Myeloma Patients Relapsing after First Line Treatment with Tandem Auto/Allo Transplant or Auto Transplant Only Have Similar Outcomes.

Background A better survival in patients with multiple myeloma (MM) progressing after tandem autologous (auto)/allogeneic (allo) hematopoietic stem cell transplantation (HSCT) has been previously reported (Htut M. et al. BBMT 2018), suggesting a persistent graft-versus-multiple myeloma (GvMM) effect even after relapse. We sought to confirm this observation in a homogeneous cohort of MM patients who relapsed after upfront tandem auto/allo HSCT in our institution. Methods 92 consecutive, newly diagnosed MM patients who received tandem auto/allo HSCT were paired with 81 patients who received auto HSCT only between 2001 and 2010. Patients pairing criteria were age ≤ 65 years at diagnosis, Durie-Salmon 1B, 2 or 3, a glomerular filtration rate ≥ 60 mL/min, only one line of induction treatment, absence of progression within 4 months of auto HSCT and cytogenetics (if available). After their 1st auto HSCT with high dose melphalan, all allo transplant recipients received an outpatient nonmyeloablative conditioning of fludarabine 30 mg/m2 and cyclophosphamide 300 mg/m2 × 5 days followed by G-CSF mobilized stem cells from a matched sibling donor. Results Median age in the auto/allo group was 53 years, compared to 57 years in the auto group (p Conclusion Tandem auto/allotransplant enables long-term survival and offers a potentially curative option in selected newly diagnosed MM patients. At time of 1st relapse, tandem auto/allo transplant does not confer a significant outcome advantage compared to auto HSCT only.