Differences in hematological and non-hematological toxicity during treatment with imatinib in patients with early and late chronic phase chronic myeloid leukemia

The prevalence of hepatic and thyroid toxicity associated with imatinib treatment of chronic myeloid leukaemia: a systematic review

BACKGROUND

Imatinib, a potent inhibitor of targeted protein tyrosine kinases, treats chronic myeloid leukaemia (CML). Data on imatinib-associated changes in hepatic and thyroid functions are limited and conflicting.

AIM

To report the prevalence of hepatic and thyroid toxicity associated with the use of imatinib in CML patients.

METHOD

Articles for the systematic review were selected from electronic databases (PubMed, CINALH, Web of Science). Readily accessible peer-reviewed full articles in English published 1st January 2000 to 18th July 2023 were included. The search terms included combinations of: imatinib, CML, liver toxicity, hepatic toxicity, thyroid toxicity. Screening of titles, abstracts, full text articles was conducted independently by two reviewers. Inclusions and exclusions were recorded following PRISMA guidelines. Detailed reasons for exclusion were recorded. Included articles were critically appraised.

RESULTS

Ten thousand one hundred and twenty-three CML patients were reported in the 82 included studies corresponding to 21 case reports, 2 case series, 39 clinical trials and 20 observational studies were selected. Excluding case studies/reports, 1268 (12.6%; n = 1268/10046) hepatotoxicity adverse events were reported, of which 64.7% were rated as mild grade I & II adverse events, 363 (28.6%) as severe, grade III and IV adverse events; some led to treatment discontinuation, liver transplantation and fatal consequences. Twenty (35.1%) studies reported discontinuation of imatinib treatment due to the severity of hepatic toxicity. Fourteen (8.4%, n = 14/167) thyroid dysfunction adverse events were reported.

CONCLUSION

High frequency of mild and severe hepatotoxicity, associated with imatinib in CML patients, was reported in the published literature. Low numbers of mild and manageable thyroid toxicity events were reported.

Marrow fibrosis is an independent predictor of hematological toxicity of tyrosine kinase inhibitors for the treatment of chronic myeloid leukemia

Hematological toxicity is a common adverse effect of tyrosine kinase inhibitors (TKIs) for the treatment of chronic myeloid leukemia (CML). We retrospectively investigated the incidence of hematological toxicity after TKI administration in 143 CML patients and parameters associated with hematological toxicity. Severe hematological toxicity (grade 3-4) existed in 26 (18.2%) patients. Marrow fibrosis (MF), age, Sokal score, and spleen enlargement were associated with severe hematological toxicity. Further multivariate analysis showed that only MF was an independent predictor. Complete cytogenetic response(CCyR) rates and major molecular response (MMR) rates with grade 3-4 hematological toxicity were 42.3% and 26.9%, respectively, significantly lower than patients with grade 1-2 and without hematological toxicity (p = .032 for CCyR and p = .044 for MMR). Similar results were observed regarding progression-free survival (PFS) and overall survival (OS) (p = .011 for PFS and p = .037 for OS). This study indicated that MF was an independent predictor of severe hematological toxicity of TKIs.

Muscle Toxicity of Drugs: When Drugs Turn Physiology into Pathophysiology

Drugs are prescribed to manage or prevent symptoms and diseases, but may sometimes cause unexpected toxicity to muscles. The symptomatology and clinical manifestations of the myotoxic reaction can vary significantly between drugs and between patients on the same drug. This poses a challenge on how to recognize and prevent the occurrence of drug-induced muscle toxicity. The key to appropriate management of myotoxicity is prompt recognition that symptoms of patients may be drug related and to be aware that inter-individual differences in susceptibility to drug-induced toxicity exist. The most prevalent and well-documented drug class with unintended myotoxicity are the statins, but even today new classes of drugs with unintended myotoxicity are being discovered. This review will start off by explaining the principles of drug-induced myotoxicity and the different terminologies used to distinguish between grades of toxicity. The main part of the review will focus on the most important pathogenic mechanisms by which drugs can cause muscle toxicity, which will be exemplified by drugs with high risk of muscle toxicity. This will be done by providing information on key clinical and laboratory aspects, muscle electromyography patterns and biopsy results, and pathological mechanism and management for a specific drug from each pathogenic classification. In addition, rather new classes of drugs with unintended myotoxicity will be highlighted. Furthermore, we will explain why it is so difficult to diagnose drug-induced myotoxicity, and which tests can be used as a diagnostic aid. Lastly, a brief description will be given of how to manage and treat drug-induced myotoxicity.

Acquired platelet antagonism: off-target antiplatelet effects of malignancy treatment with tyrosine kinase inhibitors

Platelets can contribute to tumor progression and metastasis. Cancer patients are at increased risk of thrombosis, and advanced stages of cancer are associated with thrombocytosis or increased platelet reactivity. Tyrosine kinase inhibitors (TKIs) are widely used as a targeted strategy for cancer treatment, with the aim of prolonging progression-free survival of the patients. Because of their broad kinase target spectrum, most TKIs inevitably have off-target effects. Platelets rely on tyrosine kinase activity for their activation. Frequently observed side effects are lowering of platelet count and inhibition of platelet functions, whether or not accompanied by an increased bleeding risk. In this review, we aim to give insights into: (i) 38 TKIs that are currently used for the treatment of different types of cancer, either on the market or in clinical trials; (ii) how distinct TKIs can inhibit activation mechanisms in platelets; and (iii) the clinical consequences of the antiplatelet effects of TKI treatment. For several TKIs, the knowledge on affinity for their targets does not align with the published effects on platelets and reported bleeding events. This review should raise awareness of the potential antiplatelet effects of several TKIs, which will be enhanced in the presence of antithrombotic drugs.

Evaluation of the safety of imatinib mesylate in 200 iraqi patients with chronic myeloid leukemia in the chronic phase: single-center study

OBJECTIVE

Imatinib mesylate, a tyrosine kinase inhibitor, is presently the drug of choice for chronic myeloid leukemia (CML). During therapy, a few patients may develop hematological and non-hematological adverse effects.

MATERIALS AND METHODS

The aim of this study was to evaluate the safety of imatinib therapy in patients with CML. Between December 2007 and October 2009 two hundred patients with CML in chronic phase were included in the study. Written informed consent was obtained from all patients prior to the start of the study. Imatinib was started at 400 mg orally daily. Patients were monitored carefully for any adverse effects. Complete blood count, liver, and renal function tests were done once in 2 weeks during the first month and on a monthly basis during follow-up. Toxicities that encountered were graded as per the National Cancer Institute common toxicity criteria version 2. Both hematologic and non-hematologic toxicities were managed with short interruptions of treatment and supportive measures, but the daily dose of imatinib was not reduced below 300 mg/day.

RESULTS

Two hundred CML patients in chronic phase were included in this study; the male:female ratio was 0.7:1 with mean age 39.06±13.21 years (ranged from 15-81 years). The study showed that the commonest hematological side effects were grade 2 anemia (12.5%) followed by leukopenia (8%) and thrombocytopenia (4%), while the most common non-hematological adverse effects were superficial edema and weight gain (51.5%), followed by musculoskeletal pain (35.5%), then gastro-intestinal symptoms (vomiting, diarrhea) (19%). Fluid retention was the commonest side effect, which responded to low-dose diuretics. The drug was safe and well tolerated. There were no deaths due to toxicity.

CONCLUSION

Imatinib mesylate a well-tolerated drug, and all undesirable effects could be ameliorated easily. The most common hematological and non-hematological side effects were anemia and fluid retention, respectively Conflict of interest:None declared.

Hematologic toxicities of small molecule tyrosine kinase inhibitors

Small molecule tyrosine kinase inhibitors (TKIs) are potent anti-cancer targeted therapies. TKIs are considered safe and efficacious therapeutic modalities, and are generally tolerated well. However, they are associated with certain side effects including hematologic toxicities such as anemia, macrocytosis, neutropenia, thrombocytopenia, hemolytic anemia, bone marrow aplasia and necrosis. Thrombotic microangiopathy, arterial thromboembolism and splenic infarction can also occur following treatment with TKIs. Cytopenias are the most common adverse effects associated with these agents, and other hematologic toxicities are not frequent. It is essential for clinicians to monitor patients closely, and recognize those side effects as early as possible, in order to improve efficacy of small molecule TKIs and optimize outcomes. This article summarizes hematologic toxicities associated with the commonly used small molecule TKIs. It also provides practical strategies for the management of these toxicities.