EpiTan reports "outstanding" results for Melanotan

Melbourne biotech EpiTan Ltd (ASX: EPT) has announced "outstanding" results from the Phase IIb clinical of its experimental tanning drug Melanotan - and says the data could be the subject of new patent applications.

The company says the trial sought to establish the degree to which Melanotan increased production of the protective skin pigment melanin to reduce sunburn injury in 81 Caucasian volunteers (48 males, 33 females).

It says the results represent a "massive step" towards commercial development, and is now seeking expert medical and legal opinion on whether some of the trial's findings may be patentable.

Dr Stuart Humprey, manager of clinical development for Melanoton, says the company is very excited with the results, but needs to establish that the findings are novel and patentable - "We may be able to talking about it in a week or so."

Humprey says Dr Terry Ooi and Professor Ross Barnetson, who supervised the clinical trials at Sydney's Royal Prince Alfred Hospital and the Royal Adelaide Hospital, will describe some of the new data in Sydney on November 26, at a meeting of the Mutagenesis and Experimental Pathology of Australia.

The volunteers in the trial, whose average age was 39.3 years, were subjected to controlled levels of UVA and UVB radiation on a small area of exposed skin, to simulate the effect of 30 to 120 minutes in strong sun without a sunscreen.

A skin biopsy from the exposed area was then used to assess the degree of sunburn injury. The volunteers were then administered Melanotan, and re-exposed on another patch of skin, at the same level, and another biopsy was taken.

Researchers also monitored melanin density at various skin sites throughout the three-month study.

The study observed clinically visible tanning in a large proportion of volunteers, and the differences between Melanotan- and placebo-treated groups was highly significant at all skin sites.

The percentage increase was most pronounced in fair-skinned volunteers, who are most susceptible to sunburn - their melanin levels increased by almost twice that in dark-skinned volunteers.

Humphrey says the findings for fair-skinned individuals confirms that Melanotan could be used as a prescription sunscreen to provide both UV-A and UV-B protection when commercialized. Fair-skinned individuals normally produce little melanin.

He said another interesting finding was that the number of volunteers who believed they had a skin type that rarely burned, and tanned easily, in fact had a skin type that burned readily, and did not tan easily.

The use of Melanotan in conjunction with other forms of skin protection should ensure that such individuals were better able to protect themselves against the harmful effects of UV radiation.

Melanotan is an active mimic of a naturally occurring signaling molecule, melanocyte stimulating hormone (MSH), that causes melanocyte cells in the skin to produce melanin, the dark skin pigment that absorbs ultraviolet (UV) radiation, which causes sunburn and immunosuppression.

Humphrey says unlike high-protection factor sunscreens, melanin absorbs all wavelengths of UV radiation in sunlight. Most sunscreens effectively absorb UV-B wavelengths, but are less effective at blocking UV-A wavelengths.

Scientific evidence suggests that UV-A, while causing less severe damage than UV-B, may increase the hazards due to sunburn by inducing temporary immunosupression.

A person may experience immunosuppression for several days after being sunburned, temporarily impairing of the body's immunosurveillance system, which detects and destroys potentially cancerous cells.

Sunburn-induced immunusuppression can also release latent virus infections, such as the herpesviruses that cause cold sores and genital herpes.