Measuring What Matters: How VitaloJAK® turned objective cough frequency into a powerful digital biomarker in cystic fibrosis trials

Background

Chronic cough is a hallmark symptom of cystic fibrosis (CF), reflecting mucus retention, airway inflammation, and disease activity. Cough frequency can exceed several hundred events per day and is associated with reduced quality of life, impaired physical activity, and sleep disturbance. Despite its clinical importance, cough has historically been difficult to quantify objectively in clinical trials, limiting its use as a robust endpoint.

Wearable digital health technologies now enable continuous, real-world assessment of cough, offering the potential to capture clinically meaningful treatment effects beyond conventional lung function measures. (Braeckel et al, 2026)

Clinical Context

The VitaloJAK® Cough Monitor (Vitalograph, UK) was deployed in a multicentre, phase 3b, open-label clinical study (VX‑445–126) evaluating the effects of elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) in adolescents and adults with cystic fibrosis who were previously CFTR‑modulator naïve.

The study followed an initial pilot feasibility study (VX‑445–118), which specifically assessed adherence and usability of wearable cough and activity monitoring technologies in people with CF.

About the VitaloJAK Cough Monitoring System

The VitaloJAK Cough Monitoring System offers a robust and objective method for measuring cough in clinical environments. Its primary component is a wearable device, designed to continuously capture audio signals of coughs from study participants. These audio recordings are then uploaded to a dedicated study portal, facilitating subsequent analysis.

The device incorporates a dual sensor setup, combining an adhesive chest sensor with an air microphone. This configuration ensures exceptional accuracy by recording every cough event. By cross-referencing the signals from both sensors, human annotators are able to distinguish the participant’s coughs from those of others in the vicinity, ensuring that only the relevant coughs are counted.

Once the audio data is uploaded, a validated trimming algorithm is employed to remove extraneous sounds that are not related to coughing. This automated step retains only the pertinent cough events. Following this, human annotators meticulously review and verify the cough events within a secure, controlled environment, upholding the data’s integrity and reliability.

Throughout the workflow, stringent quality assurance procedures are applied to maintain the accuracy of the cough data. These measures support the acceptability of the results by regulatory bodies. The VitaloJAK system’s utility and reliability is well established, having been used extensively to provide objective cough measurement in more than fifty commercial clinical trials.

Use of VitaloJAK in the Trial

• The VitaloJAK Cough Monitor was used as an ambulatory cough monitoring system.

• Participants wore the device continuously for 24 hours, once per week, across baseline and treatment periods

• Cough frequency (cough events per day) captured by VitaloJAK formed the primary endpoint of the phase 3b study

• Data collection occurred in a decentralised, real‑world setting, including remote participation and telemedicine visits

This study design demonstrates that VitaloJAK can be integrated into both traditional and decentralised clinical trial models without compromising data capture or participant compliance.

Utility: Feasibility, Adherence, and Endpoint Selection

High compliance
Use of VitaloJAK was associated with consistently high adherence:

• Mean compliance with the cough monitoring device was 94.3% (SD 10.5) over the course of the phase 3b study

• Compliance was sustained across baseline and treatment periods and was superior to the preceding pilot study

This confirmed that people with CF are able and willing to use chest‑worn cough monitoring technology over extended periods, even when deployed remotely.

Clinically relevant endpoint
Cough frequency was selected as the primary efficacy endpoint, highlighting recognition by investigators and sponsors of cough as a meaningful measure of symptomatic and functional disease burden in CF. The VitaloJAK device enabled objective, quantitative assessment of this endpoint, overcoming limitations of symptom diaries or patient recall.

Performance: Sensitivity to Treatment Effects

The VitaloJAK Cough Monitor demonstrated high sensitivity to treatment‑related change.

Key findings include:

• 91.7% reduction in daily cough frequency from baseline after initiation of ELX/TEZ/IVA

• Reduction observed between baseline (geometric mean 241.3 coughs/day) and weeks 8–12 (20.3 coughs/day)

• Narrow confidence intervals (95% CI 89.2%–93.6%) indicate precise estimation of treatment effect

These results show that VitaloJAK captured a large, sustained, and clinically meaningful reduction in cough, consistent with cough frequency approaching levels reported in healthy adults.

Importantly, cough reduction measured by VitaloJAK paralleled improvements in:

• Daily physical activity (increased step count and moderate‑to‑vigorous activity)

• Patient‑reported vitality and physical functioning

• Perceived sleep quality

This alignment supports the construct validity of cough frequency as measured by VitaloJAK as a marker of overall health improvement in CF.

Added Value of VitaloJAK

• Objective, quantitative cough measurement suitable for primary endpoints

• High patient adherence in adolescent and adult CF populations

• Compatibility with decentralised and hybrid study designs

• High sensitivity to therapeutic effects, even over relatively short study durations

• Clinical relevance, with outputs that correlate strongly with functional and quality‑of‑life outcomes

Conclusion

In the VX‑445–126 study, the VitaloJAK® cough monitoring sytem proved to be a robust, feasible, and highly sensitive digital biomarker platform for quantifying cough in cystic fibrosis. Its use enabled objective demonstration of substantial and clinically meaningful reductions in cough frequency following highly effective CFTR modulator therapy.

These findings demonstrate VitaloJAK as a valuable tool to collect objective cough data for:

• Interventional clinical trials

• Evaluation of symptomatic treatment effects

• Studies prioritising patient‑centred and functional endpoints

• Real‑world evidence generation

Reference:

• Eva Van Braeckel et al., 2026. “Effects of Elexacaftor/Tezacaftor/Ivacaftor on cough frequency, physical activity patterns, and sleep quality in adolescents and adults with cystic fibrosis” Journal of Cystic Fibrosis, https://doi.org/10.1016/j.jcf.2026.03.016