Oral ondansetron 8 mg twice daily is as effective as 8 mg three times daily in the prevention of nausea and vomiting associated with moderately emetogenic cancer chemotherapy. S3A-376 Study Group

Inhibiting substance p pathway for prevention of chemotherapy-induced emesis: preclinical data, clinical trials of neurokinin-1 receptor antagonists

Neurokinin-1 (NK-1) receptor antagonists are a new class of antiemetic agents that have activity in controlling cisplatin-induced acute and delayed emesis. Preclinical data in animal models show that the NK-1 receptor antagonists have broad antiemetic activity. The NK-1 receptor antagonists have activity in controlling emesis induced by peripherally acting and centrally acting emetogens, suggesting a mechanism of action at multiple sites. The effects at central and peripheral sites to control acute and delayed emesis cannot be determined at this time based on available studies. When added to a standard regimen of a 5-hydroxytryptamine-3 (5- HT3) receptor antagonist and dexamethasone, the NK-1 receptor antagonists improve control of acute emesis. The NK-1 receptor antagonists improve delayed emesis compared with placebo, and when used in combination with dexamethasone, compared with dexamethasone alone. Acute and delayed nausea may also be improved by the NK-1 receptor antagonists when they are used in combination with a 5-HT3 receptor antagonist and dexamethasone prechemotherapy or with daily dosing for 5 days after chemotherapy. The current data suggest that the mechanism of action of the NK-1 receptor antagonists appears to be different from that of the 5-HT3 receptor antagonists. Future studies may consider using NK-1 receptor antagonists with moderately emetogenic chemotherapy as well as bone marrow transplantation.

Palonosetron: a second-generation 5-hydroxytryptamine receptor antagonist

Chemotherapy-induced nausea and vomiting (CINV) is associated with a significant deterioration in quality of life. The emetogenicity of the chemotherapeutic agents, repeated chemotherapy cycles and patient risk factors (female gender, younger age, alcohol consumption, history of motion sickness) are the major risk factors for CINV. The use of 5-hydroxytryptamine (5-HT)3 receptor antagonists plus dexamethasone has significantly improved the control of acute CINV, but delayed nausea and vomiting remains a clinical problem. A new agent, palonosetron, has recently been approved for the prevention of acute CINV in patients receiving either moderately or highly emetogenic chemotherapy and for the prevention of delayed CINV in patients receiving moderately emetogenic chemotherapy. Palonosetron is a 5-HT3 receptor antagonist with a longer half-life and a higher binding affinity than first-generation 5-HT3 receptor antagonists. In a single dosing study, palonosetron was highly effective in controlling CINV compared with a single dose of dolasetron or ondansetron in patients receiving moderately emetogenic chemotherapy. Palonosetron in combination with dexamethasone demonstrated control of CINV in patients receiving highly emetogenic chemotherapy. Palonosetron appeared to be as effective in subsequent courses of chemotherapy compared with the initial course of chemotherapy. There were no clinically relevant differences seen among palonosetron, ondansetron or dolasetron in laboratory, electrocardiographic or vital-sign changes, and adverse reactions reported in the clinical trials were the most common reactions reported for the 5-HT3 receptor antagonist class. Recent studies using palonosetron-based anti-emetic combinations in moderately and highly emetogenic chemotherapy, as well as in the clinical setting of multiple-day chemotherapy, have been reported. Future studies may consider the use of palonosetron with current and other new agents and in other clinical settings, such as bone marrow transplantation and radiation therapy.

Emerging drugs for chemotherapy-induced emesis

Chemotherapy-induced nausea and vomiting (CINV) is associated with a significant deterioration in quality of life. The emetogenicity of the chemotherapeutic agents, repeated chemotherapy cycles and patient risk factors (female gender, younger age, no alcohol consumption, history of motion sickness) are the major risk factors for CINV. The use of 5-hydroxytryptamine-3 (5-HT3) receptor antagonists plus dexamethasone has significantly improved the control of acute CINV, but delayed nausea and vomiting remains a significant clinical problem. Two new agents, palonosetron and aprepitant, have recently been approved for the prevention of both acute and delayed CINV. Palonosetron is a 5-HT3 receptor antagonist with a longer half-life and a higher binding affinity than first-generation 5-HT3 receptor antagonists. Aprepitant is the first agent available in the new drug class of neurokinin-1 receptor (NK-1) antagonists. There are a number of 5-HT3 receptor antagonists and NK-1 receptor antagonists currently in Phase II and III clinical trials. Revised antiemetic guidelines for the prevention of CINV are reviewed. Future studies may consider the use of palonosetron and aprepitant with current and other new agents (olanzapine, gabapentin) in moderately and highly emetogenic chemotherapy, as well as in the clinical settings of multiple-day chemotherapy and bone marrow transplantation.

Acute emesis: moderately emetogenic chemotherapy

This paper is a review of the recommendations for the prophylaxis of acute emesis induced by moderately emetogenic chemotherapy as concluded at the Perugia Consensus Conference, which took place at the end of March 2004. The review focuses on new studies appearing since the last consensus conference in 1997. The following issues are addressed: dose and schedule of antiemetics, different groups of antiemetics such as corticosteroids, serotonin (5-HT(3))-receptor antagonists, dopamine D(2) receptor antagonists, and neurokinin (NK(1)) receptor antagonists. Antiemetic prophylaxis in patients receiving multiple cycles of moderately emetogenic chemotherapy is also reviewed. Consensus statements are given, including optimal dose and schedule of 5-HT(3)-receptor antagonists and of dexamethasone. The new 5-HT(3)-receptor antagonist, palonosetron, is a reasonable alternative to the well-established agents of this class--ondansetron, granisetron, tropisetron and dolasetron. It is concluded that the best prophylaxis in patients receiving moderately emetogenic chemotherapy is still the combination of one of the 5-HT(3)-receptor antagonists and dexamethasone. The results of studies adding a NK(1)-receptor antagonist to this combination are awaited and might change future recommendations.

Role of Neurokinin-1 Receptor Antagonists in Chemotherapy-Induced Emesis: Summary of Clinical Trials

Chemotherapy-induced nausea and vomiting (CINV) is associated with a significant deterioration in quality of life, and although the use of 5-hydroxytryptamine3 (5-HT3) receptor antagonists plus dexamethasone has significantly improved the control of acute CINV, delayed nausea and vomiting remain a significant clinical problem. Aprepitant is the first agent available in the new drug class of neurokinin-1 receptor antagonists. When added to a standard regimen of a 5-HT3 receptor antagonist and dexamethasone in patients receiving highly emetogenic chemotherapy, it improves the complete response rate of acute CINV. Aprepitant also improves the complete response of delayed CINV when used in combination with dexamethasone compared to dexamethasone alone. The use of aprepitant in patients receiving moderately emetogenic chemotherapy will await the review and analysis of recently completed phase III trials. The control of nausea is improved in some studies with the use of aprepitant when it is combined with a 5HT3 receptor antagonist and dexamethasone, but nausea control remains suboptimal. The current data suggest that the mechanism of action of the NK-1s appears to be different from the 5-HT3 receptor antagonists. Future studies may explore the use of aprepitant and other NK-1s in moderately and highly emetogenic chemotherapy, as well in the clinical settings of multiple-day chemotherapy and bone marrow transplantation.

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.

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.

5-HT3 antiemetic therapy for patients with breast cancer

Antiemetic treatment should be considered for breast cancer patients receiving moderately emetogenic chemotherapy. Although the extent of chemotherapy-induced emesis is largely dependent on the emetogenic potential of the specific agents employed, patient characteristics such as age and sex also contribute. Recent clinical studies show that treatment with the currently available 5-HT3 antagonists effectively reduces the incidence of chemotherapy-induced nausea and vomiting and improves quality of life in a substantial number of these patients. A Medline search from 1994 through February 1998 identified clinical trials that included previously untreated breast cancer patients using antiemetic therapy such as granisetron, ondansetron, dolasetron, and metoclopramide. The studies reviewed here indicate that the antiemetic efficacy of 5-HT3 antagonists is equivalent in previously untreated patients receiving moderately emetogenic chemotherapy for breast cancer, depending on the doses and schedules utilized. In particular, two comparative studies of granisetron and ondansetron with specific data for breast cancer patients showed that both agents eliminate nausea in approximately 50%, and vomiting in 60-70% of these patients, with the higher values observed when steroids were added to the 5-HT3 receptor antagonist regimen. Although the chemotherapy regimens employed for breast cancer are considered only moderately emetogenic, these regimens account for 60-90% of patients experiencing nausea and vomiting. The most recent clinical studies demonstrate that 5-HT3 antagonists can significantly reduce the incidence of nausea in breast cancer patients receiving moderately emetogenic chemotherapy and should be employed in this setting.

Guidelines for anti-emetic therapy: acute emesis

Anti-emetic therapy has become integral to the management of patients with cancer. Goals related to complete emesis control include providing treatment that reduces hospitalisation and time in the ambulatory setting, care that is convenient for the patient and therapy that enhances patients' quality of life. A panel of clinical, health economic and basic scientists with expertise in various oncology disciplines reviewed published literature to develop evidence-based consensus guidelines for the prevention and treatment of chemotherapy-induced emesis. Currently, serotonin receptor antagonists and corticosteroids are the two categories of anti-emetics that are most effective, have the fewest side-effects and are convenient to use. These agents are recommended in combination for highly emetogenic chemotherapy regimens and as single agents or in combination for moderately to highly emetogenic chemotherapy. When possible, these agents may be given orally in single doses; current evidence does not support dose escalation for either category of anti-emetics. In special situations, such as the use of high-dose chemotherapy combination regimens, the most emetogenic component of the regimen should dictate the choice of anti-emetic. Appropriate anti-emetic use described in these guidelines represents both good medical practice and a sensible economic approach to care.