Antisense pleased with animal study of eye treatment

Antisense Therapeutics (ASX:ANP) has claimed successful results from animal studies targeting the growth hormone receptor with an antisense drug, designed to reduce the growth of new blood vessels that can lead to two eye diseases which are major causes of blindness.

Diabetic retinopathy and wet age-related macular degeneration (wet AMD) are sight disorders which are caused by new blood vessel formation in the retina, and are two of the leading causes of vision loss.

Antisense research director Dr Christopher Wraight said the drug, ATL1103, acted to suppress levels of the hormone IGF-I in a mouse model.

"These results are an approximation of one aspect -- the new blood vessel growth in the retina -- of these eye diseases, but it is encouraging and a step in the right direction," Wraight said. "It supports our decision to continue to develop the drug, which is the company's first wholly developed in-house drug."

There are currently no pharmaceutical therapeutics approved for the treatment of diabetic retinopathy, Antisense said. Surgical ablative treatments such as laser therapy are available, but they may cause partial vision loss and can only be used a limited number of times. In 2004 the FDA approved the drug pegaptanib as the first therapy approved for all types of AMD. Pegaptanib is an oligonucleotide aptamer which must be administered by direct injection into the eye every six weeks.

"ATL1103 is a better solution for treating these diseases because it can be self-administered," Wraight said. "We are in the final stages of selecting the best drug candidate for the human growth hormone receptor and anticipate that a decision will be made by the end of this year."

The animal studies of ATL1103 were conducted on behalf of Antisense by Assoc Prof Jennifer Wilkinson-Berka, a principal research fellow at the University of Melbourne, and the findings were presented at the 41st Annual Meeting of the European Association for the Study of Diabetes in Athens this week.

Clinical status

Last month, the Antisense scientific advisory board unanimously recommended the resumption of phase IIa trials of its lead drug candidate for multiple sclerosis, ATL1102, which were halted after Biogen Idec pulled its MS drug Tysabri from the market.

An application to restart the Antisense trial is to be submitted before the end of September, and Antisense hopes to screen and enrol patients before the end of 2005. Results of proof-of-concept clinical trials for the company's next most advanced product, ATL1101, a topical psoriasis treatment, are also expected to be released before the end of the third quarter this year.