Abstract

Objective: This study aims to investigate the efficacy and safety of chimeric antigen receptor (CAR) T-cell bridging allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the treatment of recurrent and refractory acute B-lymphocytic leukemia (R/R B-ALL) . Methods: A total of 50 R/R B-ALL patients who underwent CAR T-scell therapy to bridge allo-HSCT in the First Affiliated Hospital of Soochow University from January 2017 to May 2019 were retrospectively analyzed. The overall survival (OS) rate, event-free survival (EFS) rate, cumulative recurrence rate (CIR) , and transplant-related mortality (TRM) of patients with different bone marrow minimal residual disease (MRD) levels were analyzed before and after CAR T-cell infusion and before allo-HSCT. Results: The response rate of CAR T-cell therapy and the incidence rate of severe cytokine release syndrome were 92% and 28% , respectively. During 55 infusions, no treatment-related deaths occurred in any of the patients. The median time of CAR T-cell infusion to allo-HSCT was 54 (26-232) days, the median follow-up time after CAR T-cell infusion was 637 (117-1097) days, and the 1-year OS and EFS rates were (80.0±5.7) % and (60.0±6.9) % . The 1-year CIR and TRM after allo-HSCT were (28.0±0.4) % and (8.0±0.2) % . After CAR T-cell infusion and before allo-HSCT, patients with bone marrow MRD<0.01% had a significantly longer EFS [ (70.0±7.2) % vs (20.0±12.6) % , P<0.001; (66.7±7.5) % vs (36.4±14.5) % , P=0.008]and lower CIR [ (25.0±0.5) % vs (70.0±2.6) % , P<0.001; (23.08±0.47) % vs (45.45±2.60) % , P=0.038]. Conclusion: CAR T-cell therapy bridging allo-HSCT is safe and effective for recurrent and refractory B-ALL.

Abstract

Anti-CD19 chimeric antigen receptor (CAR) T-cell therapy is effective in patients with advanced B-cell acute lymphoblastic leukemia (B-ALL). However, efficacy data is sparse in subgroups of patients with high-risk features such as BCR-ABL+, TP53 mutation, extramedullary disease (including central nervous system leukemia) or posttransplant relapse. It is also uncertain whether there is an added benefit of transplantation after anti-CD19 CAR T-cell therapy. We conducted a phase 1/2 study of 115 enrolled patients with CD19+ B-ALL. A total of 110 patients were successfully infused with anti-CD19 CAR T cells. In all, 93% of patients achieved a morphologic complete remission, and 87% became negative for minimal residual disease. Efficacy was seen across all subgroups. One-year leukemia-free survival (LFS) was 58%, and 1-year overall survival (OS) was 64% for the 110 patients. Seventy-five nonrandomly selected patients (73.5%) subsequently received an allogeneic hematopoietic stem cell transplant (allo-HSCT). LFS (76.9% vs 11.6%; P < .0001; 95% confidence interval [CI], 11.6-108.4) and OS (79.1% vs 32.0%; P < .0001; 95% CI, 0.02-0.22) were significantly better among patients who subsequently received allo-HSCT compared with those receiving CAR T-cell therapy alone. This was confirmed in multivariable analyses (hazard ratio, 16.546; 95% CI, 5.499-49.786). Another variate that correlated with worse outcomes was TP53 mutation (hazard ratio, 0.235; 95% CI, 0.089-0.619). There were no differences in complete remission rate, OS, or LFS between groups of patients age 2 to 14 years or age older than 14 years. Most patients had only mild cytokine release syndrome and neurotoxicity. Our data indicate that anti-CD19 CAR T-cell therapy is safe and effective in all B-ALL subgroups that have high-risk features. The benefit of a subsequent allo-HSCT requires confirmation because of nonrandom allocation. This trial was registered at www.clinicaltrials.gov as #NCT03173417.

Abstract

BACKGROUND AIMS The efficacy of CD19-targeted chimeric antigen receptor T (CAR T) cells for treatment of relapsed B-cell malignancies after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and the long-term outcomes of these patients remain inconclusive. METHODS The authors focused on the survival of 35 patients with B-cell acute lymphoblastic leukemia who relapsed after allo-HSCT and received CAR T cells. RESULTS Of the 34 eligible patients, 30 achieved minimal residual disease-negative complete remission (CR), with a total CR rate of 85.7% (79.8-91.6%). There were 14 patients who received various forms of additional therapy after achieving CR. After a median follow-up of 20.7 months, it was noted that 17 patients had relapsed at a median of 4.5 months (2-34 months). The cumulative recurrence rate (RR) at 18 months was 68.3% (57.6-79.0%). Additional treatment did not reduce the RR but seemed to delay the time to relapse (mean: 5.9 months vs 13.1 months; P = 0.046). Patients with a lower tumor burden (=10%) had a lower RR (25.0% vs 78.6% at 12 months; P = 0.006). The overall survival (OS) rate for the CR patients was 30.0% (20.3-29.7%) at 18 months, with a median OS of 12.7 months. CONCLUSIONS The authors' study indicated that for patients who relapsed after HSCT, although a high CR rate was achieved after CAR T therapy, the long-term efficacy was unsatisfactory. It is necessary to optimize additional treatment, including a second HSCT, to further improve long-term efficacy after CAR T infusion.

Abstract

Safety and efficacy of allogeneic anti-CD19 chimeric antigen receptor T cells (CAR-T cells) in persons with CD19-positive B-cell acute lymphoblastic leukemia (B-ALL) relapsing after an allotransplant remain unclear. Forty-three subjects with B-ALL relapsing post allotransplant received CAR-T cells were analyzed. 34 (79%; 95% confidence interval [CI]: 66, 92%) achieved complete histological remission (CR). Cytokine release syndrome (CRS) occurred in 38 (88%; 78, 98%) and was ≥grade-3 in 7. Two subjects died from multiorgan failure and CRS. Nine subjects (21%; 8, 34%) developed ≤grade-2 immune effector cell-associated neurotoxicity syndrome (ICANS). Two subjects developed ≤grade-2 acute graft-versus-host disease (GvHD). 1-year event-free survival (EFS) and survival was 43% (25, 62%). In 32 subjects with a complete histological remission without a second transplant, 1-year cumulative incidence of relapse was 41% (25, 62%) and 1-year EFS and survival, 59% (37, 81%). Therapy of B-ALL subjects relapsing post transplant with donor-derived CAR-T cells is safe and effective but associated with a high rate of CRS. Outcomes seem comparable to those achieved with alternative therapies but data from a randomized trial are lacking.

Abstract

Relapsed/refractory Philadelphia chromosome-positive acute lymphoblastic leukemia (r/r Ph+ ALL) has an extremely poor prognosis. Chimeric antigen receptor T-cell (CART) therapy has acquired unprecedented efficacy in B-cell malignancies, but its role in the long-term survival of r/r Ph+ ALL patients is unclear. We analyzed the effect of CART on 56 adults with r/r Ph+ ALL who accepted split doses of humanized CD19-targeted CART after lymphodepleting chemotherapy. 51/56 (91.1%) achieved complete remission (CR) or CR with inadequate count recovery (CRi), including 38 patients with negative minimal residual disease (MRD) tested by bone marrow BCR-ABL1 copies. Subsequently, 30/51 CR/CRi patients accepted consolidative allogeneic haematopoietic stem cell transplantation (alloHSCT). Their outcomes were compared with those of 21/51 contemporaneous patients without alloHSCT. The 2-year overall survival (OS) and leukemia-free survival (LFS) of CR/CRi patients with alloHSCT were significantly superior to those without alloHSCT (58.9%, CI 49.8-68.0% vs. 22.7%, CI 12.7-32.7%, p = 0.005; 53.2%, CI 43.6-62.8% vs. 18.8%, CI 9.2-28.4%, p = 0.000, respectively). Multivariate analysis revealed that alloHSCT and MRD-negative post-CART were the independent prognostic factors for OS and LFS. CART therapy is highly effective for r/r Ph+ ALL patients, and consolidative alloHSCT could prolong their OS and LFS.

Abstract

The efficacy and safety of donor-derived anti-CD19 CAR T cells vs DLI for the management of relapsed B-cell acute lymphoblastic leukemia (B-ALL) after allo-hematopoietic stem cell transplantation (HSCT) remain unclear. Thirteen B-ALL patients with relapsed after allo-HSCT and thus were treated with donor-derived anti-CD19 CAR T-cell (study group). Fifteen B-ALL patients relapsed after allo-HSCT and thus were treated with DLI (DLI group). The rates of MRD-negative complete remission (61.5%) in the study group were significantly higher than those in the DLI group (13.3%) (p?=?0.02). The complete remission duration in study group and DLI group were median 8.0 months (range, 3-25 months) and 4.4 months (range, 1-25 months; p?=?0.026), respectively. The overall survival of patients in the study group was superior to that of the DLI group: 9.5 months (range,3-25 months) versus 5.5 months (range, 1-25 months; p?=?0.030). One patient with grade 1 acute graft-versus-host disease (aGVHD) was identified in the study group. While five (33.3%) patients in the DLI group developed grades III-IV aGVHD. Three patients (23.07%) developed grade 3 or 4 cytokine release syndrome in the study group. This study suggested that donor-derived anti-CD19 CAR T-cell therapy is promising, safe, and potentially effective for relapsed B-ALL after allo-HSCT and may be superior to DLI.

Abstract

BACKGROUND Consolidative allogeneic hematopoietic stem cell transplantation is a controversial option for patients with relapsed/refractory acute lymphoblastic leukemia after chimeric antigen receptor T cell (CAR-T) therapy. We performed a multicenter retrospective study to assess whether patients can benefit from haploidentical hematopoietic stem cell transplantation after CAR-T therapy. METHODS A total of 122 patients after CAR-T therapy were enrolled, including 67 patients without subsequent transplantation (non-transplant group) and 55 patients with subsequent haploidentical hematopoietic stem cell transplantation (transplant group). Long-term outcome was assessed, as was its association with baseline patient characteristics. RESULTS Compared with the non-transplant group, transplantation recipients had a higher 2-year overall survival (OS; 77.0% versus 36.4%; P < 0.001) and leukemia-free survival (LFS; 65.6% versus 32.8%; P < 0.001). Multivariate analysis showed that minimal residual disease (MRD) positivity at transplantation is an independent factor associated with poor LFS (P = 0.005), OS (P = 0.035), and high cumulative incidence rate of relapse (P = 0.045). Pre-transplant MRD-negative recipients (MRD- group) had a lower cumulative incidence of relapse (17.3%) than those in the non-transplant group (67.2%; P < 0.001) and pre-transplant MRD-positive recipients (MRD+ group) (65.8%; P = 0.006). The cumulative incidence of relapse in MRD+ and non-transplant groups did not differ significantly (P = 0.139). The 2-year LFS in the non-transplant, MRD+, and MRD- groups was 32.8%, 27.6%, and 76.1%, respectively. The MRD- group had a higher LFS than the non-transplantation group (P < 0.001) and MRD+ group (P = 0.007), whereas the LFS in the MRD+ and non-transplant groups did not differ significantly (P = 0.305). The 2-year OS of the MRD- group was higher than that of the non-transplant group (83.3% versus 36.4%; P < 0.001) but did not differ from that of the MRD+ group (83.3% versus 62.7%; P = 0.069). The OS in the non-transplant and MRD+ groups did not differ significantly (P = 0.231). CONCLUSION Haploidentical hematopoietic stem cell transplantation with pre-transplant MRD negativity after CAR-T therapy could greatly improve LFS and OS in patients with relapsed/refractory acute lymphoblastic leukemia. TRIAL REGISTRATION The study was registered in the Chinese clinical trial registry (ChiCTR1900023957).

Abstract

With the increasing use of new regulatory tools, like the Food and Drug Administration's breakthrough designation, there are increasing challenges for European health technology assessors (HTAs) to make an accurate assessment of the long-term value and performance of chimeric antigen receptor T-cell (CAR-T) therapies, particularly for orphan conditions, such as acute lymphoblastic leukaemia. The aim of this study was to demonstrate a novel methodology harnessing longitudinal real-world data, extracted from the electronic health records of a medical centre functioning as a clinical trial site, to develop an accurate analysis of the performance of CAR-T compared with the next-best treatment option, namely allogeneic haematopoietic cell transplant (HCT). The study population comprised 43 subjects in two cohorts: 29 who had undergone HCT treatment and 14 who had undergone CAR-T therapy. The 3-year relapse-free survival probability was 46% (95% CI: 08% to 79%) in the CAR-T cohort and 68% (95% CI: 46% to 83%) in the HCT cohort. To explain the lower RFS probability in the CAR-T cohort compared with the HCT cohort, the authors hypothesised that the CAR-T cohort had a far higher level of disease burden. This was validated by log-rank test analysis (p=0.0001) and confirmed in conversations with practitioners at the study site. The authors are aware that the small populations in this study will be seen as limiting the generalisability of the findings to some readers. However, in consultation with many European HTAs and regulators, there is broad agreement that this methodology warrants further investigation with a larger study.

Abstract

Although chimeric antigen receptor T cells (CAR-T) targeted at CD19 or CD22 have achieved high complete remission (CR) in refractory/relapsed B-cell acute lymphoblastic leukaemia (B-ALL), it is uncertain if allogeneic haematopoietic stem cell transplantation (allo-HSCT) should be performed after CAR-T therapy to accomplish a sustainable remission. Fifty-two cases with relapsed/refractory B-ALL who underwent allo-HSCT after CR by CD19 or CD22 CAR-T were enrolled. The median time from CAR-T infusion to allo-HSCT was 50 (34-98) days. Myeloablative reduced-intensity conditioning (RIC) with total body irradiation/fludarabine-based or busulfan/fludarabine-based regimens was used. Incidences of grade II-IV acute graft-versus-host disease (aGVHD) and severe aGVHD were 23.1% and 5.8% respectively. Of 48 evaluable cases, 16 developed chronic GVHD (cGVHD) and in three of them the pattern was extensive. With a median follow-up of 334 (41-479) days, one-year overall survival and event-free survival (EFS) were 87.7% and 73.0%. One-year relapse rate and transplant-related mortality (TRM) were 24.7% and 2.2% respectively. With quick bridge to allo-HSCT after CAR-T therapy, high EFS for refractory/relapsed B-ALL has been achieved in this relatively large cohort. Our myeloablative RIC regimens have resulted in low incidences of aGVHD, cGVHD, viral reactivation and very low TRM even majority of transplants from haploidentical donors. Long-term follow-up is warranted.

Abstract

Posttransplant relapsed B-cell precursor ALL can be cured by 2nd hematopoietic stem cell transplantation (HSCT) in 20% of patients. The major cause of death after second HSCT is leukemic relapse. One reliable predictor for survival after 2nd-HSCT are posttransplant MRD levels. Patients with detectable or increase of MRD are likely to relapse. Patients in complete molecular remission show the best leukemia-free survival and lowest cumulative incidence (CI) of relapse. As patients who undergo second or subsequent HSCT are high-risk patients, we evaluated the prophylactic use of the chimeric Fc-optimized CD19-4G7SDIE-mAb. Posttransplant relapsed CD19(+) BCP-ALL patients, who underwent a second or subsequent haplo-HSCT from a T- and B-cell depleted graft received posttransplant prophylactic CD19-4G7SDIE-mAb treatment on compassionate use in complete molecular remission, to increase the antileukemic activity of the new reconstituting immune system by recruiting Fc-expressing effector cells. NK cells recovered early and robust. The 3 year overall survival in 15 evaluable patients was 56%, the 3 year event-free survival was 55% and the CI of relapse 38%. Compared to a historical control group, the CI of relapse was markedly lower and consecutively the EFS higher. Posttransplant-targeted therapy may overcome the need for unspecific GvL effect of undesired GvHD, that can cause severe morbidity and mortality. Due to a low adverse event profile the CD19-4G7SDIE-mAb may be suitable for broad administration to consolidate posttransplant MRD negativity.