Feasibility of oral arsenic trioxide treatment for acute promyelocytic leukemia during hemodialysis

Chemotherapy-free approaches to newly-diagnosed acute promyelocytic leukaemia: is oral-arsenic trioxide/all-trans retinoic acid/ascorbic acid the answer?

INTRODUCTION

Acute promyelocytic leukemia (APL) is a distinct form of acute myeloid leukemia characterized by the presence of t(15;17)(q24;21) and the PML:RARA gene fusion. Frontline use of intravenous arsenic trioxide (i.v.-ATO) and all-trans retinoic acid (ATRA) has vastly improved cure rates in APL. Researchers in Hong Kong invented the oral formulation of ATO (oral-ATO) and have confirmed a bioavailability comparable to i.v.-ATO. A plethora of studies have confirmed the safety and efficacy of oral-ATO-based regimens in the frontline and relapsed setting.

AREAS COVERED

Aspects on the development of oral-ATO-based regimens for APL in the frontline and relapsed setting are discussed. The short-term and long-term safety and efficacy of oral-ATO-based regimens are discussed. The frontline use of oral-ATO in combination with ATRA and ascorbic acid (AAA) induction in a 'chemotherapy-free' is highlighted.

EXPERT OPINION

Current and ongoing data on the use of oral-ATO-based regimens in APL support the use of oral-ATO as an alternative to i.v.-ATO allowing a more convenient and economical approach to the management of APL.

Arsenic trioxide impacts hepatitis B virus core nuclear localization and efficiently interferes with HBV infection

The key to a curative treatment of hepatitis B virus (HBV) infection is the eradication of the intranuclear episomal covalently closed circular DNA (cccDNA), the stable persistence reservoir of HBV. Currently, established therapies can only limit HBV replication but fail to tackle the cccDNA. Thus, novel therapeutic approaches toward curative treatment are urgently needed. Recent publications indicated a strong association between the HBV core protein SUMOylation and the association with promyelocytic leukemia nuclear bodies (PML-NBs) on relaxed circular DNA to cccDNA conversion. We propose that interference with the cellular SUMOylation system and PML-NB integrity using arsenic trioxide provides a useful tool in the treatment of HBV infection. Our study showed a significant reduction in HBV-infected cells, core protein levels, HBV mRNA, and total DNA. Additionally, a reduction, albeit to a limited extent, of HBV cccDNA could be observed. Furthermore, this interference was also applied for the treatment of an established HBV infection, characterized by a stably present nuclear pool of cccDNA. Arsenic trioxide (ATO) treatment not only changed the amount of expressed HBV core protein but also induced a distinct relocalization to an extranuclear phenotype during infection. Moreover, ATO treatment resulted in the redistribution of transfected HBV core protein away from PML-NBs, a phenotype similar to that previously observed with SUMOylation-deficient HBV core. Taken together, these findings revealed the inhibition of HBV replication by ATO treatment during several steps of the viral replication cycle, including viral entry into the nucleus as well as cccDNA formation and maintenance. We propose ATO as a novel prospective treatment option for further pre-clinical and clinical studies against HBV infection.

IMPORTANCE

The main challenge for the achievement of a functional cure for hepatitis B virus (HBV) is the covalently closed circular DNA (cccDNA), the highly stable persistence reservoir of HBV, which is maintained by further rounds of infection with newly generated progeny viruses or by intracellular recycling of mature nucleocapsids. Eradication of the cccDNA is considered to be the holy grail for HBV curative treatment; however, current therapeutic approaches fail to directly tackle this HBV persistence reservoir. The molecular effect of arsenic trioxide (ATO) on HBV infection, protein expression, and cccDNA formation and maintenance, however, has not been characterized and understood until now. In this study, we reveal ATO treatment as a novel and innovative therapeutic approach against HBV infections, repressing viral gene expression and replication as well as the stable cccDNA pool at low micromolar concentrations by affecting the cellular function of promyelocytic leukemia nuclear bodies.

The Development and Clinical Applications of Oral Arsenic Trioxide for Acute Promyelocytic Leukaemia and Other Diseases

Appreciation of the properties of arsenic trioxide (ATO) has redefined the treatment landscape for acute promyelocytic leukaemia (APL) and offers promise as a treatment for numerous other diseases. The benefits of ATO in patients with APL is related to its ability to counteract the effects of PML::RARA, an oncoprotein that is invariably detected in the blood or bone marrow of affected individuals. The PML::RARA oncoprotein is degraded specifically by binding to ATO. Thus ATO, in combination with all-trans retinoic acid, has become the curative treatment for ATO. The multiple mechanisms of action of ATO has also paved the way for application in various condition encompassing autoimmune or inflammatory disorders, solid organ tumours, lymphomas and other subtypes of AML. The development of oral formulation of ATO (oral ATO) has reduced costs of treatment and improved treatment convenience allowing widespread applicability. In this review, we discuss the mechanisms of action of ATO, the development of oral ATO, and the applications of oral ATO in APL and other diseases.

Successful treatment of relapsed acute promyelocytic leukemia with arsenic trioxide in a hemodialysis-dependent patient: A case report

BACKGROUND

Arsenic trioxide (ATO) is recommended for patients who do not achieve molecular remission or who have molecular or morphologic relapse. However, there are no guidelines for adjusting ATO dosage in patients with severe renal failure or on dialysis. Herein, we report the successful treatment of relapsed acute promyelocytic leukemia (APL) in a patient on hemodialysis with ATO single agent and review the cases in literature.

CASE SUMMARY

A 46-year-old woman who has been on hemodialysis to chronic glomerulone-phritis for 15 years visited our hospital for pancytopenia. She had been seen for pancytopenia 3 years ago and had been diagnosed with APL. She also received chemotherapy for APL but unfortunately was lost to follow-up after her second consolidation chemotherapy. She was noted to have pancytopenia by her nephrologist during hemodialysis 1 mo ago. Bone marrow biopsy and reverse transcriptase-polymerase chain reaction (RT-PCR) tests revealed a diagnosis of relapsed APL. Treatment for relapsed APL with ATO single agent was started and she achieved molecular remission after administering 24 doses of ATO. Thus far, four consolidation therapies have been performed with the ATO single agent, and, to date, the molecular remission has been maintained as negative promyelocytic leukemia/retinoic acid receptor-α fusion gene as confirmed by RT-PCR testing for two years.

CONCLUSION

This is a rare case of relapsed APL successfully treated with the single agent ATO in a patient on hemodialysis.

Resurrection of Oral Arsenic Trioxide for Treating Acute Promyelocytic Leukaemia: A Historical Account From Bedside to Bench to Bedside

Various forms of arsenic were used in China and elsewhere for over 5,000 years. Following the initial success of intravenous arsenic trioxide (i.v. As₂O₃), we revived an oral formulation of pure As₂O₃ in 1998 for the treatment of acute promyelocytic leukemia (APL). We were the first to produce a 1 mg/ml oral-As₂O₃ solution and showed that it had comparable bioavailability to i.v. As₂O₃. Moreover, we also reported that intracellular arsenic concentrations were considerably higher than the corresponding plasma values. Our oral-As₂O₃ was patented internationally and registered in Hong Kong for the treatment of APL. Safety, tolerability and clinical efficacy was confirmed in long-term follow-up studies. We have extended the use of oral-As₂O₃ to frontline induction of newly diagnosed APL. With these findings, we are moving toward an era of completely oral and chemotherapy-free management of APL.

ATO (Arsenic Trioxide) Effects on Promyelocytic Leukemia Nuclear Bodies Reveals Antiviral Intervention Capacity

Human adenoviruses (HAdV) are associated with clinical symptoms such as gastroenteritis, keratoconjunctivitis, pneumonia, hepatitis, and encephalitis. In the absence of protective immunity, as in allogeneic bone marrow transplant patients, HAdV infections can become lethal. Alarmingly, various outbreaks of highly pathogenic, pneumotropic HAdV types have been recently reported, causing severe and lethal respiratory diseases. Effective drugs for treatment of HAdV infections are still lacking. The repurposing of drugs approved for other indications is a valuable alternative for the development of new antiviral therapies and is less risky and costly than de novo development. Arsenic trioxide (ATO) is approved for treatment of acute promyelocytic leukemia. Here, it is shown that ATO is a potent inhibitor of HAdV. ATO treatment blocks virus expression and replication by reducing the number and integrity of promyelocytic leukemia (PML) nuclear bodies, important subnuclear structures for HAdV replication. Modification of HAdV proteins with small ubiquitin-like modifiers (SUMO) is also key to HAdV replication. ATO reduces levels of viral SUMO-E2A protein, while increasing SUMO-PML, suggesting that ATO interferes with SUMOylation of proteins crucial for HAdV replication. It is concluded that ATO targets cellular processes key to HAdV replication and is relevant for the development of antiviral intervention strategies.

Beyond Cisplatin: Combination Therapy with Arsenic Trioxide

Platinum drugs (cisplatin, oxaliplatin, and carboplatin) and arsenic trioxide are the only commercial inorganic non-radioactive anticancer drugs approved by the US Food and Drug Administration. Numerous efforts are underway to take advantage of the synergy between the anticancer activity of cisplatin and arsenic trioxide - two drugs with strikingly different mechanisms of action. These include co-encapsulation of the two drugs in novel nanoscale delivery systems as well as the development of small molecule agents that combine the activity of these two inorganic materials. Several of these new molecular entities containing Pt-As bonds have broad anticancer activity, are robust in physiological buffer solutions, and form stable complexes with biopolymers. This review summarizes results from a number of preclinical studies involving the combination of cisplatin and As2O3, co-encapsulation and nanoformulation efforts, and the chemistry and cytotoxicity of the first member of platinum anticancer agents with an arsenous acid moiety bound to the platinum(II) center: arsenoplatins.

In vitro stability of arsenic trioxide-liposome encapsulates for acute promyelocytic leukemia treatment

In this work, we investigated the stability of arsenic trioxide (ATO) used in leukemia treatment, encapsulated with nanoliposome, with the aid of ultrasound treatment. Stability studies of As species were followed by liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS), allowing for the detection of the conversion of low amounts of As(III) to As(V) or the formation of other As species. The influence of storage temperature and time on ATO was evaluated. Low amounts of As(III) to As(V) conversions were observed when the As encapsulated with nanoliposome was incubated at 25 °C and 40 °C. However, As(III) was stable if the solution was maintained at 5 °C, even after 90 days. No formation of other As species was observed, indicating good stability of the encapsulated ATO. Next step of the work will focus on spray drying of ATO nanoliposomes-encapsuleted with the aim of long term stability of As.

The evolution of arsenic in the treatment of acute promyelocytic leukemia and other myeloid neoplasms: Moving toward an effective oral, outpatient therapy

The therapeutic potential of arsenic derivatives has long been recognized and was recently rediscovered in modern literature. Early studies demonstrated impressive activity of this compound in patients with relapsed acute promyelocytic leukemia (APL). Over the last 2 decades, intravenous arsenic trioxide has been used successfully, both alone and in combination with other agents, for the treatment of APL and, with some success, of other myeloid neoplasms. Arsenic trioxide is currently part the standard of care for patients with APL. More recently, oral formulations of this compound have been developed and are entering clinical practice. In this review, the authors discuss the evolution of arsenic in the treatment of APL and other myeloid neoplasms.