Outcomes of HLA-mismatched HSCT with TCRαβ/CD19 depletion or post-HSCT cyclophosphamide for inborn errors of immunity

HLA-mismatched transplants with either in vitro depletion of CD3+TCRαβ/CD19 (TCRαβ) cells or in vivo T-cell depletion using post-transplant cyclophosphamide (PTCY) have been increasingly used for patients with inborn errors of immunity (IEI). We performed a retrospective multicenter study via the EBMT registry on 306 children with IEI undergoing first transplant between 2010-2019 from an HLA-mismatched donor using TCRαβ (n=167) or PTCY (n=139). Median age at HSCT was 1.2 years (range, 0.03-19.6 years). The 3-year overall survival (OS) was 78% (95% confidence interval (CI), 71-84%) after TCRαβ and 66% (57-74%) after PTCY (p=0.013). Pre-HSCT morbidity score (hazard ratio (HR) 2.27, 1.07-4.80, p=0.032) and non-Busulfan/Treosulfan conditioning (HR 3.12, 1.98-4.92, p<0.001) were the only independent predictors of unfavorable OS. The 3-year event-free survival (EFS) was 58% (50-66%) after TCRαβ and 57% (48-66%) after PTCY (p=0.804). Cumulative incidence of severe acute GvHD was higher after PTCY (15%, 9-21%) than TCRαβ (6%, 2-9%, p=0.007), with no difference in chronic GvHD (PTCY, 11%, 6-17%; TCRαβ, 7%, 3-11%, p=0.173). The 3-year GvHD-free EFS was 53% (44-61%) after TCRαβ and 41% (32-50%) after PTCY (p=0.080). PTCY had significantly higher rates of veno-occlusive disease (14.4% versus TCRαβ 4.9%, p=0.009), acute kidney injury (12.7% versus 4.6%, p=0.032) and pulmonary complications (38.2% versus 24.1%, p=0.017). Adenoviraemia (18.3% versus PTCY 8.0%, p=0.015), primary graft failure (10%, versus 5%, p=0.048), and second HSCT (17.4% versus 7.9%, p=0.023) were significantly higher in TCRαβ. In conclusion, this study demonstrates that both approaches are suitable options in IEI patients, although characterized by different advantages and outcomes.

Impact of prior JAK-inhibitor therapy with ruxolitinib on outcome after allogeneic hematopoietic stem cell transplantation for myelofibrosis: a study of the CMWP of EBMT

JAK1/2 inhibitor ruxolitinib (RUX) is approved in patients with myelofibrosis but the impact of pretreatment with RUX on outcome after allogeneic hematopoietic stem cell transplantation (HSCT) remains to be determined. We evaluated the impact of RUX on outcome in 551 myelofibrosis patients who received HSCT without (n = 274) or with (n = 277) RUX pretreatment. The overall leukocyte engraftment on day 45 was 92% and significantly higher in RUX responsive patients than those who had no or lost response to RUX (94% vs. 85%, p = 0.05). The 1-year non-relapse mortality was 22% without significant difference between the arms. In a multivariate analysis (MVA) RUX pretreated patients with ongoing spleen response at transplant had a significantly lower risk of relapse (8.1% vs. 19.1%; p = 0.04)] and better 2-year event-free survival (68.9% vs. 53.7%; p = 0.02) in comparison to patients without RUX pretreatment. For overall survival the only significant factors were age > 58 years (p = 0.03) and HLA mismatch donor (p = 0.001). RUX prior to HSCT did not negatively impact outcome after transplantation and patients with ongoing spleen response at time of transplantation had best outcome.

Impact of spleen size and splenectomy on outcomes of allogeneic hematopoietic cell transplantation for myelofibrosis: A retrospective analysis by the chronic malignancies working party on behalf of European society for blood and marrow transplantation (EBMT)

The role of spleen size and splenectomy for the prediction of post-allogeneic hematopoietic stem cell transplant (allo-HCT) outcome in myelofibrosis remains under debate. In EBMT registry, we identified a cohort of 1195 myelofibrosis patients transplanted between 2000-2017 after either fludarabine-busulfan or fludarabine-melphalan regimens. Overall, splenectomy was performed in 202 (16.9%) patients and its use decreased over time (28.3% in 2000-2009 vs 14.1% in 2010-2017 period). By multivariate analysis, splenectomy was associated with less NRM (HR 0.64, 95% CI 0.44-0.93, P = .018) but increased risk of relapse (HR 1.43, 95% CI 1.01-2.02, P = .042), with no significant impact on OS (HR 0.86, 95% CI 0.67-1.12, P = .274). However, in subset analysis comparing the impact of splenectomy vs specific spleen sizes, for patients with progressive disease, an improved survival was seen in splenectomised subjects compared to those patients with a palpable spleen length ≥ 15 cm (HR 0.44, 95% CI 0.28-0.69, P < .001), caused by a significant reduction in NRM (HR 0.26, 95% CI 0.14-0.49, P < .001), without significantly increased relapse risk (HR 1.47, 95% CI 0.87-2.49, P = .147). Overall, despite the possible biases typical of retrospective cohorts, this study highlights the potential detrimental effect of massive splenomegaly in transplant outcome and supports the role of splenectomy for myelofibrosis patients with progressive disease and large splenomegaly.

An international survey on the management of patients receiving CAR T-cell therapy for haematological malignancies on behalf of the Chronic Malignancies Working Party of EBMT

PURPOSE OF THE STUDY

Two chimeric antigen receptor (CAR) T-cell therapies - Tisagenlecleucel (Kymriah^™) and Axicabtagene ciloleucel (Yescarta^™) - have been approved for commercial use. In order to inform forthcoming EBMT guidelines on the management of adults and children undergoing autologous CAR T-cell therapy, we undertook a survey of experienced clinicians.

METHODS

An online survey with a dual focus on (1) 'real world' patient eligibility criteria and (2) models of care for patient follow-up was sent to experienced physicians.

RESULTS

There were 41 respondents (10 countries) and 93% worked in FACT-JACIE-accredited transplant centres. Most felt that a history of malignancy (57%), prior allo-HCT for B-NHL (78%-81%) and prior treatment with anti-CD19/CD3 BiTE antibodies (76%-86%) do not constitute contra-indications to CAR T therapy. Clinicians were divided as to whether CNS involvement represented an exclusion criterion. There was agreement that patients with viral infections (HIV, Hepatitis B or Hepatitis C) are not eligible. There is no common model of care for long-term follow-up. Most respondents believed that patients should attend the hospital two (43%) to three (33%) times weekly during the first month following discharge. A majority (69%) of respondents work in centres where there is an MDT meeting with a specific focus on follow-up following CAR T Therapy. Follow-up care is currently delivered either in HCT or haematology-oncology outpatient clinics.

CONCLUSION

The responses reveal wide variation in perceived patient eligibility criteria and highlight the need for consensus guidelines. The findings also illustrate the embryonic nature of current follow-up arrangements.