Multiple myeloma (MM) is a common hematologic malignancy. With the emergence of a variety of new drugs, the survival rates of patients have increased, however, further discussion on how to achieve deeper and faster remission and reduce recurrence of patients is still needed.

To investigate the efficacy and safety of daratumumab in the chemotherapy of MM.

73 MM patients treated with daletumab in Sichuan Provincial People's Hospital from January 2020 to July 2022 were included as study subjects. Baseline information of the included patients were collected through the electronic medical record system. All patients were treated with daletumab based regimen and followed up through outpatient and inpatient review and telephone once a month when it is not time for review, with the time of first use of darettuzumab since 2020-01-01 as the starting point, death, disease recurrence or end of follow-up as the ending point. Follow-up was up to 2022-07-31 with a median follow-up time of 6.5 (0.5, 26.5) months. Overall response rate (ORR) and complete response rate were used to evaluate the efficacy of the patients. Kaplan-Meier curves were plotted for different drug use, initial renal function, drug administration, cytogenetic risk stratification and M protein types, and compared by Log-rank test.

The median age of the patients was 64 (30, 86) years, including 38 males and 35 females. 28 MM patients were treated with first-line darettuzumab, 13 were switched from other regiments to darettuzumab due to adverse reactions, and 32 patients had relapsed and refractory multiple myeloma (RRMM). 18 patients were lost during follow-up, and a total of 55 patients were available for efficacy assessment. After one course of treatment with the darettuzumab-based chemotherapy regimen, ORR was 72.7% with the complete response rate of 30.9%, including 3.6% (2/55) achieved strin-gent complete response (sCR) and 27.3% (15/55) achieved complete response (CR), 10.9% (6/55) achieved very good partial response (VGPR), 30.9% (17/55) achieved partial response (PR), 9.1% (5/55) achieved minimal response (MR), 12.7% (7/55) achieved stable disease (SD), and 5.5% (3/55) achieved disease progression (PD). The median progress free survival (PFS) of the patients was 6.0 (0.5, 26.5) months, and the median overall survival was 16 (3, 103) months. There was no statistically significant difference in the PFS survival curve between patients treated first-line with darettuzumab and RRMM patients (χ²=3.676, P=0.055). The difference of PFS survival curve between patients with normal and impaired renal function was statistically significant (χ²=12.51, P=0.004). There was a statistically significant difference in the survival curve of patients treated with daletumab + bortezomib + dexamethasone and those treated with daletumab + dexamethasone (χ²=6.691, P=0.009). There was no statistically significant difference in PFS survival curves between patients with non-high risk and high-risk cytogenetic classification (χ²=0.328, P=0.567). There was no statistically significant difference in PFS survival curves among patients with M protein types of IgA, IgG, IgD, light chain, double clone and non-secretory (P>0.05). The main adverse reactions of the patients were infusion reaction and myelosuppression, of which 21 patients had adverse infusion reactions at the first infusion, 21 patients had leukopenia, 40 patients had anemia and 16 patients had thrombocytopenia.

Darettuzumab has good curative effect in MM patients, which can be used as the first-line treatment for newly diagnosed patients, improve the clinical prognosis of RRMM patients, and prolong the survival time of patients.