An important group of antiemetic drugs used in the treatment of nausea and vomiting after chemotherapy containing an indole moiety in their structures, working as 5- hydroxytryptamine type 3 serotonin receptor antagonist (5-HT3). This study focuses on compounds bearing an indole core that present a 5-HT3 receptor antagonist activity, which have been successfully used as antiemetic drugs for reducing chemotherapy adverse secondary effects during cancer treatment. Their synthesis, biological activities, and some outstanding characteristics are discussed, providing a general outlook towards the development of more efficient antiemetic drugs.

The organic cation transporter 2 (OCT2) and multidrug and toxin extrusion protein 1 (MATE1) mediate the renal secretion of drugs. Recent studies suggest that ondansetron, a 5-HT3 antagonist drug used to prevent nausea and vomiting, can inhibit OCT2- and MATE1-mediated transport. The purpose of this study was to test the ability of five 5-HT3 antagonist drugs to inhibit the OCT2 and MATE1 transporters. The transport of the OCT2/MATE1 probe substrate ASP+ was assessed using two models: (1) HEK293 kidney cells overexpressing human OCT2 or MATE1, and (2) MDCK cells transfected with human OCT2 and MATE1. In HEK293 cells, the inhibition of ASP+ uptake by OCT2 listed in order of potency was palonosetron (IC50: 2.6 μM) > ondansetron > granisetron > tropisetron > dolasetron (IC50: 85.4 μM) and the inhibition of ASP+ uptake by MATE1 in order of potency was ondansetron (IC50: 0.1 μM) > palonosetron = tropisetron > granisetron > dolasetron (IC50: 27.4 μM). Ondansetron (0.5-20 μM) inhibited the basolateral-to-apical transcellular transport of ASP+ up to 64%. Higher concentrations (10 and 20 μM) of palonosetron, tropisetron, and dolasetron similarly reduced the transcellular transport of ASP+. In double-transfected OCT2-MATE1 MDCK cells, ondansetron at concentrations of 0.5 and 2.5 μM caused significant intracellular accumulation of ASP+. Taken together, these data suggest that 5-HT3 antagonist drugs may inhibit the renal secretion of cationic drugs by interfering with OCT2 and/or MATE1 function.

Chemotherapy-induced nausea and vomiting (CINV) is 1 of the most debilitating side effects of cancer therapy, affecting up to 80% of chemotherapy patients.1 Chemotherapy drugs are classified according to the associated risk of causing CINV: minimal (less than 10%), low (10% to 30%), moderate (30% to 90%), and high (greater than 90%).2 High emetogenic chemotherapy (HEC) drugs include a high dose of cisplatin, a high dose of cyclophosphamide (1,500 mg/m2 or more), and a combination of anthracycline and cyclophosphamide (AC).2 Moderate emetogenic chemotherapy (MEC) regimens are more variable including carboplatin, oxaliplatin, doxorubicin, and cyclophosphamide.2 CINV symptoms can manifest at various time points after chemotherapy. There are 3 distinct types of CINV: Acute CINV occurs within 24 hours after administration of chemotherapy, with acute vomiting and nausea, and is primarily mediated by the 5-hydroxytryptamine-3 (5-HT3) receptor antagonist. Delayed CINV occurs from 24 hours to 5 days after chemotherapy and is predominantly mediated by the neurokinin 1 (NK1) receptor antagonists. Anticipatory CINV occurs before chemotherapy treatment as a conditioned response because of the development of significant CINV from the previous chemotherapy cycles, mediated by both physiologic and psychological mechanisms.2,3. The management of CINV has been facilitated from the development of various antiemetic agents with different mechanisms of action. Three most commonly used medications for antiemetic prophylaxis are 5-HT3 receptor antagonists (5-HT3 RA), NK1 RA, and corticosteroids, usually dexamethasone (DEX).3,4 Other antiemetic agent such as olanzapine, an atypical antipsychotic, has been used for acute and delayed CINV.3,4 These antiemetic agents are used in specific combinations depending on the emetogenicity of the chemotherapy regimen given to different population (i.e., adults or children).3,4 Currently available 5-HT3 RAs for CIVN include ondansetron, granisetron, dolasetron, and palonosetron.3,4 The NK1 RA include aprepitant, fosaprepitant, and rolapitant.3,4 On March 14, 2012, Health Canada issued a Notice of Compliance for the IV and oral formulation of palonosetron. IV palonosetron is indicated in adults for “the prevention of acute and delayed nausea and vomiting associated with MEC and the prevention of acute nausea and vomiting associated with HEC, including high dose cisplatin. Oral palonosetron is indicated in adults for the prevention of acute nausea and vomiting associated with MEC”.5 Palonosetron is a long-lasting, second-generation agent, with higher affinity and binding capacity to 5-HT3 receptor, and thus has a longer half-life of 40 hours compared to first-generation 5-HT3 RAs, ondansetron, granisetron, dolasetron, and with a half-life of 3 to 9 hours.6 Due to its long half-life, palonosetron has been suggested to produce best treatment responses in both acute and delayed CINV of varying emetogenicity.6 On September 28, 2017, Health Canada issued a Notice of Compliance for netupitant/palonosetron (NEPA) — a combination of a highly selective NK1 RA netupitant (300 mg) and palonosetron (0.5 mg) — in combination with DEX, for once-per-cycle treatment in adult patients for the “prevention of acute and delayed nausea and vomiting associated with HEC and prevention of acute nausea and vomiting associated with MEC therapy that is uncontrolled by a 5-HT3 RA.”7,8 Over the past decades, the development of new antiemetic drugs has progressed and shown promising results in the prevention of CINV. Particularly, the appearance of second-generation of 5-HT3 receptor palonosetron and its combination with netupitant in NEPA has urged a literature review on the clinical effectiveness and cost-effectiveness of these drugs relative to other 5-HT3 RAs. Both dosage forms of palonosetron (IV and oral) were reviewed by the CADTH Common Drug Review in 2012.9–12 The combination product palonosetron-netupitant (Akynzeo) was reviewed in 2017.13–15 Since then, new evidence and guidelines have emerged on the use of palonosetron as monotherapy or in combination with netupitant to treat adults and children with CINV. The aim of this report is to review the clinical effectiveness and cost-effectiveness of palonosetron for the prevention of CINV in patients receiving HEC or MEC. The report also summarizes the evidence-based guidelines regarding the use of palonosetron for the prevention CINV in patients receiving HEC or MEC.

Little information is available on the use of dolasetron during breastfeeding. Until more data become available, dolasetron should be used with caution during breastfeeding. An alternate drug may be preferred.

Inaccurately perceived as niche drugs, antiemetics are key elements of cancer treatment alleviating the most dreaded side effect of chemotherapy. Serotonin 5-HT3 receptor antagonists are the most commonly prescribed class of drugs to control chemotherapy-induced nausea and vomiting. These antagonists have been clinically successful drugs since the 1980s, yet our understanding of how they operate at the molecular level has been hampered by the difficulty of obtaining structures of drug-receptor complexes. Here, we report the cryoelectron microscopy structure of the palonosetron-bound 5-HT3 receptor. We investigate the binding of palonosetron, granisetron, dolasetron, ondansetron, and cilansetron using molecular dynamics, covering the whole set of antagonists used in clinical practice. The structural and computational results yield detailed atomic insight into the binding modes of the drugs. In light of our data, we establish a comprehensive framework underlying the inhibition mechanism by the -setron drug family.

Review the clinical evidence of tropisetron or palonosetron, an old- and new-generation serotonin (5-hydroxytryptamine) type 3 (5-HT3) receptor antagonist (RA), respectively, for the prevention of chemotherapy-induced nausea and vomiting (CINV) in patients with cancer, and evaluate any difference in efficacy trends. A literature search of the EMBASE and PubMed databases was performed to identify publications of intravenous (IV) tropisetron (generic forms or Navoban®) for the treatment of CINV in patients with various cancers. Data from the pivotal clinical studies evaluating the IV formulation of Aloxi® (palonosetron HCl) were also considered. The effectiveness and safety of each antiemetic was summarized. Sixteen papers for tropisetron fulfilled the inclusion criteria and were extracted for full analysis; publications from six pivotal palonosetron clinical trials were considered. No direct data comparisons could be made between the two drugs, due to the varying definitions of efficacy endpoints between studies. For tropisetron, the rates of no emesis were lower in patients receiving highly emetogenic chemotherapy (HEC) versus moderately emetogenic chemotherapy (MEC). For palonosetron, the rates of complete response (no emesis, no rescue medication) were comparable in the MEC and HEC settings, demonstrating the effectiveness of this agent in patients receiving HEC. Both antiemetics offered some protection against nausea, although lower rates of no nausea were achieved compared with rates of no emesis. Two trials that evaluated the efficacy of palonosetron and tropisetron within the same study reported that palonosetron was more effective than tropisetron in controlling delayed vomiting in the HEC and MEC settings, with significantly higher rates of no emesis observed (P≤0.01). Palonosetron was non-inferior or more efficacious in controlling CINV compared with other older 5-HT3RAs, such as dolasetron, ondansetron, and granisetron. Conversely, tropisetron was no more efficacious than ondansetron or granisetron. Both tropisetron and palonosetron were generally well tolerated, with adverse event profiles consistent with drugs of this class (e.g., headache, constipation, and diarrhea). These data suggest that palonosetron is a highly selective prophylactic agent that may have an improved therapeutic profile compared with tropisetron, and is a feasible treatment option for controlling CINV in patients with cancer.

The JTpeak interval has been proposed as a new biomarker to demonstrate mixed ion channel effects, potentially leading to reduced late-stage electrocardiogram (ECG) monitoring for mildly QT-prolonging drugs. ECG waveforms from the IQ-CSRC study were used. Twenty healthy subjects were enrolled with 6 subjects on placebo and 9 subjects on each of 5 mildly QT-prolonging drugs - moxifloxacin, dofetilide, ondansetron, dolasetron, and quinine - and 1 negative drug, levocetirizine. A vector magnitude lead was derived from 12-lead ECGs, and measurements were made on a median beat from three 10-second replicates. Data were analyzed using a linear concentration-response model with QTcF and heart rate corrected JTpeak (JTpeak_c) as dependent variables. For moxifloxacin, dofetilide, and ondansetron, all pure hERG blockers, slopes of the concentration (C)-QTcF and C-JTpeak_c relationships were positive and statistically significant. With the prespecified linear model, the predicted effects on ΔΔQTcF and ΔΔJTpeak_c were 11.4 and 9.4 milliseconds for moxifloxacin at the geometric mean Cmax on day 1, 9.0 and 11.7 milliseconds for dofetilide and 11.5, and 7.9 milliseconds for ondansetron, respectively. In contrast, dolasetron and quinine, both with additional ion channel effects, prolonged QTcF with a positive C-ΔQTcF slope and predicted ΔΔQTcF effect on day 1 of 6.2 and 11.4 milliseconds, whereas the C-ΔJTpeak_c slope and the predicted ΔΔJTpeak on day 1 were negative (-0.3 and -7.5 milliseconds per ng/mL). Pure hERG-blocking drugs prolonged both the QTc and the JTpeak_c intervals, whereas drugs with mixed ion channel effects, including peak sodium inhibition, prolonged QTcF but not the JTpeak_c interval.

The preclinical in vivo assay for QT prolongation is critical for predicting torsadogenic risk, but still difficult to extrapolate to humans. This study ran preclinical tests in cynomolgus monkeys on seven QT reference drugs containing the drugs used in the IQ-CSRC clinical trial and applied exposure-response (ER) analysis to the data to investigate the potential for translational information on the QT effect.

Objectives The objectives were to evaluate the pharmacokinetics (PK) of subcutaneous (SC) and intravenous (IV) dolasetron and the pharmacodynamics (PD) of SC dolasetron in healthy cats. Methods Five cats with unremarkable complete blood count, serum biochemistry and urinalyses were utilized. In the PK study, cats received 0.8 mg/kg SC and IV dolasetron in a crossover format. Serum samples were obtained via a jugular catheter at 0, 0.25, 0.5, 1, 2, 4, 8, 12, 24, 36 and 48 h after the administration of dolasetron. Dolasetron and the active metabolite hydrodolasetron were measured using liquid chromatography/tandem mass spectrometry. Non-compartmental PK analysis was performed. In the PD study, SC dolasetron (0.8 mg/kg and 1.0 mg/kg) and saline were administered 30 mins prior to administration of 0.44 mg/kg intramuscular xylazine in a randomized three-way crossover. Number of emetic events, lip licks, time to onset of emesis and visual nausea score were scored by a blinded observer. Results In the PK study, dolasetron was quickly metabolized to the active metabolite hydrodolasetron, limiting assessment of dolasetron PK parameters. Median (range) PK parameters for IV hydrodolasetron were as follows: maximum serum concentration (Cmax) 116 ng/ml (69-316 ng/ml), time to maximum concentration (Tmax) 0.5 h (0.3-0.5 h), half-life 3.3 h (2.9-7.2 h) and area under the curve until the last measurable concentration (AUClast) 323 h/ng/ml (138-454 h/ng/ml). Median (range) PK parameters for SC hydrodolasetron were as follows: Cmax 67.9 ng/ml (60.4-117 ng/ml), Tmax 0.5 h (0.5-1.0 h), half-life 3.8 h (2.9-5.3 h) and AUClast 437 h/ng/ml (221.5-621.8 h/ng/ml). There was no significant difference in exposure to hydrodolasetron between the routes of administration. With regard to PD, when dolasetron was administered prior to xylazine, there was no significant difference in the mean number of emetic events, lip licks, time to onset of emesis or visual nausea score when compared with saline. Conclusions and relevance Administration of 0.8 mg/kg dolasetron does not maintain serum concentrations of active metabolite for 24 h. Administration of dolasetron at 0.8 mg/kg and 1 mg/kg did not prevent xylazine-induced vomiting. Additional feline dose studies are needed to determine if a higher dose is efficacious.

Deoxynivalenol (DON), one of trichothecene mycotoxins produced by the fungus Fusarium, is commonly detected in cereal foods and in secondary food production across the world. Lower concentrations of DON induce a dose-related feed refusal (anorexia), whereas it acts as a potent emetic agent at higher levels. DON-induced emesis in humans and livestock can be observed and recorded in both undeveloped and developed regions such as Lixian, Guide and Huangzhong in China and Illinois in the USA. Some studies with different animal models (pigs and minks) suggested that DON could change expressions of 5-hydroxytryptamine, peptide YY, neuropeptide Y2 receptor and nucleobindin-2/nesfatin-1 in plasma and different areas of the brain. Some selective antagonist of 5-hydroxytryptamine 3 receptors can inhibit DON-induced emetic response. Otherwise, the Ca2+ homeostasis and MAPK pathway could be potential directions in future studies. Dolasetron, dantrolene and JNJ-31020028 can be used in clinical treatment but they have potential toxic effects. (-)Epicatechin, ginger phytochemicals and isoflavone can be tested in in vitro and in vivo for their usage as food additives for reducing the emesis. The present review summarizes and discusses some information from previous and recent prominent publications with the aim to provide some comprehensive and helpful data for understanding the mechanism of DON-induced emesis. Copyright © 2017 John Wiley & Sons, Ltd.

A simple and straightforward method for the determination of dolasetron mesylate (DM) in aqueous solution was developed based on the fluorescence quenching of 3-Mercaptopropionic acid (MPA) capped CdS quantum dots (QDs). The structure, morphology, and optical properties of synthesized QDs were characterized by using UV-Vis absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS) measurements. Under the optimum conditions, the MPA-CdS QDs fluorescence probe offered good sensitivity and selectivity for detecting DM. The probe provided a highly specific selectivity and a linear detection of DM in the range of 2-40 µg/mL with detection limit (LOD) 1.512 µg/mL. The common excipients did not interfere in the proposed method. The fluorescence quenching mechanism of CdS QDs is also discussed. The developed sensor was applied to the quantification of DM in urine and human serum sample with satisfactory results.

5-hydroxytryptamine 3 receptor (5-HT3 receptor) antagonists are administered for prevention and therapy of nausea and vomiting. Although regarded as safe therapeutics, they can also provoke arrhythmias by prolonging the QRS interval. However, the mechanisms mediating this cardiotoxicity are poorly understood. Here we investigated effects of 5-HT3 receptor antagonists on the cardiac Na(+) channel Nav1.5. We explored the interaction of dolasetron, tropisetron, granisetron and ondansetron on the human α-subunit Nav1.5 heterologously expressed in HEK293 cells. Sodium currents were explored by means of whole-cell patch clamp recordings. All four substances inhibited the Nav1.5 in a concentration and state-dependent manner. Dolasetron displayed the lowest blocking efficacy, and tropisetron was the most potent blocker with a half maximum blocking concentration of 18µM for tonic block of inactivated channels. Tropisetron was also the most potent use-dependent inhibitor, and it also induced a strong open -channel block. Both tonic and use-dependent block by tropisetron were abbreviated on the local-anesthetic insensitive mutant Nav1.5-F1760A. Co-administration of tropisetron and the local anesthetic bupivacaine or the hypnotic propofol augmented inhibition of Nav1.5. Our data demonstrate that 5-HT3 receptor antagonists induce a local-anesthetic like inhibition of Nav1.5, and that they display different blocking efficacies. Reports on a relevant cardiotoxicity of dolasetron as opposed to other 5-HT3 receptor antagonists do not seem to correlate with a block of Nav1.5. As inhibition of Nav1.5 was enhanced by propofol and bupivacaine however, it is possible that a combined administration of Na(+) channel blockers and 5-HT3 receptor antagonists can provoke arrhythmias.

[This corrects the article on p. 67 in vol. 4, PMID: 22427733.].

The revised ICH E14 document allows the use of exposure-response analysis to exclude a small QT effect of a drug. If plasma concentrations exceeding clinically relevant levels is achieved, a positive control is not required. In cases when this cannot be achieved, there may be a need for metrics to protect against false-negative results. The objectives of this study were to create bias in electrocardiogram laboratory QT-interval measurements and define a metric that can be used to detect bias severe enough to cause false-negative results using exposure-response analysis. Data from the IQ-CSRC study, which evaluated the QT effect of 5 QT-prolonging drugs, were used. Negative bias using 3 deterministic and 2 random methods was introduced into the reported QTc values and compared with fully automated data from the underlying electrocardiogram algorithm (COMPAS). The slope estimate of the Bland-Altman plot was used as a bias metric. With the deterministic bias methods, negative bias, measured between electrocardiogram laboratory values and COMPAS, had to be larger than approximately -20 milliseconds over a QTcF range of 100 milliseconds to cause failures to predict the QT effect of ondansetron, quinine, dolasetron, moxifloxacin, and dofetilide. With the random methods, the rate of false-negatives was ≤5% with bias severity < -10 milliseconds for all 5 drugs when plasma levels exceeded those of interest. Severe and therefore detectable bias has to be introduced into reported QTc values to cause false-negative predictions with exposure-response analysis.

Chemotherapy-induced nausea and vomiting are adverse effects responsible for worsening quality of life in cancer patients. To assess the efficacy, safety and effectiveness of serotonin receptor antagonist in cancer patients undergoing chemotherapy, comparing ondansetron with granisetron, dolasetron, tropisetron and palonosetron.

Carbonyl reductase 1 (CBR1), an enzyme belonging to the short-chain dehydrogenases/reductases family, has been detected in all human tissues. CBR1 catalyzes the reduction of many xenobiotics, including important drugs (e.g. anthracyclines, nabumetone, bupropion, dolasetron) and harmful carbonyls and quinones. Moreover, it participates in the metabolism of a number of endogenous compounds and it may play a role in certain pathologies. Plant polyphenols are not only present in many human food sources, but are also a component of many popular dietary supplements and herbal medicines. Many studies reviewed herein have demonstrated the potency of certain flavonoids, stilbenes and curcuminoids in the inhibition of the activity of CBR1. Interactions of these polyphenols with transcriptional factors, which regulate CBR1 expression, have also been reported in several studies. As CBR1 plays an important role in drug metabolism as well as in the protection of the organism against potentially harmful carbonyls, the modulation of its expression/activity may have significant pharmacological and/or toxicological consequences. Some polyphenols (e.g. luteolin, apigenin and curcumin) have been shown to be very potent CBR1 inhibitors. The inhibition of CBR1 seems useful regarding the increased efficacy of anthracycline therapy, but it may cause the worse detoxification of reactive carbonyls. Nevertheless, all known information about the interactions of polyphenols with CBR1 have only been based on the results of in vitro studies. With respect to the high importance of CBR1 and the frequent consumption of polyphenols, in vivo studies would be very helpful for the evaluation of risks/benefits of polyphenol interactions with CBR1.

Exposure-response (ER) analysis has evolved as an important tool to evaluate the effect of a drug on cardiac repolarization, as reflected in the QTc interval. It has been suggested that careful electrocardiogram (ECG) evaluation in 'first-in-human' studies using ER analysis could replace or serve as an alternative to the E14 'thorough QT' study. This commentary shares and discusses the results of a recently conducted study with the objective to evaluate this approach. Six drugs with a well-characterized QT effect, five of which are known QT prolongers, were evaluated in a study design similar to a conventional single-ascending-dose study. Each drug was given to nine healthy subjects (six for placebo) in two dose levels, which for the positive drugs (ondansetron, quinine, dolasetron, moxifloxacin, and dofetilide) were chosen with the intent to cause 10-12 ms and 15-20 ms QTc prolongation. Replicate 12-lead ECGs were extracted from continuous recordings pre-dose and serially after dosing and paired with drug concentration determinations. The ER criteria for the identification of a QT effect, a statistically significant positive ER slope and an effect above 10 ms, were met with all five positive drugs, and an effect exceeding 10 ms could be excluded at the supratherapeutic dose of the negative drug, levocetirizine. The study results thereby provided evidence to support that careful QT assessment in early phase clinical studies can be used as an alternative to the thorough QT study. Clinical and regulatory implications, as well as limitations of this approach, are discussed in the commentary.