The FDA has approved in adults, the agency announced on Wednesday.
Part of the drug class of vasodilators, iloprost can prevent blood clotting and is indicated for reducing the risk of finger or toe amputations due to severe frostbite, a stage where the skin and underlying tissue are frozen to the point that blood flow stops.
"This approval provides patients with the first-ever treatment option for severe frostbite," Norman Stockbridge, MD, PhD, of FDA's Center for Drug Evaluation and Research, said in a statement. "Having this new option provides physicians with a tool that will help prevent the life-changing amputation of one's frostbitten fingers or toes."
Data from an open-label randomized trial, published more than 13 years ago in the (NEJM), provided the primary support for the approval.
All 47 patients in the three-arm study had severe frostbite on their toes or fingers and received intravenous aspirin alongside standard of care. Those assigned to 8 days of intravenous iloprost (6 hours daily) -- alone or in combination with fibrinolysis (on day 1) -- had significantly lower predicted amputation rates compared with a group receiving buflomedil, a vasoactive drug that is not approved for frostbite. Results were based on bone scans taken 7 days after the incident frostbite.
With iloprost alone or with fibrinolysis, 0% and 19% of patients were predicted to require amputation of at least one finger or toe, as compared with 60% of those randomized to buflomedil (P<0.001 and P<0.03 for the iloprost arms versus buflomedil).
During follow-up, actual amputation rates of the patients' 407 affected fingers and toes were consistent with the bone scan predictions:
- Iloprost alone: 0%
- Iloprost plus fibrinolysis: 3%
- Buflomedil alone: 40%
Common adverse events with iloprost included headache, flushing (55%), nausea (25%), heart palpitations (15%), vomiting (5%), dizziness, and hypotension, though study investigators described these as "minor," with none leading to treatment discontinuation. Warnings and precautions in iloprost's labeling note a potential risk of symptomatic hypotension.
Iloprost was previously approved for pulmonary arterial hypertension in 2004 under the trade name Ventavis.