Salix grabs ex-Asia rights to Mitsubishi Tanabe autoimmune drug

Salix Pharmaceuticals is gearing up to test amiselimod in ulcerative colitis. (Getty/Natee Meepian)

Salix Pharmaceuticals has bagged the ex-Asia rights to Mitsubishi Tanabe’s late-phase autoimmune drug, amiselimod. The Bausch Health subsidiary plans to trial the S1P receptor functional antagonist in ulcerative colitis.

Amiselimod is designed to inhibit the receptor function of the lymphocyte S1P receptor and thereby keep lymphocytes sequestered in lymph nodes. Through this mechanism, Salix thinks amiselimod will stop the lymphocytes from contributing to immune reactions, leading to improved outcomes in people with conditions including ulcerative colitis.

Biogen paid $60 million upfront to license the ex-Asia rights to amiselimod, then known as MT-1303, in 2015 but had a change of heart a year later when it discontinued development and subsequently returned the drug to Mitsubishi Tanabe.

Multiple sclerosis was central to the prospects of amiselimod when Biogen bought into the program. But with Celgene and Novartis leading efforts to treat multiple sclerosis by modulating SP1, Salix has tied the future of amiselimod to other indications, namely the autoimmune conditions that fall under the inflammatory bowel disease (IBD) umbrella. 

"For patients living with IBD, amiselimod represents an opportunity to develop an oral, non-immunogenic treatment as an alternative to biologics and other available therapies," Salix President Mark McKenna said in a statement. 

Salix faces plenty of competition in IBD, though. Celgene is running phase 3 trials of its SP1 drug, ozanimod, in Crohn’s disease and ulcerative colitis. And a clutch of leading drug developers are going after other mechanisms to treat the diseases. McKenna and his colleagues think Salix can guide amiselimod through this competitive thicket and are gearing up to test it in ulcerative colitis. 

Salix’s parent company Bausch, formerly known as Valeant Pharmaceuticals, is paying Mitsubishi Tanabe an upfront fee of undisclosed size to license the asset and is on the hook for development and regulatory-based milestone payments.