Modified cladribine, cytarabine, and G-CSF as a salvage regimen in patients with relapsed/refractory acute myeloid leukemia: a bridge to myeloablative allogeneic hematopoietic stem cell transplantation

Impact of cladribine, cytarabine, and G-CSF (CLAG) as a bridging therapy prior to allogeneic hematopoietic stem cell transplantation in relapsed or refractory acute myeloid leukemia

The combination of cladribine, cytarabine, and G-CSF (CLAG) has exhibited robust synergistic anti-leukemia activity as an induction therapy (IT) in acute myeloid leukemia (AML). However, the impact of CLAG as a bridging therapy (BT) administered between IT and allogeneic hematopoietic stem cell transplantation (allo-HSCT) for patients with relapsed or refractory (R/R) AML remains uncertain. In this retrospective study, we examined the efficacy of CLAG as a transitional strategy prior to allo-HSCT in R/R AML. We included 234 patients with R/R AML who received the modified busulfan plus cyclophosphamide conditioning regimen for allo-HSCT in our center during the past 6 years, performed a propensity-score matching analysis, partitioned them into four distinct cohorts, and further integrated them into the CLAG group and non-CLAG group based on response to IT and utilization of CLAG. Our cohorts encompassed 12 patients in Cohort A (modified composite complete remission (mCRc) after IT, CLAG), 31 in Cohort B (mCRc after IT, non-CLAG), 35 in Cohort C (non-complete remission (non-CR) after IT, CLAG), and 80 in Cohort D (non-CR after IT, non-CLAG). Intriguingly, among patients with non-CR status, the administration of CLAG correlated with a notably statistically diminished risk of relapse and improved survival at 2-year follow-up (Cohort C vs. Cohort D). Employing CLAG as a BT prior to allo-HSCT demonstrates substantial effectiveness, a relative degree of safety, and manageable toxicity in selected R/R AML cases.

[A comparison of C+SCAV and SEAM conditioning regimens in efficacy and safety in autologous hematopoietic stem cell transplantation for non-Hodgkin's lymphoma patients]

Objective: This study aimed to compare the efficacy and safety of cladribine, smustine, etoposide, cyclophosphamide, and cytarabine (C+SCAV) and smustine, etoposide, cytarabine, and melphalan (SEAM) conditioning regimens in autologous stem cell transplantation (auto-HSCT) for non-Hodgkin's lymphoma (NHL) . Methods: A retrospective analysis was conducted on 61 NHL patients who received auto-HSCT in the Department of Hematology, the First Affiliated Hospital of Suzhou University, from March 2018 to May 2021. The C + SCAV group and SEAM group had 19 and 42 patients, respectively. Results: ① Among the 61 patients with NHL, 37 were male and 24 were female. The median age was 48 (21-66) years old. There were 19 cases in the C+SCAV group and 42 cases in the SEAM group. There was no significant difference in the baseline characteristics between the two groups (P>0.05) . ② The median time to neutrophil and platelet engraftment in the C+SCAV cohort were 10 (8-15) days and 13 (9-22) days, respectively, which does not differ from the SEAM group (P=0.103, P=0.403) . ③ No differences existed between the two groups in terms of survival. The 1-year progression-free survival (PFS) was (76.5±10.3) % for patients receiving C+SCAV and (78.4±6.8) % for those who received SEAM (P=0.841) . The 1-year overall survival was 100.0% for the C+SCAV group and 95.2±3.3% for the SEAM group (P=0.339) . ④The 1-year PFS of patients with complete remission in the C+SCAV group was similar to those who in the SEAM group [ (92.3±7.4) % vs (82.5±7.2) %, P=0.406]. ⑤ The incidence of non-hematological serious adverse events (≥ grade 3) in the C+SCAV group and SEAM group were 10.5% (2/19) and 40.5% (17/42) (P=0.013) , the incidence of severe mucositis was 5.3% (1/19) and 31.0% (13/42) (P=0.015) , and the incidence of severe infection (≥ grade 3) was 10.5% (2/19) and 19.0% (8/42) (P=0.389) , respectively. Conclusion: C + SCAV conditioning regimen appeared to be no different from the SEAM regimen in terms of survival. It can lower the incidence of SAE and does not increase the risk of severe infection. As a result, it can be used as an alternative conditioning regimen for lymphoma patients undergoing auto-HSCT.

Clinical Outcomes in Patients with FLT3-ITD-Mutated Relapsed/Refractory Acute Myelogenous Leukemia Undergoing Hematopoietic Stem Cell Transplantation after Quizartinib or Salvage Chemotherapy in the QuANTUM-R Trial

Despite the substantial clinical activity of fms-related tyrosine kinase 3 (FLT3) inhibitors in relapsed or refractory (R/R) FLT3-ITD‒positive acute myelogenous leukemia (AML), durable remissions and prolonged survival in this population require allogeneic hematopoietic stem cell transplantation (allo-HSCT). Quizartinib, a once-daily oral, highly potent, and selective FLT3 inhibitor, significantly prolonged overall survival (OS) and improved clinical benefit compared with salvage chemotherapy (median OS, 6.2 months versus 4.7 months; hazard ratio [HR], .76; 95% confidence interval [CI], .58 to .98; P = .018; composite complete remission [CRc] rate, 48% versus 27%; median duration of CRc, 2.8 months versus 1.2 months; mortality rate, .8% versus 14% by day 30, 7% versus 24% by day 60) in patients with R/R FLT3-ITD AML in the phase 3 QuANTUM-R trial. In this post hoc analysis, we described the characteristics of and clinical outcomes in patients who underwent on-study HSCT in QuANTUM-R at the investigator's discretion and institutional practices. Of 367 randomized patients, 78 (32%) in the quizartinib arm and 14 (11%) in the salvage chemotherapy arm underwent on-study allo-HSCT without any intervening therapy for AML after quizartinib or study-specified salvage chemotherapy. Pooled data of patients from both treatment arms showed a longer median overall survival (OS) in transplant recipients versus those treated without allo-HSCT (12.2 months versus 4.4 months; HR, .315; 95% CI, .233 to .427). Pooled data also showed a longer median OS in patients with a last recorded response of CRc before allo-HSCT versus patients without a CRc (20.1 months versus 8.8 months; HR, .506; 95% CI, .296 to .864). By treatment arm, the median OS was 25.1 months with quizartinib and 20.1 months with salvage chemotherapy in patients with a last recorded response of CRc before allo-HSCT. Forty-eight patients in the quizartinib arm continued quizartinib treatment after allo-HSCT. In the 31 patients with a last recorded response of CRc before allo-HSCT who continued quizartinib after allo-HSCT, the median OS was 27.1 months. Continuation of quizartinib after allo-HSCT was tolerable, and no new safety signals were identified. These results suggest that post-transplantation survival following salvage chemotherapy and quizartinib treatment are similar. However, quizartinib response occurs more frequently than with salvage chemotherapy, potentially allowing more patients to undergo transplantation and achieve durable clinical benefit. In addition, post-transplant quizartinib was found to be tolerable and may be associated with prolonged survival in some patients, highlighting its potential value in the management of patients with FLT3-ITD R/R AML.