Outcome improvement over time in reduced intensity conditioning hematopoietic transplantation: a 20-year experience

The current study includes all consecutive patients (N = 484) who received a reduced-intensity conditioning regimen (RIC) allogeneic hematopoietic stem cell transplantation in our center from 1999 to 2020. Conditioning regimens were based on fludarabine with melphalan or busulfan, with low-dose thiotepa and pharmacological GVHD prophylaxis consisted of cyclosporine A (CsA)-methotrexate (MTX)/mofetil (MMF) (n = 271), tacrolimus-sirolimus (n = 145), and post-transplantation cyclophosphamide (PTCy)-tacrolimus (n = 68). The median time of overall follow-up in survivors was 8 years (1-22 years) and was at least 3 years in all three GVHD prophylaxis groups. Thirty-three percent had a high or very high disease risk index, 56% ≥ 4 European bone marrow transplantation risk, and 65% ≥ 3 hematopoietic stem cell transplantation comorbidity index score-age score. Neutrophil and platelet engraftment was longer for PTCy-tacro (p 0.0001). Cumulative incidence of grade III-IV aGVHD was 17% at 200 days, and that of moderate-severe cGvHD was 36% at 8 years. GVHD prophylaxis was the only prognostic factor in the multivariable analyses for the development of aGVHD and moderate-severe cGVHD (p 0.0001). NRM and relapse incidences were 29% and 30% at 8 years, while OS and PFS rates were 43% and 39% at 8 years. At 3 years, OS was highest in the PTCy-tacro group (68%) than in the tacro-siro (61%) and CsA-MTX/MMF (49%) cohorts (p < 0.01). In the three groups, respectively, the 200-day incidence of grade III-IV aGvHD (6% vs. 12% vs. 23%) and 3-year moderate-severe cGVHD (8% vs. 40% vs. 38%) were lower in the PTCy cohort. These better outcomes were confirmed in multivariable analyses. Based on our recent results, the PTCy could be considered as a real GvHD prophylaxis in the RIC setting due to improve best 3-year GvHD and survival outcomes.

Low rate of infectious enterocolitis in allogeneic stem cell transplant recipients with acute diarrhea: A prospective study by the GETH-TC

Acute diarrhea is a common and debilitating complication in recipients of an allogeneic hematopoietic stem cell transplantation (HCT). In this prospective, observational, and multi-center study we examined all episodes occurring in the first 6 months of 142 consecutive adult patients who underwent a reduced-intensity conditioning (RIC) HCT in 10 Spanish tertiary University Hospitals. Fifty-four patients (38%) developed a total of 75 acute diarrhea episodes. The median time from HCT to the first episode was 38 days (4-157). The main cause of enterocolitis was lower GI-aGVHD (38%), followed by infections (21%) and drug-related toxicity (8%). Causative infectious causes were identified in only 16/75 episodes (21%). C. difficile-related infection (CDI) was the most common infectious agent with an incidence and recurrence of 13% and 2%, respectively. With a median follow-up for survivors of 32 months, the NRM and the overall survival (OS) at 1 year, were 20% (95% C.I.: 14-28%) and 69% (95% C.I.: 61-77%), respectively. Development of enterocolitis was not associated with higher NRM (p = 0.37) or worse OS (p = 0.9). This real-life study confirms that the diagnosis and management of acute diarrhea in the early stages after HCT is challenging. Nosocomial infections, seem to be relatively uncommon, probably due to more rational use of antibiotics.

Severe infections and infection-related mortality in a large series of haploidentical hematopoietic stem cell transplantation with post-transplant cyclophosphamide

Severe infections and their attributable mortality are major complications in recipients of allogeneic hematopoietic stem cell transplantation (alloSCT). We herein report 236 adult patients who received haploSCT with PTCy. The median follow-up for survivors was 37 months. The overall incidence of bloodstream infections by gram-positive and gram-negative bacteria at 37 months was 51% and 46%, respectively. The incidence of cytomegalovirus infection was 69%, while Epstein Barr virus infections occurred in 10% of patients and hemorrhagic cystitis in 35% of cases. Invasive fungal infections occurred in 11% at 17 months. The 3-year incidence of infection-related mortality was 19%. The median interval from transplant to IRM was 3 months (range 1–30), 53% of IRM occurred >100 days post-haploSCT. Risk factors for IRM included age >50 years, lymphoid malignancy, and developing grade III-IV acute GvHD. Bacterial infections were the most common causes of IRM (51%), mainly due to gram-negative bacilli BSI. In conclusion, severe infections are the most common causes of NRM after haploSCT with PTCy, with a reemergence of gram-negative bacilli as the most lethal pathogens. More studies focusing on the severe infections after haploSCT with PTCy and differences with other types of alloSCT in adults are clearly warranted.

GVHD prophylaxis with sirolimus-tacrolimus may overcome the deleterious effect on survival of HLA mismatch after reduced-intensity conditioning allo-SCT

Large studies, mostly based on series of patients receiving CSA/tacrolimus (TKR) plus MTX as immunoprophylaxis, have demonstrated a deleterious effect on survival of the presence of a single mismatch out of eight loci after allogeneic hematopoietic SCT (alloHSCT). We retrospectively analyzed a series of 159 adult patients who received sirolimus(SRL)/TKR prophylaxis after alloHSCT. We compared overall outcomes according to HLA compatibility in A, B, C and DRB1 loci at the allele level: 7/8 (n=20) vs 8/8 (n=139). Donor type was unrelated in 95% vs 70% among 7/8 vs 8/8 pairs, respectively (P=0.01). No significant differences were observed in 3-year OS (68 vs 62%), 3-year EFS (53 vs 49%) and 1-year non-relapse mortality (9 vs 13%). Cumulative incidence of grades II-IV acute GVHD (aGVHD) was significantly higher in 7/8 alloHSCT (68% vs 42%, P<0.001) but no significant differences were found for III-IV aGVHD (4.5% vs 11%), overall (35% vs 53%) and extensive (20% vs 35%) chronic GHVD in 7/8 vs 8/8 subgroups, respectively. In summary, the present study indicates favorable outcomes after alloHSCT using the combination of SRL/TKR combination as GVHD prophylaxis with OS in the range of 55-70%, and non-significant differences in overall outcomes, irrespective of the presence of any mismatches at obligatory loci.