Long-term efficacy of low-dose all-trans retinoic acid plus minimal chemotherapy induction followed by the addition of intravenous arsenic trioxide post-remission therapy in newly diagnosed acute promyelocytic leukaemia

Acute myeloid leukemia: challenges for diagnosis and treatment in Latin America

OBJECTIVE

to review the current diagnostic and therapeutic landscape of AML in Latin America as a reflection of other low- and middle-income countries and regions of the world. Encompassing both acute promyelocytic and non-promyelocytic disease types.

METHODS

We reviewed the literature and study registries concerning epidemiological features of patients with AML/APL treated in Latin America, as well as evaluated diagnostic and genetic stratification and patient fitness assessment challenges, the importance of early mortality and supportive care capacity, intensive and non-intensive chemotherapy alternatives, consolidation, and maintenance strategies including novel agents and hematopoietic stem cell transplantation.

RESULTS

Although most of the current technologies and treatment options are available in the region, a significant fraction of patients have only limited access to them. In addition, mortality in the first weeks from diagnosis is higher in the region compared to developed countries.

CONCLUSIONS

Disparities in access to technologies, supportive care capacity, and availability of novel agents and HSCT hinder results in our region, reflecting barriers common to other LMICs. Recent developments in the diagnosis and treatment of this disease must be implemented through education, collaborative clinical research, and advocacy to improve outcomes.

Updates on targeted therapies for acute myeloid leukaemia

In the past few years research in the underlying pathogenic mechanisms of acute myeloid leukaemia (AML) has led to remarkable advances in our understanding of the disease. Cytogenetic and molecular aberrations are the most important factors in determining response to chemotherapy as well as long-term outcome, but beyond prognostication are potential therapeutic targets. Our increased understanding of the pathogenesis of AML facilitated by next-generation sequencing has spurred the development of new compounds in the treatment of AML, particularly the creation of small molecules that target the disease on a molecular level. Many of the hopeful predictions outlined in our AML review of 2018 are now therapeutic realities: gemtuzumab ozogamicin, venetoclax, FLT3 inhibitors (midostaurin, gilteritinib), IDH inhibitors (ivosidenib, enasidenib), CPX-351, glasdegib, oral decitabine, and oral azacitidine. Others may soon be (quizartinib, APR246 magrolimab, menin inhibitors). The wealth of positive data allows reconsideration of what might soon be new standards of care in younger and older patients with AML. In this review we give an overview of recently approved therapies in AML and address present and future research directions.

Improved long-term survival in all Sanz risk patients of newly diagnosed acute promyelocytic leukemia treated with a combination of retinoic acid and arsenic trioxide-based front-line therapy

Limited data was available for long-term follow-up in newly diagnosed acute promyelocytic leukemia (APL) patients treated with all-trans-retinoic acid (ATRA) plus intravenously arsenic trioxide (ATO)-based front-line therapy. The aim of this work was to retrospectively analyze the long-term survival rate and frequency of therapy-related myeloid neoplasia (t-MN) occurring in a large cohort of APL patients. A total of 760 newly diagnosed patients with APL between January 1999 and May 2016 were evaluated. The early death rate was 9.2% (70/760). Of the remaining 690 patients with complete remission, patients were grouped according to front-line regimens: ATRA plus ATO with or without chemotherapy (ATO group) and ATRA with chemotherapy (non-ATO group). The median duration of follow-up was 7.5 years (1.0-18.3 years). ATO group showed significant superior 10-year estimated relapse-free survival (RFS) up to 90.3% comparing with 65.5% in the non-ATO group (P < 0.0001). In addition, the 10-year estimated overall survival (OS) was 93.9% for patients in the ATO group and 89.1% for those in the non-ATO group (P = 0.03). In the subgroup analysis, the RFS rate was also higher in ATO group comparing with non-ATO group in both low-to-intermediate-risk (94.2% vs 64.6%, P < 0.0001) and high-risk subgroup (89.6% vs 74.7%, P = 0.04). Notably, the 3-year RFS and OS rates in the chemotherapy-free subgroup of the low-to-intermediate-risk patients (n = 88) were 100% and 100%, respectively. In the entire cohort, a total of 10 patients developed secondary malignant neoplasms, including 7 patients with therapy-related myeloid neoplasms (t-MN). The estimated 5-year cumulative incidence risk of t-MN in the ATO and non-ATO groups was 1.0% and 0.4%, respectively (P = 0.34). Thus, our data revealed that the long-term outcome of patients treated with ATRA plus ATO-based regimens was associated with continuing high efficacy in all Sanz risk patients with newly diagnosed APL.

Effectivity of a modified Sanz risk model for early death prediction in patients with newly diagnosed acute promyelocytic leukemia

Early death is the main obstacle for the cure of patients with acute promyelocytic leukemia (APL). We have analyzed risk factors of early death from 526 consecutive newly diagnosed APL patients between 2004 and 2016. The overall incidence of early death was 7.2% (38/526). The peak hazard of early death occurred in the first 0-3 days. Multivariate logistic analysis demonstrated white blood cell (WBC) counts [odds ratio (OR) = 1.039; 95% confidence interval (CI): 1.024-1.055; P < 0.001], age (OR = 1.061; 95% CI: 1.025-1.099; P = 0.001) and platelet counts (OR = 0.971; 95% CI: 0.944-0.999; P = 0.038) were independent risk factors for early death. Furthermore, receiver-operator characteristic (ROC) curve analyses revealed a simple WBC/platelet ratio was significantly more accurate in predicting early death [areas under the ROC curve (AUC) = 0.842, 95% CI: 0.807-0.872) than WBC counts (AUC = 0.793; 95% CI: 0.756-0.827) or Sanz score (AUC = 0.746; 95% CI: 0.706-0.783). We stratified APL patients into four risk subgroups: low risk (WBC ≤ 10 × 10⁹/L, platelet >40 × 10⁹/L), intermediate risk (WBC/platelet <0.2 and age ≤ 60, not in low risk), high risk (WBC/platelet ≥0.2 or age > 60, not in low and ultra-high risk) and ultra-high risk (WBC > 50 × 10⁹/L), the early death rates were 0, 0.6, 12.8, and 41.2%, respectively. In conclusion, we proposed a modified Sanz risk model as a useful predictor of early death risk in patients with APL.

Is There Still a Role for Low-Dose All-Transretinoic Acid in the Treatment of Acute Promyelocytic Leukemia in the Arsenic Trioxide Era?

BACKGROUND

Low-dose all-transretinoic acid (LD-ATRA) has shown similar peak plasma concentrations and a mean area under the concentration time curve in comparison with standard doses of ATRA. We evaluated the efficacy of LD-ATRA plus anthracycline-based chemotherapy in patients with newly diagnosed acute promyelocytic leukemia (APL).

PATIENTS AND METHODS

Patients diagnosed with APL during the period of 2002 to 2014 were included. They received ATRA 25 mg/m(2) plus anthracycline (doxorubicin or mitoxantrone) as induction chemotherapy, followed by 3 consolidations with LD-ATRA and anthracycline and maintenance therapy with intermittent LD-ATRA and oral chemotherapy for 2 years.

RESULTS

Twenty-two patients with a median age of 28 years (range, 18-55 years) were included; 17 (77%) were in the low-risk group. Complete remission occurred in 86%, and the early death rate was 9%. At a median follow-up of 32 months (range, 4-126 months) disease-free survival (DFS) was 75% and overall survival (OS) was 86%, with a relapse rate of 27% for the entire follow-up period.

CONCLUSION

LD-ATRA plus anthracycline is safe and effective in achieving CR of APL. The early death rate is similar to that of treatment with standard doses, but it appears to be inferior in preventing relapses.