Astellas Pharma has acquired the rights in Japan and other Asian countries to Ironwood Pharmaceuticals of the USA’s investigational irritable bowel syndrome drug linaclotide.

Under the terms of the deal, the Japanese drugmaker will pay a $75 million upfront fee to develop linaclotide, a first-in-class treatment for IBS with constipation and chronic constipation. The licence includes rights in Japan, Indonesia, South Korea, the Philippines, Taiwan and Thailand, and Ironwood will also receive escalating royalties.

Astellas, which noted that IBS affects around 12 million people in Japan, will be responsible for clinical development of the compound in the aforementioned territories. Linaclotide is currently in Phase III trials in the USA and earlier this year its European rights were licensed to Spain’s Almirall.

Masafumi Nogimori, Astellas' chief executive, said the collaboration “fits well with our existing gastrointestinal franchise in Japan and I'm excited to deliver linaclotide to the Asian territory”. His counterpart at Ironwood, Peter Hecht, said the deal continues his firm’s strategy “to form partnerships to develop and commercialise linaclotide in the top three pharmaceutical markets: the USA, Europe, and Japan”.