The purpose of this study is to evaluate the efficacy of SHR0302 in combination with Prednisone as first line therapy in patients with moderate to severe chronic graft-versus-host disease (GVHD).

Treatment: Once patients are diagnosed with chronic GVHD, the combination therapy should be initiated as soon as possible. 1. Prednisone: 1mg/kg/d po. Taper steroid every two weeks according to patient's response. 2. SHR0302 QD po. for at least 28 days. Indication for stopping SHR0302 treatment: 1. No response after SHR0302 treatment for 12 weeks. 2. Develop life-threatening complication. 3. ANC<0.5×10e9/L or PLT< 30×10e9/L.

Inclusion Criteria:

• ≥ 18 years old and ≤ 70 years old, male or female;
• Patients receiving allogeneic peripheral blood stem cell transplantation for hematological diseases;
• The primary hematological malignancies are completely relieved and are expected to be stable for at least 3 months;
• Chronic GVHD that was first attacked after transplantation and at least 100 days after transplantation, reached a moderate or severe level by NIH classification;
• There was no previous systemic treatment (including in vitro illumination [ECP]);
• The patient may be receiving other immunosuppressive agents to prevent or treat acute GVHD, but if the subject receives prednisone to prevent or treat acute GVHD, it must be <0.5 mg/kg/d or equivalent dose of other glucocorticoids;
• The chronic GVHD that has started hormone therapy does not exceed 72 hours;
• Karnofsky score > 60 points;
• Patients must be able to understand and are willing to participate in the study and sign an informed consent form.

Exclusion Criteria:

• Can not tolerate prednisone dose 1mg / kg / d or equivalent dose of other glucocorticoids for the treatment of cGVHD;
• Receive any systemic treatment of cGVHD, except for corticosteroids that treat cGVHD within 72 hours prior to the signing of informed consent;
• Patients with GVHD overlap syndrome (NIH criteria);
• Treatment of acute GVHD has received other Jak inhibitors such as ruxolitinib;
• Pregnant or lactating women;
• The patient is judged by the investigator to have complications that may cause other risks;
• The patient is receiving other study medications;
• Patient blood routine: ANC <1.0 × 109 / L or PLT < 50 × 109 / L;
• Non-GVHD-related liver damage: the aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio is more than 3 times normal or the direct bilirubin normal value is more than 3 times;
• Renal dysfunction: endogenous creatinine clearance (Ccr) < 50mL/min or normal serum creatinine 1.5 times or more, regardless of hemodialysis treatment;
• Uncontrolled infections: hemodynamic instability associated with infection, or new signs or signs of infection, or new infections in imaging, persistent fever without symptoms or signs and cannot be ruled out Infected person
• People living with HIV;
• Active hepatitis B (HBV), active hepatitis C (HCV) requires antiviral therapy; patients with HBV activation risk refer to patients with hepatitis B surface antigen-positive or core antibody-positive patients who are not treated with anti-HBV;
• The patient's primary malignant disease recurs and the graft is rejected;
• Those who are allergic to known JAK inhibitors.