Lung Immune Challenge Study: Controlled Exposure to Inhaled Resiquimod (R848)

NCT ID: NCT06488118

Last Updated: 2024-07-10

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

NA

Total Enrollment

36 participants

Study Classification

INTERVENTIONAL

Study Start Date

2024-05-24

Study Completion Date

2025-07-31

Brief Summary

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Respiratory viral infections can be a cause of significant illness, particularly in vulnerable individuals as seen in the COVID-19 pandemic. An underactive or overactive immune response can lead to ineffective resolution of inflammation after an infection, especially in people with airway diseases such as asthma. A better understanding of immune responses to infection that does not rely on cell or animal models is crucial to help develop better treatments for lung inflammation.

An established method of studying inflammation in humans is through careful and controlled exposure (or "challenge") with a mimic of a virus to simulate an infection in a similar manner to that of a virus, but with the advantage of not causing an infection. The investigators have already developed a well-tolerated mimic of human viral infection using a sterile substance called Resiquimod (or R848). Since it does not contain living organisms there is no possibility of being infected. This has been used previously as a nasal spray to cause a mild short-lived inflammation that mimics a mild cold. This has been used safely in a range of people of different ages including those who have asthma.

There are differences however in how the nose and lungs respond to viral infections. This is particularly true in those with airway diseases such as asthma, who have cells in the airways of their lungs that respond in a different way to inflammatory triggers (such as viruses).

The current study aims to build on previous research by developing a new approach of studying inflammation in the lungs using a small volume of Resiquimod. This will be done by gently inhaling a fine mist through a mouthpiece into the lungs. Blood and phlegm samples would then be collected to assess inflammation and how well people tolerate the procedure.

Detailed Description

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Background The initial immune response to respiratory viral infections is key to determining what kind of clinical outcome is experienced. The COVID-19 pandemic highlights the key importance of gaining a thorough understanding of these immune mechanisms.

People with chronic lung conditions such as asthma often experience more severe and prolonged symptoms in response to external triggers. This can be due to ongoing inflammation in their airways and lungs. Animal and cell models fail to accurately recapitulate the disease, which limit its usefulness in developing new treatments.

Observational human studies of asthma attacks can be useful but have several confounding factors, which significantly influence the outcomes being assessed. For example, one issue may be the significant variability in time between exposure to a pathogen to the point at which they present to hospital.

One important method for understanding mechanisms of inflammation in humans, is to perform controlled and careful exposure to an inflammatory stimulus to assess why and how differences occur between individuals. This is already established using live viral infection studies - however these studies are technically difficult, resource intensive, may make participants feel unwell for several days, and can be inconvenient for them due to the need for prolonged quarantine.

An alternative approach for studying the first line of immune defence (or "innate immunity"), is to use a mimic of a virus that binds to the same receptors as respiratory viruses such as influenza and SARS-CoV-2. The study team have already established and published this research using a nasal spray with a synthetic compound called Resiquimod (R848). It generates an inflammatory response with the release of molecules such as interferons and cytokines in the nose in a very similar manner to what we see with live viral infections. This approach has been used to demonstrate differences in immune responses between healthy individuals and people with asthma.

However, there are important differences between how the nose and lungs may respond to an inflammatory stimulus. This is due to many reasons including differences in the types of cells present between the upper and lower airways, which is especially the case in people who have airway diseases such as asthma.

Lung Challenge Model A lung immune challenge model using Resiquimod would therefore represent an important approach for studying differences in innate immune responses between individuals, enable an understanding of which cells are responsible for driving inflammation, and have the potential to be a platform for testing new anti-inflammatory therapies.

The first step of this approach and the focus of the current study is to define what dose is the most suitable for generating an appropriate innate immune response, whilst also being clinically tolerable for volunteers. The dose has already been established in the respiratory tract using nasal challenge, so this is a very good starting point when designing the current study. The initial dose for lung challenge will be 100-fold lower than with nasal challenge and therefore it is not anticipated to generate an immune response. The subsequent doses will then be escalated and reach a maximum dose that has already been administered via the intranasal route in clinical trials.

Identifying whether an appropriate immune response has been generated will be done by measuring the inflammatory molecule CXCL10. It is known that CXCL10 is an excellent biomarker for immune activation as it is increased after nasal challenge with Resiquimod, as well as after natural viral infections. CXCL10 will be measured in the blood and in the lungs by analysing sputum samples.

The dose cohort design with 6 participants in each dose cohort, and 4 participants being randomised to Resiquimod, whilst 2 participants being randomised to saline is based on an already published AstraZeneca trial of a similar compound used for inhaled challenge. This will enable an accurate comparison of responses between saline and active groups.

An important aspect of this study is to ensure it is clinically tolerable for volunteers. They will have been informed in the PIS that they may experience flu-like symptoms as the purpose of the study is to mimic flu and therefore, they may have transient inflammation and cold symptoms. To ensure their safety - their symptoms, physiological observations, and airway function will be closely monitored for the first 24 hours of the study directly within the research facility with access to full healthcare resources and staff. Individuals with asthma will only undergo inhaled challenge once an appropriate dose has been established in healthy participants.

Conditions

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Innate Immunity Mucosal Immunity Asthma Viral Infection

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

SINGLE

Participants

Study Groups

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R848 0.1 μg/mL

Inhaled Resiquimod (R848) 0.1 μg/mL

Group Type ACTIVE_COMPARATOR

R848

Intervention Type DRUG

Inhaled R848 dose ranging from 0.1 to 100 μg/mL

R848 1.0 μg/mL

Inhaled Resiquimod (R848) 1.0 μg/mL

Group Type ACTIVE_COMPARATOR

R848

Intervention Type DRUG

Inhaled R848 dose ranging from 0.1 to 100 μg/mL

R848 10 μg/mL

Inhaled Resiquimod (R848) 10 μg/mL

Group Type ACTIVE_COMPARATOR

R848

Intervention Type DRUG

Inhaled R848 dose ranging from 0.1 to 100 μg/mL

R848 100 μg/mL

Inhaled Resiquimod (R848) 100 μg/mL

Group Type ACTIVE_COMPARATOR

R848

Intervention Type DRUG

Inhaled R848 dose ranging from 0.1 to 100 μg/mL

Saline

Inhaled Saline

Group Type PLACEBO_COMPARATOR

Saline

Intervention Type DRUG

Inhaled Saline control

Asthma volunteers inhaled R848

Highest tolerated dose inhaled R848 in healthy volunteers to be given to volunteers with asthma

Group Type ACTIVE_COMPARATOR

R848

Intervention Type DRUG

Inhaled R848 dose ranging from 0.1 to 100 μg/mL

Asthma volunteers inhaled saline

Inhaled saline to be given to volunteers with asthma

Group Type PLACEBO_COMPARATOR

Saline

Intervention Type DRUG

Inhaled Saline control

Sample only

Sample only collection from volunteers for protocol optimisation

Group Type NO_INTERVENTION

No interventions assigned to this group

Interventions

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R848

Inhaled R848 dose ranging from 0.1 to 100 μg/mL

Intervention Type DRUG

Saline

Inhaled Saline control

Intervention Type DRUG

Eligibility Criteria

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Inclusion Criteria

* Male or female aged between 18 and 60 years.
* Willing and able to give informed consent for participation in the study.
* Female participants of child-bearing potential and male participants whose partner is of child-bearing potential must be willing to ensure that they or their partner use effective contraception during the study.
* Clinically acceptable laboratory measurements and ECG at enrolment.
* Ability to expectorate sputum.
* Optional additional swab for SARS-CoV-2 testing will be collected from participants if required by local or/and national health and safety policies at the time of sampling.

For healthy volunteers:

* No clinical history of asthma
* Normal baseline spirometry i.e. FEV1/Forced Vital Capacity (FVC) ratio z-score greater than the lower limit of normal.

For volunteers with asthma:

* Physician-diagnosed mild to moderate asthma which is not poorly controlled as evidenced by an Asthma Control Questionnaire (ACQ-5) score of ≤1.5.
* They are permitted to be on inhaled corticosteroids (ICS), long-acting beta agonist (LABA) and long-acting muscarinic antagonists (LAMA).
* Pre-bronchodilator FEV1 ≥70% predicted.
* Evidence of bronchial hyperreactivity as evidenced by either (i) Bronchodilator reversibility (increase FEV1 ≥12% and 200 mL); (ii) Positive methacholine challenge (PC20 \< 8mg/ml), or (iii) Positive challenge test as per current CUH policy.

Exclusion Criteria

* Upper respiratory tract infection in preceding 14 days.
* Lower respiratory tract infection in preceding 28 days.
* Female participants who are pregnant, lactating or planning pregnancy.
* Respiratory diseases (other than asthma where specified).
* Significant extrapulmonary medical conditions.
* Extreme obesity (BMI \>40).
* Any other significant disease or disorder which, in the opinion of the Investigator, may either put the participants at risk because of participation in the study, or may influence the result of the study, or the participant's ability to participate in the study.
* Participants who have participated in another research study involving an investigational product in the past 12 weeks.
* No newly prescribed courses of medication including corticosteroids in the four weeks before first study dose other than mild analgesia, vitamins, and supplements.
* Smoking tobacco or vaping products in previous 6 months.
* Smoking history of \>5 pack years.
Minimum Eligible Age

18 Years

Maximum Eligible Age

60 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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University of Cambridge

OTHER

Sponsor Role collaborator

Akhilesh Jha

OTHER

Sponsor Role lead

Responsible Party

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Akhilesh Jha

MRC Clinician Scientist

Responsibility Role SPONSOR_INVESTIGATOR

Locations

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NIHR Cambridge Clinical Research Facility

Cambridge, Cambridgeshire, United Kingdom

Site Status RECRUITING

Countries

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United Kingdom

Central Contacts

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Akhilesh Jha, MBBS; MRCP; PhD

Role: CONTACT

+44 01223254642

Jade Joseph, BSc; MSc

Role: CONTACT

+44 01223254642

Facility Contacts

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Akhilesh Jha, MBBS; MRCP; PhD

Role: primary

References

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Jha A, Thwaites RS, Tunstall T, Kon OM, Shattock RJ, Hansel TT, Openshaw PJM. Increased nasal mucosal interferon and CCL13 response to a TLR7/8 agonist in asthma and allergic rhinitis. J Allergy Clin Immunol. 2021 Feb;147(2):694-703.e12. doi: 10.1016/j.jaci.2020.07.012. Epub 2020 Jul 24.

Reference Type BACKGROUND
PMID: 32717253 (View on PubMed)

Progatzky F, Jha A, Wane M, Thwaites RS, Makris S, Shattock RJ, Johansson C, Openshaw PJ, Bugeon L, Hansel TT, Dallman MJ. Induction of innate cytokine responses by respiratory mucosal challenge with R848 in zebrafish, mice, and humans. J Allergy Clin Immunol. 2019 Jul;144(1):342-345.e7. doi: 10.1016/j.jaci.2019.04.003. Epub 2019 Apr 16. No abstract available.

Reference Type BACKGROUND
PMID: 31002833 (View on PubMed)

Provided Documents

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Document Type: Study Protocol and Statistical Analysis Plan

View Document

Document Type: Informed Consent Form

View Document

Related Links

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Other Identifiers

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MR/Y000935/1

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

A096886

Identifier Type: -

Identifier Source: org_study_id

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