Prevalence, management, and clinical consequences of QT interval prolongation during treatment with arsenic trioxide

Current first- and second-line treatment options in acute promyelocytic leukemia

Outcome of acute promyelocytic leukemia (APL) has remarkably improved during the last 30 years, especially after the identification of PML-RARA oncogene as a key in the pathogenesis of APL and all-trans retinoic acid as therapeutic agent. Arsenic trioxide has been recently demonstrated to be the most effective single antileukemic agent and it has also showed synergistic action when combined with all-trans retinoic acid, decreasing relapse rate especially in low/intermediate-risk settings. Therapeutic advances led to complete remission rates of more than 90%, modifying disease history. In relapse setting, arsenic trioxide-based regimens showed efficacy for the achievement of second molecular complete remission. The most challenging issue in APL management remains the significant early deaths rate, nowadays the principal reason for treatment failure.

Time-to-Onset Analysis of Drug-Induced Long QT Syndrome Based on a Spontaneous Reporting System for Adverse Drug Events

Long QT syndrome (LQTS) is a disorder of the heart’s electrical activity that infrequently causes severe ventricular arrhythmias such as a type of ventricular tachycardia called torsade de pointes (TdP) and ventricular fibrillation, which can be fatal. There have been no previous reports on the time-to-onset for LQTS based on data from spontaneous reporting systems. The aim of this study was to assess the time-to-onset of LQTS according to drug treatment. We analyzed the association between 113 drugs in 37 therapeutic categories and LQTS including TdP using data obtained from the Japanese Adverse Drug Event Report database. For signal detection, we used the reporting odds ratio (ROR). Furthermore, we analyzed the time-to-onset data and assessed the hazard type using the Weibull shape parameter. The RORs (95% confidence interval) for bepridil, amiodarone, pilsicainide, nilotinib, disopyramide, arsenic trioxide, clarithromycin, cibenzoline, donepezil, famotidine, sulpiride, and nifekalant were 174.4 (148.6–204.6), 17.3 (14.7–20.4), 52.0 (43.4–62.4), 13.9 (11.5–16.7), 69.3 (55.3–86.8), 54.2 (43.2–68.0), 4.7 (3.8–5.8), 19.9 (15.9–25.0), 8.1 (6.5–10.1), 3.2 (2.5–4.1), 7.1 (5.5–9.2), and 254.8 (168.5–385.4), respectively. The medians and quartiles of time-to-onset for aprindine (oral) and bepridil were 20.0 (11.0–35.8) and 18.0 (6.0–43.0) days, respectively. The lower 95% confidence interval of the shape parameter β of bepridil was over 1 and the hazard was considered to increase over time.Our study indicated that the pattern of LQTS onset might differ among drugs. Based on these results, careful long-term observation is recommended, especially for specific drugs such as bepridil and aprindine. This information may be useful for the prevention of sudden death following LQTS and for efficient therapeutic planning.

Current management of newly diagnosed acute promyelocytic leukemia

The management of acute promyelocytic leukemia (APL) has considerably evolved during the past two decades. The advent of all-trans retinoic acid (ATRA) and its inclusion in combinatorial regimens with anthracycline chemotherapy has provided cure rates exceeding 80%; however, this widely adopted approach also conveys significant toxicity including severe myelosuppression and rare occurrence of secondary leukemias. More recently, the advent of arsenic trioxide (ATO) and its use in association with ATRA with or without chemotherapy has further improved patient outcome by allowing to minimize the intensity of chemotherapy, thus reducing serious toxicity while maintaining high anti-leukemic efficacy. The advantage of ATRA-ATO over ATRA chemotherapy has been recently demonstrated in two large randomized trials and this option has now become the new standard of care in low-risk (i.e. non-hyperleukocytic) patients. In light of its rarity, abrupt onset and high risk of early death and due to specific treatment requirements, APL remains a challenging condition that needs to be managed in highly experienced centers. We review here the results of large clinical studies conducted in newly diagnosed APL as well as the recommendations for appropriate diagnosis, prevention and management of the main complications associated with modern treatment of the disease.

Cardiovascular Toxicity and Management of Targeted Cancer Therapy

The advent of effective oral, molecular-targeted drugs in oncology has changed many incurable malignancies such as chronic myeloid leukemia into chronic diseases similar to coronary artery disease and diabetes mellitus. Oral agents including monoclonal antibodies, kinase inhibitors and hormone receptor blockers offer patients with cancer incremental improvements in both overall survival and quality of life. As it is imperative to recognize and manage side effects of platelet inhibitors, beta blockers, statins, human immunodeficiency virus drugs and fluoroquinolones by all healthcare providers, the same holds true for these newer targeted therapies; patients may present to their generalist or other subspecialist with drug-related symptoms. Cardiovascular adverse events are among the most frequent, and potentially serious, health issues in outpatient clinics, and among the most frequent side effects of targeted chemotherapy. Data support improved patient outcomes and satisfaction when primary care and other providers are cognizant of chemotherapy side effects, allowing for earlier intervention and reduction in morbidity and healthcare costs. With the implementation of accountable care and pay for performance, improved communication between generalists and subspecialists is essential to deliver cost-effective patient care.

Current standard treatment of adult acute promyelocytic leukaemia

The outcome of patients with acute promyelocytic leukaemia (APL) has dramatically improved over the last two decades, due to the introduction of combined all-trans retinoic acid (ATRA) and chemotherapy regimens and, more recently, to the advent of arsenic trioxide (ATO). ATRA and anthracycline-based chemotherapy remains a widely used strategy, providing cure rates above 80%, but it is associated with risk of severe infections and occurrence of secondary leukaemias. ATO is the most effective single agent in APL and, used alone or in combination with ATRA or ATRA and reduced-intensity chemotherapy, results in greater efficacy with considerably less haematological toxicity. The toxic profile of ATO includes frequent, but manageable, QTc prolongation and increase of liver enzymes. Two large randomized studies have shown that ATRA + ATO is superior to ATRA + chemotherapy for newly diagnosed low-risk APL resulting in 2-4 year event-free survival rates above 90% and very few relapses. According to real world data, the spectacular progress in APL outcomes reported in clinical trials has not been paralleled by a significant improvement in early death rates, this remains the most challenging issue for the final cure of the disease.

QT Prolongation and Oncology Drug Development

Many pharmaceutical agents interact with cardiac ion channels resulting in abnormal ventricular repolarization and prolongation of the QT interval. In rare circumstances, this has resulted in the development of the potentially life-threatening arrhythmia, torsades de pointes. It is recognized, however, that accurate measurement of the QT interval is challenging, and it is a poor predictor for the development of this arrhythmia. Nevertheless, QT interval monitoring is an essential part of pharmaceutical development, and significant increases in the QT interval may prevent a drug from gaining approval.