Consensus proposal for 5HT3 antagonists in the prevention of acute emesis related to highly emetogenic chemotherapy. Dose, schedule, and route of administration

Pattern of Adverse Drug Reactions to Anticancer Drugs: A Quantitative and Qualitative Analysis

INTRODUCTION

Anticancer drugs contribute significantly to the global burden of adverse drug reactions (ADRs). Any attempt to quantify their magnitude and provide upgraded knowledge would help oncologists in writing safer prescriptions.

AIM

This observational follow-up study was conducted on newly diagnosed cancer patients receiving anticancer therapy with an aim to determine the frequency, severity, causality, predictability, and preventability of ADRs.

SUBJECTS AND METHODS

The patients were followed up for 6 months for the appearance of adverse events. Data were analyzed using IBM SPSS Statistics for Windows, Version 22.0. (Armonk, NY) and presented in the form of descriptive statistics.

RESULTS

Each patient was prescribed approximately 6.85 ± 1.51 (mean ± standard error) drugs on average. All the patients (100%) receiving anticancer chemotherapy had ADRs. Alopecia, nausea and vomiting, burning tingling, and numbness were the most frequently encountered ADRs. The incidence of alopecia (P < 0.0004), nausea (P < 0.03), and oral ulceration (P < 0.02) was higher in females. Maximum reactions were of Grade 2 (69.53%). Most of the reactions (75.80%) appeared within 10 days of receiving the first cycle. 99.58% reactions were not serious. According to the WHO - The Uppsala Monitoring Centre criteria, 99.47% ADRs fell in possible category. According to the Naranjo's algorithm, 100% ADRs fell in probable category. About 94.80% reactions were found to be predictable. About 56.47% reactions were probably preventable, and 43.53% reactions were not preventable.

CONCLUSION

Multiple ADRs were seen in newly diagnosed cancer patients. Most of them were predictable, of mild-to-moderate severity, nonserious, and preventable. A majority of the ADRs recovered over time.

Cancer Drug Delivery

Advancements in cancer drug delivery have led to the development of personalized oncology care through molecularly-driven targeted therapies. Understanding molecular and cellular mechanisms which drive tumor progression and resistance is critical in managing new treatment strategies which have shifted from empiric to biomarker-directed therapy selection. Biomarker-directed therapies have improved clinical outcomes in multiple malignancies as monotherapy and in combination with other treatment modalities, however the changing scope of treatment options presents new opportunities and challenges for research. Furthermore, pharmacogenetics may provide a rationale method of personalizing anticancer drug dosing and supportive care management for oncology patients. This chapter reviews biomarker classifications and pharmacogenetics in anticancer therapy and supportive care. Examples of biomarker-directed therapies and clinical assays, in addition to future directions of molecular profiling in oncology therapy management are discussed.

State of the Art Antiemetic Therapy for Cancer Patients

Nausea and vomiting are common in cancer patients. The most common cause of nausea and vomiting is the administration of cytotoxic chemotherapy. Apart from chemotherapy-induced nausea and vomiting (CINV), biological agents may also cause these symptoms. In this review, discussion will be focused on management of nausea and vomiting due to antineoplastic therapies. The cornerstone of effective management of nausea and vomiting secondary to these antineoplastic drugs is the prevention with the use of appropriate guideline-directed combination antiemetic regimen. Type 3 serotonin receptor antagonists (5HT3RAs), neurokinin-1 receptor antagonists (NK1RAs), and dexamethasone are the backbone antiemetic drugs. In recent years, newer drugs and preparations have been introduced for clinical use and include second-generation 5HT3RA, palonosetron; granisetron transdermal patch; the recently introduced NK1RA rolapitant; and the novel oral combined drug NEPA (netupitant plus palonosetron); and last but not least, the atypical antipsychotic olanzapine.

Does pharmacogenomics account for variability in control of acute chemotherapy-induced nausea and vomiting with 5-hydroxytryptamine type 3 receptor antagonists?

Chemotherapy-induced nausea and vomiting is one of the most concerning adverse drug effects from cytotoxic chemotherapy. Despite appropriate use of antiemetic guidelines, 20-30 % of patients experience breakthrough nausea and vomiting secondary to chemotherapy. To assess the variability of 5-hydroxytryptamine type 3 receptor antagonist efficacy caused by genetic variation, a review of the available literature was conducted. From the literature, three sources of pharmacogenomic variability were identified: polymorphisms associated with 5-hydroxytryptamine type 3 receptor subunits, drug metabolism via cytochromes P450, and drug transport in the body. Testing for receptor subunit polymorphisms is not applicable to a clinical setting at this time; however, cytochrome P450 2D6 testing is FDA-approved and widely accessible. Cytochrome P450 2D6 ultrarapid metabolizers and poor metabolizers displayed altered antiemetic efficacy when compared with intermediate metabolizers and extensive metabolizers. We postulate that testing for cytochrome P450 2D6 phenotypes may be the most accessible way to provide individualized antiemetic therapy in the future.

A double-blind, crossover, randomized dose-comparison trial of granisetron for the prevention of acute and delayed nausea and emesis in children receiving moderately emetogenic carboplatin-based chemotherapy

BACKGROUND

Granisetron is a safe and effective prophylaxis for nausea and vomiting associated with moderate to highly emetogenic chemotherapy. Few trials have been conducted to determine the optimal effective dose of granisetron in children with cancer. The objective of this report was to compare two doses of granisetron in patients with optic pathway tumors receiving moderately emetogenic doses of carboplatin.

PATIENTS AND METHODS

In this double-blind, crossover, randomized study, antiemetic efficacy and tolerability of two dose levels (10 and 40 microg/kg) of granisetron in the prevention of acute and delayed nausea/emesis were compared in children and young adults. A total of 18 patients (13 boys) aged 1-23 years (median 7.7 years) treated with a moderately emetogenic dose of carboplatin were randomly assigned to receive either 10 or 40 microg/kg of slow granisetron intravenous (i.v.) infusions at alternating cycles of chemotherapy in a blinded fashion until the end of the study period or until their chemotherapy regimen ended. In this way, the patients acted as their own controls.

RESULTS

Patients in the granisetron 10 and 40 microg/kg groups received 104 and 121 cycles of chemotherapy, respectively. There was no significant difference in antiemetic efficacy in terms of nausea and emesis between the dose groups in the first 5 days of chemotherapy. The treatment was well tolerated.

CONCLUSION

We conclude that granisetron 10 and 40 microg/kg have comparable efficacy in controlling carboplatin-induced acute and delayed nausea/emesis and is well tolerated in children and young adults.

Comparative activity of antiemetic drugs

Nausea and vomiting continues to be an important problem for cancer patients receiving chemotherapy. Chemotherapy-induced nausea and vomiting (CINV) are classified as acute, occurring within the first 24h, or delayed, occurring after the first 24h. A number of antiemetic agents are available for the management of nausea and vomiting, including 5-HT3-receptor-antagonists, corticosteroids, NK-1-receptor-antagonists, dopamine-receptor antagonists, benzodiazepines, neuroleptics and cannabinoids. With modern antiemetic therapy, vomiting can be prevented in 70-80% of patients, whereas the control of nausea remains suboptimal. The development of acute emesis is known to depend on serotonin. The pathophysiology of delayed emesis is less well understood, and multiple mechanisms may contribute, including substance P. Here, the most recent developments in the antiemetic therapy, including new antiemetic drugs and the latest guidelines for antiemetic prophylaxis, are reviewed.

Cost-effectiveness of aprepitant for the prevention of chemotherapy-induced nausea and vomiting associated with highly emetogenic chemotherapy

OBJECTIVE

Chemotherapy-induced nausea and vomiting (CINV) is a significant problem for cancer patients. Aprepitant, a novel NK-1 receptor antagonist, is approved for use with 5-HT3 antagonists and corticosteroids to prevent CINV associated with highly emetogenic chemotherapy. Nevertheless, the cost-effectiveness of standard aprepitant use has not been established.

METHODS

We developed a Markov model to compare three strategies for CINV: conventional treatment with a 5-HT3 antagonist and a corticosteroid, conventional treatment plus aprepitant, and conventional treatment with aprepitant added after the onset of CINV. Data from published clinical trials provided probabilities and utilities for the model. Data from the Centers for Medicare and Medicaid Services and the Federal Supply Scale provided costs for medical resources and medications utilized. Resource use data were based on a randomized clinical trial and routine clinical practice. The incremental cost-effectiveness ratio (ICER) for each aprepitant strategy was calculated in US$ per healthy day equivalent (HDE) and converted to dollars per quality-adjusted life-year (QALY). Univariate and probabilistic sensitivity analyses addressed uncertainty in model parameters.

RESULTS

Adding aprepitant after CINV occurred cost $264 per HDE ($96,333/QALY). The three-drug strategy cost $267/HDE with a 95% confidence range of $248-$305/HDE ($97,429/QALY; $90,396-$111,239/QALY). In univariate analyses, the most influential factors on the ICER were: the cost of aprepitant, the likelihood of delayed CINV without aprepitant, the likelihood of acute CINV with/without aprepitant, and the increase in HDE from avoiding CINV.

CONCLUSIONS

Aprepitant provides modest incremental benefits compared with conventional management of CINV. Routine aprepitant use appears most cost-effective when the likelihood of delayed CINV or the cost of rescue medications is high.

Prevención y control de las náuseas y los vómitos inducidos por quimioterapia

Nausea and vomiting are considered one of the most distressing side-effects of chemotherapy. Complete control of acute and delayed emesis improves quality of life and increases adherence to treatment. The frequency of nausea and vomiting depends primarily on the emetogenic potential of the chemotherapeutic agents used. With the standard antiemetic therapy (5HT-3 receptor antagonists in combination with dexamethasone) approximately 13% of patients receiving chemotherapy have vomiting in the acute phase and almost 50% in the delayed phase. A new group of antiemetic drugs, the neurokinin-1 receptor antagonists, in combination with standard therapy significantly improves emesis protection in the acute and in the delayed phase, although control of nausea is not so effective. Nowadays chemotherapy-induced emesis still occurs. Recent developments in antiemetic therapy and responsibility to achieve the best control of nausea and vomiting in patients receiving chemotherapy justified a review of this problem, which is frequently underestimated by physicians and nurses.

5-hydroxytryptamine type-3 receptor antagonists for chemotherapy-induced and radiotherapy-induced nausea and emesis: can we safely reduce the dose of administered agents?

BACKGROUND

Nausea and emesis as a consequence of chemotherapy or radiotherapy can have an adverse effect on patients' quality of life during cancer treatment and may last for > 5 days after administration. Guidelines suggest that, used at appropriate doses, the 5-hydroxytryptamine type-3 (5-HT3) receptor antagonists--which are considered the antiemetic "gold standard" when they are administered in combination with corticosteroids--demonstrate equivalent efficacy and safety. However, due to financial considerations, these agents often are used at lower doses than recommended.

METHODS

A literature review of relevant publications pertaining to the control of chemotherapy-induced nausea and emesis and dosing issues of the 5-HT3 receptor antagonists was undertaken to provide a comprehensive review of dosing issues relevant to the 5-HT3 receptor antagonists.

RESULTS

The issue of "down dosing" was particularly pertinent because of the nature of the 5-HT3 receptor antagonist dose-response curve: A steep dose-response profile within a narrow dose range suggests that antiemetic control will be lost suddenly after dose deescalation. However, the array of predisposing and confounding patient factors indicates that it is unlikely that a loss of antiemetic control will be apparent across a population; rather, individuals will experience loss of control as the dose is reduced below threshold. Of the 4 5-HT3 receptor antagonists currently licensed in the United States (granisetron, ondansetron, dolasetron, and palonosetron), ondansetron is used sometimes at lower than optimal doses, and there is evidence to suggest that even the approved oral dose of dolasetron may be suboptimal.

CONCLUSIONS

Suboptimal dosing not only will be detrimental to patients' quality of life but, ultimately, will prove counterproductive in terms of hospital resources, and it will add to the already significant socioeconomic burden associated with cancer therapy. Therefore, the dose of antiemetic agent administered should be sufficiently high to ensure good emesis control across the whole patient population.

Is there a pharmacological basis for differences in 5-HT3-receptor antagonist efficacy in refractory patients?

5-HT3-receptor antagonists are the current antiemetic 'gold standard' for chemotherapy- and radiotherapy-induced nausea and vomiting. Interestingly, studies have shown that patients experiencing poor control of acute chemotherapy-induced nausea and vomiting with one antiemetic therapy may respond well to another agent, including a drug of the same class. This review examines pharmacological differences between the 5-HT3-receptor antagonists in order to determine potential reasons for their differing efficacy, particularly in relation to refractory emesis. Differences in drug metabolism by the cytochrome P450 system, inadequate dosing of the respective agents, differences in onset and duration of action, and effects on serotonin release and reuptake are discussed.

Nausea: the neglected symptom?

Advances in antiemetic therapy over the past decade have undoubtedly eased the burden of radiotherapy- and chemotherapy-induced nausea and vomiting. Despite this, these distressing side-effects of cancer therapy are still experienced by some patients. Moreover, nausea has both a higher incidence and a greater effect on patient quality of life than vomiting. The impact of nausea may therefore warrant more attention than perhaps it has received previously, and there is undoubtedly room for improvement regarding its treatment. Recognizing and treating nausea is complicated by the fact that it can only be measured subjectively by the patient rather than objectively by clinical staff. However, various patient-centred strategies may be employed by nurses to ensure self-reporting of the occurrence and impact of nausea. Nurses may also be best placed to identify patient-related prognostic factors in order to determine the risk of nausea. Antiemetic guidelines recommend the use of a 5-HT3-receptor antagonist for the control of emesis with moderate and highly emetogenic cancer therapy. Although guidelines do not distinguish between the available agents, pharmacological differences do exist, and it is necessary to consider this when tailoring regimens to individual patients. As with any therapy, less complicated dosing regimens are likely to improve compliance, an issue that may be particularly pertinent in nauseated patients who are unable to ingest multiple doses. Furthermore, the focus of antiemetic therapy should be on prevention, as the presence and severity of acute symptoms have been linked to occurrence of symptoms in the delayed phase and the likelihood of anticipatory nausea and vomiting with further treatment cycles. This review aims to assess the potentially neglected symptom of nausea and focuses on recognizing and controlling this side-effect of cancer therapy.

5-HT3A receptor subunits in the rat medial nucleus of the solitary tract: subcellular distribution and relation to the serotonin transporter

The 5-hydroxytryptamine 3 (5HT3) receptor is a serotonin-gated ion channel implicated in reflex regulation of autonomic functions within the nucleus of the solitary tract (NTS). To determine the relevant sites for 5-HT3 receptor mediated transmission in this region, we used electron microscopic immunocytochemistry to examine the subcellular distribution of the 5HT3 receptor subunit A (5HT3A) in relation to the serotonin transporter (SERT) in the intermediate medial NTS (mNTS) of rat brain. The 5HT3A immunolabeling was detected in many axonal as well as somatodendritic and glial profiles. The axonal profiles included small axons and axon terminals in which the 5HT3A immunoreactivity was localized to membranes of synaptic vesicles and extrasynaptic plasma membranes. In dendrites and glia, the 5HT3A immunoreactivity was located on the plasma membranes or in association with membranous cytoplasmic organelles. The dendritic plasmalemmal 5HT3A labeling was prominent within and near excitatory-type synapses from terminals including those that resemble vagal afferents. The 5HT3A-labeled glial processes apposed 5HT3A-immunoreactive axonal and dendritic profiles, some of which also contained SERT. Terminals containing 5-HT3A and/or SERT were among those providing synaptic input to 5HT3A-labeled dendrites. Thus, 5HT3A has a subcellular distribution consistent with the involvement of 5-HT3 receptors in modulation of both presynaptic release and postsynaptic responses of mNTS neurons, some of which are serotonergic. The results further suggest that the neuronal as well as glial 5HT3 receptors can be activated by release of serotonin from presynaptic terminals or by diffusion facilitated by SERT distribution at a distant from the synapse.

Consensus proposals for the prevention of acute and delayed vomiting and nausea following high-emetic-risk chemotherapy

This paper uses an evidence-based approach whenever possible to formulate recommendations, emphasizing the results of controlled trials concerning the best use of antiemetic agents. We address issues of dose, schedule, and route of administration of five selective 5-HT(3) antagonists. We conclude that for each of these five drugs, there is a plateau in therapeutic efficacy above which further dose escalation does not improve outcome. Furthermore, for all classes of antiemetic agents, a single dose is as effective as multiple doses or a continuous infusion. The oral route is as efficacious as the intravenous route of administration, even with chemotherapy of high emetic risk. Selective antagonists of the type 3 serotonin receptor (5-HT(3)) in combination with dexamethasone and aprepitant are the standard of care for the prevention of emesis following chemotherapy of high emetic risk.

Granisetron: An Update on its Clinical Use in the Management of Nausea and Vomiting

Nausea and vomiting are typical side effects of cytotoxic therapy and some surgical procedures. These symptoms can represent a major therapeutic challenge and, if inadequately controlled by antiemetic treatment, will result in increased mortality, morbidity, and health care costs. However, the management of nausea and vomiting has improved greatly in recent years following the introduction of the 5-HT3-receptor antagonists, known as 'setrons.' In light of recent developments in antiemetic care, including the approval of the first neurokinin-1-receptor antagonist aprepitant (Emend; Merck and Company, Inc.; West Point, PA) and a new 5-HT3 receptor antagonist palonosetron (Aloxi; MGI Pharma; Minneapolis, MN), this article provides an update on the clinical experience gained with the 5-HT3-receptor antagonist granisetron (Kytril; Roche Laboratories, Inc.; Nutley, NJ) for the management of chemotherapy-induced, radiation-induced, and postoperative nausea and vomiting, and also reviews its use in special patient populations. Granisetron is a potent and highly selective 5-HT3-receptor antagonist that has little or no affinity for other receptors, a characteristic that is thought to underlie the favorable side-effect and safety profiles of this agent. Extensive clinical trial data have shown granisetron to be an effective and well-tolerated agent for the treatment of nausea and vomiting in the oncology and surgical settings. Granisetron has also been shown to be effective and well tolerated in special populations, such as patients refractory to antiemetic treatment, patients with hepatic or renal impairment, and children. Data also suggest that its safety profile and minimal potential for drug-drug interactions would make it an antiemetic agent of choice for elderly cancer patients.

The Next Generation of Chemotherapy-Induced Nausea and Vomiting Prevention and Control: A New 5-HT₃ Antagonist Arrives

First-generation serotonin receptor antagonists greatly improved the control of chemotherapy-induced nausea and vomiting (CINV) during the 1990s. A new class of agents, neurokinin-1 receptor antagonists, was introduced in March 2003 and produced even greater control of CINV when used in combination with a serotonin receptor antagonist and a corticosteroid. In July 2003, palonosetron, a new second-generation serotonin receptor antagonist that has greater potency and a longer half-life than first-generation serotonin receptor antagonists, was introduced. This clinical update reviews studies that were conducted to evaluate these new agents.

Micromechanical measurement of membrane receptor binding for label-free drug discovery

A potential novel binding assay based on binding-driven micromechanical motion is described. A membrane preparation containing 5-HT(3AS) receptors was used to modify a microcantilever. The modified microcantilever was found to bend on application of the naturally occurring agonist (5-hydroxytryptamine, which is also called serotonin) or the antagonist MDL-72222, but not to other similar molecules. Control experiments show that cantilevers modified by membrane preparations that do not contain 5-HT(3AS) receptors do not respond to serotonin or MDL-72222. K(d) values obtained for serotonin and MDL-72222 are identical to those obtained from radio-ligand binding assays. These results suggest that the microcantilever system has potential for use in label-free, drug screening applications.

Current position of 5HT3 antagonists and the additional value of NK1 antagonists; a new class of antiemetics

The advent of the 5HT(3) receptor antagonists (5HT(3) antagonists) in the 1990 s and the combination with dexamethasone has resulted in acute emesis protection in 70% of patients receiving highly emetogenic chemotherapy. Despite complete protection in the acute phase, however, 40% of patients as yet have symptoms in the delayed phase. 5HT(3) antagonists and dexamethasone are only modestly effective in this delayed phase. Moreover, the antiemetic protection over repeated cycles is not sustained. Neurokinine 1 receptor antagonists (NK(1) antagonists) belong to a new class of antiemetic agents that specifically target the NK(1) receptor, which is involved in both the acute and, particularly, the delayed phase of emesis. Clinical studies have demonstrated that the addition of NK(1) antagonists to dual therapy with a 5HT(3) antagonist plus dexamethasone improves the acute emesis protection by a further 10-15%. In the delayed phase, the proportion of patients remaining free of emesis increases by even 20-30%. Since the effectiveness of this triplet combination was found to be sustained over six cycles of chemotherapy, the chance for an individual patient to remain completely protected during both the acute and the delayed phase over six chemotherapy cycles is nearly doubled.

Delayed chemotherapy-induced nausea in women treated for breast cancer

PURPOSE/OBJECTIVES

To describe the experience and intensity of delayed nausea in women undergoing chemotherapy for breast cancer since the advent of the 5-HT3 antagonists.

DESIGN

Multisite, longitudinal, descriptive.

SETTING

7 outpatient oncology clinics situated in hospitals, 5 outpatient oncology clinics associated with major teaching universities, 27 private outpatient oncology practices, and 1 outpatient clinic located in a county hospital.

SAMPLE

Typical participants (N = 303) were 51.9 years old, Caucasian (79%), married or partnered (65%), born U.S. citizens (92%), heterosexual (96%), living with someone (83%), and high school graduates (82%).

METHODS

Baseline and poststudy questionnaires plus a daily diary of nausea through two cycles of chemotherapy (approximately two months) were used to collect data. The Rhodes Inventory of Nausea, Vomiting, and Retching was used to assess the nausea experience.

MAIN RESEARCH VARIABLES

Nausea.

FINDINGS

The worst nausea occurred on the third day after having chemotherapy for breast cancer. The types of oral antiemetics ordered for home use were changed between the two cycles of the study only 8% (n = 24) of the time. Younger, heavier women experienced more delayed nausea. Women who had a history of nausea with stress and women receiving cyclophosphamide experienced more delayed nausea during both time periods.

CONCLUSIONS

Delayed nausea is a significant problem for women receiving chemotherapy for breast cancer. IMPLICATION FOR NURSING: Oncology nurses can use the results from this study to provide anticipatory guidance for patients undergoing chemotherapy for breast cancer.

Functional group interactions of a 5-HT3R antagonist

BACKGROUND

Lerisetron, a competitive serotonin type 3 receptor (5-HT3R) antagonist, contains five functional groups capable of interacting with amino acids in the 5-HT3R binding site. Site directed mutagenesis studies of the 5-HT3AR have revealed several amino acids that are thought to form part of the binding domain of this receptor. The specific functional groups on the ligand that interact with these amino acids are, however, unknown. Using synthetic analogs of lerisetron as molecular probes in combination with site directed mutagenesis, we have identified some of these interactions and have proposed a model of the lerisetron binding site.

RESULTS

Two analogs of lerisetron were synthesized to probe 5-HT3R functional group interactions with this compound. Analog 1 lacks the N1 benzyl group of lerisetron and analog 2 contains oxygen in place of the distal piperazine nitrogen. Both analogs show significantly decreased binding affinity to wildtype 5-HT3ASRs. Mutations at W89, R91, Y142 and Y152 produced significant decreases in binding compared to wildtype receptors. Binding affinities of analogs 1 and 2 were altered only by mutations at W89, and Y152.

CONCLUSIONS

Based on the data obtained for lerisetron and analogs 1 and 2, we have proposed a tentative model of the lerisetron binding pocket of the 5-HT3ASR. According to this model, The N-benzyl group interacts in a weak interaction with R91 while the benzimidazole group interacts with W89. Our data support an interaction of the distal amino nitrogen with Y142 and Y152.

Granisetron vs ondansetron: is it a question of duration of 5-HT3 receptor blockade?

British Journal of Cancer (2002) 86, 1662–1663. DOI: 10.1038/sj/bjc/6600313www.bjcancer.com

© 2002 Cancer Research UK

Anti-emetics for cancer chemotherapy-induced emesis: Potential of alternative delivery systems

Currently, the most commonly used routes of administration of antiemetics in chemotherapeutic regimens are oral and intravenous. Patient compliance and thus efficacy of conventional drug schedules and formulations are often impaired by difficulties associated with oral or intravenous uptake of the administered chemotherapy. Alternative or new drug delivery systems should overcome these problems by improving patient compliance. Several new drug delivery systems are available and development of these new systems is ongoing, in particular to meet delivery requirements of modern biological therapeutics and the application of gene therapy. However, at the present time, the implementation of new techniques of alternative antiemetic drug administration for chemotherapy-induced emesis is very limited. The challenge for clinical investigations to further develop new delivery systems, in particular for antiemetic therapies, remains.

Transient gene expression: recombinant protein production with suspension-adapted HEK293-EBNA cells

Transient gene expression (TGE) in mammalian cells at the reactor scale is becoming increasingly important for the rapid production of recombinant proteins. We improved a process for transient calcium phosphate-based transfection of HEK293-EBNA cells in a 1-3 L bioreactor volume. Cells were adapted to suspension culture using a commercially available medium (BioWhittaker, Walkersville, MD). Process parameters were optimized using a plasmid reporter vector encoding the enhanced green fluorescent protein (EGFP/CLONTECH, Palo Alto, CA, USA). Using GFP as a marker-protein, we observed by microscopic examination transfection efficiencies between 70-100%. Three different recombinant proteins were synthesized within a timeframe of 7 days from time of transfection to harvest. The first, a human recombinant IgG(1)-type antibody, was secreted into the supernatant of the cell culture and achieved a final concentration of >20 mg/L. An E. coli-derived DNA-binding protein remained intracellular, as expected, but accumulated to such a concentration that the lysate of cells, taken up into the entire culture volume, gave a concentration of 18 mg/L. The third protein, a transmembrane receptor, was expressed at 3-6 x 10(6) molecules/cell.

Effective cross-over to granisetron after failure to ondansetron, a randomized double blind study in patients failing ondansetron plus dexamethasone during the first 24 hours following highly emetogenic chemotherapy

In view of the similarity in chemical structure of the available 5HT(3)-receptor antagonists it is assumed, whilst these agents all act at the same receptor, that failure to one agent would predict subsequent failure to all 5HT(3)-receptor antagonists. We conducted a randomized double blind trial of granisetron 3 mg plus dexamethasone 10 mg versus continued treatment with ondansetron 8 mg plus dexamethasone 10 mg in patients with protection failure on ondansetron 8 mg plus dexamethasone 10 mg during the first 24 hours following highly emetogenic chemotherapy. Of 40 eligible patients, 21 received ondansetron + dexamethasone and 19 received granisetron + dexamethasone. We found a significant benefit from crossing-over to granisetron after failure on ondansetron. Of the 19 patients who crossed over to granisetron, 9 patients obtained complete protection, whereas this was observed in 1 of the 21 patients continuing ondansetron, P = 0.005. These results indicate that there is no complete cross-resistance between 5HT(3)-receptor antagonists, and that patients who have acute protection failure on one 5HT(3)-receptor antagonist should be offered cross-over to another 5HT(3)-receptor antagonist.

A multinational study to measure the value that patients with cancer place on improved emesis control following cisplatin chemotherapy

BACKGROUND

The neurokinin-1 (NK1) receptor antagonists are a new class of agents designed to reduce the risk of emesis following chemotherapy, particularly with cisplatin. Early data from double-blind randomised trials suggest that an orally administered NK1 antagonist can reduce the absolute risk of acute and delayed emesis following cisplatin by 20 and 30%, respectively.

OBJECTIVE

To measure the value that patients with cancer place on improved emesis control and quality of life.

DESIGN

Willingness-to-pay analysis.

SETTING

Five study sites in Canada, Italy, Spain and Greece.

PATIENTS AND PARTICIPANTS

245 patients with cancer either receiving chemotherapy with cisplatin or who had received cisplatin-based chemotherapy within the previous 6 months.

METHODS

After background information had been presented, patients were asked to define the maximum that they would pay per day for a drug that reduced their risk of acute and delayed (days 2 to 5) emesis by 20 and 30%, respectively. Costs were converted to US dollars ($US) using year 2000 exchange rates.

RESULTS

For a 20% improvement in acute emesis, Canadian, Italian and Spanish patients with cancer were willing to pay $US46, $US34 and $US63 per day, respectively, compared with $US8 for patients from Greece (p < 0.001). For a 30% improvement in delayed emesis, Canadian, Italian and Spanish patients with cancer were also willing to pay more than their Greek counterparts (SUS41, $US31, $US50 and $US9 daily for 4 days, respectively; p < 0.001). These significant differences in patient value between countries remained, even after adjusting for socioeconomic variables and previous history of emesis.

CONCLUSIONS

There are substantial cultural differences in how patients with cancer value benefit and improved quality of life. Since the majority of the world's population resides outside North America and Western Europe, there may be a need to re-evaluate perceived levels of patient benefit and measures of quality of life.

Stratified administration of serotonin 5-HT3 receptor antagonists (setrons) for chemotherapy-induced emesis. Economic implications

The serotonin 5-HT3 receptor antagonists or 'setrons' have become the standard of care for the prevention of chemotherapy-induced emesis (CIE) and are first-line therapy for acute CIE in healthcare organisations worldwide. However, their superior efficacy versus standard antiemetics comes at a significant cost. Currently, 3 agents are available in the US: ondansetron, granisetron and dolasetron. The most important treatment-related factor contributing to CIE is the emetogenicity of chemotherapy. The ability to customise, or stratify, the setron dose to match the emetogenic challenge of the chemotherapy administered has potential benefits, both clinically and economically. In adults, there is an appreciable amount of clinical literature addressing stratified administration; however, the amount of 'hard' economic data is rather limited. Intuitively, if clinical outcomes are equivalent, then stratified administration should be associated with economic benefits, as it generally promotes the use of doses lower than those recommended by the manufacturer. The literature strongly substantiates this for ondansetron, but is not as favourable for granisetron or dolasetron. As the rationale and justification for dose stratification is contained in the clinical literature, the authors have reviewed the pertinent literature supporting the clinical and economic benefits of dose stratification in both adult and paediatric patients. The authors also provide a discussion of various additional strategies that can be employed to ensure the appropriate and cost-effective use of setrons in real-world practice settings. These strategies include the use of lower doses than recommended by manufacturers, use for acute versus delayed phase emesis, enhancing the antiemetic efficacy by the addition of a corticosteroid, use of oral versus injectable formulations (when appropriate) and the implementation and use of local, national and international drug use guidelines.

Granisetron is equivalent to ondansetron for prophylaxis of chemotherapy-induced nausea and vomiting: results of a meta-analysis of randomized controlled trials

BACKGROUND

The introduction of serotonin antagonists as antiemetics for prophylaxis of chemotherapy-induced nausea and vomiting represented a major step toward better patient tolerance and adherence to this type of treatment. Several published trials compared different serotonin antagonists without demonstrating clear superiority of any one of them. Because most of these trials compared ondansetron with granisetron, the authors conducted a meta-analysis to determine if the current data available show any therapeutic difference between them.

METHODS

MEDLINE and CANCERLIT databases were searched from 1990 to May 1999, and pertinent article references also were surveyed, without restriction to English language. The authors included all randomized controlled trials (RCTs) that had more than 25 patients per arm and compared ondansetron to granisetron for prophylaxis of acute (A) (< 24 hours) and delayed (D) (> 24 hours) nausea (N) and vomiting (V) induced by highly (H) or moderately (M) emetogenic chemotherapy. Only the first chemotherapy cycle was considered for studies that involved a crossover design.

RESULTS

Fourteen studies with 6467 evaluable patients among the 21 studies retrieved were selected for this meta-analysis. In none of the eight scenarios studied (AHV, AHN, AMV, AMN, DHV, DHN, DMV, and DMN) could the authors detect any significant differences in the antiemetic efficacy of any of these medications.

CONCLUSIONS

The authors conclude that both granisetron and ondansetron have similar antiemetic efficacy for prophylaxis of chemotherapy-induced nausea and vomiting. Because the number of comparative studies that addressed the delayed nausea and vomiting scenarios is low, further RCTs are still needed to confirm these results.

High efficacy of a single oral dose of ondansetron 8 mg versus a metoclopramide regimen in the prevention of acute emesis induced by fluorouracil, doxorubicin and cyclophosphamide (FAC) chemotherapy for breast cancer

The aim of our single-center, prospective, randomized, open study was to evaluate the antiemetic efficacy and tolerability of a regimen based on a single oral dose of ondansetron 8 mg in comparison with a metoclopramide-based regimen, for prevention of acute FAC (fluorouracil, doxorubicin and cyclophosphamide) chemotherapy-induced emesis. A total of 149 chemotherapy-naive, female outpatients, under 50 years of age and with no history of alcohol consumption, scheduled to receive their first cycle of FAC chemotherapy, were included. The patients received either oral ondansetron (8 mg) or metoclopramide (1.5 mg/kg, i.v.), both combined with dexamethasone (16 mg, i.v.) and alprazolam (0.5 mg t.i.d. orally). No antiemetic prophylaxis was given for delayed emesis. Complete control of acute vomiting was obtained in 69/74 (93%) of patients receiving ondansetron, and in 49/75 (65%) of those receiving metoclopramide (p=0.00003). Complete control of acute nausea was obtained in 58% of patients receiving ondansetron and in 36% of those receiving metoclopramide (p=0.007). Complete prevention of delayed vomiting/nausea was achieved in 73%/20% and 60%/16% of patients, respectively. Sedation was more frequent in the metoclopramide arm (p=0.04). As far as we know this is the first study that supports the efficacy of a regimen based on a single oral dose of ondansetron 8 mg in the prevention of acute FAC chemotherapy-induced emesis. The ondansetron regimen was highly effective in female patients and was superior to the metoclopramide based regimen.

Survey ranking of emetogenic control in children receiving chemotherapy

PURPOSE

To determine the effect of standard antiemetic treatment in children receiving various combination chemotherapy regimens.

METHODS

A validated nausea/vomiting survey was administered to 78 patients receiving 13 different emetogenic chemotherapy regimens. Patients received antiemetic prophylaxis with ondansetron (0.3 mg/kg/day) alone for moderately emetogenic chemotherapy regimens or ondansetron (0.45 mg/kg/day) and methylprednisolone (4 mg/kg/day) for severely emetogenic chemotherapy regimens. A total of 324 different courses of chemotherapy were surveyed. Nausea and vomiting severity, duration, number of emetic episodes, appetite, daily activity interference, and rates of both complete and good antiemetic protection were determined for each chemotherapy protocol. Differences between genders and ages were analyzed.

RESULTS

Chemotherapy combinations containing platinum compounds were found to be highly emetogenic and nauseating despite antiemetic therapy with ondansetron plus a corticosteroid. In addition, complete antiemetic protection for the combination of vincristine, cyclophosphamide, and dactinomycin was poor. For most of the severely emetogenic chemotherapy protocols, patients experienced good protection from nausea and vomiting less than 60% of the time, despite the use of ondansetron plus methylprednisolone. Significant differences were found in rates of residual nausea and vomiting and failure of antiemetic protection among the severely emetogenic chemotherapy protocols despite identical antiemetic therapy. Good protection rates were higher for moderately emetogenic chemotherapy treated with ondansetron alone.

CONCLUSIONS

The currently recommended prophylactic therapy for pediatric patients receiving severely emetogenic chemotherapy fails to provide protection for many patients receiving commonly administered chemotherapy regimens and for most pediatric patients receiving platinum-containing chemotherapy combinations. New and refined antiemetic strategies are needed to improve efficacy in the pediatric population.

Balancing efficacy with cost: antiemetic control in the pediatric stem cell transplant (SCT) population

We studied the practice patterns regarding intravenous (i.v.) ondansetron in children receiving stem cell transplants (SCT) at The Children's Hospital, Boston to identify cost efficiencies. The pharmacy provided information on material and preparation costs on 36 patients who received i.v. ondansetron during 41 SCT in 1995. We examined the effects of frequency, duration, and route of administration on costs. There were 498 days of ondansetron administration costing $49,083 (95$). Tremendous variation existed in frequency and duration with one third receiving i.v. ondansetron once daily, despite published evidence of equivalence of once a day and divided dosing. A switch to once daily i.v. dosing for all patients would have resulted in >/=28% savings. The median duration of use was 11 days (range 1-48); placing a cap for 7-10 days based on the length of SCT conditioning regimens, would produce savings of 48-60% over current use. By shifting administration route from i.v. to oral, a savings of 67% over current use, without a cap on duration, would be realized. Identifying areas for cost savings can be achieved after thorough analysis of all the component costs. We demonstrated that significant cost reductions could be realized by simple changes in prescribing practices without jeopardizing efficacy. These savings are achieved by standardizing dosing interval, route of administration and duration of treatment without altering daily dosage or access to an effective antiemetic. Bone Marrow Transplantation (2000) 25, 553-557.

Advances in use of the 5-HT3 receptor antagonists

Nausea and vomiting continue to rank as important side effects for cancer patients receiving chemotherapy. The class of drugs known as the 5-HT3 receptor antagonists have become widely used for chemotherapy-induced nausea and vomiting, and are considered a standard part of care for moderately- and highly-emetogenic chemotherapy in combination with corticosteroids. Ondansetron (Zofran, Glaxo Wellcome), granisetron (Kytril, SmithKline Beecham) and dolasetron (Anzemet, Hoechst Marion Roussel) are commercially available in the US. Intravenous forms of all three drugs have demonstrated efficacy in preventing acute (< or = 24 h following chemotherapy) nausea and emesis due to moderately- and highly-emetogenic chemotherapy. Oral forms of the drugs have been shown to be effective in prevention of nausea and emesis due to moderately-emetogenic chemotherapy. More recently, oral 5-HT3 receptor antagonists have demonstrated efficacy in the prevention of nausea and vomiting due to highly-emetogenic chemotherapy as well. Comparative trials between the three agents have shown no clinically important differences in outcome and they should be considered clinically equivalent. Optimal oral anti-emetic regimens for high-dose chemotherapy with bone marrow or stem cell transplantation remain to be determined and future oral studies should target this population. In general, the decision of which 5-HT3 receptor antagonist to select for formulary inclusion should be based on the dose of anti-emetic used and the acquisition cost of the agents being compared. The oral route should be used whenever possible.