However, steroid-refractory GVHD has provided a challenge for patients and providers and led to the Food and Drug Administration (FDA) approval of ruxolitinib (Jakafi), ibrutinib (Imbruvica), and subsequently belumosudil (Rezurock), a selective Rho-associated coiled-coil containing protein kinase 2 (ROCK2) inhibitor, as the first therapies authorized for steroid-refractory cGVHD. This evidence concerns the gene ROCK2 and graft versus host disease.