Fractionated chemotherapy--granisetron or conventional antiemetics? The Granisetron Study Group

Granisetron: the second serotonin-receptor antagonist

OBJECTIVE

To review the pharmacology, pharmacokinetics, clinical efficacy, and adverse effects of granisetron, focusing on critical analysis of published clinical trials and comparison with other antiemetic agents, including ondansetron.

DATA SOURCES

MEDLINE (1966-1995) and CANCERLIT (1991-1995) searches of English-language literature using the terms "granisetron" and "granisetron (rn)" were performed.

STUDY SELECTION AND DATA EXTRACTION

All articles were considered for possible inclusion in this review. Abstracts of clinical trials were included only when they were judged to add critical information not otherwise available in the medical literature. For studies published more than once, the most recent publication was cited.

DATA SYNTHESIS

Nausea and vomiting are rated by patients as the most distressing chemotherapy-related adverse effects and may produce potentially life-threatening complications. The discovery of the role of serotonin in nausea and vomiting and the development of selective serotonin3-receptor (5-HT3) antagonists has significantly diminished the incidence and consequences of chemotherapy-related nausea and vomiting. Granisetron is the second 5-HT3-receptor antagonist to be marketed in the US. Granisetron has been compared with other antiemetic agents, including ondansetron, against highly and moderately emetogenic chemotherapy. The results of these trials have shown granisetron to be superior to conventional antiemetics and as effective as ondansetron in the prevention of chemotherapy-induced nausea and vomiting. The optimal dose of granisetron has yet to be determined. Formulary decisions should be based on a cost comparison among the 5-HT3-receptor antagonists at individual institutions.

CONCLUSIONS

Granisetron is a safe, effective antiemetic agent for the management of nausea and vomiting caused by cancer chemotherapy.

Antiemetic Therapy in the Outpatient Oncology Setting

Nausea and vomiting (N/V) are well-recognized and potentially serious complications of cancer chemotherapy that can significantly impact therapeutic outcomes and overall quality of life. As the management of cancer patients moves to the outpatient setting, therapeutic strategies for N/V control must be adapted accordingly. The purpose of this article is to provide an overview of the pathophysiology and basic principles of N/V management and the available antiemetic agents, with an emphasis on applications in outpatient oncology. Development of antiemetic guidelines promotes selection of appropriate antiemetics to maximize N/V control, while minimizing associated cost. Use of oral antiemetics when possible also significantly reduces the cost of N/V management, without compromising therapeutic efficacy. In addition to designing an appropriate treatment regimen, measures for the early evaluation of N/V outcomes must also be instituted. Pharmacists can have an important role in ensuring optimal control of N/V in cancer patients.

Oral granisetron with or without methylprednisolone versus metoclopramide plus methylprednisolone in the management of delayed nausea and vomiting induced by cisplatin-based chemotherapy. A prospective randomized trial

BACKGROUND

A single-institution, randomized open trial was prospectively performed to compare orally administered granisetron with or without intramuscularly administered methylprednisolone to metoclopramide plus methylprednisolone in the prevention of delayed nausea and vomiting induced by cisplatin-based chemotherapy. The effects of antiemetic treatments were evaluated from days 2 to 5 of the first cycle after cisplatin administration among patients who had never before received chemotherapy.

METHODS

All patients were treated with chemotherapeutic regimens containing cisplatin greater than or equal to 80 mg/m2 and received antiemetic therapy with granisetron 3 mg intravenously for the control of acute emesis. Patients who responded to treatment during the first 24 hours were randomized to receive (1) metoclopramide (0.5 mg/kg) intramuscularly three times daily plus methylprednisolone (125 mg) intramuscularly once a day or (2) granisetron (1 mg) orally twice daily or (3) oral granisetron (1 mg) orally plus methylprednisolone (125 mg) intramuscularly from days 2 to 5.

RESULTS

Of the patients treated with metoclopramide plus methylprednisolone (n = 92), 53% had complete protection from delayed emesis, 16% a major response, 15% a minor response, and 15% no response. Of the patients treated with granisetron alone (n = 84), 33% had a complete response, 21% a major response, 23% a minor response, and 21% no response. In the patients treated with orally administered granisetron plus intramuscularly administered methylprednisolone (n = 86), 47% had a complete response, 17% a major response, 23% a minor response, and 13% no response. These differences reached statistical significance only when the complete response rate achieved in the metoclopramide plus methylprednisolone group was compared with that recorded in the oral granisetron group (P = 0.012). Moreover, the metoclopramide plus methylprednisolone and the orally administered granisetron plus corticosteroid arms were superior to the orally administered granisetron alone arm in preventing nausea (P < 0.038 and P < 0.002, respectively). No extrapyramidal side effects were noted for the granisetron alone and the granisetron plus methylprednisolone arms, whereas 6% of patients treated with metoclopramide had extrapyramidal adverse effects. Headache was recorded in 8% of patients treated with granisetron alone, in 9% treated with granisetron plus methylprednisolone, and in 3% treated with metoclopramide plus methylprednisolone.

CONCLUSIONS

These data suggest that orally administered granisetron with or without methylprednisolone may be given safely to patients with cancer as prophylactic therapy against delayed emesis after high dose cisplatin therapy. Orally administered granisetron alone was less active than a standard combination of metoclopramide plus methylprednisolone. However, the addition of corticosteroid to orally administered granisetron improved the control of delayed emesis. The efficacy of the combination of metoclopramide plus methylprednisolone and oral granisetron with or without methylprednisolone against delayed emesis still is not entirely satisfactory.

Progress in reducing nausea and emesis. Comparisons of ondansetron (Zofran), granisetron (Kytril), and tropisetron (Navoban)

BACKGROUND

Nausea and vomiting are the most distressing side effects associated with the administration of chemotherapy for neoplastic diseases. Nausea, in particular, often had been ignored in studies of chemotherapy side effects. Recently, progress has been made in the control of chemotherapy-induced nausea and vomiting, due, in part, to a better understanding of the physiologic mechanisms involved.

METHODS

This paper reviews recent advances in the control of emesis, focusing on pharmacologic treatments.

RESULTS

The efficacy and safety of the serotonin (5-HT3) receptor antagonists granisetron, ondansetron, and tropisetron in the control of acute and delayed emesis and emesis induced by repeat-cycle chemotherapy are summarized. Although differences in study design and definitions of response criteria have made it difficult to compare the studies that have evaluated these three agents, the overall body of literature supports several clinical findings.

CONCLUSIONS

(1) The 5HT3 antiemetic agents have been shown to be clinically more effective in the control of nausea and emesis than previously used agents. (2) No one of the three has demonstrated consistently greater efficacy. (3) Efficacy appears to be more pronounced for cisplatin-containing regimens than for moderate or less emetogenic chemotherapy regimens. (4) Effectiveness of the 5HT3 agents appears to be less for delayed nausea and emesis than for acute symptoms. Potential control of anticipatory nausea and emesis has not been investigated. (5) Control over nausea appears to be significantly less than control over emesis. In the studies in which it has been measured, nausea control remains incomplete for approximately half the patients given 5HT3 agents. (6) The efficacy of the agents appears to diminish across repeated days and, perhaps, across repeated chemotherapy cycles. (7) The addition of a steroid such as dexamethasone increases the efficacy of both 5HT3 and other antiemetic agents. This effect also seems to apply to delayed nausea and emesis.

Antiemetics in cancer chemotherapy: historical perspective and current state of the art

Chemotherapy-related nausea and vomiting can today be controlled with available antiemetics in a high percentage of patients but emesis remains a problem for some patients, with certain drugs and with repeated cycles of chemotherapy. The fundamental steps of clinical research in antiemetics towards the improvement of the control of nausea and vomiting with new drugs or combinations are presented. Special emphasis is given to cisplatin-induced nausea and vomiting because of the frequency and relevance of this phenomenon. The use of high-dose metoclopramide, its combination with steroids, and later the addition of lorazepam or diphenhydramine represented the evolving standard of the 1980s, with the level of complete protection from vomiting improving from 30%-40% to 60%-70% with the three-drug combination. The introduction of new agents such as the 5-hydroxytryptamine 3 (5-HT3) receptor antagonists has recently offered new possibilities because of their activity and lack of toxicity. In particular, the combination of ondansetron plus dexamethasone is today the most efficacious and least toxic antiemetic treatment for prevention of emesis in patients treated with a single high dose or low repeated doses of cisplatin. A comparison of different 5-HT3 antagonists, always in combination with steroids, is now considered necessary. For patients treated with moderately emetogenic chemotherapy the use of steroids can still be considered the standard treatment. In this setting, the role of 5-HT3 receptor antagonists, alone or in combination with steroids, has to be better defined through large, well-planned clinical trials, which should have a cost-effectiveness analysis as one of their goals.

[Antiemetic treatment and chemotherapy: general review]

Chemotherapy-induced nausea and emesis are frequent and patients fearful. Emesis caused by cytotoxic agents can be related to their effects on central chemoreceptor or on the gut chemoreceptor by serotonin. 5HT3 receptor antagonists produce a major improvement in the control of cisplatin induced-emesis (70 to 80% of patients). The 5HT3-antagonist efficacy is significantly better than metoclopramide alone, or antimemetic combinations in highly emetogenic chemotherapy regimens but less good in moderately emetogenic chemotherapy. Studies with 5HT3 receptor antagonist plus corticosteroids show advantage over 5HT3 antagonist alone. Comparison studies between the different setrons didn't show any significant difference. Anticipary emesis are treated with anxiolytic drugs. The prevention of delayed emesis, not yet well controlled by 5HT3 antagonist, is a great therapeutic deal. Finally, some therapeutic problems are not resolved: minimal dose, use of oral route, efficacy in fractionated chemotherapy, treatment after loss of efficacy of 5HT3 antagonist.

Review of experience with ondansetron and granisetron

Development of the serotonin type 3 (5-HT3) receptor antagonists has facilitated a new understanding of the physiology of emesis. Three new agents, ondansetron, granisetron and tropisetron, are currently available in several countries and this review will focus on the characteristics of ondansetron and granisetron, so that a perspective of the data for tropisetron can be presented by other authors. Preclinical data indicate some possible differences among these new compounds. They differ in pharmacokinetic terms. Efficacy and a good safety profile for acute emesis control have been demonstrated for both agents, although there may be some debate as to the best schedule of ondansetron. Delayed emesis does not seem to be adequately controlled by these drugs, and they may also lose some efficacy during multiple-day chemotherapy or after several cycles of chemotherapy. While the addition of corticosteroids seems to increase the response rate to ondansetron, no such data are yet available for granisetron. Finally, considerations pertinent to the cost of these new agents are discussed.

Oral granisetron--simple and effective: a preliminary report. The Granisetron Study Group

This randomised, double-blind, study was carried out in 930 patients in order to examine the efficacy and safety of oral granisetron in the dose range 0.25, 0.5, 1.0 and 2.0 mg twice daily. Oral granisetron was administered for either 7 or 14 days according to the chemotherapy regimen used. A total of 930 patients were enrolled into this study in order to be able to detect a difference of 15% between groups (80% power). The preliminary results showed that at 7 days efficacy was significantly greater for 1.0 mg b.d. (58.5%) than for 0.25 mg b.d. (43.7%) and indicated that, of the doses examined, the 1.0 mg b.d. dose was optimal in patients receiving moderately emetogenic chemotherapy. In agreement with this there were more withdrawals from the 0.25 and 0.5 mg groups due to lack of efficacy. The adverse events most frequently reported (in greater than 5% of patients) were constipation, headache, abdominal pain, fever, leucopenia and asthenia. The latter three are recognised side effects of the primary disease and of chemotherapy. The incidence of headache was similar to that seen in previous granisetron studies. Abdominal pain may have been related to constipation. The incidence of constipation (25.9%) was higher than that reported in previous granisetron studies but was not dose related. Thus oral granisetron at 1.0 mg twice daily is an effective antiemetic, offering a convenient dosing regimen without significant adverse events.

Are granisetron and ondansetron equivalent in the clinic?

There are no published direct trials of granisetron vs. ondansetron. Difficulties exist in comparing reported trials because of differences in methodology, especially in response criteria. In this review, a comparison is made between ondansetron and granisetron by recalculating the complete response criterion for granisetron, standardising it against that in the ondansetron programme (i.e. no vomiting). Weighted means have been calculated for three areas of study. Against cisplatin-induced emesis the (weighted) mean percentage of complete responders were calculated at 64% (range 49-77%) for granisetron and 49% (range 40-55%) for ondansetron. Against moderately emetogenic stimuli, the response rates were 76% (range 68-80%) and 73% (range 60-87%) respectively. For fractionated chemotherapy the response rates were 57% and 27% for granisetron and ondansetron respectively. Although not shown by formal statistical analysis, these results suggest that a clinical advantage for granisetron may exist.