Arsenic trioxide in comparison with chemotherapy and bone marrow transplantation for the treatment of relapsed acute promyelocytic leukaemia

Efficacy of Autologous and Allogeneic Hematopoietic Cell Transplantation in Adults with Acute Promyelocytic Leukemia: Results of a Systematic Review and Meta-Analysis

Despite therapeutic advances for acute promyelocytic leukemia (APL) with the emergence of all-trans retinoic acid, arsenic trioxide, and gemtuzumab-ozogamycin, approximately 10% of patients still experience disease relapse, typically occurring within 24 to 36 months following completion of front-line treatment. Traditionally, both allogeneic (allo) and autologous (auto) hematopoietic cell transplantation (HCT) have been considered reasonable treatment options for relapsed APL; however, no randomized controlled studies have been conducted comparing allo-HCT and auto-HCT in patients with relapsed APL. We performed a systematic review/meta-analysis to assess the totality of evidence pertaining to allo-HCT or auto-HCT in relapsed APL. Our search identified 1158 references, of which 23 met our inclusion criteria. While acknowledging the limitations of comparing these 2 treatment modalities indirectly, based on results from separate meta-analyses, it appears that pooled rates of event-free survival (71% versus 54%), progression-free survival (63% versus 43%), and overall survival (82% versus 58%) are higher after auto-HCT. This difference can be explained in part by the higher risk of pooled nonrelapse mortality (NRM) in patients undergoing allo-HCT (29% versus 5%), owing to inherent risks associated with this modality. In the absence of a randomized prospective clinical trial comparing allo-HCT and auto-HCT, our results show that both modalities are acceptable in patients with relapsed APL. The higher pooled NRM rate with allo-HCT is an important consideration when choosing this option. Additionally, the comparable pooled relapse rate for auto-HCT and allo-HCT (24% versus 23%) provides a rationale for evaluating post-HCT consolidative strategies to mitigate this risk.

Successful treatment of acute promyelocytic leukemia in a patient undergoing hemodialysis with arsenic trioxide

A man undergoing hemodialysis was diagnosed with acute promyelocytic leukemia (APL). He received arsenic trioxide as a single agent and achieved complete molecular remission without severe adverse events. Arsenic trioxide can be used safely and effectively for patients with APL under hemodialysis.

Long-term survival in an acute promyelocytic leukemia patient with recurrent granulocytic sarcomas: A case report

RATIONALE

Granulocytic sarcoma (GS) is an extramedullary myeloid tumor composed of immature cells of the granulocytic series. It rarely occurs in acute promyelocytic leukemia (APL). No case of long-term survival in an APL patient with recurrent GS has been reported.

PATIENT CONCERNS

A 54-year-old female patient was diagnosed with APL in 1995 and has been in complete remission (CR) of bone marrow morphology for 24 years; however, recurrent GS occurred successively in ovary, breast, spine, body of sternum, lymph nodes, soft tissues from 2004 to 2019.

DIAGNOSES

The immunohistochemistry confirmed the diagnosis of GS, and fluorescence in situ hybridization (FISH) revealed its origin from APL.

INTERVENTIONS

She received surgery, and had an excellent response to all-trans retinoic acid (ATRA), DA (daunorubicin combined with cytarabine) regimens, and arsenic trioxide (ATO).

OUTCOMES

The patient achieved CR in March 2020 after radiotherapy followed by ATO and ATRA. So far, she is still in follow-up.

LESSONS

It is rare that recurrent GS at multiple sites is involved in APL patient with bone marrow morphology in CR. It is interesting to observe a long-term excellent response to ATRA, chemotherapy and ATO. Although multiple recurrence of GS in patients with APL is rare, the data in this case highlight the need for individualized treatment when such conditions occur.

Acute promyelocytic leukemia (APL): remaining challenges towards a cure for all

The application of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) has revolutionized the treatment of acute promyelocytic leukemia (APL). More than 80-90% of patients are expected to be cured with a combination of ATRA, ATO and/or chemotherapy. In this review, we focus on the remaining obstacles to a cure for all patients with APL. We review the issue of early death and coagulopathy and discuss the particular challenges in the care of patients with high-risk APL and patients with relapsed APL. We also give recommendations and highlight ongoing efforts to improve the persistently high early death rate and the outcomes of high risk and relapsed APL patients.

Retinoic acid and arsenic trioxide in the treatment of acute promyelocytic leukemia: current perspectives

Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia (AML) with a unique morphological appearance, associated coagulopathy and canonical balanced translocation of genetic material between chromosomes 15 and 17. APL was first described as a distinct subtype of AML in 1957 by Dr Leif Hillestad who recognized the pattern of an acute leukemia associated with fibrinolysis, hypofibrinogenemia and catastrophic hemorrhage. In the intervening years, the characteristic morphology of APL has been described fully with both classical hypergranular and variant microgranular forms. Both are characterized by a balanced translocation between the long arms of chromosomes 15 and 17, [t(15;17)(q24;q21)], giving rise to a unique fusion gene PML-RARA and an abnormal chimeric transcription factor (PML-RARA), which disrupts normal myeloid differentiation programs. The success of current treatments for APL is in marked contrast to the vast majority of patients with non-promyelocytic AML. The overall prognosis in non-promyelocytic AML is poor, and although there has been an improvement in overall survival in patients aged <60 years, only 30%-40% of younger patients are still alive 5 years after diagnosis. APL therapy has diverged from standard AML therapy through the empirical discovery of two agents that directly target the molecular basis of the disease. The evolution of treatment over the last 4 decades to include all-trans retinoic acid and arsenic trioxide, with chemotherapy limited to patients with high-risk disease, has led to complete remission in 90%-100% of patients in trials and rates of overall survival between 86% and 97%.

Molecular Monitoring as a Path to Cure Acute Promyelocytic Leukemia

Acute promyelocytic leukemia (APL) is a molecularly well-defined disease, characterized by a specific chromosomal translocation; the improvement in biologic and clinical knowledge and subsequent introduction of molecularly targeted therapies have transformed the management of APL, with survival rates now exceeding 80%. Minimal residual disease (MRD) assessment in APL is the most important tool for its treatment; the prognostic role of the molecular detection of promyelocytic leukemia retinoic acid receptor α (PML-RARα) transcript after consolidation therapy in the early identification of the following hematologic relapse is now well established and guides preemptive therapy. First experiences performed with a qualitative polymerase chain reaction (PCR) approach were replaced with more accurate real-time quantitative PCR (RQ-PCR), which guarantees a numeric quantification of MRD. The identification of arsenic trioxide (ATO) as a valid therapy not only in relapsed patients but also as an alternative to standard therapy alone or in association with all-trans-retinoic acid enlarges the setting of validation of MRD evaluation in APL patients, considering a possible different clearance of PML-RARα with innovative therapy different from the standard ones. MRD monitoring demonstrated its validity also in the setting of relapsed patients with interesting results in the autologous and allogeneic stem cell transplantation setting or with the use of other biological agents. The aim of this review is to report and discuss the actual state of the art of MRD in APL.

Budgetary impact of treating acute promyelocytic leukemia patients with first-line arsenic trioxide and retinoic acid from an Italian payer perspective

The objective of this study was to estimate the net cost of arsenic trioxide (ATO) added to all-trans retinoic acid (ATRA) compared to ATRA plus chemotherapy when used in first-line acute promyelocytic leukemia (APL) treatment for low to intermediate risk patients from the perspective of the overall Italian healthcare systemA Markov model was developed with 3 health states: stable disease, disease event and death. Each month, patients could move from stable to disease event or die from either state. After a disease event, patients discontinued initial treatment and switched to the other regimen as second-line therapy. Treatment regimens, efficacy and adverse events were derived from published sources and expert opinion; unit costs were collected from standard Italian sources. Clinical outcomes and costs for pre-ATO and post-ATO scenarios were combined with population and product utilization information to calculate the total budgetary impact using a 3-year time horizon; one-way sensitivity analyses were conducted. Three-year cumulative pharmacy costs for ATO+ATRA were €46,700 per-patient versus €6,500 for ATRA+chemotherapy; however, medical costs for ATO+ATRA were €12,300 per-patient versus €30,200 for ATRA+chemotherapy. The total budgetary impact was estimated to be an additional €127,300, €312,500 and €477,800 in the first, second and third years, respectively. The model was most sensitive to changes in the cost of the ATO+ATRA regimen during the consolidation phase. Budgetary impact models are valuable to payers making formulary decisions regarding the access and affordability of new medicines. The cost of treatment analysis showed that pharmacy costs for ATO+ATRA were higher than for ATRA+chemotherapy, while all other evaluated costs were lower for ATO+ATRA treated patients. The average budgetary impact was €305,900 per year overall, representing a 3.5% increase. Further research is needed to determine the cost-effectiveness of ATO+ATRA compared to the current first-line standard of care in APL.

New strategies in acute promyelocytic leukemia: moving to an entirely oral, chemotherapy-free upfront management approach

Incorporation of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) into the management paradigms of acute promyelocytic leukemia (APL) has markedly improved outcomes. Significant progress occurred in understanding the molecular pathogenesis of APL. ATO, in contrast with ATRA, is capable of eradicating the APL-initiating cells and can result in cure. Preclinical and clinical data confirmed the synergy of ATO and ATRA, and the ATRA-ATO combination was proved noninferior to a standard ATRA-chemotherapy regimen in patients with non-high-risk APL. Oral formulations of arsenic exhibited excellent activity in advanced clinical testing and their combinations with ATRA offer an opportunity for a completely oral, chemotherapy-free regimen for curing APL. Nonetheless, significant challenges remain. Reducing early death due to bleeding complications is an important area of unmet need. Data suggest that delays in initiation of ATRA upon suspecting APL continue to occur in the community and contribute to early mortality. Questions remain about the optimal place and schedule of arsenic in the therapeutic sequence and the role of the oral formulations. Refining the role of minimal residual disease in directing treatment decisions is important. Development of novel targeted agents to treat relapsed disease requires deeper understanding of the secondary resistance mechanisms to ATRA and ATO.

Top five medical innovations in China mainland since Xinhai revolution [1911]: results of AME survey-002

OBJECTIVE

This survey aims to scrutinize important medical innovations in Chinese mainland since Xinhai (Hsin-hai) revolution in 1911, which marked the end of Manchurian imperial rule and the beginning of China's republican era.

METHODS

An online cross-sectional survey was carried out during the period of Dec 29, 2014 to Feb 5, 2015, totaling 37 days. The survey was conducted on the platform provided by DXY (www.dxy.cn), which is the largest medical and paramedical related website in China. An email was sent to all DXY registered users to invite them to participate in a 5-minute survey. The participants were asked to nominate up to four important medical innovations in China mainland since Xinhai revolution. The participant could select 'zero' which means he/she felt there was no important medical innovations, or he/she did not know important medical innovations. It was noted that important medical innovations refer to (I) those with practical and almost immediate significance to improve healthcare; (II) should not only be introducing western technique to China, but those involve major improvement of existing western techniques count; (III) should not be those with important theoretical discovery but did not have almost immediate significance to improve healthcare.

RESULTS

In total 1,513 DXY users participated in the voting. Totally 489 (32.3%), 441 (29.1%), 342 (22.6%), 150 (9.9%), 91 (6.0%) participants provided 0, 1, 2, 3, 4 nominations respectively. (I) Artemisine (Qinghaosu) for malaria treatment (Project 523 team, 1972); (II) arsenic Trioxide (As2O3) for acute promyelocytic leukemia (APL) treatment (ZHANG Ting-Dong and colleagues, 1970s); (III) limb re-plantation (CHEN Zhong-Wei and colleagues, 1963); (IV) all-trans retinoic acid (ATRA) for APL treatment (WANG Zhen-Yi and colleagues, 1988); and (V) Wu's mask for plague prevention (WU Lien-The, 1910), were voted as the top five innovations in China mainland since Xinhai revolution, with 375, 96, 91, 53, and 8 votes respectively.

CONCLUSIONS

In this voting exercise, five achievements were voted as top innovations in China mainland since Xinhai revolution. However, only ATRA for APL treatment was accomplished after the ending of Great Proletarian Cultural Revolution in year 1976 in China.

Use of arsenic trioxide in a hemodialysis-dependent patient with relapsed acute promyelocytic leukemia

Arsenic trioxide has been established for use in both relapsed and front-line treatment of acute promyelocytic leukemia. Dose adjustments are recommended to be considered in severe renal impairment although dosage reduction guidelines are not provided. In addition, toxicities of arsenic are significant. The use of arsenic trioxide has not been well studied in dialysis patients and there is a paucity of data in the literature to support the use in such a situation. We describe an 81-year-old relapsed acute promyelocytic leukemia hemodialysis-dependent patient with a pre-existing cardiac condition who was treated with 10 mg arsenic trioxide three times weekly after dialysis. These findings provide support along with the marginal amount of currently published data for an arsenic trioxide dosing regimen in hemodialysis patients.

Economic evaluation of arsenic trioxide compared to all-trans retinoic acid + conventional chemotherapy for treatment of relapsed acute promyelocytic leukemia in Canada

OBJECTIVES

Acute promyelocytic leukemia (APL) is an uncommon type of acute leukemia characterized by high early mortality. Current first-line treatments include all-trans retinoic acid (ATRA), anthracyclines, and other conventional chemotherapies (CTs). Although APL is generally associated with a good prognosis, about 20% of patients who achieve remission subsequently relapse and are resistant to the previously administrated treatment. The objective of this study was to assess, from a Canadian perspective, the economic impact of arsenic trioxide (ATO) compared to ATRA+CT for treatment of patients with relapsed/refractory APL.

METHODS

The cost-effectiveness of ATO compared to ATRA+CT for treating patients with relapsed/refractory APL was assessed over a lifetime horizon using a Markov model. The model considers five health states: induction, second remission, treatment failure or relapse, postfailure, and death. Markov cycle length was 1 month for the first 24 months and 1 yr thereafter. The model also takes into account the incidence of grade 3-4 adverse events reported in clinical trials. Analyses were conducted from a Canadian Ministry of Health (MoH) and a societal perspective.

RESULTS

Compared to ATRA+CT, ATO was associated with incremental cost-effectiveness ratios of $ 20,551/quality-adjusted life year (QALY) from a MoH perspective and $ 22,219/QALY from a societal perspective. Results of the probabilistic sensitivity analysis indicated that ATO is a cost-effective strategy in 99.27% and 98.98% of the simulations from a MoH and a societal perspective, respectively.

CONCLUSIONS

This economic evaluation demonstrates that ATO is a cost-effective strategy compared to ATRA+CT for treatment of patients with relapsed/refractory APL in Canada.

Arsenic trioxide-based therapy of relapsed acute promyelocytic leukemia: registry results from the European LeukemiaNet

In 2008, a European registry of relapsed acute promyelocytic leukemia was established by the European LeukemiaNet. Outcome data were available for 155 patients treated with arsenic trioxide in first relapse. In hematological relapse (n=104), 91% of the patients entered complete hematological remission (CR), 7% had induction death and 2% resistance, 27% developed differentiation syndrome and 39% leukocytosis, whereas no death or side effects occurred in patients treated in molecular relapse (n=40). The rate of molecular (m)CR was 74% in hematological and 62% in molecular relapse (P=0.3). All patients with extramedullary relapse (n=11) entered clinical and mCR. After 3.2 years median follow-up, the 3-year overall survival (OS) and cumulative incidence of second relapse were 68% and 41% in hematological relapse, 66% and 48% in molecular relapse and 90 and 11% in extramedullary relapse, respectively. After allogeneic or autologous transplantation in second CR (n=93), the 3-year OS was 80% compared with 59% without transplantation (n=55) (P=0.03). Multivariable analysis demonstrated the favorable prognostic impact of first remission duration ⩾1.5 years, achievement of mCR and allogeneic or autologous transplantation on OS of patients alive after induction (P=0.03, P=0.01, P=0.01) and on leukemia-free survival (P=0.006, P<0.0001, P=0.003), respectively.

A Canadian consensus on the management of newly diagnosed and relapsed acute promyelocytic leukemia in adults

The use of all-trans-retinoic acid (atra) and anthracyclines (with or without cytarabine) in the treatment of acute promyelocytic leukemia (apl) has dramatically changed the management and outcome of the disease over the past few decades. The addition of arsenic trioxide (ato) in the relapsed setting-and, more recently, in reduced-chemotherapy or chemotherapy-free approaches in the first-line setting-continues to improve treatment outcomes by reducing some of the toxicities associated with anthracycline-based approaches. Despite those successes, a high rate of early death from complications of coagulopathy remains the primary cause of treatment failure before treatment begins. In addition to that pressing issue, clarity is needed about the use of ato in the first-line setting and the role of hematopoietic stem-cell transplantation (hsct) in the relapsed setting. The aim for the present consensus was to provide guidance to health care professionals about strategies to reduce the early death rate, information on the indications for hsct and on the use of ato in induction and consolidation in low-to-intermediate-risk and high-risk apl patients.

Acute promyelocytic leukemia: what is the new standard of care?

Acute promyelocytic leukemia (APL) is one of the most exciting stories of modern medicine. Once a disease that was highly lethal, the majority of patients are now cured with the advent of molecularly targeted therapy with all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). In many patients, chemotherapy can be omitted completely, particularly in patients with low- or intermediate-risk disease (white blood cell count ≤ 10,000/μl). Recent data show overall survival exceeding 90% with ATRA and ATO-based induction and consolidation strategies. In the uncommon patient in whom relapse does occur, most can still be cured with ATO and autologous hematopoietic cell transplantation. Remaining challenges in APL management include the rapid identification and treatment of newly diagnosed patients to decrease the early death rate, optimizing treatment strategies in high-risk patients (white blood cell count>10,000/μl), and the role of maintenance therapy in lower risk patients.

Contemporary treatment of APL

Acute promyelocytic leukemia (APL) is characterized by coagulopathy, leukopenic presentation and sensitivity to anthracyclines, all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). For the last 25 years, APL has been treated with a combination of ATRA and chemotherapy for induction followed by consolidation and maintenance therapy. This general treatment approach has resulted in cure rates of 80-90 %. ATO, originally approved in relapsed APL, has been incorporated into contemporary upfront treatment regimens with excellent response rates. Recent studies show that most patients with APL can be cured with ATRA and ATO alone, eliminating cytotoxic chemotherapy and resulting in superior outcomes compared to standard treatment. We will herein review historical treatment of APL, treatment considerations in specific patient populations, and therapeutic updates.

Treatment of acute promyelocytic leukemia with arsenic trioxide: clinical results and open questions

Acute promyelocytic leukemia (APL) is a rare form of acute myeloid leukemia. The specific translocation t(15;17), which results in the fusion gene PML-RARA is the diagnostic and pathomechanistic hallmark of APL. By combination, treatment consisting of the differentiating agent all-trans retinoic acid (ATRA), which targets this molecular lesion, and cytotoxic chemotherapy, cure can be achieved in over 70% of patients. Recently, arsenic trioxide (ATO) has emerged to be the most active single agent in the treatment of APL. Previous studies employing ATO in relapse settings reported average complete remission rates of 85% and a mean overall survival of over 60%. In recent approaches installing ATO in first-line treatment, ATO-induced response rates comparable to previous combination regimen. The results of these newer studies indicate that the backbone of chemotherapy can be dramatically reduced or completely replaced by ATO and ATRA with similar or even better outcome.

Role of arsenic trioxide in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is a unique subtype of acute myeloid leukemia that is characterized by distinct clinical, morphological, cytogenetic, and molecular abnormalities. It is associated with a striking risk of early hemorrhagic death due to disseminated intravascular coagulation and hyperfibrinolysis. The prognosis of APL has improved dramatically following the introduction of all-trans retinoic acid (ATRA) and its combination with anthracycline-based chemotherapy during induction and consolidation. Patients with high-risk APL, defined by a white cell count >10 × 10(9)/L at diagnosis, also appear to benefit from the addition of intermediate- or high-dose cytarabine during consolidation. Arsenic trioxide (ATO) has proved to be even more effective than ATRA as a single agent, and is now routinely used for the treatment of the 20%-30% of patients who manifest disease relapse after initial treatment with ATRA and chemotherapy. ATO has a toxicity profile that differs considerably from that of both ATRA and cytotoxic chemotherapy, and accordingly presents its own specific challenges during treatment. Optimizing a strategy for the incorporation of ATO into initial therapy is currently the focus of several cooperative group trials, with an emphasis on minimizing or even eradicating the use of chemotherapy. ATRA plus ATO without chemotherapy appears to be adequate during induction and consolidation for patients with standard-risk APL, but triple therapy that includes limited anthracycline or gemtuzumab ozogamicin (GO) during induction is required for high-risk APL. Uncertainty still exists regarding the minimum amount of chemotherapy and number of consolidation cycles necessary, the optimal scheduling of ATO, and the potential utility of oral ATO administration. Although prolonged oral maintenance therapy is usually included in most current APL treatment protocols, its value remains controversial, and the superior anti-leukemic efficacy of ATO-based therapy may facilitate its elimination in the future.

Role of hematopoietic stem cell transplantation for relapsed acute promyelocytic leukemia: a retrospective analysis of JALSG-APL97

For patients with relapsed acute promyelocytic leukemia (APL), all-trans retinoic acid-based salvage regimens can achieve second complete remission (CR2), but the optimal post-remission strategy for APL patients after CR2 remains unclear. Hematopoietic stem cell transplantation (HSCT) during CR2 might be effective, but data on the role of HSCT for APL patients after CR2 are limited in Japan. We retrospectively analyzed outcomes for 57 relapsed APL patients who achieved CR2 in the JALSG APL97 study. Of those, six received autologous (auto)-HSCT, 21 received allogeneic (allo)-HSCT, and 30 received various regimens other than HSCT. The 5-year event-free survival (EFS) rate, overall survival (OS) rate and cumulative incidence of relapse (CIR) were 50.7%, 77.4% and 51.0% in the non-HSCT group, 41.7%, 83.3% and 58.3% in the auto-HSCT group and 71.1%, 76.2% and 9.8% in the allo-HSCT group, respectively. Both the EFS rate and CIR were significantly better in the allo-HSCT group than in other groups. Allo-HSCT appears effective in APL patients in CR2, with a low relapse rate beyond a relatively early transplantation-related mortality (19%). Among older patients (age ≥40 years), the 5-year OS was significantly better in the non-HSCT group than in the HSCT group (78.0% vs 40.5%; P = 0.04). Further prospective studies with larger patient numbers are required to confirm the impact of HSCT alone and in combination with arsenic trioxide on outcomes for patients with APL in CR2.

Effect of therapeutic arsenic exposure on pulmonary function

AIM

Arsenic-contaminated drinking water has been associated with respiratory diseases and lung function impairment. Oral arsenic trioxide (ATO) is a standard treatment for acute promyelocytic leukaemia. This study aimed to explore the effect of therapeutic exposure to arsenic on lung function.

PATIENTS AND METHOD

This was a case-control cross-sectional study on patients with haematological malignancies with or without exposure to ATO. Full lung function tests and serum Clara cell protein 16 (CC16) were measured.

RESULTS

There were 57 cases (arsenic exposed) and 57 matched controls (arsenic non-exposed) recruited. Among cases, the median duration of ATO exposure was 519 (194-1259) days. The mean FEV(1)/FVC ratio, FEV(1) (% predicted), and RV/TLC (%), as well as % subjects with FEV(1)/FVC below lower limits of normal (LLN), were similar in the two groups with or without arsenic exposure. However the mean TLC (% predicted) and DLCO/VA were significantly higher in arsenic-exposed versus non-exposed group (p = 0.01 and p = 0.008 respectively). There were mildly reduced FEV(1)/FVC ratio and FEF(25-75) (% predicted), largely within normal limits, among high level arsenic exposure compared with non-exposure (p = 0.01 and p = 0.05 respectively). Serum CC16 was comparable among both arsenic exposed and non-exposed groups.

CONCLUSION

Therapeutic use of oral ATO for a median of around 1.5 years was not associated with clinically significant lung function impairment.

Emerging new approaches for the treatment of acute promyelocytic leukemia

The introduction of all-trans retinoic acid (ATRA) in the late 1980s combined with anthracycline-based chemotherapy has revolutionized the prognosis of acute promyelocytic leukemia (APL) with more than 90% complete response rates and cure rates of approximately 80%. The subsequent advent of arsenic trioxide (ATO) in 1990s and progress in the treatment of APL have changed its course from a highly fatal to a highly curable disease. Despite the dramatic improvement in clinical outcome of APL, treatment failure still occurs due most often to early death. Relapse has become increasingly less frequent, most commonly occurring in patients with high-risk disease. A major focus of research for the past decade has been to develop risk-adapted and rationally targeted nonchemotherapy treatment strategies to reduce treatment-related morbidity and mortality to low- and intermediate-risk or older patients while targeting more intensive or alternative therapy to those patients at most risk of relapse. In this review, emerging new approaches to APL treatment with special emhasis on strategies to reduce early deaths, risk-adapted therapy during induction, consolidation and maintenance, as well as an overview of current and future clinical trials in APL will be discussed.

Arsenic trioxide for management of acute promyelocytic leukemia: current evidence on its role in front-line therapy and recurrent disease

INTRODUCTION

Acute promyelocytic leukemia (APL), the most rapidly fatal leukemia only two decades ago, has been converted into the most frequently curable leukemia by the advent of all-trans retinoic acid (ATRA) and its combination with anthracycline-based chemotherapy. More recently, arsenic trioxide (ATO) has been shown to be the most effective single agent in this disease and has been approved for the treatment of relapsed patients both in the United States and Europe. Moreover, ATO has been included in the design of several front-line studies, with the aim to reduce therapy-related toxicity while maintaining the potential of cure.

AREAS COVERED

First, this review briefly discusses the mechanisms of action and the toxicity profile of ATO. Furthermore, the reported experience on the use of ATO as single agent or in combinatorial schemes both in relapsed and in newly diagnosed patients with APL is critically reviewed. Finally, the use of this agent in special subsets of patients unfit to receive conventional chemotherapy is discussed, along with its potential role in maintenance therapy.

EXPERT OPINION

While the role of ATO as single agent or in combination with ATRA is well established and recommended by the European LeukemiaNet guidelines as a first option for relapsed patients, the role of the drug in newly diagnosed patients is still uncertain and based only on evidence levels mostly originating from non-randomized trials. The results of ongoing randomized studies should better define the role of ATO in front-line therapy.

Oral arsenic trioxide for relapsed acute promyelocytic leukemia in pediatric patients

Four patients (age 3-11 years at diagnosis) with relapsed acute promyelocytic leukemia (APL), 12-38 months from diagnosis, were treated with oral arsenic trioxide (As(2) O(3) ). One patient was treated with oral As(2) O(3) monotherapy and chemotherapy. Three patients failed initial oral or intravenous As(2) O(3) monotherapy were treated with oral As(2) O(3) plus ATRA followed by long-term oral maintenance (cumulative As(2) O(3) dose 280-2,100 mg). All patients achieved molecular remission, at a median follow up of 122 (10-132) months with no adverse effects. Oral As(2) O(3) , particularly in prolonged maintenance with oral ATRA may obviate the need of stem cell transplantation in relapsed pediatric APL.

The treatment of elderly patients with acute myeloid leukemia

BACKGROUND

In patients over age 60 with acute myeloid leukemia (AML), cure rates are under 10% despite intensive chemotherapy. These patients often have comorbidities, and their treatment must be chosen with care. For those who are not candidates for intensive chemotherapy, one of the available options for palliative treatment should be chosen on the basis of an individual risk-benefit assessment.

METHODS

Selective literature review.

RESULTS

An evaluation of the patient's general condition and comorbidities, a geriatric assessment, and specially designed risk scores are useful aids to the choice of an appropriate treatment. Some elderly patients with AML can benefit from intensive chemotherapy despite their age; for highly selected elderly patients, allogeneic stem-cell transplantation is an increasingly feasible option. Hypomethylating agents or low-dose cytarabine can be suitable for some patients. Further options include experimental treatment as part of a clinical trial, and supportive care alone. In the special case of acute promyelocytic leukemia, more than half of all patients can be cured with combination chemotherapy including all-trans retinoic acid.

CONCLUSION

The prognosis of elderly AML patients remains poor despite recent therapeutic advances. The appropriate treatment for each patient can be chosen on the basis of a risk-benefit assessment. Clinical trials evaluating new treatments are urgently needed.

Impact of arsenic trioxide in the treatment of acute promyelocytic leukemia

Arsenic trioxide (ATO) is presently the most active single agent in the treatment of acute promyelocytic leukemia (APL). This review provides insights into the mode of action and the pharmacological properties of ATO, and summarizes the most relevant results of more than 20 treatment studies in relapsed or newly diagnosed APL published between 1997 and 2011. ATO acts by targeting multiple pathways in APL leading to apoptosis and myeloid differentiation. It induces complete remission without myelosuppression and causes only few adverse effects. In relapsed APL, ATO-based salvage therapy has been able to induce long-lasting remissions and possible cure in 50-81% of patients. In newly diagnosed APL, two main strategies are currently pursued. ATO is either included into induction therapy with the aim to minimize or eliminate chemotherapy, or it is incorporated as an additive into established first-line concepts with all-trans-retinoic acid and chemotherapy to reinforce their anti-leukemic efficacy. Recent results suggest a high efficacy of ATO in both concepts. In conclusion, experimental research and clinical studies have made contributions toward a better understanding of the molecular mechanisms induced by ATO in APL cells and have established this historic substance as an important candidate for the further improvement of APL therapy.

Long-term remission after first-line single-agent treatment with arsenic trioxide of relapsed acute promyelocytic leukemia in an 8-year-old boy

Arsenic trioxide (ATO) has been proven to be highly effective in adults with newly diagnosed or relapsed acute promyelocytic leukemia (APL). Only very limited data are published on the use of ATO as a single agent for first-line therapy of relapsed APL. The authors present a case of a 8-year-old boy with a bone marrow relapse of APL 7 years after first diagnosis, who achieved durable molecular remission with ATO as single agent: induction therapy for 12 weeks, consolidation for 4 weeks, then 6 cycles of 10 days over a period of 6 months. In total, 140 doses of ATO (0.15 mg/kg/day) were given (21 mg/kg). Consecutive promyelocytic leukemia-retinoic acid receptor α (PML-RARα) RT-PCR analyses were negative with a follow-up of 48 months. Acute or late side effects of arsenic were not observed. At present, the boy is in complete remission 4 years after the diagnosis of the relapse.

Modern Approaches to Treating Acute Promyelocytic Leukemia

The advent of all-trans-retinoic acid (ATRA) and its combination with anthracycline-containing chemotherapy have contributed in the past 2 decades to optimize the antileukemic efficacy in acute promyelocytic leukemia (APL), leading to complete remission rates greater than 90%, virtual absence of resistance, and cure rates of nearly 80%. Recently reported studies from large cooperative trials have also shown that more rational delivery of treatment and improved outcomes may derive from the use of risk-adapted protocols. In particular, patients at higher risk of relapse (ie, those presenting with WBC > 10 × 109/L) seem to benefit from treatments that include cytarabine in the ATRA-plus-chemotherapy scheme, whereas patients with standard-risk disease can be successfully managed with less-intensive regimens that contain ATRA and anthracycline-based chemotherapy. After the outstanding results with arsenic trioxide (ATO) in the treatment of APL relapse, several experimental trials have been designed to explore the role of ATO in front-line therapy with the aim not only of minimizing the use of chemotherapy but also to reinforce standard ATRA-plus-chemotherapy regimens and additionally improve therapeutic efficacy. In this review article, we discuss most recent advances in the treatment of patients with newly diagnosed and relapsed APL.

Promyelocytic sarcoma of the spine: a case report and review of the literature

Myeloid sarcoma (MS, previously named granulocytic sarcoma or chloroma) is a rare extramedullary tumour of immature myeloid cells. It can be present before, concurrently with, or after the diagnosis of acute myeloid leukemia. MS is extremely uncommon in acute promyelocytic leukemia (APL). In the case described here, MS was the sole site of APL relapse and the cause of spinal cord compression. The patient presented with neurologic symptoms due to a paravertebral mass of MS after 7 years of complete remission. He was treated with excision of the mass followed by local radiotherapy. Systemic treatment was also given with combined arsenic trioxide and all-trans retinoic acid and the patient was able to achieve a second prolonged clinical and molecular remission.

Comparison of clinical outcomes of patients with relapsed acute promyelocytic leukemia induced with arsenic trioxide and consolidated with either an autologous stem cell transplant or an arsenic trioxide-based regimen

In patients with relapsed acute promyelocytic leukemia (APL), the best consolidation regimen following induction of remission with arsenic trioxide (ATO) remains to be defined. Since January 2000, 37 patients with relapsed APL were treated at our center. The median age was 34 years (range, 6-57 years), and there were 20 males (54.1%). The median duration of first remission was 20.3 months (range, 2.9-81.2 months). Relapse was treated with single-agent ATO in 22 patients (59.5%), ATO+ATRA in 5 patients (13.5%), and ATO+ATRA + anthracycline in 10 patients (27%). Thirty-three patients (89%) achieved molecular remission after induction and a consolidation course. Fourteen patients opted to undergo autologous stem cell transplantation (SCT), and the remaining 19 patients received monthly cycles of ATO as a single agent (n=13) or ATO+ATRA (n=6) for 6 months. At a median follow-up of 32 months, the 5-year Kaplan-Meier estimate of event-free survival (EFS) was 83.33% +/- 15.21% in those who underwent autologous SCT versus 34.45% +/- 11.24% in those who did not (P=.001; log-rank test). Following remission induction with ATO-based regimens in patients with relapsed APL, consolidation with autologous SCT is associated with a significantly superior clinical outcome compared with ATO- and ATO+ATRA-based maintenance regimens.

Adverse prognostic impact ofCDKN2Bhyper-methylationin acute promyelocytic leukemia

The use of all-trans retinoic acid (ATRA) has markedly improved the survival of patients with acute promyelocytic leukemia (APL), making it potentially curable. However, the identification of prognostic markers predictive of durable remission remains an important aspect in risk-adjusted treatment algorithms. High presentation leucocyte count has been found to correlate with inferior disease-free-survival (DFS). However, recent studies have also shown aberrant promoter methylation of the CDKN2B (alias p15) gene to be a negative prognostic factor. Promoter methylation results in the formation of a repressor complex, leading to chromatin compaction and suppression of gene expression and is, therefore, an alternative mechanism of gene inactivation. CDKN2B, a cyclin-dependent kinase inhibitor, is a tumor suppressor gene inhibiting cell cycle progression. The CpG island inside the CDKN2B promoter is hyper-methylated in approximately 50 - 60% of APL patients. CDKN2B methylation correlates negatively with DFS. As methylation-induced inactivation of CDKN2B pre-disposes to unchecked cellular proliferation, CDKN2B hyper-methylation is also associated with high presentation leucocyte count. Multivariate analysis in several studies, however, has shown that the negative prognostic impact of CDKN2B methylation is independent of its association with high leucocyte counts. Therefore, CDKN2B methylation is a potential prognostic factor that may be incorporated into a risk-stratified therapeutic strategy, which aims at achieving a cure with optimal amounts of treatment.

Management of acute promyelocytic leukemia: recommendations from an expert panel on behalf of the European LeukemiaNet

The introduction of all-trans retinoic acid (ATRA) and, more recently, arsenic trioxide (ATO) into the therapy of acute promyelocytic leukemia (APL) has revolutionized the management and outcome of this disease. Several treatment strategies using these agents, usually in combination with chemotherapy, but also without or with minimal use of cytotoxic agents, have provided excellent therapeutic results. Cure of APL patients, however, is also dependent on peculiar aspects related to the management and supportive measures that are crucial to counteract life-threatening complications associated with the disease biology and molecularly targeted treatment. The European LeukemiaNet recently appointed an international panel of experts to develop evidence- and expert opinion-based guidelines on the diagnosis and management of APL. Together with providing current indications on genetic diagnosis, modern risk-adapted front-line therapy and salvage treatment, the review contains specific recommendations for the identification and management of most important complications such as the bleeding disorder, APL differentiation syndrome, QT prolongation and other ATRA- and ATO-related toxicities, as well as for molecular assessment of response to treatment. Finally, the approach to special situations is also discussed, including management of APL in children, elderly patients, and pregnant women.

Arsenic trioxide

BACKGROUND

The ancient drug, arsenic, has remarkable efficacy in the treatment of relapsed acute promyelocytic leukemia (APL) and this success has led to exploration of its use in other malignancies.

OBJECTIVE

To provide an overview of the mechanism of action of arsenic and summarize its development in the treatment of APL and other malignant disorders.

METHODS

A 20-year search of MEDLINE, EMBASE and Web of Science was conducted.

RESULTS/CONCLUSIONS

A series of clinical trials with arsenic trioxide has confirmed its benefit in the therapy of APL. Its role in the treatment of other malignancies remains to be determined. Careful attention to the clinical management of patients on arsenic trioxide therapy can significantly lessen the risk of major side effects.

Arsenic trioxide: safety issues and their management

Arsenic trioxide (As2O3) has been used medicinally for thousands of years. Its therapeutic use in leukaemia was described a century ago. Recent rekindling in the interest of As2O3 is due to its high efficacy in acute promyelocytic leukaemia (APL). As2O3 has also been tested clinically in other blood and solid cancers. Most studies have used intravenous As2O3, although an oral As2O3 is equally efficacious. Side effects of As2O3 are usually minor, including skin reactions, gastrointestinal upset, and hepatitis. These respond to symptomatic treatment or temporary drug cessation, and do not compromise subsequent treatment with As2O3. During induction therapy in APL, a leucocytosis may occasionally occur, which can be associated with fluid accumulation and pulmonary infiltration. The condition is similar to the APL differentiation syndrome during treatment with all-trans retinoic acid, and responds to cytoreductive treatment and corticosteroids. Intravenous As2O3 treatment leads to QT prolongation. In the presence of underlying cardiopulmonary diseases or electrolyte disturbances, particularly hypokalaemia and hypomagnesaemia, serious arrhythmias may develop, with torsades du pointes reported in 1% of cases. This may be related to a dose-dependent arsenic-mediated inhibition of potassium ion channels that compromises cardiac repolarization. Because of slow intestinal absorption, oral-As2O3 gives a lower plasma arsenic concentration, which is associated with lesser QT prolongation and hence a more favorable cardiac safety profile. As2O3 does not appear to enter the central nervous system. However, if the blood brain barrier is breached, elemental arsenic may enter the cerebrospinal fluid. As2O3 is predominantly excreted in the kidneys, and dose adjustment is required when renal function is impaired.

Isolated central nervous system relapse in childhood acute promyelocytic leukemia

Central nervous system (CNS) involvement is rare in acute promyelocytic leukemia (APL). The majority of CNS relapses occur in patients with hyperleukocytosis at presentation, and the optimal management of such patients is still controversial. We describe a 13-year-old boy with APL who developed an isolated CNS relapse after first-line treatment with all-trans retinoic acid and chemotherapy. A second remission was achieved with a regimen consisting of intrathecal chemotherapy, intravenous high-dose cytarabine, and oral 6-mercaptopurine. All-trans retinoic acid was avoided owing to severe complications during initial therapy. The patient remains in molecular remission at 9 months after autologous stem cell transplant. Prognostic factors of CNS relapse in children with APL are needed to define the indications for CNS prophylaxis in this group of patients.

Outcome of patients with acute promyelocytic leukemia failing to front-line treatment with all-trans retinoic acid and anthracycline-based chemotherapy (PETHEMA protocols LPA96 and LPA99): benefit of an early intervention

To determine prognosis of acute promyelocytic leukemia (APL) failing to front-line therapy with all-trans retinoic acid (ATRA) and anthracyclines, outcome of 52 patients (32 M/20 F; age: 37, 3-72) included in PETHEMA trials LPA96 and LPA99 who presented with either molecular failure (MOLrel, n=16) or hematological relapse (HEMrel, n=36) was analyzed. Salvage therapy consisted of ATRA and high-dose ara-C-based chemotherapy (HDAC) in most cases (83%), followed by stem-cell transplantation (autologous, 18; allogeneic, 10; syngeneic, 1). Fourteen patients with MOLrel (88%) achieved second molecular complete response (molCR), whereas 81% HEMrel patients responded to second-line treatment, with 58% molCR. After median follow-up of 45 months, four MOLrel and 18 HEMrel patients, respectively, experienced a second relapse. Outcome after MOLrel compared favorably to HEMrel, with longer survival (5-year survival: 64+/-14 vs 24+/-8%, P=0.01) and lower relapse risk (5-year relapse risk: 30+/-13 vs 64+/-9%; P=0.044). Additionally, age <or=40 and male gender were favorable variables for survival, whereas molecular response predicted longer leukemia-free survival. In conclusion, early institution of salvage therapy at molecular failure, before onset of hematological relapse, is beneficial in APL. Moreover, given the poor outcome of HEMrel managed with ATRA and HDAC, use of alternative therapeutic strategies in this setting is warranted.

Treatment of acute promyelocytic leukemia with arsenic trioxide without ATRA and/or chemotherapy

INTRODUCTION

Arsenic trioxide is effective and approved for treatment of relapsed or refractory acute promyelocytic leukemia (APL) cases resistant to all-trans retinoic acid (ATRA), but its effect on new cases of APL is not clear.

MATERIALS AND METHODS

We studied 111 patients with APL. Arsenic trioxide was infused at 0.15 mg/kg daily dose, until complete remission was achieved. Then, after 28 days of rest, arsenic trioxide was infused daily for 28 days as consolidation therapy. We studied minimal residual disease (MRD) by semi-sensitive reverse transcription polymerase chain reaction (RT-PCR) on peripheral blood samples.

RESULTS

Complete remission was observed in 95 patients (85.6%). With the median (range) follow-up period of 16.5 (1-57) months, 1- and 2-year disease-free survival was 88.3% and 63.7%, respectively; 24 patients relapsed, 19 of whom achieved a second complete remission, again by arsenic trioxide. Third and fourth remissions were seen in some relapsed patients, again by arsenic trioxide. For patients in complete remission, 1- and 3-year survival was 95.5% and 87.6%, respectively. MRD was positive in four (8.3%) out of 48 cases during 1 year after remission induction; three of them relapsed clinically.

CONCLUSIONS

Arsenic trioxide is effective as first-line treatment for APL. Results of arsenic trioxide combination therapy with chemotherapy/ATRA requires further study.

Arsenic trioxide in the treatment of haematological malignancies

Arsenic trioxide (As(2)O(3)) for leukaemia treatment was described a century ago. Recent resurgence in the use of arsenic trioxide is related to its high efficacy in acute promyelocytic leukaemia (APL). Most arsenic trioxide preparations are intravenous, although an oral formulation is similarly efficacious. Side effects of arsenic trioxide are usually minor, including skin reactions, gastrointestinal upset, and reversible increases in transaminases. During therapy, a leukocytosis occasionally occurs, which may be complicated by fluid accumulation and pulmonary infiltration. Arsenic trioxide causes an asymptomatic QT prolongation in most patients. However, if concomitant cardiopulmonary diseases or electrolyte disturbances are present, more sinister arrhythmias may develop. Therefore, before commencement of arsenic trioxide therapy, a full cardiac assessment and avoidance of drugs that prolong QT interval should be instituted. Arsenic trioxide is partly renally excreted and, therefore, dose adjustment is required when renal function is impaired. In addition to its use in APL, arsenic trioxide is now tested in other malignancies, notably multiple myeloma.

Management of Arsenic Trioxide Necrosis in the Maxilla

Historically, pulp-necrotizing agents were commonly used in endodontic treatments. They act quickly and devitalize the pulp within a few days. However, they are cytotoxic to gingiva and bone. If such an agent diffuses out of the cavity, it can readily cause widespread necrosis of gingiva and bone, which can lead to osteomyelitis of the jaws. Although the use of arsenic trioxide can cause severe damage to surrounding tissues, producing complications, it is still used in certain areas in the world. This article presents and discusses two cases of tissue necrosis and their surgical management. These cases showed severe alveolar bone loss in the maxilla, which affected the patients' quality of life and limited the restorative possibilities. As dentists, we should be aware of the hazardous effects of arsenic trioxide and should abandon its use. Because of its cytotoxicity, there is no justification for the use of arsenic trioxide in the modern dental practice.

FLT-3 aberrations in acute promyelocytic leukaemia: clinicopathological associations and prognostic impact

FLT-3 aberrations that occur as an internal tandem duplication (ITD) or a mutation at the activation-loop position 835, D835, are common in acute promyelocytic leukaemia (APL). We investigated the clinicopathological associations and prognostic impact of FLT-3 aberrations in a cohort of APL patients. FLT-3 exons 11 and 12 were amplified by polymerase chain reaction (PCR), and the ITD was recognized as an increase in the size of the PCR product. FLT-3 exon 17 was amplified, and D835 mutation was identified by loss of an EcoRV site, followed by DNA sequencing. Of 82 patients studied, FLT-3 aberrations were detected in 35 cases (43%) at diagnosis (ITD: 16; D835 mutation: 18; ITD + D835 mutation: 1). FLT-3 ITD, but not D835 mutations, was significantly associated with higher presentation white blood cell count (WBC) and microgranular morphology. Early/induction deaths were related to male sex and high presentation WBC. There was a trend for FLT-3 ITD to be associated with non-remission (P = 0.06). For disease-free survival, high WBC was the only significant adverse factor. Male sex, high WBC and FLT-3 ITD were significant adverse factors for overall survival. These findings have important implications on the possible use of FLT-3 inhibitors in the treatment of APL.