Tandem autologous hematopoietic cell transplantation with sequential use of total marrow irradiation and high-dose melphalan in multiple myeloma

The goal of this phase II trial was to evaluate safety and efficacy of a tandem autologous hematopoietic cell transplantation (auto-HCT) using sequentially total marrow irradiation (TMI) at the dose of 12 Gy (4 Gy on days -3, -2, and -1) and melphalan 200 mg/m(2) for patients with multiple myeloma (MM). TMI was performed using helical tomotherapy. Additional boosts (total 24 Gy) were applied for patients with active lesions as revealed by PET-FDG. Fifty patients with median age 58 years (41-64 years) were included and received tandem auto-HCT. TMI resulted in absolute neutropenia in all patients. Grade 3 infections were reported in 30% patients. Other toxicities were rare. Proportion of patients who achieved at least very good partial response increased from 46% before the first auto-HCT to 82% after tandem transplantation. Complete remission rates changed from 10% to 42%, respectively. The probabilities of overall and progression-free survival at 5 years were 74% and 55%, respectively. No patient died without progression. We conclude that conditioning with TMI +/- PET-guided boosts represents personalized treatment approach in MM and is characterized by very good toxicity profile. Tandem auto-HCT using TMI in sequence with high-dose melphalan appears safe with encouraging early efficacy.

Automated summary

The study aimed to evaluate the safety and efficacy of tandem autologous hematopoietic cell transplantation in patients with multiple myeloma. The results showed that the conditioning with TMI in sequence with high-dose melphalan had very good toxicity profile with encouraging early efficacy, with overall and progression-free survival probabilities at 5 years being 74% and 55%, respectively.