Best Practices for Respiratory Testing in ALS Clinical Trials

August 30, 2021

Amyotrophic Lateral Sclerosis (ALS) patients experience a progressive loss of functioning in the brain and spinal cord, leaving many with respiratory failure. In clinical trials, forced vital capacity (FVC) is a key biomarker of ALS’s impact on respiratory muscles, as a decrease in FVC indicates the need for ventilatory support and can predict mortality. Therefore, it is critical for clinicians to implement spirometry solutions that are not only accurate, but also as easy as possible for patients to use.

ERT recently hosted a webinar on improving the success rate in designing ALS clinical trials, in which Dr. Kai Beeh and ERT’s Respiratory Solutions directors, Kevin McCarthy and Dawn Patterson, discussed the challenges of performing respiratory tests with ALS patients and how to prevent them. Read on for key takeaways from the event.

Capturing Quality Data from ALS Patients: Mouthpiece vs. Mask

The spirometry diagnostic test captures data in ALS patients using a snorkel mouthpiece or a mask – but which attachment is best for capturing data from ALS patients?

  • Snorkel mouthpiece: Beeh, McCarthy and Patterson all say they opt for the snorkel mouthpiece. When it comes to maintaining a good seal, the snorkel is easier to use and produces better, more repeatable results in fewer efforts.
  • Mask: The panelists argue masks can be difficult to seal with one hand, especially when patients produce a significant amount of saliva.

Parameters of Spirometry: Slow vs. Forced

Forced Vital Capacity (FVC) and Slow Vital Capacity (SVC) are techniques that measure the volume of air from exhalations beginning from full inflation.

  • SVC: The panelists agree that while the slow method might sound more manageable, it doesn’t always work to the clinician’s advantage. It often does not present the patient’s best performance because they hold back to breathe slower.
  • FVC: The forced method tends to be easier for the patient and yields less variability in results. FVC produces sustained, maximum flow, which is a key criterion in spirometry testing.

How to Coach a Patient with ALS

Regardless of the attachment or technique used, coaching is essential to producing quality spirometry results. There are several factors to take into consideration when coaching a patient with ALS:

  • The procedure can bring on anxiety. First and foremost, let the patient know that you aren’t going to rush them through it. ALS patients may fatigue quickly and have a limited number of efforts that will produce maximum performance.
  • Offer patients tips on how to best perform and remind them that they have an element of control in the testing. If they are not ready to give it 100%, they should take any necessary time to rest.

Evaluating the Data

In addition to following guidance from the annual American Thoracic Society (ATS) standardization of spirometry, it is vital to understand what the data indicates. What are spirometry assessments looking for when evaluating data with ALS? According to the panelists:

  • Vital capacity is key, whereas airway parameters are not as important.
  • It’s essential to verify that the subject started forced exhalation from full inflation.
  • 2019 ATS guidelines advised considering the quality of FVC and FEV1 (first forced expiratory volume) separately, and panelists recommend this in some circumstances, noting that regulators may encourage both, as the drug may have different effects when inhaling and exhaling.

Collecting Data at Home

At-home data collection tools like ERT’s iSpiro enable clinical studies to continue despite accessibility barriers, such as the COVID-19 pandemic. Site accessibility is especially burdensome for ALS patients who suffer weakened muscles and immune systems. Virtual data collection can also collect more data and more accurate data, as patients can perform assessments more frequently and in the comfort of their everyday settings. However, the panelists stress the importance of guidance from trained coaches and constant communication between all involved parties (patient, patient’s family, providers, sites, etc.). ERT’s iSpiro Virtual Visits offer step-by-step coaching to ensure accuracy.

To watch the full webinar, visit the event page on our website. To learn more about iSpiro Virtual Visits and to watch a tutorial, click here.