Do humoral factors mediate cancer chemotherapy-induced emesis?

Opportunities and challenges to the use of neutralizing monoclonal antibody therapies for COVID-19

The coronavirus disease 2019 (COVID-19) pandemic has resulted in a substantial global public healthcare crisis, leading to the urgent need for effective therapeutic strategies. Neutralizing antibodies (nAbs) are a potential treatment for COVID-19. This article provides a brief overview of the targets and development of nAbs against COVID-19, and it examines the efficacy of nAbs as part of both outpatient and inpatient treatments based on emerging clinical trial data. Assessment of several promising candidates in clinical trials highlights the potential of nAbs to be an effective therapeutic to treat COVID-19 in outpatient settings. Nevertheless, the efficacy of nAbs treatment for hospitalized patients varies. In addition, this review identifies challenges to ending the COVID-19 pandemic, including concerns over nAbs development and clinical use. Resistant variants significantly threaten the availability of nAb-based therapeutics. This review also discusses other approaches that may improve the clinical benefit of neutralizing mAbs.

Physiology of chemotherapy-induced emesis and antiemetic therapy. Predictive models for evaluation of new compounds

The physiology of emesis has been studied for several hundred years, focusing on the different centres involved and the mechanics of expulsion. The vomiting centre receives inputs from various emetic detectors such as the gut, the vestibular labyrinths and the chemoreceptor trigger zone. Emesis is a common disabling effect in motion sickness, postoperative conditions and in radio- and chemotherapy. Our current understanding of the mechanisms has been provided mainly by the recent introduction of serotonin 5-HT3 receptor antagonists into therapeutic use. Nevertheless, despite the considerable advances made in the understanding of the different pathways involved in emesis, there are number of areas that still require experimental investigation. Different animal and human models are available to study the physiology of emesis and to evaluate the antiemetic activity of new compounds, but they need to be predictors of clinical situations.

Comparison of the anti-emetic efficacy of different doses of ondansetron, given as either a continuous infusion or a single intravenous dose, in acute cisplatin-induced emesis. A multicentre, double-blind, randomised, parallel group study. Ondansetron Study Group

A total of 535 chemotherapy naive, hospitalised patients (263 male/272 female) scheduled to receive cisplatin (50-120 mg m-2)-containing regimens participated in a randomised, double-blind, parallel group study to evaluate the efficacy and safety of three intravenous dose schedules of ondansetron in the prophylaxis of acute nausea and emesis. One hundred and eighty two patients received a loading dose of 8 mg of ondansetron followed by a 24 h infusion of 1 mg h-1 (group 1); 180 and 173 patients received single doses of 32 mg (group II) and 8 mg (group III) respectively, followed by a 24 h placebo infusion. Complete and major control (less than or equal to 2 emetic episodes) of acute emesis was achieved in 74% of patients in group I, 78% in group II and 74% in group III. Seventy seven per cent of the patients in group I, and 75% of patients in groups II and III respectively experienced no or mild nausea during the 24 h observation period. A retrospective stratification of the efficacy data on the basis of patient gender showed the response rate in females to be significant lower (43% vs 67%; less than 0.001). Ondanestron was well tolerated; mild headache was the most commonly reported adverse event (11% of patients) with a similar incidence in the three groups of patients. In conclusion, a single intravenous dose of 8 mg of ondansetron given prior to chemotherapy is as effective as a 32 mg daily dose given as either a single dose of a continuous infusion in the prophylaxis of acute cisplatin-induced emesis.

Efficacy of ondansetron (GR 38032F) and the role of serotonin in cisplatin-induced nausea and vomiting

We compared the efficacy and safety of ondansetron (GR 38032F), a selective antagonist of serotonin S3 receptors, with that of placebo in controlling the nausea and vomiting induced by cisplatin treatment in 28 patients with cancer. The patients received either three intravenous doses of ondansetron (0.15 mg per kilogram of body weight) or normal saline (placebo) at four-hour intervals, beginning 30 minutes before the administration of cisplatin. Nausea and vomiting were markedly diminished in the group given ondansetron. The median time to the first episode of emesis was 2.8 hours in the placebo group and 11.6 hours in the ondansetron group (P less than 0.001); the median number of episodes in 24 hours was 5.5 in the placebo group and 1.5 in the ondansetron group (P less than 0.001); the mean (+/- SEM) number of regurgitations or dry heaves per episode was 3.2 +/- 0.5 in the placebo group and 1.17 +/- 0.1 in the ondansetron group (P less than 0.001). None of the 14 patients given ondansetron, but 12 of 14 given placebo, required treatment with antiemetic-rescue agents for the control of nausea and vomiting. There were no adverse effects attributable to ondansetron. The urinary excretion of 5-hydroxyindoleacetic acid, the main metabolite of serotonin, was increased in all patients two to six hours after they received cisplatin chemotherapy, and the increases paralleled the episodes of emesis. We conclude that ondansetron is an effective and safe agent for controlling the nausea and vomiting induced by cisplatin treatment. We suggest that cisplatin treatment increases the release of serotonin from enterochromaffin cells, and that ondansetron acts by blocking S3 receptors for serotonin.