Evaluate the Efficacy and Safety of Interferon-α Combined With ATO in the Treatment of Arsenic-resistant APL

Inclusion Criteria:

* 1\. Must sign an informed consent form (ICF) indicating that he or she understands the purpose of, and procedures required for, the study and is willing to participate in the study.
* 2\. Age 18-70 years old (including boundary value);
* 3\. The presence of promyelocytic leukemia-retinoic acid receptor alpha (PML-RARα) confirmed by morphological features, cytogenetic analysis, and real-time quantitative polymerase chain reaction (qPCR);
* 4\. Arsenic relapse resistant patients: patients who had relapsed (including molecular relapse) after remission with ATO in the previous treatment, and could not be relieved after standard treatment;
* 5\. Eastern Cooperative Oncology Group (ECOG) performance status score 0-2;
* 6\. The expected survival time is more than 3 months.

Exclusion Criteria:

* 1\. Allergy or contraindication to any study drug involved in the protocol;
* 2\. Physical examination, electrocardiogram, laboratory examination, vital signs and test related abnormalities are clinically significant (subject to clinician's judgment);
* 3\. Other serious conditions that may limit the patient's participation in the trial, such as severe liver or kidney disease; "Patients with advanced infection, uncontrolled diabetes mellitus, severe cardiac dysfunction (e.g., clinically significant prolongation of the QT interval, potentially fatal torsades de pointes) or a history of angina or major heart disease, autoimmune diseases (as judged by the clinician);"
* 4\. Pregnant or lactating women;
* 5\. Epilepsy and central nervous system dysfunction;
* 6\. Active hepatitis B, active hepatitis A, HIV positive;
* 7\. Participate in other clinical trials at the same time
* 8\. Any condition for which, in the opinion of the investigator, participation would not be in the best interest of the participant (eg, compromise the well-being) or that could prevent, limit, or confound the protocol-specified assessments.