[A Propensity Score Matching Study of Autologous Hematopoietic Stem Cell Transplantation and New Drug Chemotherapy...

To compare the clinical efficacy, survival, and prognosis of autologous hematopoietic stem cell transplantation (ASCT) with new drug chemotherapy in the treatment of newly diagnosed multiple myeloma (NDMM) in the new drug era.

The clinical data of 149 patients with NDMM treated with new drug induction regimen in Union Hospital, Tongji Medical College, Huazhong University of Science and Technology from January 2012 to December 2019 were retrospectively analyzed. Twenty-four patients who received ASCT were in ASCT group, and 125 patients who did not receive ASCT were in non-ASCT group. The median follow-up time was 43 (1-90) months. The propensity score matching (PSM) method was used to balance confounding factors, then depth of response, overall survival (OS), and progression-free survival (PFS) between the two groups were compared and subgroup analysis was performed.

After matching, the covariates were balanced between the two groups. Fifty-one patients (15 cases in ASCT group and 36 cases in non-ASCT group) were included. ASCT patients had a better complete response (CR) rate than non-ASCT patients receiving maintenance therapy (93.3% vs 42.3%, P=0.004), while there were no statistical differences in deep response rate and overall response rate (ORR) between the two groups (93.3% vs 65.4%, P=0.103; 93.3% vs 96.2%, P=1.000). Before matching, the 3 and 5-year PFS rate and median PFS (mPFS) in ASCT group and non-ASCT group were [89.6% vs 66.5%, P=0.024; 69.8% vs 42.7%; non-response (NR) vs 51.0 months], and the 3 and 5-year OS rate and median OS (mOS) were (100% vs 70.6%, P=0.002; 92.3% vs 49.6%; NR vs 54.0 months). After matching, the 3 and 5-year PFS rate and mPFS in ASCT group and non-ASCT group were (83.6% vs 61.7%, P=0.182; 62.7% vs 45.7%; NR vs 51.0 months), the 3 and 5-year OS rate and mOS were (100% vs 65.6%, P=0.018; 88.9% vs 46.9%; NR vs 51.0 months). Subgroup analysis showed that patients with mSMART 3.0 high risk stratification, the 3-year PFS rate and mPFS in ASCT group and non-ASCT group were (83.3% vs 41.5%, P=0.091; NR vs 34.0 months), and the 3-year OS rate and mOS were (100% vs 41.5%, P=0.034; NR vs 34.0 months). Patients with mSMART 3.0 standard risk stratification, the 3-year PFS rate and OS rate in ASCT group and non-ASCT group were (83.3% vs 76.8%, P=0.672; 100% vs 87.2%, P=0.155). The 3-year PFS and OS rate in MM patients who achieved deep response within 3 months after transplantation compared with non-ASCT patients who achieved deep response after receiving maintenance therapy were (83.1% vs 56.7%, P=0.323; 100% vs 60.5%, P=0.042), and the 3-year PFS and OS rate in patients who achieved overall response in both groups were (83.1% vs 62.5%, P=0.433; 100% vs 68.1%, P=0.082). After matching, Cox multivariate regression analysis showed that mSMART 3.0 risk stratification and ASCT were independent prognostic factors for OS.

In the new drug era, ASCT can increase CR rate and prolong OS of NDMM patients. ASCT patients who are mSMART 3.0 high risk stratification or achieved deep response within 3 months after transplantation have better OS than non-ASCT patients receiving new drug chemotherapy. ASCT and mSMART 3.0 risk stratification are independent prognostic factors for OS in NDMM patients.