MTOR and acute graft versus host disease: Similar to acute GVHD, corticosteroids have traditionally been the recommended first-line treatment for chronic GVHD.23,36 Although there is no consensus treatment for SR chronic GVHD, commonly used agents include calcineurin inhibitors, extracorporeal photopheresis (ECP), mammalian target of rapamycin (mTOR) inhibitors, rituximab, and mycophenolate mofetil.