Allogeneic stem cell transplantation (allo-SCT) for de novo Ph+ AML: a study from the French Society of Bone Marrow Transplantation and Cell Therapy

Imatinib with intensive chemotherapy in AML with t(9;22)(q34.1;q11.2)/BCR::ABL1. A DATAML registry study

Acute myeloid leukemia (AML) with t(9;22) (q34.1; q11.2)/BCR::ABL1, a distinct entity within the group of AML with defining genetic abnormalities, belong to the adverse-risk group of the 2022 ELN classification. However, there is little data on outcome since the era of tyrosine kinase inhibitors. Among 5819 AML cases included in the DATAML registry, 20 patients with de novo BCR::ABL1+AML (0.3%) were identified. Eighteen patients treated with standard induction chemotherapy were analyzed in this study. Imatinib was added to chemotherapy in 16 patients. The female-to-male ratio was 1.25 and median age was 54 years. The t(9;22) translocation was the sole chromosomal abnormality in 12 patients. Main gene mutations detected by NGS were ASXL1, RUNX1 and NPM1. Compared with patients with myeloid blast phase of chronic myeloid leukemia (CML-BP), de novo BCR::ABL1+AML had higher WBC, fewer additional chromosomal abnormalities, lower CD36 or CD7 expression and no ABL1 mutations. Seventeen patients (94.4%) achieved complete remission (CR) or CR with incomplete hematologic recovery. Twelve patients were allografted in first remission. With a median follow-up of 6.3 years, the median OS was not reached and 2-year OS was 77% (95% CI: 50-91). Four out of five patients who were not transplanted did not relapse. Comparison of BCR::ABL1+AML, CML-BP, 2017 ELN intermediate (n = 643) and adverse-risk patients (n = 863) showed that patients with BCR::ABL1+AML had a significant better outcome than intermediate and adverse-risk patients. BCR::ABL1+AML patients treated with imatinib and intensive chemotherapy should not be included in the adverse-risk group of current AML classifications.

Allogeneic hematopoietic cell transplantation for acute myeloid leukemia with BCR::ABL1 fusion

BCR::ABL1 fusion is found in < 1% of de novo acute myeloid leukemia (AML) cases and confers a poor prognosis. This Japanese nationwide survey analyzed patients with AML (n = 22) and mixed phenotype acute leukemia (MPAL) (n = 10) with t(9;22) or BCR::ABL1 who underwent allogeneic hematopoietic cell transplantation (allo-HCT) between 2002 and 2018. The 3-year overall survival (OS) rates were 81.3% and 56.0%, respectively (p = 0.15), and leukemia-free survival (LFS) rates were 76.2% and 42.0%, respectively (p = 0.10) in patients with AML and MPAL. The relapse rates were 9.5% and 14.0% (p = 0.93), and the non-relapse mortality (NRM) rates were 14.3% and 44.0%, respectively (p = 0.10) in patients with AML and MPAL. One in 17 patients with AML, with pre-transplant tyrosine kinase inhibitors (TKI), and three in five patients with AML, without pre-transplant TKI, did not achieve complete remission (CR) before allo-HCT (p = 0.024). Among the 20 patients with known disease status after allo-HCT, 95.0% were in hematological or molecular CR. None of the four patients who received post-transplant TKI for prophylaxis or measurable residual disease relapse experienced hematological relapse. In conclusion, our results suggest that pre-transplant TKI could improve disease status before allo-HCT. Moreover, allo-HCT resulted in high OS, high LFS, low relapse, and low NRM rates in patients with AML with BCR::ABL1.

Molecular genetic characterization of Philadelphia chromosome-positive acute myeloid leukemia

BACKGROUND

Philadelphia chromosome-positive acute myeloid leukemia (Ph+ AML) is a provisional disease entity in the 2016 WHO classification, while its genetic profile of Ph+ AML remains poorly defined. In addition, the differentiating features of Ph+ AML and chronic myeloid leukemia in myeloid blast crisis (CML-MBC) remain controversial.

METHODS

We conducted a retrospective study of 15 Ph+ AML patients to compare their clinical and laboratory profiles with 27 CML-MBC patients.

RESULTS

Compared to CML-MBC, Ph+ AML patients presented with significantly higher peripheral WBC count and bone marrow blast percentage. The immunophenotypic profiles were largely similar between Ph+ AML and CML-MBC, except for CD4 expression, which was significantly enriched in CML-MBC. Ph+ AML patients less frequently harboured co-occurring additional cytogenetic abnormalities (ACA) compared to CML-MBC, and trisomy 19 (23%) and IDH1/2 (46%) were the most common ACA and mutated genes in Ph+ AML, respectively. Overall survival (OS) did not significantly differ between Ph+ AML and CML-MBC. Ph+ AML without CML-like features appeared to have a better outcome compared to Ph+ AML with CML-like features; ACA in Ph+ AML may confer an even worse prognosis.

CONCLUSIONS

Our results indicate that patients with Ph+ AML share similar genetic profiles and clinical outcomes with those with CML-MBC, thus should be classified as a high-risk entity.

Allogeneic hematopoietic cell transplantation efficacy in patients with Philadelphia chromosome-positive acute myeloid leukemia in complete remission

Philadelphia chromosome-positive acute myeloid leukemia (Ph+ AML) confers a dismal prognosis when treated with chemotherapy alone. Data on allogeneic hematopoietic cell transplantation (allo-HCT) outcomes are limited. We retrospectively analyzed 4649 AML patients who received allo-HCT and were in complete remission. Outcomes of Ph+ AML (n = 30), intermediate-risk, and poor-risk AML patients were compared. The 3-year overall survival after allo-HCT was similar in intermediate-risk (62.7%; 95% CI: 61.0-64.3%) and Ph+ AML (73.3%; 95% CI: 51.5-86.4%) groups (P = 0.42); however, it differed significantly between the poor-risk (49.7%; 95% CI: 45.9-53.4%) and Ph+ AML (73.3%; 95% CI: 51.5-86.4%) groups (P = 0.049). Disease-free survival in Ph+ AML patients was comparable to that in intermediate-risk patients but better than that in poor-risk patients. Relapse rates were significantly lower in Ph+ AML patients than in other groups. Non-relapse mortality (NRM) rates were similar among groups. Multivariate analysis showed that Ph+ AML was not a significant predictor of poor prognosis in terms of overall survival, disease-free survival, relapse, and NRM. Our data showed better post-transplant outcomes for Ph+ AML patients than for those with poor-risk AML. Hence, allo-HCT could be a feasible treatment option for Ph+ AML patients.

Impact of an Additional Chromosome on the Clinical Outcomes of Hematopoietic Stem Cell Transplantation in Philadelphia Chromosome-Positive Acute Myeloid Leukemia in Adults

The incidence of Philadelphia chromosome positivity (Ph⁺) in adults with acute myeloid leukemia (AML) is very low. Ph⁺ AML is considered to be high risk for failure to attain remission or for early relapse after standard chemotherapy. Because of the low incidence of the disease, it has been difficult to determine the best treatment, including the effects of tyrosine kinase inhibitors. We retrospectively analyzed 29 patients with Ph⁺ AML (median age, 45 years; range, 18 to 80) managed at our center between 2002 and 2016. Two patients were not treated at all, 3 received repeated low-dose cytarabine, and 24 were treated with 3 + 7 standard induction chemotherapy. All 27 treated patients also received interim imatinib 400 mg orally until the day of the next chemotherapy cycle began or as conditioning for allogeneic hematopoietic cell transplantation (HCT), which was performed in 17 patients. Of the 29 patients with Ph⁺ AML, 7 (24.1%) had additional inv(16), 3 of whom had therapy-related AML. In the 7 with inv(16), the median age was younger (31 versus 44 years, P = .083) and the complete remission (CR) rate was relatively higher (85.7% versus 54.5%, P = .214) than in those without inv(16). Among the 27 treated patients, 20 (74.1%) achieved CR after standard chemotherapy with interim imatinib and 2 (7.4%) achieved CR after low-dose cytarabine with interim imatinib. After a median follow-up of 65.5 months (range, 13.4 to 156.6), the 5-year overall survival (OS) among all 27 treated patients was 43.1%. For the 17 patients who underwent HCT the 5-year OS of 17 patients (10 in subgroup without inv(16) and 7 in subgroup with inv(16)) treated with allogeneic HCT was 69.3%. All 7 with inv(16) were still alive at the end of the study. In contrast, all patients not treated with HCT died within a median of 6.25 months (range, .2 to 18.2). Interim imatinib combined with chemotherapy yielded an acceptable remission rate in adult patients with Ph⁺ AML. Allogeneic HCT as a postremission therapy provided long-term disease control in two-thirds of those who underwent the transplant. We also demonstrated that inv(16) was related to a favorable outcome in Ph⁺ AML, including therapy-related AML.

Relatively favorable outcome after allogeneic stem cell transplantation for BCR-ABL1-positive AML: A survey from the acute leukemia working party of the European Society for blood and marrow transplantation (EBMT)

The aim of the study was to assess the role of allogeneic stem cell transplantation (SCT) in patients diagnosed with BCR-ABL1-positive acute myeloid leukemia (AML). Fifty-seven patients (median age, 48 years, range: 19-67) with BCR-ABL1 positive AML undergoing SCT were identified. The majority of the patients (70%) received a TKI before the transplant. At SCT 48 patients were in CR (45 in CR1), while 9 patients were transplanted in a more advanced stage of the disease. MRD was negative (BCR-ABL1/ABL < 10⁴ ) at time of SCT in 36.1% (14/40). After SCT, 16 (61.5%) out of 26 patients with MRD positive at transplantation reached MRD negativity. After a median follow-up of 6.3 years (0.7-14.2), NRM, RI, LFS, OS, and GRFS at 5 years were 18.1%, 37%, 44.2%, 53.8%, and 32.1%, respectively. The cumulative incidence of acute GvHD grade II-IV was 16.4%, incidence of chronic GvHD 24.9%, and of extensive cGvHD 21.4%, respectively. In patients who received SCT in CR1, 5-yr NRM, RI, LFS, OS, and GRFS were 15.9%, 36.4%, 46.5%, 59.4%, and 34.9%, respectively. Univariate analysis showed that age (<50 vs. ≥50 years) was associated with RI (5-yr: 22.7 vs. 50%), LFS (5-yr: 61.9 vs. 31.8%), and GRFS (5-yr: 52.4 vs. 18.2%), whereas MRD-negative status before SCT was associated with an improved GRFS (38.9 vs. 16.7%). We conclude that the outcome of patients <50 years of age with BCR-ABL1-positive AML receiving allogeneic SCT in CR is relatively favorable, possibly reflecting the beneficial effect of the use of TKI.

Mixed phenotype acute leukemia with t(9;22): success with nonacute myeloid leukemia-type intensive induction therapy and stem cell transplantation

Mixed phenotype acute leukemia with t(9;22) is a rare disease with poor prognosis, and information on optimal treatment is limited. We describe a case where our patient experienced positive outcome after nonacute myeloid leukemia‐type intensive induction therapy followed by postremission therapy with stem cell transplant.