High-Dose Chemotherapy with Early Autologous Stem Cell Transplantation Compared to Standard Dose Chemotherapy or Delayed Transplantation in Patients with Newly Diagnosed Multiple Myeloma: A Systematic Review and Meta-Analysis.

Autologous stem cell transplantation (SCT) is the standard of care for all transplantation-eligible patients diagnosed with multiple myeloma (MM). Various studies have compared clinical outcomes with frontline SCT ("early SCT") versus standard-dose therapy (SDT) alone, with or without salvage SCT ("SDT/late SCT"). In this meta-analysis, we compare overall survival (OS) and progression-free survival (PFS) outcomes between these 2 treatment approaches. Twelve studies were identified, including a total of 3633 patients, of whom 1811 received early SCT and 1822 received SDT/late SCT. In our analysis of all 12 studies, OS was not significantly different between the 2 groups (hazard ratio [HR], .86; 95% confidence interval [CI], .70 to 1.04), but PFS was better with early SCT (HR, .67; 95% CI, .54 to .82). In a subgroup analysis of 3 studies in which novel agents were used for induction, OS again was similar in the 2 groups, and PFS was favorable with early SCT (HR, .50; 95% CI, .36 to .70). This analysis shows that over the years, early SCT has been associated with prolonged PFS, but this did not consequently translate into prolonged OS in patients with newly diagnosed MM. The benefit of early SCT in terms of OS is less clear in the era of novel agents, given the limited follow-up of these studies.