Description

Multiple myeloma (MM) is the second most common hematologic malignancy in adults. Overall survival (OS) in MM has improved significantly in the last 15 years with the emergence of novel therapies such as thalidomide, bortezomib and lenalidomide. The median life expectancy of patients with MM treated in the current era is more than 6 years, while SEER data from a slightly earlier time period (2008-12) estimated the 5 year survival at 48.5%. However, prognosis is not uniform and varies considerably based on a presenting features and response to therapy.

The current standard of care for MM patients fit to undergo high dose conditioning chemotherapy is an autologous HCT (autoHCT). There is controversy regarding the timing of autoHCT after initial novel therapy induction with randomized trials showing similar OS whether done early or delayed to time of relapse as salvage therapy. However, more recent trials comparing early versus delayed transplant support the benefit of early upfront autoHCT.

Allogeneic HCT (alloHCT) is the only potentially curative therapy available to patients with MM. However, the significant morbidity and mortality of this procedure historically limited its application in older patients. Current data from the Center for International Blood and Marrow Research (CIBMTR) show transplant-related mortality rates of 23 (20-26)% at 5 years with myeloablative conditioning.

Thus, although potentially curative, standard risk MM patients have excellent prognoses in the era of novel therapies which reduces the overall benefit of alloHCT. However, because the outcomes for high-risk MM remain poor despite the best available standard therapies (overall survival of 24-36 months), initial data suggest that alloHCT should be explored in this subset.