A Focus on Improving Inhaler Technique in Clinical Trials

Inhaled therapies are foundational in managing many conditions including asthma and COPD. Their appeal in drug development lies in targeted delivery to the lungs, rapid onset of action, and reduced systemic exposure compared with oral or injectable routes. However, the effectiveness of inhaled treatments is uniquely dependent on how well patients use their inhaler device [1].

If clinical trial participants do not inhale correctly, the amount of drug reaching the lungs can be unpredictable. In a clinical trial, this introduces a behavioural variable that can affect results, inflate variability, and distort true efficacy. As the volume of inhaled therapy trials continues to grow, the need to manage this variable becomes more critical.

Clinical Trial Growth in Inhaled Therapies

Clinical trial data from the past decade shows a clear increase in studies investigating inhaled interventions [3].

Over a 10 year span, inhaled therapy trial activity has increased by over 40 percent [3]. Peaks in 2020 and 2021 align with broader respiratory research investment and the emergence of novel inhaled therapeutics. While there is natural fluctuation year-to-year, the overall trend remains strong. Studies of inhaled drugs have greater inherent variability due to being tied to a user dependent delivery mechanism.

The Consequence of Technique Errors on Trial Data

Incorrect inhaler use introduces variability that cannot be confined by randomisation or statistical adjustment alone.

1. Reduced efficacy signals

If participants are not inhaling correctly, the drug’s effect is diluted. An investigational product may be disadvantaged not because it lacks pharmacologic activity, but because it is not being delivered consistently.

2. Increased variability

Technique introduces two types of variability:

• Inter‑subject variability, where different participants inhale differently

• Intra‑subject variability, where a participant’s technique fluctuates over time

Both forms reduce statistical power, require larger sample sizes to detect effects, and increase the risk of false negative findings.

Evidence [6] linked critical inhaler errors with worse clinical outcomes and reduced effectiveness, underscoring that technique is not just a procedural detail but a key determinant of trial success.

3. Compromised dose–response interpretation

Difficulty in establishing a clear dose–response relationship is often tied to inconsistent drug deposition rather than true pharmacology [5]. This complicates key regulatory and development decisions.

The Role of the Vitalograph Aerosol Inhalation Monitor (AIM)

The Aerosol Inhalation Monitor (AIM™) from Vitalograph®, is a dedicated tool used in the clinic to train and assess inhaler technique for both DPIs and MDIs. This is the only solution that verifies that the patient’s inhaler technique meets the inhaler manufacturer’s requirements to ensure that medication has been appropriately deposited in the lungs for therapeutic effectiveness.

The AIM is used for pre-screening and monitoring inhalation technique throughout the study. During a training session, the participant inhales using the AIM device. Site staff receive instant results that classify technique performance as good, poor, or fail, and identify specific technique errors.

Training then continues until the participant demonstrates correct technique. This ensures competence. The AIM is used in the controlled environment of the clinic. It does not depend on remote over-reading, third party scoring, or post-hoc interpretation. The outcome is determined at the point of care. Once successful, participants use their inhalers independently at home.

The system provides straightforward results that site staff can document and act on and gives sponsors confidence in patient data relating to the efficacy of inhaled treatments.

Centralised Data

Once a participant completes an AIM training session, data is stored in a centralised database, within the Vitalograph Spirotrac® 6 software. From there, it can be transmitted to a central study-specific web portal.  The data can then be reported on and be part of a study dataset.

Each participant’s technique history is recorded. Sponsors and study teams can track performance over time, identify participants with repeated errors, and organise follow-up training based on objective data.

Site staff can generate inhaler training reports. Aggregating technique data across sites allows teams to monitor trends, identify site level training variability, and deploy corrective measures where needed.

What Causes Technique Errors

The reasons for incorrect usage are multifactorial:

Impact on Study Conduct

The operational burden of repeat technique training includes:

• Extended site visit times

• Increased demands on clinical staff

• Repeated demonstration and observation

• Costs associated with retraining

These demands affect timelines and budgets, and when technique fails to improve, participant confidence and engagement can decline.

Measurable Gains from Correct Technique

Correct inhaler use offers measurable improvements for clinical trials including:

How Structured Inhaler Training Can Help

Given the demonstrated impact of technique errors, clinical trial sponsors increasingly include structured inhaler training within protocol design.

Traditional approaches have relied on verbal instruction, printed materials, and occasional observation. These methods are subjective and uneven, leading to incomplete mastery and technique regression.

A structured, technology enabled approach enables training outcomes to be objectively measured and documented.

Operational Value for Sponsors

Integrating structured inhaler training with centralised data capture delivers operational benefits:

Reconsidering Inhaler Training in Protocol Design

Given the evidence and operational impact, sponsors should consider inhaler training not as an ad-hoc procedure, but as an integral endpoint within the visit schedule,  supporting interpretation of results and reducing the impact of variable technique on data quality.

Selecting structured, measurable training methods ensures that the variability introduced by technique is understood, documented, and managed. By embedding this into trial design, sponsors improve the likelihood that observed outcomes reflect the drug’s true pharmacology, not user behaviour.

Conclusion

Inhaler technique is a behavioural variable with measurable impact on clinical trial performance. Incorrect use is common, persistent, and linked to worse outcomes. In trials, unmonitored technique introduces variability, weakens endpoints, and risks misinterpretation.

Structured inhaler training using tools like the Vitalograph AIM offers a scalable, objective method to ensure participants demonstrate correct use. When systems are integrated for centralised data capture and reporting, inhaler technique becomes a measurable component of trial execution.

This approach reduces variability, improves data quality, and strengthens confidence in trial outcomes. As inhaled therapy development continues to grow, so too does the importance of managing the variables that influence its success.

References

1.      Chrystyn H, van der Palen J, Sharma R, et al. Device errors in asthma and COPD. NPJ Primary Care Respiratory Medicine. 2017;27:22.

2.      d’Ancona G, Weinman J. Improving adherence in chronic airways disease. Breathe. 2021;17(2):210022.

3.      GlobalData. Clinical Trials Investigating Inhaled Therapies by Start Year (2017–2026). GlobalData report; 2026.

4.      Marko M, Pawliczak R. Inhalation technique related errors after education among asthma and COPD patients using different types of inhalers. NPJ Primary Care Respiratory Medicine. 2025.

5.      Perumal R, et al. Inhaler technique errors in asthma and COPD patients. International Journal of COPD. 2020;15:1779–1788.

6.      Roche N, Aggarwal B, Boucot I, et al. Impact of inhaler technique on clinical outcomes. Respiratory Medicine. 2022;193:106713.