Yi-Bin Chen, MD: The definition of steroid refractory for acute graft-versus-host disease [GvHD] involves several different types of patients. If you look in the literature at trials, it’s been defined in multiple ways. I’m going to list the various criteria that have been used. If patients progress or become significantly worse after 3 days of systemic steroids, that meets the definition for steroid refractory. If patients don’t respond after 1 week of systemic steroids, if patients initially respond to steroids and then as we taper the steroids they have a worsening of symptoms, that has been included as steroid refractory. And in certain patients who say, develop skin disease first, then you treat them with a certain dose of steroids and a week later they develop disease in another organ, that is steroid refractory.

The final category has been called steroid refractory. It’s also been called steroid dependent. These are patients who do respond to steroids, and as you taper and taper and taper, you figure out that they have to be maintained on a certain dose of steroids or their symptoms flare. All of these definitions have at one point or other been called steroid refractory. They’re probably all biologically different, and this is part of the reason why trials in steroid-refractory acute graft-versus-host disease have often been tough to do because of heterogeneity in these populations.

Corey Cutler, MD: By the numbers, acute GvHD is primarily refractory to steroids in about 25% of cases, and then there’s another 20% to 25% of cases where the disease might be steroid dependent, which is defined as the inability to wean the patient off steroids without a recurrence. The patients who are primarily refractory to corticosteroids really have the worst prognosis. What we need to do is find ways of predicting who those patients are going to be and work on escalated therapies for them initially to prevent initial steroid refractoriness. It’s associated with very poor outcomes, and so at that point, we need to move into second-line therapies quite rapidly.

Transcript Edited for Clarity