A Phase II Study Evaluating the Efficacy and Safety of ABSK021 (Pimicotinib)) in the Treatment of cGvHD Chronic Graft Versus Host Disease (cGvHD)

Inclusion Criteria:

1. Sign the informed consent and agree to comply with the requirements and restrictionsset out in the informed consent.

2. At the time of signing the informed consent., the patient must be at least 18 yearsold, regardless of gender ；

3. Allogeneic hematopoietic stem cell transplantation from any donor source using bonemarrow, peripheral blood stem cells, or cord blood.

4. Patients who have received at least 1 line of systemic therapy

5. If the patient is being treated with glucocorticoids or calcineurin inhibitor(CNI),the patient should have received a stable dose of the above treatment for not lessthan 2 weeks prior to the first use of ABSK021.

6. ECOG (Eastern Cooperative Oncology Group Performance Status) physical strength score 0-2;7. The patient had sufficient organ and bone marrow function within 14 daysprior to the first use of ABSK021.

7. For patients with Part A only: antifungal drugs that are currently being used incombination with CYP3A4 potent inhibitors should have been continuously used inaccordance with regulations for no less than one week before the first use ofABSK021

Exclusion Criteria:

1. In previous treatment, he received highly selective colony stimulating factor 1receptor (CSF-1R) targeted therapy, including small molecule or large moleculedrugs;

2. A known history of allergy to components of the investigational drug composition ;

3. Patients continued to use CYP3A4 in combination with antifungal agents or in the twoweeks prior to the initial administration of ABSK021 Strong inducer;

4. The patient has received more than 5 lines of systemic therapy for cGvHD;

5. The patient presented with aGvHD symptoms without cGvHD symptoms ;

6. Any evidence of potential tumor or recurrence of post-transplant lymphoproliferativedisease at the screening stage .

7. There are factors that have been determined by the investigators to have asignificant influence on oral drug absorption

8. Present with cholestatic disease, or unresolved hepatic sinus obstructionsyndrome/venous obstructive disease;

9. active infection.

10. During the screening period, the investigators judged that the patients hadinsufficient pulmonary function reserve, with FEV1≤ 39% or pulmonary functionclassification score of 3;

11. Prior treatment (adverse events did not return to ≤ Grade 2 (CTCAE v5.0);

12. Pregnant or lactating women;

13. Patients who are unable to or disagree with contraception.