Evaluation of two frailty indices, with practical application in a vaccine clinical trial

Recombinant zoster vaccine in immunocompetent and immunocompromised adults: A review of clinical studies

Herpes zoster (HZ) is a debilitating vaccine-preventable disease. Impairment of cell-mediated immunity, as observed with aging and immunosuppressive disorders and therapies, increases risk. Recombinant zoster vaccine (RZV) is efficacious against HZ in adults aged ≥50 years in different settings, and in immunocompromised adults aged ≥18 years who are at increased risk of developing HZ. RZV is the first and only HZ vaccine approved for use in immunocompromised adults globally, including in Europe and the US. RZV has a clinically acceptable safety profile and elicits robust immune responses in adults aged ≥50 years, and in immunocompromised adults aged ≥18 years who are at increased risk of HZ. Additionally, RZV is efficacious against HZ complications such as post-herpetic neuralgia and HZ-related pain. This review updates knowledge from a randomized controlled trial setting on the efficacy, safety, immunogenicity, and impact on quality of life of RZV.

Efficacy and safety of the recombinant zoster vaccine: A systematic review and meta-analysis

In this systematic review with meta-analysis, the efficacy, effectiveness, and safety of the new GSK recombinant zoster vaccine (RZV) were assessed.Twenty three publications reporting on 14 studies were selected, including 2 pivotal RCTs in older immunocompetent adults (ZOE-50 and ZOE-70), 4 RCTs on immunocompromised patients (haematopoietic stem cell transplantation (HSCT), haematological malignancies, solid tumour, and renal transplantation), and 8 observational studies. Vaccine efficacy of RZV against herpes zoster (HZ) and postherpetic neuralgia (PHN) was very high in immunocompetent older adults (respectively 94% and 91.2% in adults ≥50 years and 91.3% and 88.8% in adults ≥70 years). However, the number needed to vaccinate (NNV) was relatively high (between 32 and 36 for HZ and between 261 and 335 for PHN). Slow waning of the vaccine efficacy has been described after a median follow-up of 10 years after vaccination. In patients after HSCT, vaccine efficacy of RZV against HZ was lower compared to immunocompetent adults (68.2%), while vaccine efficacy of RZV against PHN was similar (89.3%). Higher incidences of HZ and PHN in patients after HSCT resulted in higher absolute reduction of cases and lower NNV (respectively 10 and 115). Observational studies confirmed a good vaccine effectiveness, albeit lower than in RCTs (ranging between 70% and 85%). No safety signal was identified neither in RCTs with immunocompetent or immunocompromised adults nor in observational studies and post-marketing surveillance. Increased reactogenicity after RZV vaccination, limited in extent and duration, did not result in low second dose compliance.

Conclusion

Although vaccine efficacy in RCTs and effectiveness in the real world has been reported to be good, it needs to be stressed that high numbers of immunocompetent adults need to be vaccinated to prevent HZ and PHN. Due to higher incidence, more acceptable NNVs were calculated in immunocompromised adults after HSCT.

An Easy-to-Implement Clinical-Trial Frailty Index Based on Accumulation of Deficits: Validation in Zoster Vaccine Clinical Trials

Purpose

Despite being among those most in need of protection, frail older adults are often not well represented in clinical trials. Although frailty likely influences responses to treatments and vaccines, frailty may not be explicitly considered in trials even when frail participants are enrolled due to the perception that frailty is difficult to measure effectively and efficiently without adding to participant or data collection burden. We developed an easy-to-implement frailty index, the Clinical Trial-Frailty Index (CT-FI), based on baseline medical history and standard patient-reported outcomes using data from clinical trials of recombinant Zoster vaccine (the ZOE-50 and ZOE-70 studies). Our objective was to demonstrate that the CT-FI is a robust measure that may be used retrospectively or prospectively in clinical trials where sufficient patient data have been collected.

Methods

The CT-FI was based on baseline medical history and Quality of Life questionnaires (SF-36 and EQ-5D). Items meeting criteria for inclusion were scored from 0 to 1, then summed for each participant and divided by the total number of deficits considered. Validation analyses included descriptive verification of distribution and age- and sex-associations in relation to usual patterns of the frailty index, regressions in relation to outcomes hypothesized to be related to frailty, and resampling methods within the index.

Results

The CT-FI distribution was well represented by a gamma distribution with a range of 0–0.70. Deficit accumulation increased with chronological age and was higher for females. Multivariate Cox regression survival analysis showed that the CT-FI, age, and sex were significant predictors of mortality. Jackknife and Bootstrap resampling methods highlighted the robustness of the CT-FI, which was not sensitive to inclusion/exclusion of specific individual or groups of variables.

Conclusion

We have developed a reliable, robust and easy-to-implement CT-FI with potential retrospective or prospective application in other clinical trials.

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Considering Frailty in SARS-CoV-2 Vaccine Development: How Geriatricians Can Assist

The COVID-19 pandemic has disproportionately impacted frail older adults, especially residents of long-term care (LTC) facilities. This has appropriately led to prioritization of frail older adults and LTC residents, and those who care for them, in the vaccination effort against COVID-19. Older adults have distinct immunological, clinical, and practical complexity, which can be understood through a lens of frailty. Even so, frailty has not been considered in studies of COVID-19 vaccines to date, leading to concerns that the vaccines have not been optimally tailored for and evaluated in this population even as vaccination programs are being implemented. This is an example of how vaccines are often not tested in Phase 1/2/3 clinical trials in the people most in need of protection. We argue that geriatricians, as frailty specialists, have much to contribute to the development, testing and implementation of COVID-19 vaccines in older adults. We discuss roles for geriatricians in ten stages of the vaccine development process, covering vaccine design, trial design, trial recruitment, establishment and interpretation of illness definitions, safety monitoring, consideration of relevant health measures such as frailty and function, analysis methods to account for frailty and differential vulnerability, contributions in regulatory and advisory roles, post-marketing surveillance, and program implementation and public health messaging. In presenting key recommendations pertinent to each stage, we hope to contribute to a dialogue on how to push the field of vaccinology to embrace the complexity of frailty. Making vaccines that can benefit frail older adults will benefit everyone in the fight against COVID-19.

Impact of Reactogenicity After Two Doses of Recombinant Zoster Vaccine Upon Physical Functioning and Quality of Life: An Open Phase III Trial in Older Adults

BACKGROUND

Herpes zoster may significantly impact quality of life (QoL) in older adults. The recombinant zoster vaccine (RZV) is efficacious in adults aged ≥50 and older and is associated with increased reactogenicity compared to placebo. We report here on the impact of reactogenicity of the second RZV dose on the QoL and physical functioning (PF) of vaccine recipients, and summarize findings following both doses.

METHOD

In this single-arm study, 401 adults aged ≥50 and older were enrolled to receive two RZV doses 2 months apart. Change in mean Short Form Survey-36 (SF-36) PF and EuroQol-5 Dimension (EQ-5D) scores, reactogenicity, safety, productivity loss, and healthcare resource utilization were evaluated.

RESULTS

In total, 391 (97.5%) participants received dose 2. Post-dose 2, the most common solicited local symptoms were injection site pain (75.1%), erythema (22.4%), and swelling (13.9%), and the most common systemic symptoms were fatigue (46.3%), headache (37.5%), and myalgia (32.9%). Grade 3 solicited (local and systemic) adverse events were reported by 61 (15.6%) participants and were associated with a transient clinically significant decrease in SF-36 PF score on Days 1-2 post-dose 2 that recovered by Day 3. Overall, no clinically important reduction in mean SF-36 PF scores was observed from baseline to post-dose 2 (mean change -0.4), and no quality-adjusted-life-year loss was recorded.

CONCLUSIONS

Overall, QoL and PF of RZV vaccinees were not affected by vaccine-related reactogenicity. A transient reduction was observed in the first 2 days after RZV vaccination in individuals with Grade 3 adverse events. No safety concerns were identified.

Patient-reported outcomes in vaccines research: relevance for decision-making

The development and demand for effective vaccines have witnessed an exponential growth over the last century. In the meantime, the vaccine market involves more knowledgeable stakeholders, with a shift in emphasis by regulatory agencies on understanding the patient perception and experience. The Food and Drug Administration's publication of the patient-reported outcomes (PRO) guidance has elevated the discipline of PROs and has resulted in a transition from clinician reports of patient outcomes to PROs. This review reports various research methods, which utilize PROs, including qualitative and quantitative research, clinical trials, and patient preference studies. With the advancement of electronic PRO data capture, additional advantages of PROs are being observed and utilized (e.g. as a trigger for clinical endpoints). We discuss uses and advantages of including PROs into the clinical trial program to improve efficiencies, clinical relevance and overall validity of the program in the vaccine field. (See Plain Language Summary).

Recombinant Zoster Vaccine Is Efficacious and Safe in Frail Individuals

BACKGROUND/OBJECTIVES

Frail participants are often under-represented in randomized trials, raising questions about outcomes of interventions in real-world settings. Frailty is strongly associated with vulnerability to illness and adverse health outcomes. We studied the impact of frailty on recombinant zoster vaccine (RZV) clinical outcomes.

DESIGN/SETTING

Data from two previously conducted phase III randomized trials of RZV were pooled. These two parent trials were conducted concurrently at the same study sites using the same methods.

PARTICIPANTS/INTERVENTION

In the two parent studies, participants aged ≥50 years (ZOE-50 study) and ≥70 years (ZOE-70 study), respectively, were randomized 1:1 to receive two doses of RZV or placebo.

MEASUREMENTS

In the current ZOE-Frailty study (NCT03563183), a frailty index was created using previously validated methods. Clinical outcomes assessed by frailty status included vaccine efficacy, immunogenicity, reactogenicity, and safety.

RESULTS

Of 29,305 participants from the pooled ZOE-50 and ZOE-70 total vaccinated cohort, 92% were included in this study. Mean age was 68.8 years; 58.1% were women; 45.6% were pre-frail and 11.3% frail. The percentage of frail participants increased with age from 5.7% aged 50-59 years to 22.7% aged ≥80 years. RZV vaccine efficacy against herpes zoster was >90% for all frailty subgroups (non-frail: 95.8% (95% confidence interval = 91.6-98.2), pre-frail: 90.4% (84.4-94.4), frail: 90.2% (75.4-97.0)). The RZV group demonstrated robust anti-gE antibody and gE-specific CD4²⁺ responses, with mean concentrations remaining above pre-vaccination levels at least 3 years post-dose two, in all frailty subgroups. In the RZV group, the percentage of participants reporting solicited adverse events tended to decrease with increasing frailty.

CONCLUSION

The relatively nonrestrictive inclusion/exclusion criteria in the parent ZOE studies resulted in a range of participants that included frail and pre-frail older adults. RZV significantly reduced the risk of herpes zoster across all frailty subgroups.