NEW YORK – As breath-based diagnostics become more prevalent in the industry, companies are developing new methods to capitalize on the growing interest with Singapore-based Breathonix joining the fray.
Cofounded by CEO Zhunan Jia and spun off from the National University of Singapore, Breathonix's method of testing breath grew out of Jia's Ph.D. research, where she focused on performing breath analysis for the early detection of lung cancer and determining the metabolic signatures of different histological types of lung cancer, as described in a paper published in 2018 in Metabolomics.
She said that for her research and Breathonix's development, she tried using all kinds of mass spectrometry before settling on the basis of her company's technology — proton transfer reaction-mass spectrometry, or PTR-MS, which she called the most accurate.
While gas chromatography-mass spectrometry, or GC-MS, is more commonly used for breath-based testing, when Breathonix worked with that technology platform, it found getting reproducible results "very hard," Jia said.
One downside to PTR-MS, however, according to Raed Dweik, chairman of the Respiratory Institute at the Cleveland Clinic and an expert in breath testing, is that the library of compounds is smaller for PTR-MS than for GC-MS. Because GC-MS has been around longer, more compounds have been identified for it, he said.
While many things can be seen using PTR-MS, the "the question is what are these compounds," and are they relevant, he added.
Jia noted that although the PTR-MS library is less established, it "has advantages in compound identification due to less fragmentation." Based on the exact mass measured, "we can narrow down the molecular formula of the detected compound, and then identify the compound that is most likely present in exhaled breath samples."
She added that while GC-MS may have a more extensive library, most of the breath compounds "are small molecules and prone to fragmentations," making unique identification difficult.
Using PTR-MS, Breathonix is able to test breath rapidly and noninvasively for cancer and infectious diseases in real time, with the company currently focusing on testing for COVID-19. Its BreFence Go COVID-19 Breath Test System is undergoing a deployment trial at Tuas Checkpoint between Malaysia and Singapore, and Jia said it can be used at airports and land border checkpoints for mass screening, as well as at the point of care. Jia noted that in the future, home use of the system could be possible, but that it would take time for the technology to develop enough.
The system also received provisional authorization from Singapore's Health Sciences Authority last month.
To use the system, someone exhales into a disposable one-way mouthpiece connected to a breath sampler, where the sample is directed into the mass spectrometer. The mass spectrometer measures more than 500 different volatile organic compounds, which are molecules produced by cell metabolism.
Differences in concentrations of VOCs that signal changes in biochemical pathways are measured to indicate the presence of a virus or disease, Jia said.
There is a baseline level of VOCs found in healthy populations, and the patient's VOC profile from the sample is compared to that baseline to determine if the virus is present, Jia said. The COVID-19 test's sensitivity is 85 percent and specificity is 97 percent, she added.
This method has the benefit of not needing transportation or storage for the sample, since everything is connected to the mass spec and there's a short turnaround time. Sample loss and contamination are also minimized, and the environment inside the sampler is kept at a high temperature to avoid condensation, which can contribute to sample loss, Jia said.
Before the patient exhales the sample, the device measures 10 seconds of background air to set a baseline for the final measurement because compounds in the "room air background" can be a "significant confounding factor in breath analysis," Jia said.
Dweik also noted the importance of confounding factors, since mass spectrometry measures byproducts, such as the drugs taken and the compounds inhaled outside, in breath, as well. "To make sure that these confounding variables are looked at is important," he said.
While the current version of the system is "the size of a small table," Breathonix has plans to develop a "less bulky and more portable" version in the future, Jia said. All of the manufacturing, including the mass spectrometers and consumables, is outsourced to partners both in Singapore and around the world, Jia said.
The system can also be used by a healthcare non-professional because the software is designed for ease of use, making it easier to implement at the point of care. "Anyone who can operate a PC will be able to operate this machine," Jia said.
Breathonix is currently working with an undisclosed software company to integrate the test system with the Singapore government's application to store COVID-19 test results and vaccination status.
Compared to other breath tests, which often use biosensors to detect VOCs and don't require mass spectrometers, Breathonix's system is expensive — "the mass spectrometer is definitely not cheap," Jia said. However, the company provides all of the hardware and software, including the instrument, to users and instead charges per test with a minimum order quantity, which Jia said can be as low as $5 per test depending on the volume.
Breathonix is just one company participating in the growing field of breath-based diagnostics. Companies such as Canary Health Technologies and Rapid Biosensor Systems use sensors to detect different compounds in breath, including antigens for COVID-19. Meanwhile, Owlstone Medical, another breath testing company, has identified breath-based biomarkers for lung cancer, liver disease, and respiratory conditions and has plans to launch breath testing for digestive health using gas chromatography.
Dweik noted that not a lot of breath testing systems are in clinical use, but "a lot of it is promising in research."
The benefit of using mass spectrometry over biosensors, Dweik said, is that mass spectrometry can provide more detailed answers. Biosensors may not be as sensitive, he said, but they are easier to use.
Breathonix started with a focus on early cancer detection, and its switch to COVID has meant it doesn't have large-scale clinical trial data for the system's use with cancer. But Jia said that cancer trials are the next step for the company, with a test potentially available in two to three years. The firm is currently doing a lung cancer trial in Singapore. It's also looking into tuberculosis and other infectious diseases, Jia said.
Breathonix is planning on expanding its COVID-19 testing to the European Union and Middle East, and Jia said the firm plans to submit for regulatory approval in countries in the Middle East in the next few months, with CE marking for its COVID-19 system anticipated by the end of this year. The company is also working to expand to other Southeast Asian markets, although the system is currently only available in Singapore.
Widespread breath-based testing could be another weapon in the diagnostics industry's arsenal to prepare for another pandemic or advance earlier detection of deadly diseases such as cancer, according to Dweik. "It's definitely a very promising way to look at health and disease because everything that is in our blood is potentially measurable in our breath," he said. "There's a huge potential for breath testing."