IDO has been the leading small molecule darling and Incyte a pioneering deal-maker partnering with multiple major checkpoint inhibitor players and more recently grabbing its own in a deal with MacroGenics. The failure of Keytruda/epacadostat is not unique but certainly the most advanced and high profile over the past year or two in the frenzied space of IO combinations where the number of combo trials is now around 1200. A number of costimulatory agonists (e.g., OX40) and innate targets (e.g., KIR) have stumbled or showed underwhelming data. Does this raise questions on the early IL-2 data from Nektar? I would think probably not, but scrutiny will be ramped up for sure.

We will discuss some of these issues at our upcoming Cancer Progress conference May 8-9 on the session about innate and acquired resistance to checkpoint inhibitors, chaired by Bruce Booth and featuring a stellar set of panelists including Tom Gajewski, Llew Keltner and Dimitriy Zamarin.