Rigel makes Forma wait for olutasidenib payday

Two competitive datasets on olutasidenib in IDH1-mutated AML at last year’s Ash meeting boded well for Forma’s ambitions to find a partner, so the terms of yesterday's licensing deal come as a surprise. Rigel is buying worldwide olutasidenib rights for just $2m, plus $17.5m in near-term and $215.5m in longer-term milestones; royalties are at least healthy, stretching to the mid-30s. One explanation for the small up-front is that IDH mutations are rare; the market is tiny and has several competitors. Servier’s Tibsovo is dominant and Rigel will have to work hard to grab share; the private French group does not disclose sales, although Agios generated $120m in 2020, before it sold out to Servier. B Riley analysts estimate peak sales of $100m for olutasidenib in front-line and refractory AML. Pipeline IDH projects are focused on glioma, where Servier is also in the lead with a second Agios asset. Lilly is probably the one to watch, however, with a Loxo-originated project. Data due next year from two large phase 1 trials could show whether Rigel was right to backend load the deal terms.