Inclusion Criteria:
1. ≥ 18 years of age
2. Diagnosed with multiple myeloma according to IMWG criteria.
3. Patients who have received only first-line bortezomib-based triple therapy, including bortezomib/lenalidomide/dexamethasone (VRD), bortezomib/thalidomide/dexamethasone (VTD）,bortezomib/ cyclophosphamide/dexamethasone (VCD), and bortezomib/adriamycin//dexamethasone (PAD).
4. Eastern cooperative oncology group(ECOG) score 0-2
5. Patients who develop toxicities associated with bortezomib therapy evaluated by the investigator, including the presence of Grade 1 with pain or Grade 2 peripheral neuropathy (PN), Grade 3 hepatic impairment, Grade 3 diarrhea, and any other Grade 3 non-hematologic adverse events and resulting in bortezomib dose reduction or discontinuation.
6. Patients who agree to and sign informed consents to participate in this study.
Exclusion Criteria:
1. Patients currently participating in other interventional clinical studies (except those currently participating in non-interventional observational studies)
2. Patients who have received prior carfilzomib treatment or participated in carfilzomib associated studies (with or without carfilzomib treatment).
3. Patients with a primary diagnosis of MM combined with plasma cell leukemia (peripheral blood monoclonal plasma cells ≥5% of the total number of differentiated mature leukocytes)
4. Patients who have not fully recovered from the reversible effects of prior chemotherapy (i.e., \<= grade 1 toxicity).
5. Patients with other malignancies diagnosed prior to the MM diagnosis, excluding squamous and basal cell carcinomas of the skin, and carcinoma in situ of the cervix or breast, which can be cured within 3 years with minimal risk of recurrence.
6. Patients with an active systemic infection, active hepatitis B or C virus infection, or known positive test results for human immunodeficiency virus.
7. Evidence of current uncontrolled cardiovascular disease, including hypertension, arrhythmias (prolonged QT interval, ventricular tachycardia, ventricular flutter, ventricular fibrillation, frequent ventricular premature beats (24-hour premature loading of ≥15% of the total number of beats), grade Ⅲ atrioventricular block, and a heart rate of \<30-40 bpm congestive heart failure, unstable angina, or myocardial infarction in the past 3 months,. New York Heart Association (NYHA) class III and IV heart failure. left ventricle ejection fraction（LVEF） \<40% on cardiac ultrasound.
8. Participants with known chronic obstructive pulmonary disease (COPD) (defined as forced expiratory volume in 1 second \[FEV1\] \<50% of predicted normal value), persistent asthma, or a history of asthma within the past 2 years (controlled intermittent asthma or mild persistent asthma that is allowed). Participants with known or suspected COPD must undergo FEV1 testing during screening.
9. Inability to comply with protocol/procedure.
10. Patients with hypersensitivity to the active ingredient or excipients of carfilzomib.
11. Pregnant or lactating women
