Allogeneic hematopoietic cell transplantation for multiple myeloma: A retrospective analysis of the Polish Myeloma Group

Purpose: In this multicenter retrospective analysis of the Polish Myeloma Group we assessed the real-life application of allogeneic transplantations (alloHCT) in multiple myeloma (MM) outside clinical trials in Poland. Methods: Anonymized clinical data of patients who underwent alloHCT were retrospectively collected from eight transplant centers and analyzed to identify factors affecting the outcome. Results: Sixty patients (34 males, 26 females) at median age of 45 (22-59) years who received alloHCT between 1993 and 2016 were included. In this group, 16 (27%) patients underwent myeloablative conditioning and 44 (73%) reduced-intensity conditioning alloHCT. Acute graft versus host disease (GvHD) occurred in 27 (45%) patients, while chronic GvHD was diagnosed in 13 (22%) patients. With the median observation time after alloHCT of 10 months, the relapse rate was 38%. Median progression-free survival (PFS) reached 9 months (0-183) while median overall survival (OS) was 23 months (0-183). Main causes of death included disease progression in 16 (43%), infections in 10 (27%), and GvHD in 7 patients (19%). Presence of chronic GvHD was the only factor associated with prolonged PFS (28 vs. 6 months; p = 0.05), however its impact on OS was not statistically significant (73 vs. 8 months; p = 0.09). Conclusions: In this relatively small and heterogeneous study we observed that alloHCT was associated with high risk of severe complications, but resulted in long-term survival in a proportion of patients. Decisions on optimal indications and timing of the alloHCT in MM need to be taken in the broader context of reported outcomes including data from large studies.