Impact of High-Risk Cytogenetics and Achievement of Molecular Remission on Long-Term Freedom from Disease after Autologous-Allogeneic Tandem Transplantation in Patients with Multiple Myeloma

Abstract Within a prospective protocol, the incidence and impact of achievement of molecular remission (mCR) and high-risk cytogenetics was investigated in 73 patients with multiple myeloma (MM) after autologous (auto)–allogeneic (allo) tandem stem cell transplantation (SCT). After induction chemotherapy, patients received melphalan 200 mg/m 2 before undergoing auto-SCT, followed 3 months later by melphalan 140 mg/m 2 and fludarabine 180 mg/m 2 before allo-SCT. Sixteen patients had high-risk cytogenetic features, defined by positive FISH for del(17p13) and/or t(4;14). Overall, 66% of the patients achieved CR or near-CR, and 41% achieved mCR, which was sustained negative (at least 4 consecutive samples negative) in 15 patients (21%), with no significant difference in incidence between the patients with high-risk cytogenetics and others ( P  = .70). After a median follow-up of 6 years, overall 5-year progression-free survival was 29%, with no significant difference between del 17p13/t(4;14)-harboring patients and others (24% versus 30%; P  = .70). The 5-year progression-free survival differed substantially according to the achieved remission: 17% for partial remission, 41% for CR, 57% for mCR, and 85% for sustained mCR. These results suggest that auto–allo tandem SCT may overcome the negative prognostic effect of del(17p13) and/or t(4;14) and that achievement of molecular remission resulted in long-term freedom from disease.