Clinuvel Pharmaceuticals Ltd. said the U.S. Food and Drug Administration needs an additional three months to decide on the approval of the company's drug Scenesse.

Scenesse, or afamelanotide, is a potential treatment for a rare metabolic disorder known as erythropoietic protoporphyria, or EPP. The condition is characterized by photosensitivity, in which sun exposure causes itching, reddening, swelling, pain and even burns.

The regulator moved the Prescription Drug User Fee Act goal date to Oct. 6 from July 6 as the agency's Division of Dermatology and Dental Products needs more time to complete a full review of the application, Australia-based Clinuvel said in a news release.

Clinuvel's chief scientific officer Dennis Wright expressed frustration about the review extension, while at the same time admitting that the agency usually extends its timelines when it needs to. "It is most frustrating that, while Scenesse is being prescribed in the European Union and Switzerland and some of the U.S. patients travel to Europe to obtain the treatment, the majority of U.S. EPP patients have no access," Wright said.

The FDA also changed the expected date to provide product labeling commentary and post-marketing authorization commitments to Sept. 6 from April 8.

Scenesse received orphan drug and fast-track status from the FDA in 2008 and 2016, respectively. The drug, which Clinuvel evaluated in five clinical trials, is approved in Europe to prevent phototoxicity in EPP patients.