Lupin has expanded its earlier collaboration in respect of rifaximin with Salix Pharmaceuticals, headquartered in Raleigh, North Carolina, and granted exclusive worldwide rights (except for India) to exploit Lupin technology and technology jointly developed by Lupin and Salix for all rifaximin products for human use.

The agreement covers the development and commercialization of rifaximin products and provides for Lupin to supply Salix with rifaximin active pharmaceutical ingredient (API) and certain finished rifaximin products.

Salix is required to make a $10 million up–front payment to Lupin along with potential US regulatory milestone payments in respect of products covered by Lupin patents or jointly–held patents. Royalties at a percentage rate in the low teens will be payable by Salix to Lupin in respect of sales of products covered by Lupin patents or jointly–held patents. Additionally, Salix will pay Lupin minimum quarterly payments for product development and other activities.

Rifaximin is a gut–selective antibiotic with negligible systemic absorption and broad–spectrum activity in vitro against both gram–positive and gram–negative pathogens. Rifaximin has a similar tolerability profile to that of placebo.

Rifaximin tablets 200 mg is approved in over 30 countries worldwide. Alfa Wassermann S.p.A. in Bologna, Italy has marketed rifaximin in Italy under the trade name Normix for over 30 years. Salix acquired rights to market rifaximin in North America from Alfa Wassermann.

Salix Pharmaceuticals, develops and markets prescription pharmaceutical products for the prevention and treatment of gastrointestinal diseases. Salix's strategy is to in–license late–stage or marketed proprietary therapeutic drugs, complete any required development and regulatory submission of these products, and market them through the company's gastroenterology specialty sales and marketing team.