Evaluation of symptoms in respiratory syncytial virus infection in adults: psychometric evaluation of the Respiratory Infection Intensity and Impact Questionnaire™ symptom scores

BACKGROUND

The Respiratory Infection Intensity and Impact Questionnaire (RiiQ™) is a patient-reported outcome measure designed to assess symptoms and impacts of respiratory syncytial virus (RSV) infection. This study evaluated the construct validity, reliability, and responsiveness of the RiiQ™ Respiratory and Systemic Symptoms Scale scores.

METHODS

Prospective data were analyzed from a total of 1795 participants, including from non-hospitalized patients with acute respiratory infection (ARI) and no coinfections enrolled in a Phase 2b RSV vaccine study (RSV-positive: n = 60; RSV-negative: n = 1615), and two observational studies of patients hospitalized with RSV (n = 20; n = 100). Descriptive statistics, confirmatory factor analysis (CFA), test-retest intraclass correlation coefficients (ICCs), construct validity correlations (between a clinician-assessed clinical questionnaire and the RiiQ™ symptoms scale), known-groups validity, and responsiveness (correlations of change scores) were evaluated.

RESULTS

Mean patient age ranged from 66.5 to 71.5 years and the majority of patients were female. Initial assessments in the vaccine trial (ARI Day 1) were suggestive of less severe illness than in the observational studies with hospitalized patients. CFA loadings (> 0.40) supported summary scores. ICCs exceeding the recommended threshold of 0.70 supported test-retest reliability for Respiratory and Systemic Symptoms, except in the small observational study. At the scale level, correlations were moderate to strong (|r| ≥ 0.3) and positive between the Respiratory Symptoms Scale and the related clinical questionnaire scores, reflecting measurement of similar symptoms in support of convergent validity. Correlations with change in Patient Global Impression of Severity > 0.30 supported responsiveness.

CONCLUSIONS

Psychometric tests applied to the RiiQ™ Symptoms scales provide evidence of its reliability, construct validity, discriminating ability, and responsiveness for use in clinical studies to assess the onset and severity of RSV symptoms.

Safety and Immunogenicity of Ad26-Vectored HIV Vaccine With Mosaic Immunogens and a Novel Mosaic Envelope Protein in HIV-Uninfected Adults: A Phase 1/2a Study

BACKGROUND

Developing a cross-clade, globally effective HIV vaccine remains crucial for eliminating HIV.

METHODS

This placebo-controlled, double-blind, phase 1/2a study enrolled healthy HIV-uninfected adults at low risk for HIV infection. They were randomized (1:4:1) to receive 4 doses of an adenovirus 26-based HIV-1 vaccine encoding 2 mosaic Gag and Pol, and 2 mosaic Env proteins plus adjuvanted clade C gp140 (referred to here as clade C regimen), bivalent protein regimen (clade C regimen plus mosaic gp140), or placebo. Primary end points were safety and antibody responses.

RESULTS

In total 152/155 participants (clade C, n = 26; bivalent protein, n = 103; placebo, n = 26) received ≥1 injection. The highest adverse event (AE) severity was grade 3 (local pain/tenderness, 12%, 2%, and 0% of the respective groups; solicited systemic AEs, 19%, 15%, 0%). HIV-1 mosaic gp140-binding antibody titers were 79 595 ELISA units (EU)/mL and 137 520 EU/mL in the clade C and bivalent protein groups (P < .001) after dose 4 and 16 862 EU/mL and 25 162 EU/mL 6 months later. Antibody response breadth against clade C gp140 and clade C/non-clade C gp120 was highest in the bivalent protein group.

CONCLUSIONS

Adding mosaic gp140 to the clade C regimen increased and broadened the elicited immune response without compromising safety or clade C responses. Clinical Trials Registration. NCT02935686.

Burden of respiratory syncytial virus infection in older and high-risk adults: a systematic review and meta-analysis of the evidence from developed countries

Background

Respiratory syncytial virus (RSV) significantly impacts the health of older and high-risk adults (those with comorbidities). We aimed to synthesise the evidence on RSV disease burden and RSV-related healthcare utilisation in both populations.

Methods

We searched Embase and MEDLINE for papers published between 2000 and 2019 reporting the burden and clinical presentation of symptomatic RSV infection and the associated healthcare utilisation in developed countries in adults aged ≥60 years or at high risk. We calculated pooled estimates using random-effects inverse variance-weighted meta-analysis.

Results

103 out of 3429 articles met the inclusion criteria. Among older adults, RSV caused 4.66% (95% CI 3.34–6.48%) of symptomatic respiratory infections in annual studies and 7.80% (95% CI 5.77–10.45%) in seasonal studies; RSV-related case fatality proportion (CFP) was 8.18% (95% CI 5.54–11.94%). Among high-risk adults, RSV caused 7.03% (95% CI 5.18–9.48%) of symptomatic respiratory infections in annual studies, and 7.69% (95% CI 6.23–9.46%) in seasonal studies; CFP was 9.88% (95% CI 6.66–14.43%). Data paucity impaired the calculation of estimates on population incidence, clinical presentation, severe outcomes and healthcare-related utilisation.

Conclusions

Older and high-risk adults frequently experience symptomatic RSV infection, with appreciable mortality; however, detailed data are lacking. Increased surveillance and research are needed to quantify population-based disease burden and facilitate RSV treatments and vaccine development.

Antibody effector functions are associated with protection from respiratory syncytial virus

Respiratory syncytial virus (RSV) infection is a major cause of severe lower respiratory tract infection and death in young infants and the elderly. With no effective prophylactic treatment available, current vaccine candidates aim to elicit neutralizing antibodies. However, binding and neutralization have poorly predicted protection in the past, and accumulating data across epidemiologic cohorts and animal models collectively point to a role for additional antibody Fc-effector functions. To begin to define the humoral correlates of immunity against RSV, here we profiled an adenovirus 26 RSV-preF vaccine-induced humoral immune response in a group of healthy adults that were ultimately challenged with RSV. Protection from infection was linked to opsonophagocytic functions, driven by IgA and differentially glycosylated RSV-specific IgG profiles, marking a functional humoral immune signature of protection against RSV. Furthermore, Fc-modified monoclonal antibodies able to selectively recruit effector functions demonstrated significant antiviral control in a murine model of RSV.

Phase 2b Study of an Ad26.RSV.preF Vaccine for Prevention of RSV-mediated Respiratory Tract Disease in Older Adults

Respiratory syncytial virus (RSV) may cause serious lower respiratory tract disease (LRTD) in older adults, and there is currently no licensed vaccine. CYPRESS (NCT03982199) is a randomized, double-blind, placebo-controlled Phase 2b proof-of-concept trial of an Ad26.RSV.preF-based vaccine for the prevention of RSV-mediated LRTD in older adults. Adults aged ≥65 years were randomized 1:1 before the RSV season to receive Ad26.RSV.preF-based vaccine or placebo. Acute respiratory infection symptoms were collected through a patient eDiary and/or clinician assessment until the end of the RSV season. The primary endpoint was the first occurrence of RTPCR-confirmed RSV-mediated LRTD according to any of 3 case definitions: (1) ≥3 symptoms of lower respiratory tract infection (LRTI), (2) ≥2 symptoms of LRTI, or (3) ≥2 symptoms of LRTI or ≥1 symptom of LRTI with ≥1 systemic symptom. Immunogenicity was assessed in a subset of approximately 200 participants. A total of 2891 participants in each study arm received study treatment. Vaccine efficacy was 80% (94.2% CI, 52.2-92.9%), 75% (50.1-88.5%), and 69.8% (43.7-84.7%) for case definition 1, 2, and 3, respectively (all P &lt;0.001). In the vaccine arm, geometric mean fold increase in antibody titers 14 days after vaccination was 13.5 for RSV neutralizing antibodies and 8.6 for RSV prefusion F-specific binding antibodies, and median frequency of RSV-F-specific INFγ T-cells increased from 34 to 444 SFC/10^6 PBMC; no relevant changes were observed in the placebo arm. The Ad26.RSV.preF-based vaccine was highly effective against RSV-mediated LRTD through the first RSV season and elicited robust immune responses in older adults.

Safety and Tolerability of an Ad26.RSV.preF-based Vaccine in a Phase 2b Study in Older Adults

Our objective was to measure the association between structural racism, a previously unmeasured but theoretically causal factor, and assisted living communities (ALCs) location as fewer ALCs are located in counties with a greater percentage of the population reported as Black (PPB). We used a recently developed measure of structural racism—the racial opportunity gap (ROG), which compares the economic mobility of Black and White people who grew up in the same area with parents who had similar incomes. We estimated a multilevel mixed-effects bivariate regression model to examine the factors contributing to the presence of ALC. We relied on state and county random effects. The likelihood of an assisted living being located in a census tract in 2019 was significantly positively associated with the percent of the population over the age of 65 (OR=150.1573, p=<0.001), the PPB (OR=2.9916, p=0.004), and higher median incomes (OR=1.0, p=<0.001). In contrast, rurality (OR=0.5656, p=<0.001), unemployment rates (OR=0.0288, p=<0.001), and census tracts that have a high PPB in addition to a high county ROG (OR=.0058, p=0.0137) are all associated with a lesser likelihood of an ALC. The interaction coefficient between the ROG and PPB reverses the previously documented negative association between the PPB and ALC presence. This result empirically supports the premise that structural racism, not population race alone, is a negative determinant of where an ALC is located within a county.

LB14. Efficacy and Immunogenicity of an Ad26.RSV.preF-based Vaccine in the Prevention of RT-PCR-confirmed RSV-mediated Lower Respiratory Tract Disease in Adults Aged ≥65 Years: A Randomized, Placebo-controlled, Phase 2b Study

Background

Respiratory syncytial virus (RSV) can cause serious lower respiratory tract disease (LRTD) in older adults. Despite a high burden of disease, there is currently no licensed vaccine for RSV. Here, we report the primary efficacy and immunogenicity results from a Phase 2b proof-of-concept trial of an Ad26.RSV.preF-based vaccine for the prevention of RSV-mediated LRTD in adults aged ≥65 years.

Methods

CYPRESS (NCT03982199) is a randomized, double-blind, placebo-controlled Phase 2b trial. Adults ≥65 years of age were randomized 1:1 prior to the RSV season to receive an Ad26.RSV.preF-based vaccine or placebo. Symptoms of acute respiratory infection (ARI) were collected through an RSV-specific patient-reported Respiratory Infection Intensity and Impact Questionnaire (RiiQ) and/or by a clinician assessment until the end of the RSV season. The primary endpoint was the first occurrence of RT-PCR-confirmed RSV-mediated LRTD according to any of 3 case definitions: (1) ≥3 symptoms of lower respiratory tract infection (LRTI), (2) ≥2 symptoms of LRTI, or (3) ≥2 symptoms of LRTI or ≥1 symptom of LRTI with ≥1 systemic symptom. The secondary endpoint was the first occurrence of any RT-PCR-confirmed RSV-mediated ARI. Immunogenicity assessments were performed in a subset of approximately 200 participants.

Results

A total of 5782 participants (2891 in each study arm) received study treatment (92.5% white, 57.7% female, median age 71 years). Vaccine efficacy was 80% (94.2% CI, 52.2–92.9%), 75% (50.1–88.5%), and 69.8% (43.7–84.7%) for case definition 1, 2, and 3, respectively (all P values < 0.001). Efficacy for any RSV-mediated ARI was 69.8% (95% CI, 42.7–85.1%). In the vaccine arm of the immunogenicity subset, geometric mean fold increase in antibody titers 14 days after vaccination was 13.5 for RSV neutralizing antibodies and 8.6 for RSV prefusion F-specific binding antibodies. Median frequency of RSV-F-specific INFγ T-cells increased from 34 to 444 SFC/10⁶ PBMC 14 days after vaccination in the vaccine arm; no relevant changes were observed in the placebo arm.

Conclusion

In CYPRESS, the Ad26.RSV.preF-based vaccine was highly effective against RSV-mediated LRTD through the first RSV season and elicited robust humoral and cellular immune responses in adults aged ≥65 years.

Disclosures

Ann R. Falsey, MD, AstraZeneca (Individual(s) Involved: Self): Grant/Research Support; BioFire Diagnostics (Individual(s) Involved: Self): Grant/Research Support; Janssen (Individual(s) Involved: Self): Grant/Research Support; Merck, Sharpe and Dohme (Individual(s) Involved: Self): Grant/Research Support; Novavax (Individual(s) Involved: Self): Other Financial or Material Support, Paid DSMB member; Pfizer (Individual(s) Involved: Self): Grant/Research Support Kristi Williams, PhD, Janssen R&D US (Employee) Efi Gymnopoulou, MSc, Janssen Infectious Diseases BV (Employee) Arangassery Rosemary Bastian, PhD, Janssen Vaccines & Prevention BV (Employee) Joris Menten, n/a, Janssen Infectious Diseases BV (Employee) Els De Paepe, MSc, Janssen Infectious Diseases BV (Employee) Hilde de Boer, MSc, Janssen-Cilag (Employee) Sjoukje Vandenberghe, n/a, Janssen Infectious Diseases BV (Employee) Eric Chan, PhD, Janssen Global Services, LLC (Employee) Jerald Sadoff, MD, Johnson & Johnson (Employee, Shareholder) Macaya Douoguih, MD, MPH, Janssen (Employee) Benoit Callendret, PhD, Janssen Vaccines & Prevention BV (Employee) Christy Comeaux, MD, Janssen Vaccines & Prevention BV (Employee) Esther Heijnen, MD, Janssen Vaccines & Prevention BV (Employee)

Prevention of Respiratory Syncytial Virus Infection in Healthy Adults by a Single Immunization of Ad26.RSV.preF in a Human Challenge Study

BACKGROUND

Respiratory syncytial virus (RSV) is a significant cause of severe lower respiratory tract disease in children and older adults, but has no approved vaccine. This study assessed the potential of Ad26.RSV.preF to protect against RSV infection and disease in an RSV human challenge model.

METHODS

In this double-blind, placebo-controlled study, healthy adults aged 18-50 years were randomized 1:1 to receive 1x1011 vp Ad26.RSV.preF or placebo intramuscularly. Twenty-eight days post-immunization, volunteers were challenged intranasally with RSV-A (Memphis 37b). Assesments included viral load (VL), RSV infections, clinical symptom score (CSS), safety and immunogenicity.

RESULTS

Post-challenge, VL, RSV infections and disease severity were lower in Ad26.RSV.preF (n=27) versus placebo (n=26) recipients: median VL-AUC (area under the curve) qRT-PCR: 0.0 versus 236.0 (P=.012; predefined primary endpoint); median VL-AUC quantitative culture: 0.0 versus 109; RSV infections 11 (40.7%) versus 17 (65.4%); median RSV AUC-CSS 35 versus 167, respectively. From baseline to 28 days post-immunization, geometric mean fold-increases in RSV A2 neutralizing antibody titers of 5.8 and 0.9 were observed in Ad26.RSV.preF and placebo, respectively. Ad26.RSV.preF was well tolerated.

CONCLUSIONS

Ad26.RSV.preF demonstrated protection from RSV infection through immunization in a human challenge model, and therefore could potentially protect against natural RSV infection and disease.

CLINICAL TRIALS REGISTRATION

NCT03334695.

Safety and Immunogenicity of the Ad26.RSV.preF Investigational Vaccine Coadministered With an Influenza Vaccine in Older Adults

Background

Respiratory syncytial virus (RSV) and influenza cause significant disease burden in older adults. Overlapping RSV and influenza seasonality presents the opportunity to coadminister vaccines for both infections. This study assessed coadministration of the investigational vaccine, Ad26.RSV.preF, an adenovirus serotype 26 (Ad26) vector encoding RSV F protein stabilized in its prefusion conformation (pre-F), with a seasonal influenza vaccine in older adults.

Methods

In this phase 2a, double-blind, placebo-controlled study, 180 adults aged ≥60 years received Ad26.RSV.preF plus Fluarix on day 1 and placebo on day 29, or placebo plus Fluarix on day 1 and Ad26.RSV.preF on day 29 (control).

Results

The coadministration regimen had an acceptable tolerability profile. Reactogenicity was generally higher after Ad26.RSV.preF versus Fluarix, but symptoms were generally transient and mild or moderate. At 28 days after the first vaccination, the upper confidence intervals of the hemagglutination inhibition antibody geometric mean ratio (control/coadministration) for all influenza strains were &lt;2, demonstrating noninferiority. Robust neutralizing and binding antibody responses to RSV A2 were observed in both groups.

Conclusions

Coadministration of Fluarix with Ad26.RSV.preF vaccine had an acceptable safety profile and showed no evidence of interference in immune response. The results are compatible with simultaneous seasonal vaccination with both vaccines.

Clinical Trials Registration

NCT03339713.

902. A Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Efficacy of a Single Immunization of Ad26.RSV.preF against RSV Infection in a Viral Challenge Model in Healthy Adults

Background

Despite the high disease burden of RSV in older adults and children, there is currently no approved vaccine. Ad26.RSV.preF, an experimental RSV vaccine, has demonstrated immunogenicity and tolerability in first-in-human clinical studies. The aim of this study was to assess the potential of the Ad26.RSV.preF vaccine to protect against RSV infection and disease in an established RSV human challenge model, used for the first time to evaluate a vaccine.

Methods

We conducted a randomized, double-blind, placebo-controlled, human challenge study (NCT03334695). Healthy adults received 1 × 1011 vp Ad26.RSV.preF vaccine (active) or placebo (pbo) intramuscularly. After 28 days, volunteers were challenged intranasally with a low-passage clinical strain of RSV-A (0.8 mL of Memphis 37b) and then quarantined for 12 days. Nasal washes were collected twice daily throughout quarantine, starting 2 days post-challenge (viral load [VL] by qRT-PCR and quantitative cultures). Disease severity was recorded thrice daily using symptom diary cards.

Results

Fifty-three volunteers (active, n = 27; pbo, n = 26) were challenged with RSV-A. Quantitative viral assessments were consistently lower in active than pbo. The primary endpoint of the study was met: the area under the curve (AUC) for RSV VL over time (via qRT-PCR) was significantly lower in active pbo (P = 0.012). Median peak VL was lower for active (0 log10 copies/mL) than pbo (5.4 log10 copies/mL). Median AUC for RSV VL over time (quantitative culture) was lower for active than pbo (0 vs. 109, P = 0.002). Disease severity was lower for active than pbo, with a median AUC total symptom score of 35 (active) vs. 167 (pbo) (P = 0.002). Overall, RSV infection (defined by qRT-PCR alone or combined with symptoms) and disease severity over time were lower in active vs. pbo.

Conclusion

RSV infections, VL, and RSV disease severity were consistently lower in healthy adults receiving Ad26.RSV.preF vs. placebo, demonstrating promising protection from RSV infection and disease. This was the first time that antiviral prevention was observed against RSV after active immunization. Ad26.RSV.preF warrants further evaluation in field trials for efficacy against natural RSV infections in populations considered at risk of severe RSV disease.

Disclosures

All Authors: No reported Disclosures.

2775. Safety and Immunogenicity of a Seasonal Influenza Vaccine and Ad26.RSV.preF Vaccine With and Without Co-Administration: A Randomized, Double-Blind, Placebo-Controlled Phase 2a Study in Adults Aged ≥ 60 Years

Background

Influenza and RSV can cause respiratory tract infections leading to severe illness, hospitalization and mortality in at-risk populations, particularly the elderly. The seasonality of influenza and RSV present the potential to co-administer vaccines. This study aimed to demonstrate the non-inferiority of co-administration of the experimental RSV vaccine Ad26.RSV.preF with an influenza vaccine (Fluarix) vs. Fluarix alone in terms of immunogenicity against influenza.

Methods

This was a single-center, randomized, double-blind, placebo-controlled Phase 2a study (NCT03339713) in healthy adults ≥60 years old. Volunteers were randomized 1:1 to receive Fluarix + 1 × 1011 vp Ad26.RSV.preF on Day 1 and placebo on Day 29 (Group 1), or Fluarix + placebo on Day 1 and 1 × 1011 vp Ad26.RSV.preF on Day 29 (Group 2). Blood samples were taken prior to each vaccination and at Day 57. The primary endpoints were geometric mean titers (GMTs) of hemagglutination inhibition (HI) antibody titers against Fluarix strains (A/Michigan, A/Hong Kong, B/Brisbane and B/Phuket) and the safety and tolerability of Ad26.RSV.preF administered with or without Fluarix. A key secondary endpoint was neutralizing antibody titers to RSV A2.

Results

Volunteers (N = 180) were included in Group 1 (n = 90) or Group 2 (n = 90). Most volunteers were white (89%) and female (63%), with a median age of 65 years. Both groups exhibited an increase from baseline in HI antibody response on Day 29. The 95% one-sided upper confidence limit of all GMT ratios were below the non-inferiority margin of 2. The frequency of solicited adverse events (AE) after Ad26.RSV.preF vaccination was similar with and without influenza co-administration. Solicited AEs were mainly of Grade 1 and 2 and of transient duration. Most unsolicited AEs were considered unrelated to the study vaccination and were Grade 1 or 2. There were no serious AEs related to the study vaccine and there were no discontinuations due to AEs. RSV neutralizing antibody titers 29 days post- Ad26.RSV.preF immunization were similar in both groups (1404, Group 1; 1690, Group 2).

Conclusion

Co-administration of Ad26.RSV.preF with Fluarix was non-inferior to Fluarix alone in terms of immunogenicity against influenza and had an acceptable tolerability profile.

Disclosures

All authors: No reported disclosures.

Cooperativity between Plasmodium falciparum adhesive proteins for invasion into erythrocytes

Plasmodium falciparum is the most virulent of the Plasmodium species infective to humans. Different P. falciparum strains vary in their dependence on erythrocyte receptors for invasion and their ability to switch in their utilization of different receptor repertoires. Members of the reticulocyte-binding protein-like (RBL) family of invasion ligands are postulated to play a central role in defining ligand-receptor interactions, known as invasion pathways. Here we report the targeted gene disruption of PfRh2b and PfRh2a in W2mef, a parasite strain that is heavily dependent on sialic-acid receptors for invasion, and show that the PfRh2b ligand is functional in this parasite background. Like the parental line, parasites lacking either PfRh2a or PfR2b can switch to a sialic acid-independent invasion pathway. However, both of the switched lines exhibit a reduced efficiency for invasion into sialic acid-depleted cells, suggesting a role for both PfRh2b and PfRh2a in invasion via sialic acid-independent receptors. We also find a strong selective pressure for the reconstitution of PfRh2b expression at the expense of PfRh2a. Our results reveal the importance of genetic background in ligand-receptor usage by P. falciparum parasites, and suggest that the co-ordinate expression of PfRh2a, PfRh2b together mediate efficient sialic acid-independent erythrocyte invasion.