Cystic Fibrosis vs Asthma — Clinical Trial Comparison
Cystic Fibrosis
Genetic disorder causing thick mucus in lungs and organs
Asthma
Reversible airway inflammation and bronchoconstriction
Cystic fibrosis and asthma are both significant respiratory conditions, but they represent fundamentally different disease mechanisms. CF is a genetic disorder causing progressive lung damage through thick mucus accumulation, while asthma is an inflammatory condition with reversible airway narrowing. The CF trial landscape has been transformed by CFTR modulator drugs, while asthma trials focus on biologics targeting specific inflammatory pathways.
Key Differences at a Glance
| Feature | Cystic Fibrosis | Asthma |
|---|---|---|
| Primary mechanism | CFTR gene mutation → thick mucus, chronic infection | Type 2 inflammation → airway hyperresponsiveness |
| Genetic basis | Autosomal recessive (CFTR mutations) | Complex polygenic + environmental triggers |
| Key symptom | Chronic productive cough, recurrent infections, malabsorption | Wheeze, breathlessness, chest tightness, cough |
| Diagnostic test | Sweat chloride test + genetic testing | Spirometry with reversibility, FeNO, peak flow |
| UK prevalence | ~11,000 people (rare disease) | ~5.4 million people (1 in 12 adults) |
| NICE first-line | CFTR modulators (if eligible), physiotherapy, antibiotics | Inhaled corticosteroids + bronchodilators |
Clinical Trial Availability
| Trial Aspect | Cystic Fibrosis | Asthma |
|---|---|---|
| UK trials actively recruiting | 25–40 studies | 40–60 studies |
| Most common trial phase | Phase 2–3 | Phase 2–3 |
| Top interventions tested | Next-gen CFTR modulators, gene therapy, anti-infectives, mucus modifiers | Biologics (anti-IL-5, anti-IgE), bronchial thermoplasty, inhaled formulations |
| Gene therapy trials | Active — viral vector and mRNA approaches | Not applicable (no single gene cause) |
| Paediatric vs adult | Both — paediatric significant due to early onset | Both — adult and paediatric cohorts |
| Cure-focused research | Major focus (gene editing, CFTR modulators for all mutations) | Management-focused (no cure concept) |
Exciting Emerging Treatments
Cystic Fibrosis Trials
- Next-generation CFTR modulators — targeting rare mutations not covered by current drugs
- Gene therapy and editing — CRISPR and viral vector approaches to correct CFTR
- mRNA therapy — delivering functional CFTR instructions to lung cells
- Anti-infective innovations — tackling chronic Pseudomonas and Burkholderia infections
- Mucus-modifying agents — new approaches to thinning and clearing thick secretions
- Organoid-based personalised medicine — testing treatments on patient-derived intestinal organoids
Asthma Trials
- Novel biologics — next-gen anti-IL-5, anti-TSLP, and anti-IL-4Rα for severe asthma
- Bronchial thermoplasty refinements — improved patient selection and delivery
- Type 2-low asthma treatments — targeting neutrophilic and non-eosinophilic phenotypes
- Smart inhaler technology — connected devices with adherence monitoring and dose optimisation
- Microbiome-based therapies — airway and gut microbiome modulation for asthma control
- Precision asthma medicine — biomarker-driven treatment selection (FeNO, eosinophils, periostin)
💡 CFTR modulators have transformed CF care — but not everyone benefits yet
Drugs like Kaftrio (elexacaftor/tezacaftor/ivacaftor) have been revolutionary for many CF patients, improving lung function and quality of life dramatically. However, they don't work for all CFTR mutations, and long-term effects are still being studied. Clinical trials are actively working on solutions for patients with rare mutations who don't respond to current modulators.
Eligibility Differences
Cystic Fibrosis Trial Criteria
- Confirmed CF diagnosis with identified CFTR mutations
- Specific mutation groups may be required for CFTR modulator trials
- Lung function thresholds common (FEV1 % predicted ranges)
- Recent exacerbation history and colonisation status (e.g., Pseudomonas-positive)
- Current CFTR modulator use may determine eligibility (naïve vs switching trials)
- Pancreatic insufficiency status and BMI may be stratification factors
Asthma Trial Criteria
- Confirmed asthma diagnosis with objective evidence (spirometry reversibility ≥ 12%)
- Severity classification: mild, moderate, severe (many trials require severe)
- Eosinophilic phenotype required for many biologic trials (blood eosinophils ≥ 150–300/μL)
- Inhaled corticosteroid dose and adherence documentation
- Exacerbation history commonly required (≥ 2 in past year for severe asthma trials)
- Smoking history — current smokers often excluded; pack-year limits apply
🫁 Cystic Fibrosis Trials
Find actively recruiting cystic fibrosis clinical trials across the UK
View Cystic Fibrosis Trials