respiratory
COPD

Pivotal findings for endobronchial valves


Patients with severe emphysema treated with endobronchial valves (EBV) have been shown to have improved lung function, exercise tolerance and quality of life one year following their procedure.

However it comes with a pneumothorax rate of 26.6%.

The LIBERATE trial, the largest and longest study of the procedure, was presented at the ATS 2018 and published simultaneously in the American Journal of Respiratory and Critical Care Medicine.

The international study randomised 190 patients from 24 sites to either Zephyr EBVs delivered to occlude all bronchi of the targeted lobe, or standard medical care. Target lobar volume reduction of ≥350mL was achieved in 84.2% of EBV patients. A median of four valves were implanted into each patient either with general anaesthesia or conscious sedation.

At 12 months, 47.7% of patients in the EBV group had achieved a ≥15% increase in post-bronchodilator FEV1 compared to 16.8% in the standard of care group.

Secondary endpoints, including an absolute change in post-bronchodilator test (BD) FEV1 from baseline, Six-Minute Walk Distance and the St. George’s Respiratory Questionnaire (SGRQ), all favoured the EBV treatment. All benefits were evident at 45 days and maintained out to at least 12 months.

Principal investigator Dr Gerard Criner, from Temple University in Philadelphia, defended the rate of pneumothorax.

Five deaths occurred in the EBV group – four either probably or definitely related to pneumothorax – compared to one death in the control group.

“If you divide the follow-up into two epochs – the periprocedural period [first 45 days] where you see the spike of morbidity and mortality versus the longer epoch [12 months] – you can see the mortality periprocedural is higher than it is for standard of care but as you follow patients over a longer period of time from the procedure, people that benefit as with lung reduction have a mortality benefit.”

“You can see the exacerbation risk goes down, the incidence of respiratory failure goes down and the numbers of deaths [in the longer term period] are the same but the rate is higher because the standard of care group was smaller.”

“If you follow this patient group out longer and get larger numbers, we would expect based on prior data with lung reduction that you could improve survival.”

Dr Criner told the limbic the rate of pneumothorax with EBV was also less than would be expected for patients undergoing lung volume reduction surgery.

“You need to make sure that people know pneumothorax can occur and how to treat it appropriately,” he said.

Appropriate patient and lobe selection was also critical to help prevent pneumothorax, as was a minimum three-day stay in hospital for timely management during the highest risk period, he added.

Endobronchial valves are approved in most countries in Europe and Asia including Australia but not in the US. Dr Criner said LIBERATE was expected to be the pivotal study for US consideration.

The study was sponsored and funded by the valve manufacturer Pulmonx Corporation.