The comparison of plasma arsenic concentration and urinary arsenic excretion during treatment with Realgar-Indigo naturalis formula and arsenic trioxide in children with acute promyelocytic leukemia

Prognostic significance of MRD and its correlation with arsenic concentration in pediatric acute promyelocytic leukemia: a retrospective study by SCCLG-APL group

Background

Treatment outcomes for acute promyelocytic leukemia (APL) have improved with all-trans-retinoic acid and arsenic trioxide, yet relapse remains a concern, especially in pediatric patients. The prognostic value of minimal residual disease (MRD) post-induction and the impact of arsenic levels during induction on MRD are not fully understood.

Objectives

To evaluate the relationship between post-induction MRD levels and relapse-free survival (RFS) in pediatric APL patients, and to investigate the correlation between blood arsenic concentration levels during induction therapy and MRD status.

Design

A retrospective analysis of pediatric APL patients enrolled in a clinical trial from September 2011 to July 2020.

Methods

We assessed the relationship between RFS and post-induction MRD levels using the log-rank test. The optimal MRD cut-off was determined using the "surv_cutpoint" function in the survminer R package. Arsenic concentration levels were monitored in 16 patients on days 7 and 14 of induction therapy, and Spearman correlation was used to analyze the relationship between arsenic concentrations and MRD levels.

Results

Among 176 pediatric APL patients, with a median follow-up of 6 years, 4 relapsed. Patients with MRD >3.1% had significantly lower RFS compared to those with MRD ⩽3.1% (94.6% vs 100%, p = 0.023). In addition, a negative correlation was found between blood arsenic concentration levels and post-induction MRD levels. Lower arsenic concentrations were associated with higher MRD levels, with significant correlations observed for trough concentrations (R = -0.666, p = 0.005) and peak concentrations (R = -0.499, p = 0.049) on day 7.

Conclusion

Our study highlights the prognostic significance of post-induction MRD assessment in pediatric APL. We also demonstrate a negative correlation between blood arsenic concentration levels and MRD, suggesting that lower arsenic concentrations during induction therapy may contribute to a higher MRD burden. These findings may inform strategies to optimize treatment and improve outcomes in pediatric APL.Trial registration: www.clinicaltrials.gov (NCT02200978).

Induction treatments with and without addition of one dose anthracycline to all-trans retinoid acid and arsenic in pediatric non-high-risk acute promyelocytic leukemia: study protocol for a randomized controlled trial

BACKGROUND

The treatment of all-trans retinoic acid (ATRA) and arsenical agent has revolutionarily improved the prognosis of acute promyelocytic leukemia (APL) both in adults and children. Nevertheless, coagulation disorder and differentiation syndrome (DS) are the main causes of early death in APL patients. Early chemotherapy to reduce leukocytes during induction is an important measure to reduce complications and mortality. However, the incidence of hyperleukocytosis (WBC > 10 × 109/L) was significantly higher in pediatric patients without chemotherapy than in adults. Although ATRA plus arsenic is the standard therapy for non-high-risk adult patients, it remains controversial whether chemotherapy is necessary for induction therapy in pediatric APL.

METHODS

This study was designed as a multicenter randomized controlled trial. Children with APL were randomly assigned into experimental group (ATRA-RIF plus chemotherapy) and control group (ATRA-RIF). The experimental group was treated with ATRA-RIF plus chemotherapy for induction, while the control group was treated with ATRA-RIF alone. In addition, both groups received the same regimen of ATRA-RIF plus chemotherapy for consolidation and maintenance.

DISCUSSION

This trial aims to compare the efficacy of ATRA-RIF plus chemotherapy versus ATRA-RIF in pediatric non-high-risk patients with APL to demonstrate that chemotherapy during induction therapy can reduce the incidence of complications such as hyperleukocytosis and DS, thereby reducing mortality.

TRIAL REGISTRATION

Chinese Clinical Trials Registry, ID: ChiCTR2000038877. Registered on October 8, 2020, https://www.chictr.org.cn/showproj.html?proj=60733 . V1.0 date 08/01/2020.

Long-term outcome of children with acute promyelocytic leukemia: a randomized study of oral versus intravenous arsenic by SCCLG-APL group

Realgar-Indigo naturalis formula (RIF), an oral traditional Chinese medicine mainly containing Realgar (As4S4), is highly effective in treating adult acute promyelocytic leukemia (APL). However, the treatment efficacy and safety of RIF have not been verified in pediatric patients. SCCLG-APL group conducted a multicenter randomized non-inferiority trial to determine whether intravenous arsenic trioxide (ATO) can be substituted by oral RIF in treating pediatric APL. Of 176 eligible patients enrolled, 91 and 85 were randomized to ATO and RIF groups, respectively. Patients were treated with the risk-adapted protocol. Induction, consolidation, and 96-week maintenance treatment contained all-trans-retinoic acid and low-intensity chemotherapy, and either ATO or RIF. The primary endpoint was 5-year event-free survival (EFS). The secondary endpoints were adverse events and hospital days. After a median 6-year follow-up, the 5-year EFS was 97.6% in both groups. However, the RIF group had significantly shorter hospital stays and lower incidence of infection and tended to have less cardiac toxicity. All 4 relapses occurred within 1.5 years after completion of maintenance therapy. No long-term arsenic retentions were observed in either group. Substituting oral RIF for ATO maintains treatment efficacy while reducing hospitalization and adverse events in treating pediatric APL patients, which may be a future treatment strategy for APL.

An overview of arsenic trioxide-involved combined treatment algorithms for leukemia: basic concepts and clinical implications

Arsenic trioxide is a first-line treatment drug for acute promyelocytic leukemia, which is also effective for other kinds of leukemia. Its side effects, however, limit its clinical application, especially for patients with complex leukemia symptoms. Combination therapy can effectively alleviate these problems. This review summarizes the research progress on the combination of arsenic trioxide with anticancer drugs, vitamin and vitamin analogs, plant products, and other kinds of drugs in the treatment of leukemia. Additionally, the new progress in arsenic trioxide-induced cardiotoxicity was summarized. This review aims to provide new insights for the rational clinical application of arsenic trioxide.

Differentiation syndrome and coagulation disorder - comparison between treatment with oral and intravenous arsenics in pediatric acute promyelocytic leukemia

Realgar-Indigo naturalis formula (RIF), with A₄S₄ as a major ingredient, is an oral arsenic used in China to treat pediatric acute promyelocytic leukemia (APL). The efficacy of RIF is similar to that of arsenic trioxide (ATO). However, the effects of these two arsenicals on differentiation syndrome (DS) and coagulation disorders, the two main life-threatening events in children with APL, remain unclear. We retrospectively analyzed 68 consecutive children with APL from South China Children Leukemia Group-APL (SCCLG-APL) study. Patients received all-trans retinoic acid (ATRA) on day 1 of induction therapy. ATO 0.16 mg/kg day or RIF 135 mg/kg·day was administrated on day 5, while mitoxantrone was administered on day 3 (non-high-risk) or days 2-4 (high-risk). The incidences of DS were 3.0% and 5.7% in ATO (n = 33) and RIF (n = 35) arms (p = 0.590), and 10.3% and 0% in patients with and without differentiation-related hyperleukocytosis (p = 0.04), respectively. Moreover, in patients with differentiation-related hyperleukocytosis, the incidence of DS was not significantly different between ATO and RIF arms. The dynamic changes of leukocyte count between arms were not statistically different. However, patients with leukocyte count > 2.61 × 10⁹/L or percentage of promyelocytes in peripheral blood > 26.5% tended to develop hyperleukocytosis. The improvement of coagulation indexes in ATO and RIF arms was similar, with fibrinogen and prothrombin time having the quickest recovery rate. This study showed that the incidence of DS and recovery of coagulopathy are similar when treating pediatric APL with RIF or ATO.

Realgar and arsenene nanomaterials as arsenic-based anticancer agents

Arsenic trioxide (ATO) is an approved therapy for the treatment of acute promyelocytic leukemia, but the extension of arsenic-based therapies to other types of malignancies, notably tumor-forming cancers, has been slow. Nanodelivery vehicles offer a means of effectively delivering ATO to tumors. Very recently, there has been a series of developments in the formulation of arsenic-based nanomedicines that are not simply loaded with ATO. Realgar nanoparticles are comprised of molecular As₄S₄ units. Current studies suggest that realgar nanoparticles ultimately act in a manner similar to ATO, but with greatly attenuated toxic side effects. A drastically different approach is taken with arsenene nanosheets, a 2-dimensional form of elemental As. The electronic properties of this material allow it to mediate both photothermal therapy and photodynamic therapy. The exploration of these nanomaterials is still in its infancy but is poised to allow arsenic-based therapy to make yet another significant impact on cancer treatment.

Targeting regulated cell death with plant natural compounds for cancer therapy: A revisited review of apoptosis, autophagy-dependent cell death, and necroptosis

Regulated cell death (RCD) refers to programmed cell death regulated by various protein molecules, such as apoptosis, autophagy-dependent cell death, and necroptosis. Accumulating evidence has recently revealed that RCD subroutines have several links to many types of human cancer; therefore, targeting RCD with pharmacological small-molecule compounds would be a promising therapeutic strategy. Moreover, plant natural compounds, small-molecule compounds synthesized from plant sources, and their derivatives have been widely reported to regulate different RCD subroutines to improve potential cancer therapy. Thus, in this review, we focus on updating the intricate mechanisms of apoptosis, autophagy-dependent cell death, and necroptosis in cancer. Moreover, we further discuss several representative plant natural compounds and their derivatives that regulate the above-mentioned three subroutines of RCD, and their potential as candidate small-molecule drugs for the future cancer treatment.