Modest survival benefits of autologous stem cell transplantation in multiple myeloma with renal impairment: a critical appraisal of the pre-antibody era

The benefit of high-dose melphalan followed by autologous hematopoietic stem cell transplantation (HDM-ASCT) for multiple myeloma (MM) patients with renal insufficiency (RI) is debated. A systematic review and meta-analysis were conducted to assess the safety and efficacy of HDM-ASCT in MM patients with RIs, and the findings were compared with real-world data. The study included 26 articles, 13 of which were pooled for meta-analysis. We compared three different types of MM patients with RI against MM patients with normal renal function (NRF). These patients were: MM patients with RI at the time of transplantation; MM patients with RI at the time of diagnosis; MM patients with RI at diagnosis but with NRF at transplantation. The meta-analysis indicated that MM patients with RIs conditioned with melphalan <= 140 mg/m2 followed by ASCT had transplant-related mortality rates comparable to those without RIs. The complete response rates post-ASCT were similar between MM patients with RIs and those with NRF. Although progression-free survival (PFS) was statistically similar between the groups, MM patients with RIs had significantly poorer overall survival (OS) than those with NRF. The real-world data supported these findings. With a reduced dose of melphalan, ASCT is safe and effective for MM patients with RI. MM patients with RI have similar complete response rates and PFS after ASCT compared to MM patients with NRF. The lower OS in MM patients with RI indicates the need for further research to improve OS in these patients.