Oral arsenic trioxide for treating acute promyelocytic leukaemia: Implications for its worldwide epidemiology and beyond.

This account describes how orally administered Arsenic-trioxide (ATO) therapy influences the epidemiology of acute promyelocytic leukaemia (APL), and how the experience that ensued may expand the indications for oral ATO as a treatment for diseases/disorders other than APL. Over the last two decades, experience with APL patients in Hong Kong treated with an oral regimen comprising ATO, all-trans retinoic acid (ATRA), and ascorbic acid (also known as "AAA") has confirmed a dramatic improvement in overall survival. Over that period, there has been an estimated 60-fold increase in the prevalence of APL (proportion of surviving APL patients in the population on December 31 including those deemed to be 'cured'). In contrast to regimens entailing intravenous (IV) ATO, the consequential therapeutic benefits of using oral ATO have been achieved with much less patient inconvenience and quality of life disruption, reduced burdens on health care facilities (hospitalisations and staff involvement), and much enhanced affordability (retail drug & other cost reductions). Numerous experimental and a few clinical studies suggest that ATO may also have a therapeutic role in many other diseases/disorders. Several such diseases (e.g. autoimmune disorders & idiopathic pulmonary fibrosis) are far more prevalent than APL, which means that very large numbers of patients may potentially benefit from ATO treatment, even if its efficacy is limited to selected populations with these diseases. The known safety of oral ATO and its advantages over repeated long-term IV delivery suggests that this route be used in future clinical studies of its possible role in treating such patients. If the clinical utility of oral ATO treatment is validated for patients enduring any such non-APL diseases, very large numbers of patients may stand to benefit.

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.

Characteristics and predictors of early hospital deaths in newly diagnosed APL: a 13-year population-wide study.

Despite therapeutic advances, early death (ED) remains a major factor curtailing survival of acute promyelocytic leukemia (APL). Studies examining factors that cause early death (ED; within 30 days of admission) and the correlation of survival with the timing of administration of all-trans retinoic acid (ATRA) and hemostatic parameters are scarce. We performed a cohort analysis of nonselect patients with newly diagnosed APL who presented to the health care system in Hong Kong, where oral arsenic trioxide was used. From 1 January 2007 to 30 April 2020, 358 patients (median age, 47 [1-97] years) with newly diagnosed APL were identified. ED occurred in 56 patients (16%): 11 (3%) died in the first 2 days after admission (intracranial hemorrhage [ICH], n = 6; APL-differentiation syndrome [APL-DS], n = 4; infection, n = 1); 22 (6%) died within 3 to 7 days (ICH, n = 12; APL-DS, n = 8; infections, n = 2), and 23 (6%) died within 8 to 30 days (ICH, n = 7; APL-DS, n = 11; infection, n = 5). Factors significantly associated with ED by multivariate analysis included male sex (P = .01); presenting leukocyte count ≥10 × 109/L (P = .03); fibrinogen <1.5 g/L (P = .02); and ATRA administration >24 hours after hospital admission (P < .001). After a median follow-up of 47 (0-166) months, the 5- and 10-year overall survival (OS) was 68.6% and 61.2%, respectively. Excluding EDs, the 5- and 10-year post-30-day OS improved to 81.3% and 72.5%. Early administration of ATRA (<24 hours) and vigorous correction of hemostatic abnormalities, including hypofibrinogenemia, are key to reducing ED.

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.

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.

Oral arsenic trioxide incorporation into frontline treatment with all-trans retinoic acid and chemotherapy in newly diagnosed acute promyelocytic leukemia: A 5-year prospective study.

BACKGROUND: Strategies using oral arsenic trioxide (As2 O3 ) are efficacious in relapsed acute promyelocytic leukemia (APL), but they have not been examined in newly diagnosed cases. METHODS: Sixty-two consecutive patients (24 men and 38 women) with a median age of 52 years (range, 22-85 years), 36% of whom had high-risk features, underwent induction with all-trans retinoic acid at 45 mg/m2 /d, oral As2 O3 at 10 mg/d, and ascorbic acid at 1 g/d (the all-trans retinoic acid-arsenic trioxide-ascorbic acid [AAA] regimen) for 6 weeks (with patients younger than 70 years additionally receiving daunorubicin at 50 mg/m2 /d × 3); they then underwent consolidation with 2 monthly cycles of daunorubicin (50 mg/m2 /d × 2) and cytarabine (100 mg/m2 /d × 5) and received AAA maintenance (2 weeks every 8 weeks) for 2 years. A contemporaneous cohort of 37 newly diagnosed patients (15 men and 22 women) with a median age of 51 years (range, 23-78 years), not consenting to oral As2 O3 induction but receiving similar induction, consolidation, and AAA maintenance, served as a comparator group; 46% of these patients had high-risk features. RESULTS: The oral As2 O3 induction cohort showed a complete remission (CR) rate of 100%. After a median of 37 months (range, 13-82 months), there were no relapses, so conventional risks (age, leukocyte and platelet counts, and Fms-like tyrosine kinase 3 [FLT3] mutations) were not relevant. The leukemia-free survival (LFS) and overall survival (OS) rates were 100% at 3 years and 94.1% at 5 years. The non-As2 O3 induction cohort showed a CR rate of 100%. After a median of 52 months (range, 14-77 months), there were 3 relapses (8%). Comparable patients in the oral As2 O3 induction and non-As2 O3 induction cohorts showed similar OS, but LFS was significantly superior in the oral As2 O3 induction cohort. CONCLUSIONS: The incorporation of oral As2 O3 into induction for newly diagnosed APL was safe and decreased relapses.

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.

Non-vitamin K Oral Anticoagulants Versus Warfarin for Patients with Atrial Fibrillation: Absolute Benefit and Harm Assessments Yield Novel Insights.

BACKGROUND AND OBJECTIVES: Benefits and/or harms (including costs) of non-vitamin K oral anticoagulants (NOACs) versus warfarin therapy need appreciation in relative and absolute terms. METHODS: Accordingly, we derived clinically relevant relative and absolute benefit/harm parameters for NOACs (apixaban, dabigatran, rivaroxaban, edoxaban) compared to warfarin from four clinical trials involving atrial fibrillation (AF) patients. For each trial, we tabulated patient numbers enduring four important outcomes and calculated unadjusted relative risk reduction (RRR) and number needed to treat (NNT)/year values (and 95% confidence intervals) for the NAOC compared to warfarin. These outcomes were as follows: stroke/systemic embolism (primary endpoint), hemorrhagic stroke, major bleeds, and death. We also addressed drug acquisition costs. RESULTS: Each NOAC was noninferior to warfarin for primary-outcome prevention; RRRs were 12-33% and NNT/year values were 182-481, and all but one indicated statistically significant superiority. All the NOACs yielded statistically significant reductions in hemorrhagic stroke risk; RRRs were 42-74% and NNT/year values were 364-528. Major bleeding risk was comparable in both groups. Apixaban yielded a lower NNT/year for preventing death than for primary-outcome prevention. Compared to warfarin, NOAC acquisition costs were 70- to 140-fold greater. CONCLUSIONS: For the primary outcome, the absolute benefits of NOACs were modest (NNT/year values being large). Reduced hemorrhagic stroke rates with NOACs could be due to superior embolic infarct prevention and fewer consequential hemorrhagic transformations. Among apixaban recipients, the absolute mortality benefit exceeded that for the primary outcome, indicating prevention of additional unrelated deaths. The substantially greater NOAC acquisition costs need viewing against probable greater safety and the avoidance of monitoring bleeding risks.

Utility of infrared thermography for screening febrile subjects.

OBJECTIVE: To assess the utility of remote-sensing infrared thermography as a screening tool for fever. DESIGN: Cross-sectional study comparing body temperatures measured by remote-sensing infrared thermography (maximum for frontal, forehead, or lateral views) with core temperatures measured by aural or oral methods. SETTING: Accident and Emergency Department, Queen Mary Hospital, Hong Kong. PARTICIPANTS: A total of 1517 patients (747 men, 770 women) with or without fever; 34 of whom entered a substudy to measure the effects of distance on recorded temperature. MAIN OUTCOME MEASURES: The proportions of subjects with fever (core temperature of 38°C or above) detected by remote-sensing infrared thermography compared with the proportion detected by conventional thermometry. RESULTS: The correlations between infrared thermography temperatures and core temperature were only moderate (r=0.36-0.44), albeit statistically significant. The temperature recorded by infrared thermography was inversely proportional to the distance from the camera. There were 113 (7.4%) subjects with a core temperature of 38°C or above. The areas under the receiver operating characteristic curves for the three infrared thermography measurements were around 0.8. However, the maximum sensitivity achieved at a low cut-off temperature of 35°C was only 0.87 (for frontal and lateral infrared thermography views), resulting in 13% of febrile subjects being missed. The maximum forehead temperature in general had the poorest performance among the three infrared thermography views. CONCLUSIONS: Forehead infrared thermography readings from a distance should be abandoned for fever screening. Although maximum lateral or frontal infrared thermography temperatures have reasonable correlations with core temperatures and areas under the receiver operating characteristic curves, the sensitivity-specificity combination might still not be high enough for screening febrile conditions, especially at border crossings with huge numbers of passengers.

Oral arsenic trioxide-based maintenance regimens for first complete remission of acute promyelocytic leukemia: a 10-year follow-up study.

Seventy-six patients with acute promyelocytic leukemia (APL) in first complete remission after induction and consolidation by daunorubicin and cytosine arabinoside received oral arsenic trioxide (As(2)O(3))-based maintenance. Three regimens were used: oral As(2)O(3) (10 mg/day, regimen A, n = 20), oral As(2)O(3) plus all-trans retinoic acid (ATRA, 45 mg/m(2) per day, regimen AA, n = 19), and oral As(2)O(3) plus ATRA plus ascorbic acid (1000 mg/day, regimen AAA, n = 37), each given for 2 weeks every 2 months for 2 years. Patients receiving A, AA, and AAA maintenance did not differ significantly in clinicopathologic features and risk factors. Headache, dyspepsia, reversible liver function derangement, and herpes zoster reactivation were adverse effects observed during maintenance. QTc prolongation and arrhythmias were not encountered. At a median follow-up of 24 months (range, 1-115 months), there were 8 relapses. The 3-year leukemia-free-survival, event-free-survival, and overall-survival were 87.7%, 83.7%, and 90.6%, respectively. Adverse prognostic factors included male gender for leukemia-free-survival, and unrelated cancers for overall survival. Age, presentation WBC count and platelet count, and the type of oral As(2)O(3) maintenance regimens had no impact on survivals. Prolonged oral As(2)O(3) maintenance was feasible and safe and resulted in favorable outcomes when used with a simple induction and consolidation regimen compared with other protocols composed of multiple chemotherapeutic agents.

Raising highly desirable lipoprotein versus lowering deleterious lipoprotein.

Evaluation of: Taylor AJ, Villines TC, Stanek EJ et al. Extended-release niacin or ezetimibe and carotid intima-media thickness. N. Engl. J. Med. 361(22), 2113-2122 (2009). Epidemiological evidence suggests that elevated low-density lipoprotein cholesterol (LDL-C) and reduced high-density lipoprotein cholesterol (HDL-C) are both factors causing coronary heart disease. These authors compared extended-release niacin, which raises HDL-C, with ezetimibe, which lowers LDL-C, in a study named Arterial Biology for the Investigation of the Treatment Effects of Reducing Cholesterol 6-HDL and LDL Treatment Strategies (ARBITER 6-HALTS). The study was terminated early and only 208 patients were included in the analysis. Ezetimibe decreased LDL-C by 19.2%, to 66 mg/dl (1.7 mmol/l), whereas niacin increased HDL-C by 18.4%. Ezetimibe did not reduce carotid intima-media thickness, whereas niacin decreased it significantly. Moreover, major adverse cardiovascular events occurred in 5% of the ezetimibe group but only 1% of the niacin group (p = 0.04). The study suggests that niacin may be more effective than ezetimibe as an adjunct to statin in regressing atherosclerosis and in preventing cardiovascular events. This small study of short duration reported a very large treatment effect, so the findings need to be confirmed in a larger longer trial. Nevertheless, it provides the evidence that we now have an additional class of drugs besides statins that can reduce atherosclerosis and cardiovascular events.

Aspects of general medicine.

Horizons in Medicine is a series produced annually by the Royal College of Physicians. Volume 19 is based on their Advanced Medicine Conference held in 2007 and offers updates on a wide range of topics in clinical medicine. This 'review of reviews' covers developments described in a selection of chapters. The chapters summarised include: Contemporary management of acute myocardial infarction; Imported infectious disease emergencies; New therapies in the management of type 2 diabetes; Stress and adrenal insufficiency; Making sense of a 'funny thyroid function test'; Myeloproliferative disorders: management and molecular pathogenesis; Drug allergies; Osteoporosis; Rheumatoid arthritis; Understanding migraine from bench to bedside.

Solid tumors subsequent to arsenic trioxide treatment for acute promyelocytic leukemia.

Arsenic trioxide (As(2)O(3)) is highly efficacious for acute promyelocytic leukemia (APL). Environmental arsenic exposure predisposes to malignancies, but the risk for therapeutic arsenic is undefined. Three APL patients (de novo, 2; therapy-related, 1) in a cohort of 59 cases given oral-As(2)O(3) for induction and maintenance treatment developed secondary cancers (nasopharyngeal carcinoma, 2; colonic adenocarcinoma, 1) at 16, 36 and 55 months post-As(2)O(3) therapy. Retrospective analysis of biomarkers (Epstein Barr virus serology and quantification, carcinoembryonic antigen) showed the potential presence of cancers before or shortly after As(2)O(3) therapy, suggesting that As(2)O(3) had not initiated these malignancies. Compared against matched background population, there was an increased risk of second cancer (p=0.012, standard incidence ratio=6.5; 95% confidence interval=1.4-19.0).

Effects of oral arsenic trioxide therapy on QT intervals in patients with acute promyelocytic leukemia: implications for long-term cardiac safety.

Ventricular tachyarrhythmias may occur during intravenous arsenic trioxide (As2O3). This has not happened during oral As2O3. Sixteen patients were studied by electrocardiography and 24-hour Holter monitoring at baseline, during and after oral As2O3 (As2O3-ON, As2O3-OFF). QT and corrected QT (QTc) were significantly longer during As2O3-ON than in As2O3-OFF, but QT and QTc dispersions were comparable. The patients' 24-hour heart rates were higher during As2O3-ON than in As2O3-OFF. QTc intervals at each hour were longer during As2O3-ON than in As2O3-OFF. However, QTc prolongation of more than 30 milliseconds only occurred at one time point (2 hours) after oral As2O3, resulting in QTc of more than 500 milliseconds in 3 of 16 patients, all within 4 hours of oral As2O3. Although the standard deviation of normal RR interval was lower during As2O3-ON, ratios of low frequency to high frequency power for As2O3-ON and As2O3-OFF were comparable. No ventricular proarrhythmias were observed. These observations, due to the lower peak plasma arsenic reached during oral As2O3, may explain the relative cardiac safety of oral As2O3.

Rhythm vs. rate control of atrial fibrillation meta-analysed by number needed to treat.

BACKGROUND: Whenever feasible, rhythm control of atrial fibrillation (AF) was generally preferred over rate control, in the belief that it offered better symptomatic relief and quality of life, and eliminated the need for anticoagulation. However, recent trials appear to challenge these assumptions. AIMS: To explore the desirability of rhythm vs. rate control of AF by systematic review of pertinent, published, randomized controlled trials (RCTs) and a meta-analysis by number needed to treat (NNT) year(-1), with respect to diverse clinically important outcomes. METHODS: RCTs of outcome primarily comparing rate vs. rhythm control in patients with spontaneous AF were identified. For each outcome and assuming rhythm control to be the active treatment, relative risk reduction (RRR) and NNT year(-1) were derived for individual trials together with an NNT year(-1) for all trials combined; corresponding 95% confidence intervals (CI) were also calculated. Adverse drug reaction (ADR) and quality of life reporting were also assessed. RESULTS: In all, data from five suitable RCTs (entailing 5239 patients) were analysed. For hospitalization, available RRRs and NNT year(-1) values were all clinically and statistically significant. Overall, one additional patient was hospitalized for every 35 assigned to rhythm control (95% CI 27, 48). For the endpoints of death, 'ischaemic' stroke and 'non-CNS' bleeding, there was no significant difference. ADRs were significantly more common in rhythm control patients, whereas quality of life assessments revealed no difference. Thromboembolism was associated with cessation of or subtherapeutic anticoagulation, irrespective of treatment assignment. CONCLUSION: Reduced risk of hospitalization and non-inferiority for other endpoints all favour rate control, the less costly strategy. If symptoms of AF are not a problem, treatment should target optimizing rate control and more widespread and effective prophylactic anticoagulation.