Patients will receive oral SKLB1028 for 28 days as a course of treatment, and then to evaluate the side effects,tolerability and best dose for treating relapsed or refractory acute myeloid leukemia With FLT3 Mutations.

It is an open,multicenter,queue extension study designed to characterize the efficacy and safety of different administration regimens of SKLB1028 capsules in patients with recurrent/refractory acute myeloid leukemia with FLT3 mutation. Divided into three dose groups,150mg BID,200mg BID,300mg QD. The main end point is total remission rate (ORR), total survival time (OS), progress-free survival time (PFS), remission duration, FLT3 suppression rate, competitive parameters, safety (incidence of adverse events).

Inclusion Criteria:

1. Volunteer and sign informed consent forms
2. Male or female Chinese patients, age ≥ 18 years old
3. In patients with primary or secondary aml diagnosed according to (who) classification of the World Health Organization, patients with FLT3 mutation were detected by leukemia cell gene, and refractory aml; after at least one cycle of induction treatment of: a) met any of the following conditions. B) recurrent aml; after at least one cycle of induction therapy
4. Ecog score 0-3
5. Expected survival time greater than 3 months
6. The study drug was at least 2 weeks apart from prior cytotoxic chemotherapy (except for hydroxyl groups), or at least 5 half-lives or 4 weeks with prior non-cytotoxic chemotherapy agents, short-term
7. Upper limit of normal value of serum creatinine ≤ 1.5 times
8. The upper limit of the normal value of total bilirubin ≤ 1.5 times, except for gilbert's syndrome and leukemia involving organs.
9. Upper limit of serum AST,ALT ≤ 3.0 times normal value, except where leukemia involves organs
10. The subjects of childbearing age agreed to take effective contraceptives during the treatment and 6 months after the completion of the treatment.

Exclusion Criteria:

1. Diagnosed acute promyelocytic leukemia
2. Recent symptomatic central neurosystemic leukemia
3. There are grade 2 or more non-hematological toxicity caused by previous chemotherapy
4. Bone marrow transplants within 100 days of the study
5. Uncontrollable active infections (acute or chronic fungi, bacteria, viruses, or other infections)
6. Major surgical treatment of major organs was performed in the first 4 weeks of the study
7. Radiotherapy was performed within 4 weeks before entering the study
8. Cardiac ejection fraction below 50% or below the lower limit of normal value; patients with prolonged history of qtc (male > 450 Ms, female > 470ms); severe history of heart
9. Hiv positive
10. Active hepatitis B virus infection (hepatitis B virus surface antigen positive and hepatitis B dna quantity ≥ 1 × 10^3copies/ml), hepatitis C virus infection or other liver diseases
11. Pregnant or lactating women
12. There are serious diseases or complications, or diseases that the researchers determine may endanger the safety of the patient or interfere with the study
13. Patients who are not considered to be able to enter the study
14. Treatment is currently under way in another clinical trial or in another clinical trial within four weeks of the commencement of SKLB1028 treatment
15. Patients who have previously received sklb1028 or other FLT3 inhibitors (midostaurin,gilteritinib, quizartinib)