A/Prof David Langton

Evidence that bronchial thermoplasty can reverse airway remodelling is now ‘pretty strong’, with a recent randomised controlled trial showing significant effects in six month follow-up, the TSANZ 2023 ASM has heard.

Promoted as the ‘new frontier’ in severe asthma, bronchial thermoplasty has sparked heated debate at previous TSANZ meetings, mostly involving questions around the research backing the therapy. At the 2017 ASM, one delegate even went so far as to claim the technique had been devised simply to “give respiratory physicians a procedure to do”.

But significant results in a number of recent studies mean the science is now a lot closer to settled, Associate Professor David Langton of Peninsula Health in Melbourne told this year’s conference.

The founder of the Australian Bronchial Thermoplasty Register, who is currently undertaking a PhD on the subject, pointed to a trial from the Netherlands published in 2021 (link here) which he said left “no doubt” of an effect.

The trial involved 20 Dutch patients who received bronchial thermoplasty and a control arm of the same number who received the procedure at a later stage.

Subsequent biopsies showed “significant reduction in the airway muscle and no change in the control,” according to  A/Prof Langton.

“We can conclude from this that there is no doubt that bronchial thermoplasty does reduce airway smooth muscle,” he said.

A/Prof Langton went on to outline one of his own studies, where his team used CT scans to examine the effects of thermoplasty performed on each lung independently.

By counting the number of air-containing pixels on the CT scan, the researchers measured a roughly 50% increase in airway volume, both immediately following the procedure and after 12 months.

“So this confirms that our therapy is indeed improving airway volume, which is what we are hoping to achieve,” he told the conference.

“And that improvement in airway volume corresponded to a progressive improvement in patients’ symptoms as measured by the asthma control questionnaire.”

More evidence

Other studies had come out suggesting the therapy improved regional ventilation, while a 10-year follow-up of 200 patients who had participated in  earlier trials had shown persistent improvements, he said (more details here).

“And to summarise the registry data, we’d be perfectly happy to say that bronchial thermoplasty improves symptoms, exacerbations, steroid use, reliever medication use but is not so certain about spirometry.”

In addition, there was optimism that other novel techniques in various stages of development may also have an effect on airway remodelling, Professor Langton said.

These included targeted lung denervation, which used heat to target the cholinergic fibers on the outside of the airway. Early studies had been promising and researchers were now attempting to recruit 500 patients for a much larger trial, he said.

Another technique was bronchial rheoplasty. A treatment for chronic bronchitis, this used an electric field with an aim to ablate goblet cell hyperplasia and allow mucosal regeneration with healthy epithelium.

Evidence for this method was “fairly weak” so far, although a much larger trial involving over 250 patients was now underway in Europe, Professor Langton said.