Melbourne-based Clinuvel Pharmaceuticals (ASX:CUV) has announced that its lead drug Scenesse (afamelanotide 16mg) has received an additional orphan drug designation (ODD) from the US FDA for the treatment of cutaneous variants of porphyria.
The ODD recognises the potential of afamelanotide to treat or prevent symptoms in rare forms of porphyria and offers incentives to Clinuvel to develop the drug for these patients.
The company said Scenesse has been clinically evaluated as a photoprotective drug in one severe form of porphyria – erythropoietic protoporphyria or EPP – for which it has received marketing authorisation in Europe.
Scenesse may also have a photoprotective effect for patients with other rare forms of cutaneous porphyria: variegate porphyria (VP), hereditary coproporphyria (HCP) and congenital erythropoietic porphyria (CEP).
Porphyrias are a family of seven genetic metabolic disorders that cause malfunctions in the haem biosynthetic pathway.
While classically grouped together, each of the five cutaneous porphyrias has clinically distinct symptoms, generally characterised as acute dermal reactions – affecting the skin and anaphylactoid in nature – which are caused by the accumulation and storage of phototoxic molecules (porphyrins) in the body.
When patients with cutaneous porphyria expose their skin to visible light – both sunlight and certain artificial lights – the porphyrins react and cause symptoms such as oedema and incapacitating deep burns leading to damage of soft tissue and eventually scarring. Patients are conditioned from childhood to recognise the source of their symptoms and withdraw from light and sun exposure to prevent phototoxicity, resulting in light starvation and social isolation.
Scenesse has previously been granted orphan designation by the FDA for EPP and CEP. While the company said no further trials are currently planned in cutaneous porphyrias, it said it is working to make Scenesse available to several patients with CEP on a name-patient basis due to the extreme severity and progressive character of this disorder. Only a few hundred cases of CEP have ever been recorded in the literature.
Orphan-drug designation is granted by the FDA to drugs which have the potential to diagnose or treat rare conditions, defined as those affecting less than 200,000 individuals in the US.
The additional orphan designation entitles Clinuvel to technical assistance throughout the development process for cutaneous porphyrias, potential fee reductions and tax credits, and market exclusivity of seven years if approved by the FDA.
“Beyond EPP we have always recognised that patients with other forms of cutaneous porphyria are deeply affected by their condition,” said Clinuvel’s Acting Chief Scientific Officer, Dr Dennis Wright. “The FDA’s designation acknowledges the potential of afamelanotide to assist those patients.”