Is there a role for vadadustat in addition to an ESA in ESKD patients who are hyporesponsive to ESA’s alone?

I am not aware of any published studies of HIF-PHIs such as vadadustat used in combination with ESAs in ESKD patients who are hyporesponsive to ESAs alone. The vadadustat label recommends pausing vadadustat treatment for patients receiving ESA rescue for Hb <9 during the transition phase from ESAs, so the implication is that the agents should not be used together. The safest approach, until there is published data otherwise, is to convert ESA hyporesponsive patients to vadadustat and not to use vadadustat as an add-on therapy.