Asthma & Respiratory Immunology Flashcards
Discuss the epidemiology of asthma in the UK.
Why is this important?
- 5.4 million people in UK currently receiving treatment for asthma
- 1.1m children affected ( ~3 in every class)
- On average, 3 people die of an asthma attack/day in UK
- NHS spends ~ £1b/yr treating asthma
Epidemiology showing importance of asthma and how big of a problem it is
On average, how many people die of an asthma attack every day in the UK?
Why is this significant?
We know how to diagnose and treat asthma but people are still dying from asthma attacks
What are the cardinal features of asthma?
- Wheeze +/- dry cough
- on exertion
- worse with colds
- with allergen exposure
- breathlessness/dyspnoea - Atopy/allergen sensitisation
- Reversible airflow obstruction
- Airway inflammation
- Eosinophilia
- Type 2 - lymphocytes
A wheeze is a whistling sound that comes from the airways.
What causes this sound?
Bronchoconstriction (narrowing) of the airway lumen
Narrowed airways —-> turbulent flow of air through airways —-> wheezing noise
What are the physiological abnormalities in asthma?
Pathophysiology
Reversible airflow obstruction
Airway inflammation
What 3 things must we test for in order to make a diagnosis of asthma?
- Atopy/allergen sensitisation
- Reversible airflow obstruction
- Airway inflammation
What feature is really important to test for when looking for evidence of asthma?
Airway inflammation
What are the two main cell types contributing to the airway inflammation that occurs in asthma?
Eosinophils
Type 2 - lymphocytes
What test would you use to look for reversible airway obstruction?
Lung function tests, e.g. spirometry (one of the most common tests done)
What loop is obtained during spirometry?
Flow volume loop
When considering airway obstruction, what part of a flow volume loop are they most concerned about: the expiratory part or the inspiratory part?
The expiratory part
What would show evidence of reversible airway obstruction?
Someone with untreated asthma would have demonstrate an obstructive flow volume loop
Following use of a bronchodilator, their flow volume loop would look normal
This shows evidence of reversibility
In asthma, there is reversible airway obstruction.
What is the significance of this?
Use of a bronchodilator can help reverse this airway obstruction
Compare the structure of a normal (healthy) airway vs an “asthmatic” airway.
Normal airway:
- Patent airway lumen allowing laminar flow through airway
- No noise with breathing (e.g. wheezing)
- No difficulty in breathing
Asthmatic airway: (if not controlled with treatment)
- Airway looks abnormal at baseline
- Thickened airway wall due to inflammation (eosinophilic)
- Baseline increase in airway smooth muscle (thickened wall)
- Develop wheeze because airway lumen is narrowed (turbulent flow)
What kind of flow occurs through a patent airway lumen?
Turbulent flow
- Describe the structural abnormalities of the airways in a patient with asthma.
- How does this affect the flow of air through the lumen?
- Structural Abnormalities:
- Thickened wall
- Inflammation in walls
During attack
- Tightened smooth muscles
- Trapped air in alveoli
- Turbulent flow
What is a spirometry test?
A lung function test
- Check how well lungs are working
- Measure how much you inhale, exhale + how fast you exhale
- Forced expiratory measure
- Ask patient to take a deep breath out as hard + as fast as they can to empty their lungs
What does a spirometry test require of the patient?
- Effort
- Co-operation from the patient
Why is spirometry not possible for very young children?
Requires both effort + co-operation from the patient
How might spirometry be adapted for children to ensure they exert maximum effort when carrying out this test?
Might use an incentive device on a computer
Patient A has asthma.
At their baseline, with proper treatment, their lumen is patent and normal.
However, following an injection of an allergen directly into their airways (in controlled situation) they are now exhibiting signs of an asthma attack.
What changes could be observed in the lumen 10 mins after injecting the allergen?
Increased swelling + inflammation
Both lumen = completely occluded
Describe the pathogenesis of allergic asthma.
- Usually h/v normal airway with bronchial epithelium sitting on a small amount of matrix and some smooth muscle
- In a patient that has susceptibility to asthma, if exposed to allergens and sensitised, might develop inflammation and remodelling (in parallel)
- Recruitment of inflammatory cells into airway - predominantly eosinophils
AND
Structural changes, inc. changes in epithelium:
- develop increased goblet cells
- increased amount of matrix
- increased amount + size of muscle cells
What process occurs in a patient with pre-existing susceptibility to asthma who is exposed to an allergen?
Sensitisation
What two process will occur in parallel upon sensitisation to an allergen in a patient who is susceptible to asthma?
- Airway Inflammation
2. Air Remodelling
What is airway remodelling?
Changes in the structural cells of the airway
What structural changes will the airway undergo during remodelling in the pathogenesis of allergic asthma?
Changes in epithelium
- develop increased goblet cells
- increased amount of matrix
- increased amount + size of muscle cells
What inflammatory cells are predominantly recruited to the airways in the pathogenesis of allergic asthma?
Eosinophils
What are the fundamental physiological abnormalities of asthma?
Recruitment of inflammatory cells into airway - predominantly eosinophils
AND
Structural changes, inc. changes in epithelium:
- develop increased goblet cells
- increased amount of matrix
- increased amount + size of muscle cells
Why do only some people who are sensitised develop asthma?
There’s a definite underlying genetic susceptibility
Why do only some people who are sensitised develop asthma?
There’s a definite underlying genetic susceptibility (e.g. have allergy or allergic disease)
What are the events and stages required for development of asthma?
- Genetic susceptibility
- Allergy
- Allergic disease - Environmental exposures, e.g.
- Allergen
- Infection, e.g. colds
- Pollution - Leading to
- Allergy
- Reversible airflow obstruction
- Inflammation
What type of studies can be used to investigate genetic susceptibility in asthma?
Genome Wide Association Studies, GWAS
How could a GWAS be used to investigate genetic susceptibility in asthma?
Whole population level investigation of the genome in people
Comparison of genome (with asthma vs no asthma)
Look for variability in gene expression between 2 groups
What are some advantages to using GWAS to investigate genetic susceptibility in asthma?
Finding genes involved to help us find novel therapies
What kind of plot is used in GWAS?
Manhattan Plot
What do the P-values involved of genes in GWAS shown in Manhattan plots show?
How likely gene is to be increased normally
logP-values therefore has to be very high for it to be significant
What are some advantages to using GWAS to investigate genetic susceptibility in asthma?
Consistent results
Reproducible results
Identify genes that increase in expression in asthmatic patients
Finding genes involved to help us find novel therapies
Give an example of a known gene involved in genetic susceptibility to asthma.
IL33 - specific interleukin involved in asthma
GSDMB - very consistently comes up as increased in both children and adults with asthma
We know that patients with asthma have an underlying genetic susceptibility.
GWAS can be used to further investigate this.
However, this is not simple.
What kind of gene disorder is asthma?
Asthma is a multi-gene disorder and is polyfactorial –> asthma not caused by any 1 thing
- What type immunity reaction occurs in allergic asthma?
2. What does this determine?
- Type 2 immunity reaction
2. Determines the tests we do
Describe the type 2 immunity reaction that occurs in allergic asthma.
- Allergen (antigen) inhaled
- Presented to APC
- APC = dendritic cells in context of the lung
APC carries antigen via MHC class II to lymph nodes (mediastinal nodes because APC is in lung in case of asthma)
- Naive T cells (Th0) differentiate at mediastinal lymph nodes following APC arrival
Differentiate into Th1 & Th2
- Th2 subsequently secretes archetypal Th2 cytokines: IL-4, IL-5 & IL-13
- Cytokines have various actions:
- VCAM-1 expression
- Mast cell proliferation
- IgE synthesis
- Mucin secretion
- Eosinophilic airway inflammation
Describe the type 2 immunity reaction that occurs in allergic asthma.
- Allergen (antigen) inhaled
- Presented to APC
- APC = dendritic cells in context of the lung
APC carries antigen via MHC class II to lymph nodes (mediastinal nodes because APC is in lung in case of asthma)
- Naive T cells (Th0) differentiate at mediastinal lymph nodes following APC arrival
Differentiate into Th1 & Th2
- Th2 subsequently secretes archetypal Th2 cytokines: IL-4, IL-5 & IL-13
- Cytokines have various actions:
- VCAM-1 expression
- Mast cell proliferation
- IgE synthesis
- Mucin secretion
- Eosinophilic airway inflammation
What are the main class of Th cells involved in the pathogenesis of allergic asthma?
Th0 differentiates into Th1 & Th2
What are the 3 main interleukins involved in the pathogenesis of allergic asthma?
IL-4
IL-5
IL-13
Describe the type 2 immunity reaction that occurs in allergic asthma.
- Allergen (antigen) inhaled
- Presented to APC
- APC = dendritic cells in context of the lung
APC carries antigen via MHC class II to lymph nodes (mediastinal nodes because APC is in lung in case of asthma)
- Naive T cells (Th0) differentiate at mediastinal lymph nodes following APC arrival
Differentiate into Th1 & Th2
- Th2 subsequently secretes archetypal Th2 cytokines: IL-4, IL-5 & IL-13
- Cytokines have various actions:
- VCAM-1 expression
- Mast cell proliferation
- IgE synthesis
- Mucin secretion
- Eosinophilic airway inflammation
What is the main role of IL-13 in allergic asthma?
Involved in mucus secretion
What is the main role of IL-5 in allergic asthma?
Recruits eosinophils into airways
Promotes eosinophil survival which contributes to eosinophilic airway inflammation in asthma
What is the main interleukin responsible for eosinophilic airway inflammation in allergic asthma?
IL-5
What are the main processes that occur due to Th2 cytokine action in the development of allergic asthma?
- VCAM-1 expression
- Mast cell proliferation
- IgE synthesis
- Mucin secretion
- Eosinophilic airway inflammation
What are the 5 main stages involved in T2 immune reaction in the pathogenesis of allergic asthma?
[1 sentence per stage)
- Allergen presentation to airway epithelium
- Recognised by dendritic cells
- Presentation of antigen
- Th cell differentiation
- Th2 actions
In type 2 immune reaction, mast cells are degranulated following binding of IgE.
What substances might be released? (contributing to allergic asthma)
[6]
- Histamines
- Eicosanoids
- Cytokines
- Chemokines
- Enzymes
- Growth factors
Once sensitisation has occurred, what immunoglobulin will recognise the allergen in allergic asthma?
IgE
In a sensitised patient, what will IgE bind to in allergic asthma?
Mast cells
- In a sensitised patient, what process occurs upon IgE binding to mast cells in allergic asthma?
- What does this result in?
- Degranulation
- Mast cells will release various chemicals, inc.
- Histamines
- Eicosanoids
- Cytokines
- Chemokines
- Enzymes
- Growth factors
Results in allergic reaction and asthma
What are the main 2 tests for detecting allergic sensitisation?
- Allergy skin tests
2. Blood tests
In type 2 immune reaction, mast cells are degranulated following binding of IgE.
What chemicals might be released? (contributing to allergic asthma)
[6]
- Histamines
- Eicosanoids
- Cytokines
- Chemokines
- Enzymes
- Growth factors
In order to detect allergy sensitisation, what can you test for in blood tests?
Can test for specific IgE antibodies to allergens of interest
Total IgE alone not sufficient to define atopy
What do allergy skin tests involve?
- Intradermal injection of a positive control
HISTAMINE - because we all react to histamine
- Intradermal injection of a negative control - SALINE
- Compare with allergens, e.g. dust mite, grass, pollen, cat dander, dog dander etc.
- What suggests a positive result to an allergen in allergy skin tests?
- How can we determine whether someone is sensitised to an allergen with a skin test?
- Develop wheal and flare as positive marker
AND
- Measure size of wheal to determine whether they are sensitised to that allergen
There are several tests that can be conducted to test for eosinophilia.
What are the main 3?
- Blood eosinophil count when stable (not during asthma attack):
> /=300 cells/mcl is ABNORMAL
- Induced sputum eosinophil count: >/=2.5% eosinophils is ABNORMAL (see bilobar nucleus)
- Exhaled nitric oxide
- Breath test
- Being used more and more
- Recommended as diagnostic test
What significance does FeNO have in asthma?
A non-invasive biomarker of airway (type 2) inflammation
This reaction occurs in asthma
Exhaled nitric oxide (FeNO) is routinely used for 3 main purposes concerning asthma.
What are these 3 purposes?
- Aid diagnosis
- Predicting steroid response
- Measuring adherence to ICS
Exhaled nitric oxide (FeNO) is routinely used for 3 main purposes concerning asthma.
What supports an asthma diagnosis?
Elevated FeNO
Provided patient is not on treatment with steroids
Exhaled nitric oxide (FeNO) is routinely used for diagnosis of asthma.
Why?
Fractional concentration of exhaled FeNO is a method for measuring airway inflammation
= an indirect marker of T2-high eosinophilic airway inflammation in asthma
Method =
- Quantitative
- Non-invasive
- Safe
What is FeNO an indirect marker of?
An indirect marker of T2-high eosinophilic airway inflammation in asthma
Exhaled nitric oxide (FeNO) is routinely used for diagnosis of asthma.
What are the main advantages of this test?
Fractional concentration of exhaled FeNO:
- Quantitative method
- Non-invasive method
- Safe method
- Both children and adults can do test
- Incentive device can be used to help them do measurement correctly
Exhaled nitric oxide (FeNO) is routinely used in clinic.
What are the 3 main roles of exhaled nitric oxide concerning asthma?
- Aiding asthma diagnosis
- Predicting steroid responsiveness
- Assessing adherence to ICS
FeNO is very sensitive to steroids.
What might a “sky-high” exhaled reading suggest?
Probably suggests that patient hasn’t been taking treatment
A “sky-high” exhaled reading of FeNO might suggest that a patient has not been taking their treatment for asthma.
Why is this?
FeNO is very sensitive to steroids
A single non-invasive biomarker does not reflect airway eosinophilic
inflammation.
What 3 requirement need to be met for a definite diagnosis of asthma?
- Symptoms
- Characteristic lung function of asthma
- Combination of blood or airway eosinophils AND exhaled nitric oxide (probably)
What are the clinical guidelines for NICE asthma diagnosis concerning clinical assessment of asthma?
- History & examination
- Assess/confirm wheeze when acutely unwell
What are the clinical guidelines for NICE asthma diagnosis in regards to objective tests for asthma?
[3]
- Airway obstruction on spirometry - FEV1/FVC ratio <0.7
- Reversible airway obstruction - Bronchodilator reversibility >/= 12%
- Exhaled nitric oxide (FeNO) >35ppb (children), >40ppb (adults)
What is the suggested order of tests for diagnosis of asthma in children and young people outlined in the NICE clinical guidelines?
- Spirometry - if symptoms of asthma
- Consider BDR test if spirometry shows obstruction
- If diagnostic uncertainty remains after spirometry and BDR, consider FeNO
- If diagnosis uncertainty remains after FeNO, monitor peak flow variability for 2 to 4 weeks
What is needed for diagnosis of asthma in children and young people (ages 5-16) according to NICE guidelines?
- Symptoms suggestive of asthma
AND
- FeNO level - 35ppb or more and positive peak flow variability
OR
- Obstructive spirometry + positive bronchodilator reversibility
How many positive tests do NICE guidelines suggest are needed for a diagnosis of asthma?
At least 2
What are the 3 main categories of treatment in asthma management?
- Reduce airway eosinophilic inflammation
- Acute symptomatic relief
- Treatment of severe asthma - steroid sparing therapies
What maintenance therapy is prescribed for all asthma patients, regardless of the severity of their illness?
Inhaled corticosteroids (ICS)
Leukotriene receptor antagonists
What is the target of the maintenance therapy prescribed for all asthma patients?
Maintenance therapy (involves preventer treatments)
What therapies are used to reduce airway eosinophilic inflammation in asthma management?
Inhaled corticosteroids
What purpose do inhaled corticosteroids have in asthma management?
Preventer treatment
- Target and reduce eosinophilic airway inflammation
- Reduce baseline bronchoconstriction
What purpose do leukotriene receptor antagonists have in asthma management?
Reduce type II inflammation
What therapies are there for acute symptomatic relief in asthma management?
- Beta-2 agonists
- Anticholinergic therapies
When might a patient with asthma use a beta-2 agonist?
For acute symptomatic relief - if they suddenly develop symptoms
When might a patient with asthma use anti-cholinergic therapy?
For acute symptomatic relief - if they suddenly develop symptoms
What purpose do beta-2 agonists have in asthma management?
They are bronchodilators
Aid smooth muscle relaxation
For acute symptomatic relief - if they suddenly develop symptoms
What purpose do anti-cholinergic therapies have in asthma management?
They are bronchodilators
Aid smooth muscle relaxation
For acute symptomatic relief - if they suddenly develop symptoms
Beta-2 agonists and anti-cholinergic therapies can be used for acute symptomatic relief of asthma.
These therapies should not be used regularly.
Why?
This would be dangerous
To just have bronchodilators without an anti-inflammatory could result in asthma death
Therefore, must minimise background airway inflammation (with maintenance therapy) all the time
What type of therapies are used in the management of severe asthma?
Steroid sparing therapies
When might steroid sparing therapies be used to manage asthma?
To treat severe asthma - asthma that’s not responding to basic treatments
If not responding to ICS despite increasing dose + are adhering to treatment = severe asthma
Biologics (steroid sparing therapies) reduce exacerbations and reduce attacks; these things contribute to asthma mortality
Give an example of steroid sparing therapies that might be prescribed to help manage severe asthma.
Biologic targeted to IgE
- Anti-IgE antibody
Biologics targeted to airway eosinophils
- Anti-interleukin-5 antibody
- Anti-interleukin-5 receptor antibody
What interleukin can biologics target in order to help decrease airway eosinophils?
Il-5
What is the mechanism of action of corticosteroids in asthma management?
Target and reduce type 2 inflammation
Primary function:
- reduce eosinophil number by promoting apoptosis
- reduce Type 2 mediators released by Th2 cells (e.g. reduce IL-5)
- reduce mast cell number
- some evidence that steroids can also impact structural cells and can help deal with the airway remodelling that develops in asthma pathophysiology
What are the most important aspects of asthma management?
Optimal device and technique - does patient know best technique?
Clear asthma management plan - what to do when feeling well and are taking daily treatments; what to do with symptom onset.
Adherence to ICS - preventer treatment
(Before escalating to biologics for treatment of severe asthma, important to make sure these bases are covered first)
Why might patients with asthma not use their inhaler everyday?
Most days, they’ll feel completely fine
If not feeling symptoms, might not feel they need to take maintenance therapy (ICS)
A patient with asthma seems to not be responding to the basic treatments.
What must you check before escalating to biologics (used in the treatment of severe asthma)?
Must check that they are adhering to their inhaled corticosteroids and taking as they should (maintenance therapy)
Check that they have optimal device and technique
Check understanding of asthma management plan
What can be used to objectively assess adherence to asthma ICS therapy?
Electronic adherence monitoring device
What is the purpose of electronic adherence monitoring in asthma management?
Attached to corticosteroid inhaler to help objectively assess adherence
(records date and number of doses)
The British Thoracic Society have published guidelines containing an algorithm for asthma management.
What are the 4 main stages of asthma therapies?
- Regular preventer
- Initial add-on therapy
- Additional controller therapies
- Specialist therapies
The British Thoracic Society have published guidelines containing an algorithm for asthma management.
What are the 6 aspects that are evaluated in a patient with diagnosed aspect?
1,2,3. Assess symptoms; Measure lung function; Check inhaler technique and adherence
- Adjust dose
- Update self-management plan
- Move up and down as appropriate
The British Thoracic Society have published guidelines containing an algorithm for asthma management.
The clinician is instructed to move up and down the algorithm (in terms of strength of treatment) as needed.
Why might a clinical move up the algorithm?
To improve control as needed
If using 3+ doses of SABA a week
If not responding to basic treatments
The British Thoracic Society have published guidelines containing an algorithm for asthma management.
The clinician is instructed to move up and down the algorithm (in terms of strength of treatment) as needed.
Why might a clinical move down the algorithm?
To find and maintain the lowest controlling therapy
Asthma deaths still occur in the UK.
How might asthma mortality (death) relate to maintenance therapy adherence?
If not taking maintenance therapy and then get cold or sudden allergen exposure, could result in a severe attack which can be fatal
In asthma, death occurs due to asthma attacks
What must we seek to prevent in order to reduce asthma mortality?
Asthma attacks
Asthma attacks can also be called acute lung attacks.
“Exacerbation” is another term that has been used to mean asthma attacks.
Why are we now moving away from the term “exacerbation” to describe asthma attacks?
Moving away from term “exacerbation” to try and get people to understand the severity and seriousness of asthma “attacks”
Describe the pathogenesis of an acute lung attack in asthma.
Background exposure to allergens (e.g. house dust)
On top of that, there are several other exacerbating factors (e.g. infection with a virus, bad day of pollution, tobacco smoke)
These factors can come together and culminate in a significant final event = asthma attack
Resulting in various responses:
- eosinophilia –> eosinophilic airway inflammation
- reduced anti-viral responses
- reduced peak expiratory flow)
People with asthma are affected by background exposure to allergens. There are also exposed to other factors that can contribute to acute lung attacks.
Name 3.
Pathogens (virus +/- bacteria)
Pollution
Tobacco smoke
Describe the 3 main responses that occur as a result of an asthma attack.
- If infection is the predominant precipitant of an asthma attack:
INF-a, B + y reduce
Reduced anti-viral responses + increased viral replication results in a prolonged illness
- Eosinophilia
Increased airway eosinophilic inflammation (responsive to corticosteroids)
- Reduced peak expiratory flow rate + increased airway obstruction (background airway obstruction significantly exacerbated during an attack) resulting in acute wheeze
Responsive to bronchodilators
Describe the 3 main responses that occur as a result of an asthma attack.
- If infection is the predominant precipitant of an asthma attack:
INF-a, B + y reduce
Reduced anti-viral responses + increased viral replication results in a prolonged illness
- Eosinophilia
Increased airway eosinophilic inflammation (responsive to corticosteroids)
- Reduced peak expiratory flow rate + increased airway obstruction (background airway obstruction significantly exacerbated during an attack) resulting in acute wheeze
Responsive to bronchodilators
- How are anti-viral responses impacted during an asthma attack?
- How does this affect illness?
- Reduced anti-viral responses (reduced IFN-a,B+y)
2. As there’s a reduced anti-viral response and increased viral replication —-> prolonged illness
How does eosinophil number change during an asthma attack?
Eosinophilia —-> increased airway eosinophilic inflammation
- What happens to peak expiratory flow during an asthma attack?
- What does this result in?
- Reduced peak expiratory flow rate
2. Reduced PEFR + increased airway obstruction resulting in acute wheeze
- How do the corticosteroids used in asthma attacks differ to those used routinely as maintenance therapy in asthma?
- What is the reason for this difference?
1.
- How do the corticosteroids used in asthma attacks differ to those used routinely as maintenance therapy in asthma?
- What is the reason for this difference?
- Treat acute attacks with systemic high dose steroids, usually prednisolone
- ICS used as maintenance therapy in asthma isn’t enough to dampen inflammatory airways in an acute attack
Humanised anti-IgE monoclonal antibody is a biologic used in the treatment of severe asthma.
What is its mechanism of action?
Binds and captures circulating IgE
To prevent interaction with mast cells and basophils to stop allergic cascade during acute allergen exposure
Humanised anti-IgE monoclonal antibody is a biologic used in the treatment of severe asthma.
IgE production can decrease with time when patients are given anti-IgE Ab.
What is the implication of this?
Reduction in serum IgE over time means the therapy may not need to be used indefinitely
However, no evidence yet (Nov ‘21) that stopping anti-IgE Ab after some time is a long-term solution
Studies have shown that symptoms return a few months after stopping treatment
The treatments that currently exist for asthma manage/control symptoms. They’re not disease-modifying treatments.
True or False?
True
What type of drug is Omalizumab?
Monoclonal antibody
Anti-IgE antibody
What can Omalizumab be used to treat?
Severe (allergic) asthma
Nasal polyps
Urticaria (hives)
What is the criteria for prescribing Omalizumab to a patient who has severe asthma?
Severe, persistent allergic (IgE-mediated) asthma in patients >/= 6yo who need continuous or frequent treatment with oral corticosteroids
4+ courses of oral corticosteroids in previous year
Optimised standard therapy
Documental compliance (and still not responding to treatment despite good adherence)
What is the total serum IgE level for which Omalizumab can be prescribed in the treatment of severe asthma?
30-15000
For Omalizumab to prescribed in the treatment of severe asthma, total serum IgE levels must be between 30-1500.
What is the implication of this?
[Disadvantage of Omalizumab]
Very fixed and tight serum IgE level for which Omalizumab can be prescribed
Problem because many patients have IgE level that’s outside of this specified range —-> ~2/3 patients not eligible for it
Omalizumab can be used in the treatment of severe asthma.
What is its dosing based on?
Weight and serum
Omalizumab can be used in the treatment of severe asthma.
How is it administered?
2-4 weekly s/c injections
Compare the cost of Omalizumab: Min 75mg 4 weekly s/c injections vs Max 600mg 2 weekly s/c injections.
Min 75mg 4 weekly s/c injections = £1,655/patient /year
Max 600mg 2 weekly s/c injections = £26,640/patient/year
Omalizumab can be used in the treatment of severe asthma.
How is improvement of asthma management tracked?
Main output/improvement is in reduction of asthma attacks
What type of drug is Mepolizumab?
Monoclonal antibody
Anti-IL5-antibody
Licensed for adults and children >/= 6yo
What is Mepolizumab used to treat?
Severe eosinophilic asthma
Mepolizumab can be used in the treatment of severe asthma.
What is its mechanism of action?
Binds IL-5
Prevents IL-5 binding IL-5Ra receptor
IL-5 regulates growth, recruitment, activation and eosinophil survival
What are the current UK for recommendations for prescribing Mepolizumab to treat severe asthma?
Severe eosinophilic asthma
Blood eosinophils >/= 300 cells/mcl in the last 12 months (with previous asthma diagnosis)
Min. 4 exacerbations requiring oral steroids in the last 12 months
Trial for 23 months - 50% reduction in attacks, then continue
What is an RDBPC trial?
Randomised Double Blind Placebo Controlled Trial
What is the biggest set of data that we have for the efficacy of Mepolizumab?
The DREAM trial
A multi-centre RDBPC trial held across 81 centes in 13 countries
The “DREAM trial” is the biggest set of data that we have for the efficacy of Mepolizumab.
What were the criteria for patient admittance into this trial?
Patients aged 12-74yo
Diagnosis of severe/refractory asthma (high dose ICS)
> /= 2 exacerbations in previous year
Sputum eosinophils >3% or FeNO >50ppb or blood eosinophils >/= 0.3x10^9/ml
Mepolizumab can be used in the treatment of severe asthma.
How is improvement of asthma management tracked?
Reduction in asthma attacks (exacerbations)
The lowest dose of Mepolizumab is used in the treatment of severe asthma.
Why is this?
Study shows clinically significant exacerbations reduced with Mepolizumab in asthma.
Not really dependent on dose so use lowest dose (75mg)
