Objectives: ASCT has been considered the standard of care for younger patients with NDMM, however, not all the studies published so far have uniformly demonstrated the complete superiority of ASCT over chemotherapy at standard doses. A systematic review and meta-analysis of randomized studies has shown a significant benefit with single ASCT in terms of prolonged progression-free survival (PFS), but not of overall survival (OS). In our retrospective analysis we investigated the impact of high dose (HD) chemotherapy followed by ASCT in special population of patients with high risk cytogenetic profile on the PFS and treatment outcome.
Methods: Retrospective analysis of NDMM patients eligible for HD chemotherapy followed by upfront ASCT in the era of novel agents, who underwent the ASCT in the Department of hematology and oncohematology LF UPJŠ and UNLP Košice in the timeframe of 54 months (from 01/JAN/2019 to 30/JUN/2023). Patients were stratified according to their cytogenetic profile. PFS was defined by the time from ASCT to the disease progression. The OS was defined as the time from the the start of treatment to the death from disease progression. The high risk cytogenetic abnormalities (HRCA) were defined as t(4;14), del(17/17p), t(14;16), t(14;20), nonhyperploidy, gain (1q).
Results: Inclusion criteria were met by 65 patients with NDMM who received HD chemotherpy followed by ASCT. We identified 22 (33.8 %) patients with HRCA and 43 (66.2 %) patients with standard cytogenetic risk. During the monitored period we recorded 4 deaths due to disease progression, all of them in the HCRA subgroup. The response was enhanced by the ASCT in both subgroups. The very good partial response (VGPR) increased from 42 % to 46 % and complete remission (CR) increased from 23 % to 45 % after the ASCT. The number of patients achieving only partial response (PR) decreased from 35 % to 9 % after ASCT. In the subgroup of patients with HRCA the median PFS after ASCT was lower compared to the patients with standard cytogenetic risk (17 vs 38 months). The average PFS in both subgroups was 22.9 months. The median OS in both subgroups was not reached, however the only deaths due to disease progression were recorded in the HRCA subgroup. At the time of analysis, 100 % (43) of patients are alive in the standard cytogenetic subgroup versus 72 % (18) of patients in HRCA subgroup.
Conclusion: HD chemotherapy followed by ASCT remains the standard of care for NDMM eligible for high dose chemotherapy. Our results confirm the benefit of ASCT even in the presence of HRCA. Lower PFS in the HRCA subgroup might indicate the need for more intensive treatment, which may be achieved by tandem ASCT defined as two ASCT performed within a period of no more than six months. Additionally, as three- and four-drug induction therapies are becoming increasingly available and effective, resulting in high minimal residual disease (MRD) negative rates, it is important to continue discussing and further personalizing upfront ASCT to avoid overtreatment and possible toxicities especially in the non-high-risk patient population (Tab. 5, Fig. 2, Ref. 9).
Keywords: autologous stem cell transplantation; multiple myeloma; overall survival high-risk cytogenetics.; progression free survival.