There’s Finally a Drug That Can Keep Your Fingers and Toes Safe From Frostbite

A reliable way to keep appendages safe from the ravages of the cold is finally here. This month, the Food and Drug Administration approved the first treatment meant to prevent limb amputation from severe frostbite, Eicos Sciences’ Aurlumyn. Compared to standard care, the intravenous drug was shown to significantly reduce the risk of frostbitten victims needing amputations in a clinical trial.

Frostbite is a broad term for injuries caused by the cold, in which the skin and underlying tissues can literally freeze. Mild frostbite, or frostnip, doesn’t result in permanent damage, but the longer someone is left out in the cold, the more likely that their blood vessels will constrict and ice crystals will form inside the vessels and surrounding tissues. And when a person is rescued and brought back inside, the thawing of these crystals can further harm the body, such as by bursting blood vessels open or otherwise cutting off circulation. It can take months after rewarming to know the full extent of injury, but those with severe frostbite can experience permanent nerve damage or tissue loss so extensive that amputation is needed and/or happens on its own.

Historically, there haven’t been interventions known to prevent limb amputation from severe frostbite once it’s already suspected to have occurred. Patients will get aspirin or other anti-inflammatory drugs soon after rescue and urgent rewarming, but from there, it’s just a matter of waiting to see if people will escape with their limbs intact.

Over the years, though, scientists and doctors have experimented with potential off-label treatments for severe frostbite, including iloprost, the active ingredient in Aurlumyn. In 2011, a crucial study found that people treated with an IV infusion of iloprost were less likely to need amputation. Iloprost is an vasodilator already approved for pulmonary hypertension, or high blood pressure that affects the arteries of the lung. Eventually, the pharmaceutical company Eicos Sciences decided to try seeking formal FDA approval for its version of iloprost as a frostbite treatment.

The drug is thought to keep limbs safe by opening up blood vessels and preventing the clots that can permanently damage the body. It’s intended to be given several hours a day for up to a week. In a small clinical trial of 47 adults evaluated by the FDA for approval, those given Iloprost (either alone or in combination with another off-label treatment) and standard care appeared to be much less at risk for amputation than those given standard care, based on medical scans of their bones a week after the initial frostbite. Subsequent follow-up data confirmed that those on iloprost were less likely to lose a finger or toe.

“This approval provides patients with the first-ever treatment option for severe frostbite,” said Norman Stockbridge, director of the Division of Cardiology and Nephrology in the FDA’s Center for Drug Evaluation and Research, in a statement from the FDA.

Severe frostbite is rare, so the market for the drug will be limited, and the company has not yet set a list price. But there are groups reliably exposed to extreme temperatures who will benefit from having the drug available on hand, such as mountain climbers, military personnel, and homeless populations.

“Having this new option provides physicians with a tool that will help prevent the lifechanging amputation of one’s frostbitten fingers or toes,” said Stockbridge.