Chronic Refractory Cough

Chronic Refractory Cough can be a severely debilitating condition that is thought to affect up to 1 in 10 people globally. Sufferers report that it has a devastating impact on their daily lives, affecting their relationships, careers and ability to participate in social activities. In some cases, the severity of the cough can also lead to patients suffering internal damage. There is a huge unmet medical need when it comes to treating this condition.

Study Overview

Illingworth Research Group worked as the partner on a chronic refractory cough programme including 5 studies over a 2-year period providing multiple services, including the identification, set-up and management of the UK sites. The programme included a phase I study, 2 cough challenge studies, 2 phase II trials and involved 13 sites in the UK with another 37 sites across the USA.

For the larger phase II study the UK made a significant contribution to recruitment and really helped drive the study to come in on time after a slow start in the US. The UK recruited 35% of the total study population in just 4 months and the screen-fail rate was also considerably lower. In the UK, these studies were performed by specialised, regional cough centres. Illingworth Research has close links with many specialised cough centres and also know the best enrolling sites in the US.

Screen Fail Rate


Enrollment Rate


The average patient enrollment rate across the US was 0.56 patients per site per month whereas the UK sites recruited 88 patients with an average of 2.2 patients per site per month. Meaning the UK recruited patients almost 4x as quickly as the US sites with Illingworth's support. 

Specialist Cough Team

The Illingworth specialist cough team are available to work on other trials. All members of this specialist team have extensive industry experience and experience of working with a range of cough monitoring systems, specifically the market leading monitor.

Additionally, we have conducted cough studies involving the inhalation of tussive agents/substances such as ATP, Capsaicin, Citric Acid and Distilled Water. These substances were inhaled via a nebulizer, controlled by the KoKo DigiDoser and the number of induced cough counted.

“I would consider Illingworth Research experts in this indication and they have established strong relationships with key investigators. They have been a true partner with open, honest communication, exhibiting a high degree of professionalism and flexibility.”

Quote from Sponsor

“Thank you and what a great job Illingworth did for this study!”

Prof Surinder S Birring

Consultant Respiratory Physician and Honorary Senior Lecturer, Kings College Hospital, London