Hyperpolarized helium MRI tests effectiveness of cystic fibrosis drug

More than 30,000 Americans have cystic fibrosis, a genetic lung disorder that affects the pancreas and other organs, according to the Cystic Fibrosis Foundation. Although there is no cure, there is a drug approved by the U.S. Food and Drug Administration (FDA) that treats the underlying cause of the disease.

While the drug’s effectiveness remaining unknown, researchers from the University of Missouri School of Medicine developed an imaging technique using a specific form of helium to measure the drug’s effectiveness.

“People with cystic fibrosis have an imbalance of salt in their bodies caused by the defective cystic fibrosis transmembrane conductance regulator (CFTR) protein,” said Talissa Altes, MD, chair of the department of radiology at the MU School of Medicine and lead author of the study in a statement. “The drug ivacaftor targets this defective protein, but to what extent it is successful is not well understood. Our study sought to use a new way of imaging the lung to understand how well the drug is working in patients with a specific gene mutation known as G551D-CFTR.”

The team of researchers used helium-3 as a harmless contrast agent in conjunction with MRI to visualize lung function. In part one of the study, eight patients were given an ivacaftor or a placebo for four weeks to measure short-term effectiveness. In the second part of the study, nine patients were given ivacaftor for 48 weeks to test the long-term effectiveness. After each phase, participants performed a spirometry test and underwent MRI using hyperpolarized helium.

“We found that after using ivacaftor, patients experienced a dramatic increase in lung improvement in both the short and long term,” said Altes. “On an MRI, a healthy lung should look completely white when helium-3 is used as a contrast agent. Conversely, areas that are not white indicate poor ventilation. That’s the beauty of this technique—it’s very obvious if the drug is working or not.”

The researchers are looking to continue this study and are hoping to apply helium-3 MRI to younger patients with impaired lung function or other respiratory diseases.

“More drugs are under development to treat cystic fibrosis and other lung conditions, and improved imaging techniques are needed to test their effectiveness,” Altes said. “The importance of this technique is that it may well be a cost-effective tool to aid in the development of these drugs. However, it also can help patients know which medications may work best for their unique conditions.”