After Biogen Idec and Elan Corp decided to withdraw their multiple sclerosis drug Tysabri (natalizumab) from the market [[01/03/05a]], and Australia’s Antisense Therapeutics halted a Phase IIa trial of its antisense treatment ATL-1102, a new report suggests that drugs targeting alpha-4-beta-1 integrin (VLA-4) may no longer be viable.

Pharmaprojects, a database which tracks pharmaceutical R&D worldwide, says the two aforementioned cases highlight a decreasing trend in research involving drugs targeting VLA-4 and goes on to note that if this continues, “a further 11 drugs currently in active development could possibly be under threat.”

It claims that 12 VLA-4 antagonists are under development, with the majority (seven) being targeted as treatments for asthma and five for MS. These include GlaxoSmithKline and Tanabe Seiyaku’s T-0047 (also known as 683699), which was in Phase II development for MS until the US Food and Drug Administration recently halted trials [[17/03/05a]] and TR-14035, in Phase II for arthritis, asthma, MS and irritable bowel syndrome.

Pharmaprojects adds that preclinical compounds targeting the protein include Schering-Plough’s TBC-4746, with potential in asthma and MS, and a compound under development at Spain’s Grupo Uriach.