (RSVPreF3 OA) were well tolerated and immunogenic in older adults. This multicenter phase 2b extension study assessed safety and immunogenicity of a revaccination (third) dose of the 120 μg RSVPreF3-AS01E formulation.

METHODS

In total, 122 older adults (60-80 years), previously vaccinated with 2 doses of RSVPreF3-AS01E formulations (containing 30, 60, or 120 μg RSVPreF3 antigen), received an additional 120 μg RSVPreF3-AS01E dose 18 months after dose 2. Vaccine safety was evaluated in all participants up to 6 months and immunogenicity in participants who received 120 μg RSVPreF3-AS01E doses until 1 month after dose 3.

RESULTS

Similar to the parent study, mostly mild-to-moderate solicited adverse events and no vaccine-related serious adverse events or potential immune-mediated disorders were reported. Neutralizing titers and cell-mediated immune responses persisted for 18 months after 2-dose vaccination. Dose 3 increased RSV-specific neutralizing titers against RSV-A and RSV-B and median CD4+ T-cell frequencies. After dose 3, RSV-specific neutralizing titers but not CD4+ T-cell frequencies were below levels detected 1 month after dose 1.

CONCLUSIONS

Revaccination with 120 μg RSVPreF3-AS01E 18 months after dose 2 is well tolerated and immunogenic in older adults.

CLINICAL TRIALS REGISTRATION

NCT04657198; EudraCT, 2020-000692-21.

Incidence of Cytomegalovirus Primary and Secondary Infection in Adolescent Girls: Results From a Prospective Study

Developing a vaccine to prevent congenital cytomegalovirus (CMV) infection and newborn disability requires an understanding of infection incidence. In a prospective cohort study of 363 adolescent girls (NCT01691820), CMV serostatus, primary infection, and secondary infection were determined in blood and urine samples collected at enrollment and every 4 months for 3 years. Baseline CMV seroprevalence was 58%. Primary infection occurred in 14.8% of seronegative girls. Among seropositive girls, 5.9% had ≥4-fold increase in anti-CMV antibody, and 23.9% shed CMV DNA in urine. Our findings provide insights on infection epidemiology and highlight the need for more standardized markers of secondary infection.

The RSVPreF3-AS01 vaccine elicits broad neutralization of contemporary and antigenically distant respiratory syncytial virus strains

The RSVPreF3-AS01 vaccine, containing the respiratory syncytial virus (RSV) prefusion F protein and the AS01 adjuvant, was previously shown to boost neutralization responses against historical RSV strains and to be efficacious in preventing RSV-associated lower respiratory tract diseases in older adults. Although RSV F is highly conserved, variation does exist between strains. Here, we characterized variations in the major viral antigenic sites among contemporary RSV sequences when compared with RSVPreF3 and showed that, in older adults, RSVPreF3-AS01 broadly boosts neutralization responses against currently dominant and antigenically distant RSV strains. RSV-neutralizing responses are thought to play a central role in preventing RSV infection. Therefore, the breadth of RSVPreF3-AS01-elicited neutralization responses may contribute to vaccine efficacy against contemporary RSV strains and those that may emerge in the future.

Safety and immunogenicity of a respiratory syncytial virus prefusion F protein (RSVPreF3) candidate vaccine in older Japanese adults: A phase I, randomized, observer-blind clinical trial

BACKGROUND

Respiratory syncytial virus (RSV) causes lower respiratory tract infection, with a high burden of disease among adults ≥60 years. This study assessed the safety, reactogenicity, and immunogenicity of an investigational adjuvanted RSV vaccine (RSVPreF3/AS01_B) in Japanese adults aged 60-80 years.

METHODS

Forty participants were randomized to receive two doses of RSVPreF3/AS01_B or the placebo, in a 1:1 ratio, two months apart, in this placebo-controlled study. Solicited administration-site and systemic adverse events (AEs) were collected within 7 days and unsolicited AEs within 30 days post-vaccination. Serious AEs (SAEs) and potential immune-mediated diseases (pIMDs) were collected throughout the study (12 months post-dose 2). RSVPreF3-specific immunoglobulin G (IgG) antibody concentrations and neutralizing antibody (nAb) titers against RSV-A were evaluated on day (D)1, D31, D61, D91 and those against RSV-B on D1, D31, D91.

RESULTS

Solicited AEs were reported more frequently in RSVPreF3/AS01_B recipients (80.0%-90.0%) than in placebo recipients (10.0%-20.0%). Two RSVPreF3/AS01_B recipients experienced grade 3 solicited AEs. Rate of unsolicited AEs were similar (30.0%-35.0%) in both groups. No RSVPreF3/AS01_B recipient reported SAEs/pIMDs, while one placebo recipient reported two SAEs that were unrelated to vaccination. Baseline RSVPreF3-specific IgG and RSV-A/-B nAb levels were above the assay cut-off values. In the RSVPreF3/AS01_B group, RSVPreF3-specific IgG concentrations increased 12.8-fold on D31 and 9.2-fold on D91 versus baseline while nAb titers increased 7.3-fold (RSV-A) and 8.4-fold (RSV-B) on D31 and 6.3-fold (RSV-A) and 9.9-fold (RSV-B) on D91.

CONCLUSIONS

The RSVPreF3/AS01_B vaccine was well tolerated and immunogenic in older Japanese adults.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04090658.

2139. Immunogenicity, reactogenicity and safety of a Respiratory Syncytial Virus prefusion F (RSVPreF3) candidate vaccine co-administered with the seasonal quadrivalent influenza vaccine in older adults

Background

Respiratory syncytial virus (RSV) can cause severe respiratory disease in older adults (OAs). However, there is no approved vaccine against RSV disease in OAs. Co-administration of vaccines against RSV and influenza could be considered given their overlapping seasonality. Here, we assessed the immunogenicity, reactogenicity and safety of an RSV prefusion F Older Adult (RSVPreF3 OA) investigational vaccine when co-administered with the seasonal quadrivalent influenza vaccine (FLU-QIV) in OAs.

Methods

In this Phase 3, open-label, controlled, multi-country study (NCT04841577), OAs aged ≥ 60 years recruited in New Zealand, Panama and South Africa were randomized 1:1 to receive either RSVPreF3 OA and FLU-QIV simultaneously on day 1 (Co-Ad group), or FLU-QIV on day 1 and RSVPreF3 OA on day 31 (Control group). The co-primary objectives were to demonstrate the non-inferiority of i) RSVPreF3 OA in terms of RSV-A neutralizing antibody geometric mean titers (GMT) ratio and ii) FLU-QIV in terms of hemagglutinin inhibition antibody GMT ratio for each Flu strain when co-administered versus when administered alone. Blood samples were collected from all participants pre vaccination and 1 month post vaccination. Non-inferiority was demonstrated if the upper limit (UL) of the 95% confidence interval (CI) of the group GMT ratio (Control/Co-Ad) was ≤ 1.5. Secondary descriptive outcomes included reactogenicity and safety.

Results

885 participants received at least 1 dose of the study interventions. Of these, 838 were included in the per protocol set at 1 month post vaccination. The demographic characteristics of the participants were similar across groups. The study co-primary objectives were met; for both vaccines, the UL of the 95% CI of the GMT ratio was ≤ 1.5 (Table 1). The observed safety events were balanced between Co-Ad and Control groups (Table 2). The reactogenicity profile of the Co-ad group compared with the Control group was driven by the RSVPreF3 OA investigational vaccine.

Conclusion

Our results support simultaneous seasonal vaccination with RSVPreF3 OA and FLU-QIV in adults ≥ 60 years, as co-administration elicits a statistically non-inferior immune response to the administration of each vaccine alone, with no safety concerns identified.

Disclosures

Nathali Montenegro, MD, GSK: Support for the present abstract/study Lorena Noriega-Aguirre, MD, ScD, Astra Zeneca: Advisor/Consultant|Astra Zeneca: Honoraria|Astra Zeneca: Support for attending meetings and/or travel|Boehringer Ingelheim: Honoraria|Boehringer Ingelheim: Support for attending meetings and/or travel|GSK: Advisor/Consultant|GSK: Support for the present abstract/study|Novartis: Honoraria Mohammed Bensellam, PhD, GlaxoSmithKline Biologicals SA: Agency worker on assignment at GSK Nathalie De Schrevel, PhD, GlaxoSmithKline Biologicals SA: Employee|GlaxoSmithKline Biologicals SA: Ownership Interest Sherine Kuriyakose, MSc, GSK: GSK Employee Axel Lambert, MSc, GSK: GSK Employee Aurélie Olivier, PhD, GlaxoSmithKline Biologicals SA: I’m an employee of GSK Biologicals|GlaxoSmithKline Biologicals SA: Ownership Interest Veronica Hulstrøm, PhD MD, GlaxoSmithKline Biologicals SA: Employee.

LB745. Respiratory Syncytial Virus (RSV) Prefusion F Protein Candidate Vaccine (RSVPreF3 OA) is Efficacious in Adults ≥ 60 Years of Age (YOA)

Background

RSV-associated acute respiratory infections (ARI), particularly lower respiratory tract diseases (LRTD), present a significant disease burden in older adults. Currently, there are no approved vaccines against RSV. We present results from an ongoing study designed to demonstrate the vaccine efficacy (VE) of the AS01_E-adjuvanted RSVPreF3 OA in adults ≥ 60 YOA.

Methods

This ongoing, phase 3, observer-blind, placebo-controlled, multi-country study (NCT04886596) enrolled adults ≥ 60 YOA from the northern and southern hemispheres. Participants were randomized (1:1) to receive a single dose of RSVPreF3 OA or placebo before the RSV season. The primary objective was to demonstrate VE of a single dose of RSVPreF3 OA in preventing RSV-confirmed LRTD during one RSV season (criterion: lower limit of VE confidence interval [CI] > 20%). VE is reported also against severe RSV-confirmed LRTD, RSV-confirmed ARI, RSV-confirmed LRTD and RSV-confirmed ARI by RSV subtype (RSV-A and RSV-B), and RSV-confirmed LRTD by age, baseline comorbidity and frailty status. RSV-A/B was confirmed by quantitative RT-PCR.

Results

A total of 26,664 participants were enrolled, of whom 24,966 (RSVPreF3 OA: 12,467; placebo: 12,499) were included in the exposed set and 24,960 (RSVPreF3 OA: 12,466; placebo: 12,494) in the efficacy analysis. The mean age was 69.5 (±6.5) years and 51.7% were women. Over a median follow-up of 6.7 months (maximum 10.1 months), 47 RSV-confirmed LRTD episodes were reported (RSVPreF3 OA: 7; placebo: 40), resulting in a VE of 82.6% (96.95% CI: 57.9–94.1), thus the primary objective was met. Consistently high VE across the clinical spectrum of RSV disease, from RSV-confirmed ARI (71.7% [95% CI: 56.2–82.3]) to severe RSV-confirmed LRTD (94.1% [95% CI: 62.4–99.9]) was observed. High VE was seen in different age groups and regardless of RSV subtype, baseline comorbidity or pre-frail status (Figure 1). Cumulative incidence curves for RSV-confirmed LRTD and RSV-confirmed ARI showed persistent efficacy throughout the follow-up (Figure 2).

Conclusion

A single RSVPreF3 OA dose is highly efficacious against RSV-confirmed LRTD and RSV-confirmed ARI in adults ≥ 60 YOA, regardless of RSV disease severity, RSV subtype, baseline comorbidity and pre-frail status.

Funding: GlaxoSmithKline Biologicals SA.

Abstract and information is also available at the following link : Efficacy results for GSK's older adult RSV vaccine (investis.com).

Disclosures

Michael G. Ison, MD MS, GlaxoSmithKline: Advisor/Consultant|GlaxoSmithKline: Grant/Research Support Alberto Papi, MD, CHIESI, ASTRAZENECA, GSK, BI, MENARINI, NOVARTIS, ZAMBON, MUNDIPHARMA, SANOFI, AVILLION: Honoraria|CHIESI, ASTRAZENECA, GSK, NOVARTIS, SANOFI, IQVIA, AVILLION, ELPEN PHARMACEUTICALS: Advisor/Consultant|CHIESI, ASTRAZENECA, GSK, NOVARTIS, SANOFI, IQVIA, AVILLION, ELPEN PHARMACEUTICALS: Board Member|CHIESI, ASTRAZENECA, GSK, SANOFI: Grant/Research Support Joanne M. Langley, MD, GSK, Merck, Medicago, Sanofi, VBI, VIDO, Entos, Pfizer: Grant/Research Support Isabel Leroux-Roels, PhD MD, Curevac: payment to my institution for the conduct of clinical trials|GSK: payment to my institution for the conduct of clinical trials|ICON Genetics: payment to my institution for the conduct of clinical trials|Janssen Vaccines (J&J): Board Member|Janssen Vaccines (J&J): payment to my institution for the conduct of clinical trials|Osivax: payment to my institution for the conduct of clinical trials Federico Martinon-Torres, MD, PhD, Assoc. Prof, GlaxoSmithKline, Pfizer, Sanofi, Merck, Moderna, Astra Zeneca, Biofabri, Janssen, Novavax: Advisor/Consultant|GlaxoSmithKline, Pfizer, Sanofi, Merck, Moderna, Astra Zeneca, Biofabri, Janssen, Novavax: Grant/Research Support|GlaxoSmithKline, Pfizer, Sanofi, Merck, Moderna, Astra Zeneca, Biofabri, Janssen, Novavax: Honoraria|GlaxoSmithKline, Pfizer, Sanofi, Merck, Moderna, Astra Zeneca, Biofabri, Janssen, Novavax: Clínical trials fees paid to my institution Tino F. Schwarz, Prof. Dr. MD, GlaxoSmithKline: Advisor/Consultant Richard N. Van Zyl-Smit, PhD MD, MSD, Pfizer, GSK, Astra Zeneca, Roche, Novartis, Boehringer Ingelheim, Cipla, J&J, Glenmark: Advisor/Consultant|MSD, Pfizer, GSK, Astra Zeneca, Roche, Novartis, Boehringer Ingelheim, Cipla, J&J, Glenmark: Honoraria Nancy Dezutter, PhD, PharmD, GlaxoSmithKline: GSK employee|GlaxoSmithKline: Stocks/Bonds Nathalie De Schrevel, PhD, GlaxoSmithKline: GSK employee Laurence Fissette, Master in Statistics, GlaxoSmithKline: GSK employee|GlaxoSmithKline: Stocks/Bonds Marie-Pierre David, Master in Statistics, GlaxoSmithKline: GSK employee|GlaxoSmithKline: Stocks/Bonds Marie Van Der Wielen, MD, GlaxoSmithKline: GSK employee|GlaxoSmithKline: Stocks/Bonds Lusine Kostanyan, MD, GlaxoSmithKline: GSK employee|GlaxoSmithKline: Stocks/Bonds Veronica Hulstrøm, PhD MD, GlaxoSmithKline: GSK employee.

96. A Candidate Respiratory Syncytial Virus (RSV) Prefusion F Protein Investigational Vaccine (RSVPreF3 OA) Is Immunogenic when Administered in Adults ≥ 60 Years of Age: Results at 6 Months after Vaccination

Background

RSV infections are frequent and can lead to respiratory complications in older adults (OA). However, there is no licensed RSV vaccine yet. Here we present immunogenicity results up to month (M) 6 after vaccination with the RSVPreF3 OA.

Methods

In this phase 3 multi-country ongoing study (NCT04732871), adults ≥ 60 years of age were randomized (3:1:1) to receive RSVPreF3 OA and to be followed up for 3 years. All participants received a dose of RSVPreF3 on day (D) 1. Humoral immune (HI) and cell-mediated immune (CMI) responses were measured in subsets of participants at pre-vaccination (D1), D31 and M6. HI outcomes included RSV-A and RSV-B neutralizing antibody (NAb) geometric mean titers (GMTs) and RSVPreF3-specific immunoglobulin G (IgG) antibody geometric mean concentrations (GMCs). The CMI response was assessed in terms of frequency of RSVPreF3-specific CD4⁺ T-cells and CD8⁺ T-cells expressing at least 2 activation markers including at least 1 cytokine among CD40L, 4-1BB, IL-2, TNF-α, IFN-γ, IL-13, IL-17 (polypositive T-cells).

Results

A total of 1653 participants received a dose of RSVPreF3 OA. Of these, 987 participants were included in the HI subset and 566 in the CMI subset at D1. The RSV-A and RSV-B GMTs and RSVPreF3-specific IgG GMCs increased between D1 and D31 followed by a decline until M6. At D31, RSV-A and RSV-B NAb GMTs were 10.5-fold and 7.8-fold higher than pre-vaccination (Figure), and RSVPreF3-specific IgG antibody GMCs was 12.2-fold higher than pre-vaccination levels. At M6, the RSV-A and RSV-B GMTs were 4.4-fold and 3.5-fold, and RSVPreF3-specific IgG antibody GMCs were 4.7-fold above pre-vaccination levels. The RSVPreF3-specific polypositive CD4⁺ T-cell median frequency (events/10⁶ cells) increased from 191 (below assay quantification limit) to 1339 at D31 and declined to 666 (above assay quantification limit) by M6. No RSVPreF3-specific CD8⁺ T-cell response was detected after RSVPreF3 OA vaccination.

Conclusion

In adults ≥ 60 years of age, 1 dose of RSVPreF3 OA was shown to be immunogenic, with both high HI and specific CMI responses at D31 post-vaccination and remained 3.5–4.7 fold above pre-vaccination levels at M6. This study will continue to monitor the immunogenicity of RSVPreF3 OA up to 3 years.

Funding

GlaxoSmithKline Biologicals SA.

Disclosures

Tino F. Schwarz, Prof. Dr. MD, Biogen, Merck-Serono, Pfizer, Alexion, Bavarian Nordic, Janssen-Cilag, AstraZeneca, Biontech, MSD: Grants|GlaxoSmithKline Biologicals SA: Honoraria John E. Ervin, MD, The Alliance for Multispecialty Research – KCM: Contractual agreement for conduct of study protocol Charles Andrews, MD, GlaxoSmithKline Biologicals SA: Institutional grant|Merck and Boehringer Ingelheim: Consulting fees outside of the submitted work Delphine Collete, PhD, GlaxoSmithKline Biologicals SA: Employee|GlaxoSmithKline Biologicals SA: Stocks/Bonds Magali de Heusch, PhD, GlaxoSmithKline Biologicals SA: Employee|GlaxoSmithKline Biologicals SA: Stocks/Bonds Nathalie De Schrevel, PhD, GlaxoSmithKline Biologicals SA: Employee|GlaxoSmithKline Biologicals SA: Ownership Interest Bruno Salaun, PhD, GlaxoSmithKline Biologicals SA: Employee|GlaxoSmithKline Biologicals SA: Stocks/Bonds Marc Lievens, MSc, GlaxoSmithKline Biologicals SA: Employee|GlaxoSmithKline Biologicals SA: Stocks/Bonds Céline Maréchal, PhD, GlaxoSmithKline Biologicals SA: Employee|GlaxoSmithKline Biologicals SA: Stocks/Bonds Phoebe Nakanwagi, Master’s in Biostatistics, GlaxoSmithKline Biologicals SA: Employee Veronica Hulstrøm, PhD MD, GlaxoSmithKline Biologicals SA: Employee.

Safety and immunogenicity of a respiratory syncytial virus prefusion F (RSVPreF3) candidate vaccine in older adults: phase I/II randomized clinical trial

BACKGROUND

The aim was to investigate safety and immunogenicity of vaccine formulations against respiratory syncytial virus (RSV) containing the stabilized prefusion conformation of RSV fusion protein (RSVPreF3).

METHODS

This phase I/II, randomized, controlled, observer-blind study enrolled 48 young adults (YA; 18-40 years) and 1005 older adults (OA; 60-80 years) between January and August 2019. Participants were randomized into equally sized groups to receive two doses of unadjuvanted (YA and OA) or AS01-adjuvanted (OA) vaccine or placebo two months apart. Vaccine safety and immunogenicity were assessed until one (YA) or 12 months (OA) after second vaccination.

RESULTS

The RSVPreF3 vaccines boosted humoral (RSVPreF3-specific IgG and RSV-A neutralizing antibody) responses, which increased in an antigen-concentration-dependent manner and were highest post-dose one. Compared to pre-vaccination, the geometric mean frequencies of polyfunctional CD4+ T-cells increased after each dose and were significantly higher in adjuvanted than unadjuvanted vaccinees. Post-vaccination immune responses persisted until end of follow-up. Solicited adverse events (AEs) were mostly mild-to-moderate and transient. Despite a higher observed reactogenicity of AS01-containing vaccines, no safety concerns were identified for any assessed formulation.

CONCLUSIONS

Based on safety and immunogenicity profiles, the AS01E-adjuvanted vaccine containing 120 μg of RSVPreF3 was selected for further clinical development.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03814590; URL: https://clinicaltrials.gov/ct2/show/NCT03814590.

Ten-Year Antibody Persistence and Booster Response to MenACWY-TT Vaccine After Primary Vaccination at 1-10 Years of Age

This phase 3B, open-label, extension study (NCT01962207) evaluated long-term persistence of antibodies induced by the quadrivalent meningococcal vaccine conjugated to tetanus toxoid (MenACWY-TT) compared with the meningococcal serogroup C vaccine conjugated to CRM (MenC-CRM) and the quadrivalent meningococcal polysaccharide vaccine (MenACWY-PS) 6 to 10 y after primary vaccination in toddlers (aged 1–<2 y; MenACWY-TT and MenC-CRM) and children (aged 2–<11 y; MenACWY-TT and MenACWY-PS). Antibody responses against meningococcal serogroups A, C, W, and Y were assessed by serum bactericidal antibody assays using rabbit (rSBA) or human (hSBA) complement. A MenACWY-TT booster dose at Year 10 was given to all eligible subjects regardless of the primary vaccine received. At Year 10, the percentages of subjects with rSBA titers ≥1:8 for serogroups A, C, W, and Y were as follows: MenACWY-TT (toddlers), 65.6%, 82.8%, 31.3%, 43.8%, respectively; MenC-CRM, 88.2% for serogroup C; MenACWY-TT (children), 88.9%, 84.1%, 67.1%, 65.9%; and MenACWY-PS, 28.6%, 81.0%, 23.8%, and 23.8%. Corresponding percentages for hSBA titers ≥1:4 were as follows: MenACWY-TT (toddlers), 31.1%, 91.9%, 44.4%, 41.4%; MenC-CRM, 93.8% for serogroup C; MenACWY-TT (children), 34.8%, 91.1%, 61.2%, 72.6%; and MenACWY-PS, 33.3%, 100.0%, 26.3%, and 44.4%. One month after the MenACWY-TT booster, the percentage of subjects with vaccine response ranged from 75.7% to 100.0% across serogroups in all study groups. Postbooster vaccine responses were generally comparable between groups across serogroups. No new safety signals were identified. Antibody responses persisted 10 y after MenACWY-TT vaccination. The MenACWY-TT booster dose was well tolerated and elicited robust immune responses.

121. A Respiratory Syncytial Virus Prefusion F Protein (RSVPreF3) Candidate Vaccine Administered in Older Adults in a Phase I/II Randomized Clinical Trial Is Immunogenic

Background

RSV causes significant disease burden in older adults, since reinfections are common and may lead to severe disease presentations while only supportive treatment is available. We present immunogenicity of different formulations of an investigational vaccine (RSVPreF3) in young and older adults.

Methods

This is a phase I/II, placebo-controlled, multi-country trial (NCT03814590). Healthy adults aged 18–40 years were randomized 1:1:1:1 to receive 2 doses of either Low-, Medium- or High-dose of RSVPreF3 non-adjuvanted vaccine or placebo, 2 months apart. Following favorable safety outcomes, adults aged 60–80 years were randomized 1:1:1:1:1:1:1:1:1:1 in a 2-step staggered manner to receive 1 of the 9 RSV vaccine formulations containing Low-, Medium- or High-dose of RSVPreF3, non-adjuvanted or adjuvanted with AS01_E or AS01_B, or placebo (same schedule). Humoral and cellular-mediated immune responses are assessed before and after each dose; results up to 1 month post-dose 1 are shown here.

Results

Of 48 adults aged 18–40 years and 1005 aged 60–80 years included in the exposed set, 42 and 933, respectively, were part of per-protocol set at 1 month post-dose 1. RSVPreF3 IgG geometric mean antibody concentrations were 8.4–13.5 and 7.2–12.8 fold-higher at 1 month post-dose 1 vs baseline in the 18–40- and 60–80-year-old vaccinees, respectively (Fig 1A). RSV-A neutralization activity significantly increased in all RSV vaccinees, geometric mean antibody titers being 7.5–13.7 and 5.6–9.9 fold-higher in 18–40- and 60–80-year-olds, respectively, at 1 month post-dose 1 vs baseline (Fig 1B). Geometric mean ratios of the fold increase between RSVPreF3 IgG antibody concentrations and RSV-A neutralizing antibody titers ranged between 0.9–1.1 in 18–40-year-old and 1.3–1.5 in 60–80-year-old vaccinees. A robust RSVPreF3-specific CD4+ T-cell response was elicited at 1 month post-dose 1 vs baseline in both 18–40- and 60–80-year-olds (Fig 2).

Figure 1. RSVPreF3 IgG geometric mean antibody concentrations (GMCs, enzyme-linked immunosorbent assay, panel A), RSV-A neutralizing geometric mean antibody titers (GMTs, neutralization assay, panel B)

Figure 2. RSVPreF3-specific CD4+ T-cells identified as expressing ≥2 markers among IL2, CD40L, TNF-□, IFN-□ (intracellular cytokine staining assay)

Conclusion

One dose of RSVPreF3 candidate vaccine boosted humoral and cellular immune responses in all vaccinees. In older adults, higher humoral response, mostly neutralizing, was observed with increased RSVPreF3 antigen dosage and a tendency of higher cellular response was observed after adjuvanted formulations.

Funding

GlaxoSmithKline Biologicals SA

Disclosures

Javier Ruiz Guiñazú, MD MSc, GSK group of companies (Employee, Shareholder) Jelena Tica, PhD, GSK group of companies (Employee, Shareholder) Charles P. Andrews, MD, GSK group of companies (Scientific Research Study Investigator) Charles Fogarty, MD, GSK group of companies (Grant/Research Support) Edward Kerwin, MD, Amphastar (Consultant, Scientific Research Study Investigator, Advisor or Review Panel member, Speaker’s Bureau)AstraZeneca (Consultant, Scientific Research Study Investigator, Advisor or Review Panel member, Speaker’s Bureau)Boehringer Ingelheim (Consultant, Scientific Research Study Investigator, Advisor or Review Panel member, Speaker’s Bureau)Chiesi (Consultant, Scientific Research Study Investigator, Advisor or Review Panel member, Speaker’s Bureau)Cipla (Consultant, Scientific Research Study Investigator, Advisor or Review Panel member, Speaker’s Bureau)GSK group of companies (Employee, Scientific Research Study Investigator, Advisor or Review Panel member, Speaker’s Bureau)Mylan (Consultant, Scientific Research Study Investigator, Advisor or Review Panel member, Speaker’s Bureau)Novartis (Employee, Advisor or Review Panel member, Research Grant or Support, Speaker’s Bureau)other around 40 pharmaceutical companies (Other Financial or Material Support, conducted multicenter clinical research trials)Pearl (Consultant, Scientific Research Study Investigator, Advisor or Review Panel member, Speaker’s Bureau)Sunovion (Consultant, Scientific Research Study Investigator, Advisor or Review Panel member, Speaker’s Bureau)Theravance (Consultant, Scientific Research Study Investigator, Advisor or Review Panel member, Speaker’s Bureau) Isabel Leroux-Roels, MD PhD, GSK group of companies (Scientific Research Study Investigator) Corinne Vandermeulen, MD PhD, GSK group of companies (Other Financial or Material Support, My university only received Grant/Research Support) Marie-Pierre David, MSc, GSK group of companies (Employee, Shareholder) Nancy Dezutter, PhD, PharmD, RPh, GSK group of companies (Employee, Shareholder) Nathalie De Schrevel, PhD, GSK group of companies (Employee) Laurence Fissette, MSc, GSK group of companies (Employee) Narcisa Mesaros, MD, MSc, GSK group of companies (Employee)

A phase 2b/3b MenACWY-TT study of long-term antibody persistence after primary vaccination and immunogenicity and safety of a booster dose in individuals aged 11 through 55 years

BACKGROUND

A previous phase 2 study demonstrated the immunogenicity of a single dose of meningococcal A, C, W, Y-tetanus toxoid conjugate (MenACWY-TT) or polysaccharide (MenACWY-PS) vaccine for up to 5 years in individuals aged 11-55 years. This follow-up study evaluated long-term antibody persistence up to 10 years and the immunogenicity and safety of a single MenACWY-TT booster dose given 10 years after primary vaccination.

METHODS

Blood draws were conducted annually in Years 7-10. At Year 10, all subjects received a MenACWY-TT booster dose. Blood was drawn at 1 month and safety data were collected ≤6 months postbooster. Study endpoints included immunogenicity during the persistence phase (primary), and immunogenicity and safety during the booster phase (secondary). Statistical analyses were descriptive.

RESULTS

A total of 311 subjects were enrolled in the persistence phase (MenACWY-TT, 235; MenACWY-PS, 76); 220 were enrolled in the booster phase (MenACWY-TT, 164; MenACWY-PS, 56). Descriptive analyses indicated that at Years 7-10, the percentages of subjects achieving serum bactericidal antibody assay using baby rabbit complement (rSBA) titers ≥1:8 and ≥1:128 were higher for serogroups A, W, and Y in the MenACWY-TT versus MenACWY-PS group; percentages were similar across groups for serogroup C. rSBA geometric mean titers (GMTs) for serogroups A, W, and Y were higher in the MenACWY-TT group and slightly higher in the MenACWY-PS group for serogroup C. One month postbooster, all primary MenACWY-TT and ≥98.1% of primary MenACWY-PS recipients had rSBA titers ≥1:8. For all serogroups, rSBA GMTs postbooster were higher in the MenACWY-TT versus MenACWY-PS group. Most local and general reactogenicity events were similar between groups and mild to moderate in severity. Adverse events at 1 month postbooster were 9.1% for the MenACWY-TT and 3.6% for the MenACWY-PS groups; all were nonserious.

CONCLUSIONS

Immune responses to a single MenACWY-TT primary dose administered at age 11-55 years persisted in >70% of individuals evaluated at Years 7-10. A MenACWY-TT booster dose administered at Year 10 was safe and immunogenic with no new safety signals observed. These results provide important insights regarding long-term protection from primary vaccination and the benefits of booster dosing.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT01934140. Registered September 2013.