Let There Be Light

Skin damage caused by sunlight may seem relatively trivial in the global context of disease. However, the acute clinical manifestation of such damage, ‘sunburn’, is associated with several chronic morbidities – including malignant melanoma – that represent a significant disease burden. Despite this, a pharmaceutical market for prevention and therapy of solar radiation-induced disorders has not yet arisen.

The human body protects itself from the damaging ultraviolet light (UV) component of solar radiation by producing a UV-absorbing pigment, melanin, in the skin. However, this process – termed melanogenesis – occurs only after skin has been damaged by sun exposure. Australian company EpiTan is developing a platform technology for pharmaceutical stimulation of melanogenesis based on Melanotan®, a peptide analog of alpha-melanocyte-stimulating hormone – the major physiological agonist of melanogenesis. This groundbreaking work may help create pharmaceutical markets for prevention of photodamage and therapy of photosensitive skin disorders. Proof of concept was achieved in a phase II trial in which Melanotan increased skin melanin content by as much as 100% and reduced sunburn by up to 50% in fair-skinned Caucasians. Sustained-release and transdermal formulations of Melanotan are being developed for commercial use. In addition to clinical trials for prevention of photodamage, Melanotan is also in phase II clinical trials in Europe for therapy of polymorphous light eruption, a sunlight-induced skin allergy affecting as much as 20% of the population. EpiTan intends to market Melanotan in three distinct markets: as a prescription ‘sunscreen’ for prevention of sunburn; as a pharmacotherapy for photosensitive skin disorders; and for cosmetic use as a sunless tanning product. The putative pharmaceutical markets are estimated to be worth several billion dollars globally, but it is as a cosmeceutical that Melanotan could be most profitable, with the market for tanning in the US alone valued at over $US5 billion per annum. Whether Melanotan can achieve this multi-billion dollar potential as a pharmacosmeceutical will depend on the outcome of its clinical development program, with a favorable safety profile likely to be particularly important for gaining regulatory approval.