Allogeneic Stem Cell Transplantation in Refractory Acute Myeloid Leukaemia.

Refractory acute myeloid leukaemia is very difficult to treat and represents an unmet clinical need. In recent years, new drugs and combinations of drugs have been tested in this category, with encouraging results. However, all treated patients relapsed and died from the disease. The only curative option is allogeneic transplantation through a graft from a healthy donor immune system. Using myeloablative conditioning regimens, the median overall survival regimens is 19%. Several so-called sequential induction chemotherapies followed by allogeneic transplantation conditioned by reduced intensity regimens have been developed, improving the overall survival to 25-57%. In the allogeneic transplantation field, continuous improvements in practices, particularly regarding graft versus host disease prevention, infection prevention, and treatment, have allowed us to observe improvements in survival rates. This is true mainly for patients in complete remission before transplantation and less so for refractory patients. However, full myeloablative regimens are toxic and carry a high risk of treatment-related mortality. In this review, we describe the results obtained with the different modalities used in more recent retrospective and prospective studies. Based on these findings, we speculate how allogeneic stem cell transplantation could be modified to maximise its therapeutic effect on refractory acute myeloid leukaemia.

The place of allogeneic stem cell transplantation in aggressive B-cell non-Hodgkin lymphoma in the era of CAR-T-cell therapy.

Chimeric antigen receptor T (CAR-T) cells are a treatment option for patients with relapse/refractory (R/R) non-Hodgkin lymphoma (NHL), acute lymphoid leukemia and multiple myeloma. To date, diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL), follicular lymphoma (FL), and chronic lymphocytic leukemia (CLL) have been successfully treated with CAR-T cells directed against the CD19 antigen. However, when R/R disease persists after several treatment lines, patients with these diseases are often referred to transplantation centres to receive allogeneic stem cell transplantation (ALLO-SCT). ALLO-SCT and CAR-T cells share mechanism of actions, inducing immune effects of T-cells (and other cells after transplantation) against lymphoma cells, but they differ in several other characteristics. These differences justify unique positioning of each therapy within treatment algorithms. In this paper, we analyzed the results obtained after ALLO-SCT and CAR-T-cell therapy in patients with aggressive lymphomas (large B-cell lymphoma and MCL) to identify the ideal scenarios in which these 2 immunological therapies should be employed.

Myeloablative conditioning with thiotepa-busulfan-fludarabine does not improve the outcome of patients transplanted with active leukemia: final results of the GITMO prospective trial GANDALF-01.

The outcome of refractory/relapsed (R/R) acute leukemias is still dismal and their treatment represents an unmet clinical need. However, allogeneic transplantation (allo-HSCT) remains the only potentially curative approach in this setting. A prospective study (GANDALF-01, NCT01814488; EUDRACT:2012-004008-37) on transplantation with alternative donors had been run by GITMO using a homogeneous myeloablative conditioning regimen with busulfan, thiotepa and fludarabine while GVHD prophylaxis was stratified by donor type. The study enrolled 101 patients; 90 found an alternative donor and 87 ultimately underwent allo-HSCT. Two-year overall survival of the entire and of the transplant population (primary endpoint) were 19% and 22%, without significant differences according to disease, donor type and disease history (relapsed vs refractory patients). Two-year progression-free survival was 19% and 17% respectively. The cumulative incidences of relapse and non-relapse mortality were 49% and 33% at two years. Acute grade II-IV and chronic GVHD occurred in 23 and 10 patients. Dose intensification with a myeloablative two-alkylating regimen as sole strategy for transplanting R/R acute leukemia does seem neither to improve the outcome nor to control disease relapse. A pre-planned relapse prevention should be included in the transplant strategy in this patient population.

Letermovir Prophylaxis for Cytomegalovirus Infection in Allogeneic Stem Cell Transplantation: A Real-World Experience.

Despite effective treatments, cytomegalovirus (CMV) continues to have a significant impact on morbidity and mortality in allogeneic stem cell transplant (allo-SCT) recipients. This multicenter, retrospective, cohort study aimed to evaluate the reproducibility of the safety and efficacy of commercially available letermovir for CMV prophylaxis in a real-world setting. Endpoints were rates of clinically significant CMV infection (CSCI), defined as CMV disease or CMV viremia reactivation within day +100-+168. 204 adult CMV-seropositive allo-SCT recipients from 17 Italian centres (median age 52 years) were treated with LET 240 mg/day between day 0 and day +28. Overall, 28.9% of patients underwent a haploidentical, 32.4% a matched related, and 27.5% a matched unrelated donor (MUD) transplant. 65.7% were considered at high risk of CSCI and 65.2% had a CMV seropositive donor. Low to mild severe adverse events were observed in 40.7% of patients during treatment [gastrointestinal toxicity (36.3%) and skin rash (10.3%)]. Cumulative incidence of CSCI at day +100 and day +168 was 5.4% and 18.1%, respectively, whereas the Kaplan-Meier event rate was 5.8% (95% CI: 2.4-9.1) and 23.3% (95% CI: 16.3-29.7), respectively. Overall mortality was 6.4% at day +100 and 7.3% at day +168. This real-world experience confirms the efficacy and safety of CMV.

The role of ponatinib in adult BCR-ABL1 positive acute lymphoblastic leukemia after allogeneic transplantation: a real-life retrospective multicenter study.

The experience of third-generation tyrosine kinase inhibitor ponatinib treatment in Philadelphia chromosome-positive acute lymphoblastic leukaemia (Ph'+ ALL) patients post-allogeneic transplantation is limited. We retrospectively collected data on 25 Ph'+ ALL patients who were started on ponatinib after allogeneic transplantation between July 2015 and July 2019 from nine transplantation centers in Italy. Ponatinib was given in prophylaxis in five (20%), as pre-emptive treatment in seven (28%), and as salvage therapy in thirteen (52%) patients. It was combined with donor leukocyte infusions in ten patients. Half of the patients (12/25) harbored T315I mutation of BCR/ABL1, while in the remaining mutational analysis was negative or not performed. Among the 20 patients who received ponatinib as pre-emptive/salvage treatment, complete molecular response was achieved in 15 (75%) patients. Estimated overall survival at 2-year post-initiation of treatment in the whole cohort was 65% (respectively 60%, 60%, and 78% for the prophylaxis, pre-emptive, and salvage therapy groups). In patients with T315I-positive mutational status, the estimated 2-year survival was 40%. Fourteen patients (56%) experienced toxicity, requiring temporary or definitive suspension of treatment. In conclusion, treatment of Ph'+ ALL patients with ponatinib after transplantation is effective, although the question of adequate drug dose and treatment duration remains unanswered.