Antisense halts MS drug trial

By Renate Krelle
Thursday, 10 March, 2005

Antisense Therapeutics (ASX:ANP) bowed to the inevitable today, announcing that it would halt the Phase IIa trial of its lead drug candidate for multiple sclerosis, ATL1102, following the withdrawal of Biogen Idec and Elan Pharmaceuticals' Tysabri from the market. However the Melbourne company has not yet terminated the project altogether.

Antisense is in the process of convening an advisory group to consider development options for the drug. "We're still looking at the composition of the advisory committee," said Antisense chief executive officer Mark Diamond.

"We see it as being a bump on the road," he said. "We're taking the opportunity to assess the implications, which we consider is the ethical position for us to take in this situation." He said Antisense continued to monitor further news on Tysabri closely.

Antisense has been consulting with its trial investigators and advisors since Biogen Idec and Elan voluntarily suspended Tysabri -- a multiple sclerosis treatment -- on March 1 after one patient died and another was infected with a rare virus, progressive multifocal leukoencephalopathy (PML). Both patients had been on a combined therapy of Tysabri and Avonex for at least two years.

Tysabri is a humanised monoclonal antibody targeting a cellular adhesion molecule called VLA-4. Antisense's ATL1102 is a gene-silencing therapy, also targeting VLA-4.

On the day of the suspension announcement, Elan's stock price plunged 70 per cent and Biogen Idec dropped 43 per cent. Antisense shares have plummeted from $0.12, and at time of writing were trading at $0.07, a "a disappointing outcome" according to Diamond

Antisense said in a statement that it would be "reviewing its overall product development strategy", including possibly advancing its candidates ATL1103 for growth and sight disorders and ATL1102 for asthma treatment. The company's next most advanced product is ATL1101, a topical psoriasis treatment, which is currently undergoing a proof of concept clinical trial at the Royal Adelaide Hospital.