Bradycardia induced by irinotecan: a case report

Development of Irinotecan Liposome Armed with Dual-Target Anti-Epidermal Growth Factor Receptor and Anti-Fibroblast Activation Protein-Specific Antibody for Pancreatic Cancer Treatment

Pancreatic cancer is one of the most common causes of death in Taiwan. Previous studies have shown that more than 90% of pancreatic cancer cells presented epidermal growth factor receptor (EGFR) cell marker, and this marker is thought to be important as it is related to activation of cancer cell proliferation, angiogenesis, and cancer progression. Moreover, tumor-associated fibroblasts were involved in tumor proliferation and progression. In this study, we fabricated an anti-EGFR and anti-fibroblast activation protein bispecific antibody-targeted liposomal irinotecan (BS−LipoIRI), which could specifically bind to pancreatic cancer cells and tumor-associated fibroblasts. The drug encapsulation efficiency of BS−LipoIRI was 80.95%, and the drug loading was 8.41%. We proved that both pancreatic cancer cells and fibroblasts could be targeted by BS−LipoIRI, which showed better cellular uptake efficacy compared to LipoIRI. Furthermore, an in vivo mouse tumor test indicated that BS−LipoIRI could inhibit pancreatic cancer growth up to 46.2% compared to phosphate-buffered saline control, suggesting that BS−LipoIRI could be useful in clinical cancer treatment.

Characterization of Differential Tissue Abundance of Major Non-CYP Enzymes in Human

The availability of assays that predict the contribution of cytochrome P450 (CYP) metabolism allows for the design of new chemical entities (NCEs) with minimal oxidative metabolism. These NCEs are often substrates of non-CYP drug-metabolizing enzymes (DMEs), such as UDP-glucuronosyltransferases (UGTs), sulfotransferases (SULTs), carboxylesterases (CESs), and aldehyde oxidase (AO). Nearly 30% of clinically approved drugs are metabolized by non-CYP enzymes. However, knowledge about the differential hepatic versus extrahepatic abundance of non-CYP DMEs is limited. In this study, we detected and quantified the protein abundance of eighteen non-CYP DMEs (AO, CES1 and 2, ten UGTs, and five SULTs) across five different human tissues. AO was most abundantly expressed in the liver and to a lesser extent in the kidney; however, it was not detected in the intestine, heart, or lung. CESs were ubiquitously expressed with CES1 being predominant in the liver, while CES2 was enriched in the small intestine. Consistent with the literature, UGT1A4, UGT2B4, and UGT2B15 demonstrated liver-specific expression, whereas UGT1A10 expression was specific to the intestine. UGT1A1 and UGT1A3 were expressed in both the liver and intestine; UGT1A9 was expressed in the liver and kidney; and UGT2B17 levels were significantly higher in the intestine than in the liver. All five SULTs were detected in the liver and intestine, and SULT1A1 and 1A3 were detected in the lung. Kidney abundance was the most variable among the studied tissues, and overall, high interindividual variability (>15-fold) was observed for UGT2B17, CES2 (intestine), SULT1A1 (liver), UGT1A9, UGT2B7, and CES1 (kidney). These differential tissue abundance data can be integrated into physiologically based pharmacokinetic (PBPK) models for the prediction of non-CYP drug metabolism and toxicity in hepatic and extrahepatic tissues.

Irinotecan inducing sinus pause bradycardia in a patient with small round cell cancer

Irinotecan is a novel anticancer drug that has worked wonders in combination with other anticancer drugs. It can be used as a single chemotherapy agent in colonic cancer treatment or in combination with 5-fluorouracil. Irinotecan has been found a better salvage therapy in patients who are resistant to 5-fluorouracil. It is also used in combination with cisplatin and other drugs for cancers such as pleural mesothelioma, Ewing's sarcoma, lung cancer and others, and has helped reduce tumour burden. Irinotecan is generally associated with gastrointestinal side effects including nausea, vomiting and diarrhoea, while cardiovascular toxicity (5%) has been reported mainly as vasodilatation and possible bradycardia with no known incidence. A case was reported in 1998 by Miya et al of a 65-year-old man with bradycardia which was managed with atropine without modifications in the dosage of irinotecan or in the rate of infusion. We report a case of a patient with small round cell cancer who presented with sinus pause bradycardia after infusion with irinotecan. The patient was managed with atropine during chemotherapy.

Vascular Disrupting Agents in cancer treatment: Cardiovascular toxicity and implications for co-administration with other cancer chemotherapeutics

Destruction of the established tumour vasculature by a class of compound termed Vascular Disrupting Agents (VDAs) is showing considerable promise as a viable approach for the management of solid tumours. VDAs induce a rapid shutdown and collapse of tumour blood vessels, leading to ischaemia and consequent necrosis of the tumour mass. Their efficacy is hindered by the persistence of a viable rim of tumour cells, supported by the peripheral normal vasculature, necessitating their co-administration with additional chemotherapeutics for maximal therapeutic benefit. However, a major limitation for the use of many cancer therapeutics is the development of life-threatening cardiovascular toxicities, with significant consequences for treatment response and the patient's quality of life. The aim of this review is to outline VDAs as a cancer therapeutic approach and define the mechanistic basis of cardiovascular toxicities of current chemotherapeutics, with the overall objective of discussing whether VDA combinations with specific chemotherapeutic classes would be good or bad in terms of cardiovascular toxicity.

Out of the frying pan and into the fire: damage-associated molecular patterns and cardiovascular toxicity following cancer therapy

Cardio-oncology is a new and rapidly expanding field that merges cancer and cardiovascular disease. Cardiovascular disease is an omnipresent side effect of cancer therapy; in fact, it is the second leading cause of death in cancer survivors after recurrent cancer. It has been well documented that many cancer chemotherapeutic agents cause cardiovascular toxicity. Nonetheless, the underlying cause of cancer therapy-induced cardiovascular toxicity is largely unknown. In this review, we discuss the potential role of damage-associated molecular patterns (DAMPs) as an underlying contributor to cancer therapy-induced cardiovascular toxicity. With an increasing number of cancer patients, as well as extended life expectancy, understanding the mechanisms underlying cancer therapy-induced cardiovascular disease is of the utmost importance to ensure that cancer is the only disease burden that cancer survivors have to endure.

Irinotecan side effects relieved by the use of HI-6 oxime: in vivo experimental approach

Some compounds, although not primarily designed as supportive drugs in chemotherapy, are promising candidates for clinical use. The ability of HI-6 oxime to relieve the side effects of irinotecan was recently determined in vitro. In this animal study, we investigated the efficacy of HI-6 in vivo, when given as a pre-treatment and concomitantly with irinotecan. We evaluated the cholinesterase (ChE)/acetylcholinesterase (AChE) activity, the levels of oxidative stress markers, DNA damage and the radical scavenging capacity of HI-6. Both HI-6 and irinotecan inhibited ChE/AChE activity but showed different levels of ChE inhibition in plasma and AChE inhibition in the liver and brain tissue. We also observed a weak antioxidant capacity of HI-6, undiscovered until now, and found an acceptable genotoxicity profile in three types of somatic cells in rats. The in vivo erythrocyte micronucleus assay showed that HI-6 did not significantly change either the frequency of micronuclei or the ratio of polychromatic and normorchromatic erythrocytes. Taken together, our results provide a good argument in favour of HI-6 as a promising molecule for further studies and eventual use in humans.

The diagnosis and management of cardiovascular disease in cancer patients

Cardiovascular disease is commonly found in cancer patients. The co-existence of heart disease and cancer in a patient often complicates treatment, because therapy for one disease may negatively affect the outcome of the other disease. In addition, guidelines for the treatment of cardiovascular disease are often based on studies, which exclude patients who have cancer. In this review we will discuss the diagnosis and management of cardiovascular disease in cancer patients. We will focus on cancer-related causes of cardiovascular disease and special treatment options for cardiovascular disease in cancer patients. The cardiac complications of cancer therapy will be discussed according to common syndromes: left ventricular dysfunction, myocardial ischemia, blood pressure changes, thromboembolism, bradyarrhythmias, and prolonged QT interval.

Acetylcholinesterase blockade does not account for the adverse cardiovascular effects of the antitumor drug irinotecan: a preclinical study

This study investigates the mechanisms that account for the adverse cardiovascular effects of the antitumor drug irinotecan. The activities of irinotecan, its active metabolite 7-ethyl-10-hydroxycamptothecin (SN-38), and camptothecin were assayed in urethane-anesthetized rats to determine their effects on heart rate and blood pressure. In vitro experiments were performed to assess the effects of test drugs on acetylcholinesterase activity. Intravenous irinotecan (10 micromol/kg) decreased heart rate and blood pressure, but SN-38, camptothecin, or intracerebroventricular irinotecan had no effect. The bradycardic and hypotensive responses induced by irinotecan were abolished by bilateral vagotomy or atropine. Physostigmine caused a transient bradycardia, followed by a tachycardic response, and promoted a marked increment of blood pressure. Vagotomy or atropine prevented the bradycardic action of physostigmine, whereas the tachycardic and hypertensive responses were sensitive to atropine, but not to vagotomy. Five minutes after irinotecan administration (10 micromol/kg i.v.), its concentration in plasma and atrial tissue accounted for 2.29 +/- 0.19 micromol/L and 1.08 +/- 0.16 micromol/kg, respectively. The in vitro activity of human erythrocyte acetylcholinesterase was significantly inhibited by irinotecan (-21.5% at 100 microM) or physostigmine (-84.8% at 1 microM), whereas SN-38 or camptothecin had no effect. Rat atrial acetylcholinesterase was also significantly inhibited in vitro by irinotecan (-16.9% at 100 microM). The present results indicate that irinotecan exerts depressant effects on both heart rate and arterial blood pressure. A direct activation of cholinergic receptors or an interaction with central nervous sites does not appear to account for these inhibitory actions, whereas a blockade of acetylcholinesterase seems to occur at concentrations of irinotecan that may not be relevant in clinical settings.

Toxicity of irinotecan (CPT-11) and hepato-renal dysfunction

Various clinical and laboratory parameters have been investigated for their ability to predict toxicity arising from the use of the anticancer drug, irinotecan (CPT-11). In particular, patients deficient in the conjugation of SN-38, a metabolite of CPT-11, are known to be at greater risk. We describe one case of a patient with metastatic colorectal cancer treated with a single dose of CPT-11 at 125 mg/m(2). Although this patient lacked any known predictive factors for toxicity, he experienced severe side-effects several days later. We hypothesized that the toxicity in this patient was due to compromised SN-38 conjugation. Plasma samples were analyzed by reversed-phase high-performance liquid chromatography assay for CPT-11 and its metabolites at 96, 144, 168, 192 and 288 h post-administration. We observed that the concentrations of both the parent drug and its metabolites were markedly raised (11- to 60-fold expected). Additionally the estimated terminal half-lives were 1.5-7 times those expected (29.5, 101, 39.6 and 41.8 h for CPT-11, APC, SN-38G and SN-38, respectively). We conclude that the toxicity in this patient was not caused by deficient SN-38 conjugation, but by decreased drug excretion through both hepatic and renal routes.