Dr Yi-Bin Chen reviews treatment options for patients with steroid-refractory chronic GVHD. Yi-Bin Chen, MD: In chronic graft versus host disease, historically, the treatment options were quite similar. We felt that we just had to suppress the donor immune system, and a lot of patients, again, suffered from opportunistic infection. We need to realize for chronic graft versus host disease, that by the time we treat it, there is some irreversible damage, and we should try to only reverse what we can reverse and shape our expectations for ourselves and our patients that way. But after steroids, we do have an agent that was approved, which is ibrutinib. That's a Bruton tyrosine kinase (BTK) inhibitor, which targets the B-cell arm in the immune system. There is evidence that the B-cell arm is active in many patients with chronic graft versus host disease. A lot of exciting laboratory work had shown in male recipients with female donors the formation of these anti H-Y antibodies directed against the Y chromosome, at least showing there was some B-cell or plasma cell activity. Ruxolitnib has been shown to be quite active in chronic graft versus host disease as well, and we're fairly impressed with that and use it very routinely for that indication. There is an agent called belumosudil, made by Kadmon, that recently had exciting results in the ROCKstar (KD025-213) clinical trials that we hope to see approval for this year. And that targets that ROCK (Rho-associated coiled kinase), an arm thought to be active in fibrosis. And there are other clinical trials ongoing, studying different pathways; a lot of it in chronic graft versus host disease is focused on fibrosis. That is the pathological hallmark we see.