FLT3 internal tandem duplication is associated with a high relapse rate and central nervous system involvement in acute promyelocytic leukemia cases: single institutional analysis

Acute Promyelocytic Leukemia Presenting With a Myeloid Sarcoma of the Spine: A Case Report and Literature Review

Myeloid sarcoma is a rare extramedullary tumor of immature myeloid cells. Certain known acute myeloid leukemia cytogenetic abnormalities, in particular t(8,21), has been associated with a higher incidence. Myeloid sarcoma, which rarely happens in acute promyelocytic leukemias, is more common in recurrent patients after the advent of all-trans retinoic acid (ATRA) and are rare in untreated acute promyelocytic leukemia. We described a case of, to our knowledge, de novo myeloid sarcoma of the spine confirmed as acute promyelocytic leukemia. Myeloid sarcoma is diagnosed by spinal tumor biopsy, and microscopic examination of a bone marrow smear and cytogenetic analysis led to a confirmed diagnosis of acute promyelocytic leukemia.

Oral arsenic trioxide, all-trans retinoic acid, and ascorbic acid maintenance after first complete remission in acute promyelocytic leukemia: Long-term results and unique prognostic indicators

BACKGROUND

The role of arsenic trioxide (As₂ O₃ ) in the maintenance of first complete remission (CR1) in acute promyelocytic leukemia (APL) is unclear.

METHODS

A total of 129 consecutive adult patients with APL of all risk categories who achieved CR1 with conventional induction (all-trans retinoic acid [ATRA]/daunorubicin) and consolidation (daunorubicin/cytarabine [induction daunorubicin and consolidation omitted for age ≥70 years]) underwent maintenance comprising ATRA (45 mg/m² /day), oral As₂ O₃ (10 mg/day), and ascorbic acid (1 g/day) (AAA) for 2 weeks every 2 months for 2 years.

RESULTS

Over a 17-year period from August 1, 2002, to July 31, 2019, 63 men and 66 women (median age, 46 years [range, 18-82 years]) received AAA maintenance, which was already completed in 117 patients. At a median follow-up of 100 months (range, 8-215 months), 17 patients (13%) developed first relapse (R1) (hematologic, n = 14; molecular, n = 3) after a median of 19 months (range, 7-96 months) from CR1. Two R1 patients had concomitant central nervous system (CNS) involvement. All patients achieved CR2 with oral As₂ O₃ -based salvage. Five patients had a subsequent relapse and died. Eight patients died of unrelated causes while still in CR1. The 5-year and 10-year rates of relapse-free survival (RFS) were 89% and 85%, respectively. The 5-year and 10-year rates of overall survival (OS) were 94% and 87%, respectively. Multivariate analysis showed that inferior RFS was associated with FLT3-ITD (P = .005) and CNS involvement on presentation (P = .004), and inferior OS was associated with therapy-related APL (P = .03), FLT3-ITD (P = .03), and relapse (P = .03). The safety profile was favorable, with no grade 3/4 organ toxicities.

CONCLUSION

CR1 maintenance with AAA is safe and results in favorable long-term survival in patients with APL.

Long-term outcome of relapsed acute promyelocytic leukemia treated with oral arsenic trioxide-based reinduction and maintenance regimens: A 15-year prospective study

BACKGROUND

For patients who have acute promyelocytic leukemia (APL) in second complete remission (CR2), optimal postremission strategies remain undefined.

METHODS

The role of an oral arsenic trioxide (As₂ O₃ )-based regimen in the management of patients who had APL in CR2 was examined.

RESULTS

Seventy-three patients with APL in first relapse (R1) were studied. Oral As₂ O₃ -based reinduction resulted uniformly in CR2, irrespective of previous As₂ O₃ exposure. All patients received oral As₂ O₃ -based maintenance in CR2. At a median follow-up of 94 months (range, 9-205 months), 43 patients (58.9%) were still in CR2, and 49 (67.1%) had finished the planned 2-year CR2 maintenance with all-trans retinoic acid, oral As₂ O₃ , and ascorbic acid. Reinduction and maintenance treatments were well tolerated. Grade 1 and 2 headache occurred in 20 patients (27.4%). Hepatotoxicity, all in the form of transaminitis, occurred in 35 patients (47.9%; grade 1 and 2, n = 26; grade 3 and 4, n = 9). Three patients had self-limiting QTc prolongation. The 10-year leukemia-free survival rate was 56.8%. Thirty patients developed R2. Oral As₂ O₃ -based reinduction led to CR3 in 27 patients (90%). Post-CR3 strategies included autologous hematopoietic stem cell transplantation and oral As₂ O₃ maintenance. At a post-CR3 follow-up of 30 months (range, 3-166 months), 11 patients were still in CR3. The 5-year and 10-year overall survival rates in the R1 cohort were 79.5% and 67.3%, respectively. Prior receipt of oral As₂ O₃ maintenance in CR1 was the only risk factor for inferior leukemia-free survival. Central nervous system involvement occurred in 15 patients, including 5 who remained alive. Relapse during oral As₂ O₃ therapy was the only significant risk factor for central nervous system involvement.

CONCLUSIONS

For patients with relapsed APL, As₂ O₃ remained effective despite repeated As₂ O₃ exposures. Oral As₂ O₃ maintenance was an effective postremission strategy for CR2. Cancer 2018;124:2316-26. © 2018 American Cancer Society.

Arsenic trioxide and all-trans-retinoic acid selectively exert synergistic cytotoxicity against FLT3-ITD AML cells via co-inhibition of FLT3 signaling pathways

FLT3-ITD mutations occur in approximately 30% of acute myeloid leukemia (AML) and are associated with a poor outcome. Currently available FLT3 inhibitors have in vitro but limited clinical activity in FLT3-ITD AML. Reports have shown that an arsenic trioxide (ATO)/all-trans-retinoic acid (ATRA) combination improves prognosis in acute promyelocytic leukemia, especially with FLT3-ITD, and ATO or ATRA alone enhances apoptosis in FLT3-ITD AML cells treated with FLT3 inhibitors, providing a rationale to investigate the role of ATO/ATRA in FLT3-ITD AML. Here, we demonstrate that an ATO/ATRA combination selectively exerts synergistic cytotoxicity against FLT3-ITD AML cell lines (MV4;11/MOLM-13). The signaling pathways affected by ATO/ATRA include FLT3/STAT5/MYC, FLT3/STAT5/E2F1, FLT3/ERK/ATF5 and FLT3/AKT/ATF5.ATF5 may function as an oncogene in FLT3-ITD AML. Our findings provide experimental evidence that supports further exploration of ATO/ATRA in FLT3-ITD AML in vivo and warrants a clinical evaluation of regimens comprising an ATO/ATRA combination.

Evolution of a FLT3-TKD mutated subclone at meningeal relapse in acute promyelocytic leukemia

Here, we report the case of an acute promyelocytic leukemia (APL) patient who—although negative for FLT3 mutations at diagnosis—developed isolated FLT3 tyrosine kinase II domain (FLT3-TKD)-positive meningeal relapse, which, in retrospect, could be traced back to a minute bone marrow subclone present at first diagnosis. Initially, the 48-yr-old female diagnosed with high-risk APL had achieved complete molecular remission after standard treatment with all-trans retinoic acid (ATRA) and chemotherapy according to the AIDA (ATRA plus idarubicin) protocol. Thirteen months after the start of ATRA maintenance, the patient suffered clinically overt meningeal relapse along with minute molecular traces of PML/RARA (promyelocytic leukemia/retinoic acid receptor alpha) in the bone marrow. Following treatment with arsenic trioxide and ATRA in combination with intrathecal cytarabine and methotrexate, the patient achieved a complete molecular remission in both cerebrospinal fluid (CSF) and bone marrow, which currently lasts for 2 yr after completion of therapy. Whole-exome sequencing and subsequent ultradeep targeted resequencing revealed a heterozygous FLT3-TKD mutation in CSF leukemic cells (p.D835Y, c.2503G>T, 1000/1961 reads [51%]), which was undetectable in the concurrent bone marrow sample. Interestingly, the FLT3-TKD mutated meningeal clone originated from a small bone marrow subclone present in a variant allele frequency of 0.4% (6/1553 reads) at initial diagnosis. This case highlights the concept of clonal evolution with a subclone harboring an additional mutation being selected as the “fittest” and leading to meningeal relapse. It also further supports earlier suggestions that FLT3 mutations may play a role for migration and clonal expansion in the CSF sanctuary site.

Acute promyelocytic leukemia harbouring rare FLT3-TKD and WT1 mutations: A case report

The involvement of the central nervous system (CNS) is rare in acute promyelocytic leukemia (APL). The present study reported the case of a 34-year-old male patient with APL that possessed a rare point mutation (p.Asn841Gly, c.2523C>A) in the tyrosine kinase domain of the FMS-like tyrosine kinase 3 (FLT3) gene and a novel Wilm tumor gene mutation (c.1209_1210insT/p.K404X). The patient suffered central nervous system and systemic relapses twice during systemic and intrathecal chemotherapy. At present, the patient is undergoing alternative induction and consolidation therapies, including the administration of FLT3 inhibitor, tetraarsenic tetrasulfide and novel cytotherapy, and is prepared for salvage allogeneic hematopoietic stem cell transplantion (allo-HSCT). The present study indicated that patients with APL that are at a high risk of relapse and unfavorable gene mutations should receive immediate allo-HSCT, whenever possible.

Acute promyelocytic leukemia with Flt3-TKD and WT1 mutations relapsing in a testicle and followed by systemic relapse

Extramedullary relapse is a rare phenomenon in patients with acute promyelocytic leukemia (APL), especially that derived from urogenital systems like the testicles. In this report, we describe an APL patient who had received standard induction/maintenance therapy resulting in durable remission for 4.5 years, when he presented with a unilateral testicular mass confirmed as myeloid sarcoma; this was followed by systemic relapse of APL. Retrospective analysis of the involved blood and bone marrow samples at the time of the initial diagnosis revealed a rare point mutation of FLT3-TKD and a novel mutation of WT1. These mutations were detected recurrently throughout the course of the disease. After reinduction therapy with arsenic trioxide and all-trans retinoic acid combined with daunorubicin, complete hematological remission was achieved for the ensuing salvage allogeneic hematopoietic stem cell transplant.

Gene mutation patterns and their prognostic impact in a cohort of 1185 patients with acute myeloid leukemia

To evaluate the prognostic value of genetic mutations for acute myeloid leukemia (AML) patients, we examined the gene status for both fusion products such as AML1 (CBFα)-ETO, CBFβ-MYH11, PML-RARα, and MLL rearrangement as a result of chromosomal translocations and mutations in genes including FLT3, C-KIT, N-RAS, NPM1, CEBPA, WT1, ASXL1, DNMT3A, MLL, IDH1, IDH2, and TET2 in 1185 AML patients. Clinical analysis was mainly carried out among 605 cases without recognizable karyotype abnormalities except for 11q23. Of these 605 patients, 452 (74.7%) were found to have at least 1 mutation, and the relationship of gene mutations with clinical outcome was investigated. We revealed a correlation pattern among NPM1, DNMT3A, FLT3, IDH1, IDH2, CEBPA, and TET2 mutations. Multivariate analysis identified DNMT3A and MLL mutations as independent factors predicting inferior overall survival (OS) and event-free survival (EFS), whereas biallelic CEBPA mutations or NPM1 mutations without DNMT3A mutations conferred a better OS and EFS in both the whole group and among younger patients < 60 years of age. The use of molecular markers allowed us to subdivide the series of 605 patients into distinct prognostic groups with potential clinical relevance.