• At least one diagnostic or distinctive cGVHD manifestation(s), with a clinical diagnosis of cGVHD,but patients do not need to meet National Institute of Health (NIH) criteria for cGVHD

• If eye involvement only, cGVHD must be confirmed on exam by an ophthalmologist or optometrist

• No new immune suppressive therapy added within preceding 2 weeks prior to study enrollment for any indication

‣ Continuation of agents previously given as either GVHD prophylaxis or acute/late acute GVHD therapy are permitted. Modification of dose of these agents for targeting of therapeutic drug levels is permitted, as are decreases in existing prednisone or prednisone equivalent dose based on routine clinical tapering practices. Increases in prednisone or prednisone equivalents are not allowed in the 2 weeks prior to enrollment

• Age 18 and older

• Karnofsky performance score \>= 70

• Able to take oral medications

• Signed informed consent

• Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) =\< 3 x upper limit of normal (ULN)

• Total bilirubin =\< 1.5 x ULN, unless due to Gilbert's disease

• Glomerular filtration rate (estimated glomerular filtration rate \[eGFR\]) \>= 30 mL/min/1.73 m\^2

• Female subjects of childbearing potential have a negative serum or urine pregnancy test at screening. Females of childbearing potential are defined as sexually mature females without prior hysterectomy or who have had any evidence of menses in the past 12 months. However, females who have been amenorrheic for 12 or more months are still considered to be of childbearing potential if the amenorrhea is possibly due to prior chemotherapy, anti-estrogens, or ovarian suppression

• Sexually active females of childbearing potential enrolled in the study must agree to use two forms of accepted methods of contraception during the course of the study and for 3 months after their last dose of study drug. Effective birth control includes:

‣ Intrauterine device (IUD) plus one barrier method

⁃ Stable doses of hormonal contraception for at least 3 months (eg, oral, injectable, implant, transdermal) plus one barrier method

⁃ 2 barrier methods. Effective barrier methods are male or female condoms, diaphragms, and spermicides (creams or gel that contain a chemical to kill sperm)

⁃ Surgical sterilization (tubal ligation)

⁃ A vasectomized partner

• For male subjects who are sexually active and who are partners of females of childbearing potential: Agreement to use two forms of contraception as per above and to not donate sperm during the treatment period and for at least 3 months after the last dose of study drug

• No evidence of active malignancy