Induction chemotherapy before autologous stem cell transplantation for symptomatic plasma cell myeloma - does it matter?

Autologous stem cell transplantation is the preferred treatment option for younger patients with symptomatic plasma cell myeloma. Most patients with newly diagnosed plasma cell myeloma receive 3-4 cycles of induction chemotherapy to achieve a level of disease control before proceeding to stem cell transplant. The ideal induction regimen for transplant-eligible patients shall allow more patients to proceed with transplant, rapidly and effectively control the disease, reverse disease-related complications, avoid early death, and is associated with minimal acute and long-term toxicities. Because of the concerns of potential damages to hematopoietic stem cells, alkylating agent regimens, specifically melphalan, are usually avoided for induction in transplant-eligible patients. Before the advance of immunomodulatory agents (IMiD) and proteasome inhibitors, the combination of vincristine, adriamycin, and dexamethasone (VAD) and variants were the most commonly used induction regimens. Recent reports as discussed in this review suggests that VAD is no longer the induction chemotherapy of choice for transplant eligible patients. Newer regimens incorporating IMiD and/ or proteasome inhibitor into the induction regimen improve response rates and progression-free survival before and after the transplant and are evolving as the treatment of choice. Here, we review the available data on these newer induction regimens and to evaluate the potential impacts on the patient outcomes.