FDA Issues Complete Response Letter To Avedro For Corneal Cross‐Linking NDA
By Cyndi Root
Avedro Inc. issued a press release announcing receipt of a Complete Response Letter (CRL) from the Food and Drug Administration (FDA). The federal agency is responding to the company’s New Drug Application (NDA). The riboflavin ophthalmic solution/KXL system is indicated for keratoconus and corneal ectasia, both orphan conditions.
The FDA accepted the application in November of 2013 and granted it priority review. At the time, the FDA provided the PDUFA data to take action by March 15, 2014. The letter outlined the issues the FDA is concerned with. David Muller, CEO of Avedro said, “While we do not yet have an estimate on how long it will take to resolve the issues, we are confident that we can adequately answer their questions.”
Keratoconus
Keratoconus is a cornea disorder wherein the front part of the eye loses its round shape, becoming cone shaped. Vision is distorted as light does not focus properly. Early symptoms and mild cases present with slightly distorted vision and sensitivity to light. Severe cases may cause blindness. There are no medicines for this condition.
Corneal Ectasia
Corneal ectasia is rare with estimates ranging from 1 in 2,500 to 1 in 5,000 people. Many cases are surgically induced from procedures like LASIK. The condition is progressive and difficult to manage. Treatments often begin with contact lenses and, as a last resort, penetrating keratoplasty (PK), surgically removing part of the damaged cornea and replacing it with donor tissue.
Riboflavin Ophthalmic Solution/KXL
The riboflavin ophthalmic solution/KXL is Avedro’s proprietary treatment system. It combines medicine with a medical device to deliver the treatment. Outside the U.S., over 75,000 surgeries have been performed to treat keratoconus and corneal ectasia. The company calls the procedure, “Lasik Xtra.” The riboflavin ophthalmic solution called “VibeX Xtra” is the agent used in the Lasik Xtra procedure.
The physician performs excimer laser ablation, then applies the drug to the stromal bed, and replaces the flap. The drug diffuses quickly, minimizing flap exposure time. After the flap is positioned on the cornea, the KXL medical device issues UVA light, activating the riboflavin drug, restoring integrity to the cornea.
About Avedro
Avedro, Inc. is a privately held company. It distributes products in over 60 countries, but none in the U.S. yet. Clinical studies are still underway for the KXL system at over 100 sites in the U.S.