Pharmacokinetics of palonosetron in combination with aprepitant in healthy volunteers

Guideline for the prevention of acute chemotherapy-induced nausea and vomiting in pediatric cancer patients: A focused update

This update of the 2013 clinical practice guideline provides clinicians with guidance regarding the use of aprepitant and palonosetron for the prevention of acute chemotherapy-induced nausea and vomiting (CINV) in children. The recommendations were based on three systematic reviews. Substantive changes were made to the guideline recommendations including the inclusion of palonosetron to the 5-HT₃ antagonists recommended for children receiving highly emetogenic chemotherapy (HEC) and the recommendation of aprepitant for children 6 months of age or older receiving HEC. To optimize CINV control in children, future work must focus on closing critical research gaps.

Aprepitant and fosaprepitant drug interactions: a systematic review

AIMS

Aprepitant and fosaprepitant, commonly used for the prevention of chemotherapy-induced nausea and vomiting, alter cytochrome P450 activity. This systematic review evaluates clinically significant pharmacokinetic drug interactions with aprepitant and fosaprepitant and describes adverse events ascribed to drug interactions with aprepitant or fosaprepitant.

METHODS

We systematically reviewed the literature to September 11, 2016, to identify articles evaluating drug interactions involving aprepitant/fosaprepitant. The clinical significance of each reported pharmacokinetic drug interaction was evaluated based on the United States Food and Drug Administration guidance document on conducting drug interaction studies. The probability of an adverse event reported in case reports being due to a drug interaction with aprepitant/fosaprepitant was determined using the Drug Interaction Probability Scale.

RESULTS

A total of 4377 publications were identified. Of these, 64 met inclusion eligibility criteria: 34 described pharmacokinetic drug interactions and 30 described adverse events ascribed to a drug interaction. Clinically significant pharmacokinetic interactions between aprepitant/fosaprepitant and bosutinib PO, cabazitaxel IV, cyclophosphamide IV, dexamethasone PO, methylprednisolone IV, midazolam PO/IV, oxycodone PO and tolbutamide PO were identified, as were adverse events resulting from an interaction between aprepitant/fosaprepitant and alcohol, anthracyclines, ifosfamide, oxycodone, quetiapine, selective serotonin reuptake inhibitors/serotonin-norepinephrine reuptake inhibitors and warfarin.

CONCLUSIONS

The potential for a drug interaction with aprepitant and fosaprepitant should be considered when selecting antiemetic therapy.

Drug-drug interaction profile of components of a fixed combination of netupitant and palonosetron: Review of clinical data

Neurokinin-1 (NK₁) receptor antagonists (RAs) are commonly coadministered with serotonin (5-HT₃) RAs (e.g. palonosetron (PALO)) to prevent chemotherapy-induced nausea/vomiting. Netupitant/palonosetron (NEPA), an oral fixed combination of netupitant (NETU)—a new NK₁ RA—and PALO, is currently under development. In vitro data suggest that NETU inhibits CYP3A4 and is a substrate for and weak inhibitor of P-glycoprotein (P-gp). This review evaluates potential drug–drug interactions between NETU or NEPA and CYP3A4 substrates/inducers/inhibitors or P-gp substrates in healthy subjects. Pharmacokinetic (PK) parameters were evaluated for each drug when NETU was coadministered with PALO (single doses) and when single doses of NETU or NEPA were coadministered with CYP3A4 substrates (erythromycin (ERY), midazolam (MID), dexamethasone (DEX), or oral contraceptives), inhibitors (ketoconazole (KETO)), or inducers (rifampicin (RIF)), or a P-gp substrate (digoxin (DIG)). Results showed no relevant PK interactions between NETU and PALO. Coadministration of NETU increased MID and ERY exposure and significantly increased DEX exposure in a dose-dependent manner; NETU exposure was unaffected. NEPA coadministration had no clinically significant effect on oral contraception, although levonorgestrel exposure increased. NETU exposure increased after coadministration of NEPA with KETO and decreased after coadministration with RIF; PALO exposure was unaffected. NETU coadministration did not influence DIG exposure. In conclusion, there were no clinically relevant interactions between NETU and PALO, or NEPA and oral contraceptives (based on levonorgestrel and ethinylestradiol exposure). Coadministration of NETU or NEPA with CYP3A4 inducers/inhibitors/substrates should be done with caution. Dose reduction is recommended for DEX. Dose adjustments are not needed for NETU coadministration with P-gp substrates.

Aprepitant for the prevention of nausea and vomiting associated with chemotherapy and postoperative recovery

Chemotherapy-induced nausea and vomiting (CINV) and postoperative nausea and vomiting (PONV) can negatively impact patient quality of life, functional performance and activities of daily living. Although the development of serotonin receptor antagonists has greatly improved the control of acute emesis, delayed CINV remains a significant clinical issue. Aprepitant (Emend(®)) is the first commercially available drug from a new class of agents, the neurokinin-1 receptor antagonists. Elucidation of its mechanism of action has produced a greater understanding of the pathophysiology of nausea and vomiting. Oral aprepitant, in combination with a selective serotonin (5-HT3) receptor antagonist and corticosteroids, is indicated for the prevention of acute and delayed nausea and vomiting associated with highly and moderately emetogenic chemotherapy in adults. Aprepitant alone or in combination only with dexamethasone does not optimally control acute emesis compared with triple combination therapy. By contrast, aprepitant as monotherapy is indicated for the prevention of PONV. Aprepitant represents an emerging class of agents and its addition to standard therapy provides an advanced benefit in the prevention and treatment of CINV and PONV. Investigations of aprepitant for other indications are ongoing.

Combined use of multiday palonosetron with aprepitant and low-dose dexamethasone in prevention of nausea and emesis among patients with multiple myeloma and lymphoma undergoing autologous hematopoietic stem cell transplant: A pilot study

BACKGROUND

The current standard for prevention of chemotherapy-induced nausea/vomiting in autologous stem cell transplant only achieves 4-20% emetic control.

OBJECTIVES

To assess emetic responses to multiday palonosetron, aprepitant, and low-dose dexamethasone among patients with myeloma and lymphoma undergoing autologous hematopoietic stem cell transplant.

METHODS

Oral aprepitant 125/80/80 mg was administered with intravenous dexamethasone 4 mg and palonosetron 0.25 mg on days -3, -2, -1 for multiple myeloma and days -7 through -3 for lymphoma. Palonosetron was repeated day +3 in both groups.

RESULTS

A total of 20 patients were enrolled and 18 analyzed. None experienced emetic failure with complete control achieved in 78, 33, and 17% in the acute, delayed, and extended phases, respectively. Nausea occurred in 78% although not significant in 61%, with median Nausea Visual Score of 4.5. Quality of life correlated with emetic and nausea control. Eight patients developed grade 2-3 nonhematologic toxicities with only one event attributed to the study medications.

CONCLUSIONS

This triplet regimen was feasible with acceptable safety profile in the autologous hematopoietic stem cell transplant setting. Emetic control was best achieved in the acute phase. Lesser degree of emetic and nausea control in the delayed and extended phases impacted quality of life. Our results warrant further evaluation in a larger autologous hematopoietic stem cell transplant population.

Compatibility of intravenous fosaprepitant with intravenous 5-HT3 antagonists and corticosteroids

PURPOSE

Fosaprepitant dimeglumine for injection is the water-soluble phosphorylated prodrug of the neurokinin-1 receptor antagonist aprepitant. Both agents are approved (in combination with a 5-HT3 antagonist and a corticosteroid) for prevention of chemotherapy-induced nausea and vomiting. Because fosaprepitant is likely to be combined and stored in the same intravenous (IV) bag with 5-HT3 antagonists and corticosteroids, the in vitro compatibility of fosaprepitant with these agents and other IV diluents was assessed.

METHODS

Fosaprepitant (1 mg/mL in 0.9 % sodium chloride injection solution) was combined in binary or tertiary fashion with therapeutic-dose preparations of a 5-HT3 antagonist (ondansetron, granisetron, palonosetron, or tropisetron) and/or a corticosteroid (dexamethasone sodium phosphate or methylprednisolone sodium succinate). For diluent compatibility assessment, fosaprepitant was also prepared 1 mg/mL in 0.9 % sodium chloride injection solution, water for injection, or 5 % dextrose injection solution. After 24-h storage under ambient conditions, samples were assayed for degradation.

RESULTS

Fosaprepitant demonstrated compatibility when combined in the same IV infusion bag with common 5-HT3 antagonists and corticosteroids for storage and IV coadministration, with the exception of palonosetron (incompatible under all experimental conditions) and tropisetron (incompatible unless combined with a corticosteroid). No incompatibility was observed between fosaprepitant and any of the 3 diluents tested.

CONCLUSIONS

Use of fosaprepitant in combination with other antiemetics may provide a flexible option for administration of antiemetics to patients receiving moderately or highly emetogenic chemotherapy.

Prevention of chemotherapy-induced nausea and vomiting: focus on fosaprepitant

Fosaprepitant is a prodrug of aprepitant, a neurokinin₁ (NK₁) receptor antagonist used in prophylactic antiemetic regimens used prior to cytotoxic chemotherapy. Fosaprepitant is being developed to provide a parenterally administered alternative to the orally administered aprepitant. Fosaprepitant is rapidly converted to aprepitant and an intravenous dose of 115 mg is bioequivalent to 125 mg orally, with similar plasma concentrations at 24 hours. In phase I and II trials fosaprepitant shows efficacy, but the large randomized efficacy studies have utilized aprepitant. When it is added to dexamethasone and a 5HT₃ receptor antagonist on day 1 prior to chemotherapy aprepitant improves the control of acute post chemotherapy emesis and when continued on days 2 and 3 with dexamethasone it demonstrated even greater improvement in the control of delayed emesis. This has been shown with both cisplatin-containing regimens and those based upon cyclophosphamide and an anthracycline. Fosaprepitant is well tolerated with mild to moderate venous irritation being the only additional toxicity to those seen with oral aprepitant, and that is a function of dose, concentration, and infusion rate. Headaches are the other toxicity most commonly reported. Fosaprepitant can be used as a parenteral alternative to aprepitant in regimens to control chemotherapy-induced emesis.

Determination of palonosetron in human urine by LC-MS/MS

BACKGROUND

Palonosetron is used for the prevention of chemotherapy-induced nausea and vomiting. However, quantification of this drug in human urine has been rare.

RESULTS

A one-step dilution method for the analysis of palonosetron in human urine using LC coupled to positive MS/MS has been developed and validated according to US FDA guidelines. The method uses 200 µl of urine and covers a working range from 2.5-1000 ng/ml with a LLOQ of 2.5 ng/ml.

CONCLUSION

This new LC-MS/MS assay is sensitive and specific despite using an external standard method. It is suitable for clinical studies of palonosetron.

Safety evaluation of aprepitant for the prevention of chemotherapy-induced nausea and vomiting

INTRODUCTION

Aprepitant is the only neurokinin (NK(1)) receptor antagonist (RA) approved for prevention of chemotherapy-induced nausea and vomiting (CINV). Aprepitant is co-administered with a 5-HT(3) RA and a corticosteroid. Although aprepitant is safe, in most clinical settings potential drug-drug interactions need to be considered before prescription.

AREAS COVERED

This article thoroughly reviews aprepitant and, in particular, clinically relevant safety aspects of the drug. The literature review was performed using Medline with the following search terms: adverse events, aprepitant, chemotherapy, CYP3A4, MK-0869, neurokinin(1) receptor antagonist, safety and tolerability.

EXPERT OPINION

The recommended antiemetic regimen of aprepitant, a 5-HT(3) RA and a corticosteroid is safe. The combination of aprepitant, a 5-HT(3) RA and dexamethasone is now the gold standard of antiemetic treatment in prevention of CINV induced by HEC, or by the combination of an anthracycline and cyclophosphamide. The intravenous formulation of aprepitant used as a single dose is expected to be of benefit to cancer patients.

Pharmacokinetics of aprepitant and dexamethasone after administration of chemotherapeutic agents and effects of plasma substance P concentration on chemotherapy-induced nausea and vomiting in Japanese cancer patients

Purpose

This study was conducted to determine the pharmacokinetics of aprepitant and dexamethasone as well as the relationship between the plasma concentration of substance P and nausea/vomiting in Japanese cancer patients.

Methods

After administration of aprepitant (125/80 mg group [10 patients]: 125 mg on day 1 and 80 mg on days 2–5; 40/25 mg group [10 patients]: 40 mg on day 1 and 25 mg on days 2–5) and dexamethasone (6 mg on day 1 and 4 mg on days 2 and 3 in the 125/80 mg group, and 8 mg on day 1 and 6 mg on days 2 and 3 in the 40/25 mg group) to Japanese cancer patients receiving at least moderately emetogenic antitumor agents, the plasma concentrations of aprepitant, dexamethasone, and substance P were measured.

Results

All of 20 patients were treated with the highly emetogenic agent cisplatin (≥70 mg/m²). The C_max and AUC_0–24 h of aprepitant in Japanese cancer patients were similar with those in non-Japanese patients. The clearance of dexamethasone in the 125/80 mg group was approximately one-half of that previously determined in the absence of aprepitant. The substance P concentration in plasma significantly increased only in patients with delayed nausea/vomiting.

Conclusions

This study demonstrated similar plasma pharmacokinetics of aprepitant in Japanese and non-Japanese, the validity of reducing dexamethasone dose, and the existence of increased plasma substance P concentration in patients receiving highly emetogenic cisplatin-based chemotherapy.

Double-blind crossover study to assess potential differences in cytochrome P450 3A4 activity in healthy subjects receiving ondansetron plus dexamethasone, with and without aprepitant

PURPOSE

Because glucocorticoids and the neurokinin-1 receptor antagonist aprepitant influence CYP3A4 activity, this study assessed whether aprepitant added to a 5-HT(3) antagonist and glucocorticoid would affect CYP3A4 induction.

METHODS

In this double-blind, 2-period crossover study, 12 subjects were randomized to receive a triple regimen (oral aprepitant [A] 125 mg, intravenous ondansetron [O] 32 mg, and oral dexamethasone [D] 12 mg day 1; A 80 mg and D 8 mg days 2-3; D 8 mg day 4) in 1 of 2 periods, and a dual regimen (O 32 mg and D 20 mg day 1; D 8 mg bid days 2-4); the D dose was adjusted to account for known dexamethasone/aprepitant interaction. Oral (2 mg) and intravenous (1 mg) stable isotope ((13)C(5) (15)N(1))-labeled midazolam were simultaneously given as probes on days -1, 6, 8, 15, and 22 of each period. If the a priori 90% confidence interval for the day 6 geometric mean oral midazolam AUC(0-∞) ratio (triple/dual regimen) of fold-change from baseline was above 0.5, it would be concluded that there was no clinically meaningful between-regimen difference in CYP3A4 activity.

RESULTS

Day 6 oral midazolam AUC(0-∞) geometric mean fold-change from baseline was 0.84 (0.30-1.58 with A, 0.46-1.69 without A). The ratio of geometric mean oral midazolam AUC(0-∞) fold-changes was 1.00 (90% confidence interval 0.80, 1.25).

CONCLUSIONS

Aprepitant plus a 5-HT(3) antagonist and dexamethasone is unlikely to have a significant additional inductive effect on CYP3A4 activity beyond that of the dual regimen.

Aprepitant: drug-drug interactions in perspective

The implications of chemotherapeutic drug-drug interactions can be serious and thus need to be addressed. This review concerns the potential interactions of the antiemetic aprepitant, a neurokinin-1 receptor antagonist indicated for use (in Europe) in highly emetogenic chemotherapy and moderately emetogenic chemotherapy (MEC) in combination with a 5-hydroxytryptamine-3 (5-HT3) receptor antagonist and corticosteroids and (in the United States) in combination with other antiemetic agents, for the prevention of acute and delayed nausea and vomiting associated with initial and repeat courses of highly emetogenic cancer chemotherapy including high-dose cisplatin. When considering use of aprepitant for prevention of chemotherapy-induced nausea and vomiting, its potential drug-drug interaction profile as a moderate inhibitor of cytochrome P-450 isoenzyme 3A4 (CYP3A4) has been a source of concern for some physicians and other health care professionals. We explore in this paper how real those concerns are. Our conclusion is that either no interaction or no clinically relevant interaction exists with chemotherapeutic agents (intravenous cyclophosphamide, docetaxel, intravenous vinorelbine) or 5-HT3 antagonists (granisetron, ondansetron, palonosetron). For relevant interactions, appropriate measures, such as corticosteroid dose modifications and extended International Normalized Ratio monitoring of patients on warfarin therapy, can be taken to effectively manage them. Therefore, the concern of negative interactions remains largely theoretical but needs to be verified with new agents extensively metabolized through the 3A4 pathway.

Palonosetron hydrochloride for the prevention of chemotherapy-induced nausea and vomiting

A large number of different 5-hydroxytryptamine (HT)(3) receptor antagonists have been marketed with the indication of preventing nausea and vomiting induced by chemotherapy--palonosetron is the most recently developed of these. Pharmacologic studies have revealed that palonosetron has a long half-life, a high affinity for 5-HT(3) receptors, exhibits allosteric binding to 5-HT(3) receptors and possess positive cooperativity. Although interesting, pharmacologic differences are only useful if they result in clinical advantages, such as an increase in efficacy and/or an improvement in tolerability. We summarize preclinical and clinical studies of palonosetron and compare the efficacy and tolerability with the other 5-HT(3) receptor antagonists, ondansetron, granisetron and dolasetron.

Aprepitant: a review of its use in the prevention of nausea and vomiting

Aprepitant (Emend) is a neurokinin-1 (NK(1)) receptor antagonist that is able to alleviate the emetic effects of substance P. When combined with a standard regimen of a corticosteroid (dexamethasone) and a serotonin 5-HT(3) receptor antagonist (ondansetron), oral aprepitant (125 mg on day 1 then 80 mg once daily on days 2 and 3) was effective in the prevention of acute and delayed chemotherapy-induced nausea and vomiting (CINV) associated with single or multiple cycles of highly emetogenic chemotherapy (HEC). This aprepitant regimen was also effective in the prevention of CINV in patients treated with single or multiple cycles of moderately emetogenic chemotherapy (MEC). A single oral dose of aprepitant 40 mg administered prior to patients undergoing abdominal surgery was also effective in the prevention of postoperative nausea and vomiting (PONV). Aprepitant was generally well tolerated. Aprepitant is a recommended option for the treatment of PONV, and when combined with a corticosteroid and 5-HT(3) receptor antagonist is a recommended regimen for the treatment of CINV.

Effect of casopitant, a novel NK-1 antagonist, on the pharmacokinetics of dolasetron and granisetron

OBJECTIVE

The objective of this study was to characterize the impact of casopitant, a novel neurokinin-1 receptor antagonist under investigation for the prevention of postoperative and chemotherapy-induced nausea and vomiting, on the pharmacokinetics of the commonly prescribed 5-hydroxytryptamine receptor 3 receptor antagonists, dolasetron or granisetron.

MATERIALS AND METHODS

In a phase I, open-label, two-part, two-period, single-sequence study, two cohorts of healthy subjects received either oral dolasetron (100 mg once daily for 3 days) or oral granisetron (2 mg once daily for 3 days) alone (period 1) and combined with oral casopitant, 150 mg day 1, 50 mg days 2 and 3 (period 2). Pharmacokinetics of hydrodolasetron and granisetron were assessed on days 1 and 3 of each period. Log-transformed area under the curve (AUC) and Cmax were statistically analyzed by performing an analysis of variance. Eighteen subjects were enrolled in the dolasetron cohort; nine subjects were CYP2D6 extensive metabolizers (EMs) and nine subjects were CYP2D6 poor metabolizers. Nineteen subjects were enrolled in the granisetron cohort.

RESULTS

The largest changes in hydrodolasetron exposure after coadministration with casopitant were seen in CYP2D6 EMs, with a 24% increase in hydrodolasetron AUC on day 1 and 30% increase in Cmax on days 1 and 3. All other changes in hydrodolasetron exposure were <20%, and granisetron exposure was not altered to any relevant extent (<11%).

CONCLUSION

None of the changes observed are considered clinically meaningful, and coadministration of casopitant with dolasetron or granisetron was well tolerated.

Fosaprepitant dimeglumine (MK-0517 or L-785,298), an intravenous neurokinin-1 antagonist for the prevention of chemotherapy induced nausea and vomiting

BACKGROUND

This paper reviews the existing literature on fosaprepitant, an intravenous neurokinin-1 anatgonist for the prevention of chemotherapy induced nausea and vomiting.

OBJECTIVES

To describe the development of fosaprepitant and to situate the intravenous form of aprepitant in the current market of available antiemetics.

METHODS

Literature was screened and selected in order to compare the intravenous form of the already commonly used NK-1 receptor antagonist aprepitant.

RESULTS

Aprepitant is the first and still the only marketed neurokinin-1 (NK-1) antagonist. Interestingly, the first studies were performed with fosaprepitant dimeglumine (MK-0517 or L-785,298), the water-soluble prodrug of aprepitant. Fosaprepitant is converted into aprepitant within 30 min after intravenous administration. Based on equivalence studies, 115 mg fosaprepitant seems to be the substitute for 125 mg orally administrated aprepitant. Tolerability of the prodrug is no different from the active drug. The number of efficacy studies with fosaprepitant is very limited and most data are derived from existing aprepitant results. Fosaprepitant has recently been approved by FDA and EMEA as an intravenous substitute for oral aprepitant on day 1 of the standard 3-day CINV prevention regimen, which also includes dexamethasone and a 5-HT3 antagonist.

Caring for children and adolescents with osteosarcoma: a nursing perspective

The nurse plays a vital role in caring for patients with osteosarcoma. From the very outset when the disease is explained to the patient and his/her family, the nurse provides comfort and support, as well as enhances and explains the information provided by the physician. All aspects of medical care are addressed, and he/she is frequently the first line of communication when the patient telephones and requests information or wishes to report a problem to the physician. He/She arranges and coordinates appointments to suit the patient's medical, and often social needs to provide comprehensive care with attention to detail. This communication will provide a perspective of the role assumed by the nurse in his/her effort to ensure total care of the patient and the family.

Effectiveness of a single-day three-drug regimen of dexamethasone, palonosetron, and aprepitant for the prevention of acute and delayed nausea and vomiting caused by moderately emetogenic chemotherapy

PURPOSE

Chemotherapy-induced nausea and vomiting includes both Acute (0-24 h) and Delayed (24-120 h) components with different physiologic mechanisms. A combination of a serotonin antagonist, a corticosteroid, and an NK-1 antagonist has proven effective against this problem. However, standard antiemetic regimens require administration over 3-4 days after chemotherapy. The present study evaluated a more convenient single-day three-drug antiemetic regimen for patients receiving moderately emetogenic chemotherapy.

MATERIALS AND METHODS

Chemotherapy-naïve patients with solid tumors receiving cyclophosphamide and/or doxorubicin were eligible. Patients could not have pre-existing etiologies for vomiting. Prior to chemotherapy, patients received a single dose of aprepitant 285 mg p.o., dexamethasone 20 mg p.o., and palonosetron 0.25 mg i.v. A daily patient diary recording episodes of emesis and severity of nausea was then kept for 5 days. Any further antiemetics were considered rescue medication.

RESULTS

Forty-one eligible and evaluable patients (40 women, one man) with breast cancer were entered on study. Most were receiving adjuvant chemotherapy. Complete Response (no vomiting, no rescue medication) was seen in 51% of patients, including 76% with Complete Response for the Acute period and 66% for the Delayed period. No emesis was reported for 100% of patients in the Acute period and 95% in the Delayed period. No Nausea was seen in 32% of patients. No untoward toxicities were seen.

CONCLUSION

A single-day three-drug antiemetic regimen is feasible and effective for protection against both Acute and Delayed vomiting after moderately emetogenic chemotherapy. Formal comparison to a standard multi-day antiemetic regimen is warranted.

Effect of aprepitant on intravenous tacrolimus disposition in reduced intensity hematopoietic stem cell transplantation

Aprepitant (AP) is a known inhibitor of cytochrome P450 3A4 which may affect tacrolimus metabolism. We retrospectively examined the effect of oral AP on intravenous tacrolimus concentrations in 26 patients undergoing reduced intensity transplantation from 09/2005 to 09/2006. Oral AP 125 mg daily was administered on transplant day +1 and 80 mg on days +2 and +3. Intravenous tacrolimus was administered as a 0.03 mg/kg/day continuous infusion on day -6 through day +1 (pre-AP), during-AP (days +2 to +7), and post-AP starting on day +8. Tacrolimus doses were adjusted to achieve concentrations of 5—20 ng/mL. Dose-corrected tacrolimus concentrations (ng/mL/mg per dose) in the pre-AP, during-AP, and post-AP time periods were: 8.12 (95% CI: 7.3—9.1), 11.63 (95% CI: 9.63—13.63), and 11.42 (95% CI: 8.12—14.7), respectively (P<0.01 between pre-AP and during-AP, P<0.01 between during-AP and post-AP, P = 0.01 between pre-AP and post-AP time periods). Although statistically significant, the observed rise was not clinically significant between during-AP and post-AP time periods. Previous work has shown that AP is not expected to exert an inhibitory effect within 48 h of AP discontinuation. Collectively, these data suggest that AP effect on tacrolimus metabolism is of minor clinical significance. A controlled trial is needed to confirm these findings. J Oncol Pharm Practice (2008) 14: 113—121.

Antiemetic care for patients with breast cancer: focus on drug interactions and safety concerns

PURPOSE

The drug interactions and adverse events that should be considered when individualizing antiemetic therapy for patients undergoing treatment for breast cancer are reviewed.

SUMMARY

A variety of antiemetic agents are available, including antihistamines, dopamine-receptor antagonists, serotonin-receptor antagonists, and neurokinin-receptor antagonists. To ensure optimal symptom control for each patient without unnecessarily prolonging treatment, patient- and treatment-specific risk factors must be considered. Neurokinin-receptor antagonists, the newest class of antiemetics, are effective in preventing acute and delayed chemotherapy-induced nausea and vomiting but must be used in combination with a serotonin-receptor antagonist and a corticosteroid. The serotonin-receptor antagonists have become the mainstay of antiemetic therapy, but current guidelines do not distinguish among the different agents in this class. However, there are distinct pharmacologic differences that may affect the potential for drug interactions and, ultimately, patient outcomes and the occurrence of adverse events. Therefore, the potential for drug interactions must be considered when selecting an antiemetic, particularly for patients who are taking multiple concomitant medications. Further, because a number of breast cancer therapies and some antiemetic agents carry cardiovascular warnings or precautions and since breast cancer patients may already be suffering from cardiovascular complications, the possible cardiotoxic effects of the antiemetic or chemotherapy agents or the combinations of these agents should be considered.

CONCLUSION

Antiemetic treatment is essential for patients with breast cancer who are undergoing moderately to highly emetogenic cytotoxic treatment. When selecting an antiemetic, clinicians must select an agent that provides optimal protection against nausea and vomiting while avoiding drug-drug interactions and additional adverse events.

Nanomedicines in the treatment of emesis during chemotherapy: focus on aprepitant

Aprepitant, a selective high-affinity antagonist of human substance P/neurokinin 1 (NK₁) receptors, is the active ingredient of EMEND^® which has recently been approved by the FDA for the prevention of chemotherapy-induced nausea and vomiting (CINV). Aprepitant undergoes extensive metabolism, primarily via CYP3A4 mediated oxidation. It is eliminated primarily by metabolism and is not renally excreted. The apparent terminal half-life in humans ranged from 9 to 13 hours. Early development studies led to the development of a nanoparticle formulation to enhance exposure and minimize food effects. Two large randomized trials accruing 1099 patients studied the effect in patients receiving cisplatin of adding aprepitant to ondansetron and dexamethasone on day 1 then to dexamethasone on days 2 and 3 to control delayed emesis. The complete response of no vomiting and no rescue medication overall from days 1 to 5 improved from 48% to 68% (p < 0.001), a 13% improvement in acute emesis but a 21% improvement in delayed emesis with the improvement from 51% to 72% (p < 0.001). Similarly, 866 patients treated with cyclophosphamide plus either doxorubicin or epirubicin, received either ondansetron, dexamethasone, and aprepitant on day 1 followed by aprepitant on days 2 and 3 or ondansetron and dexamethasone on day 1 and dexamethasone on days 2 and 3. The overall complete response rate over 5 days was better for the aprepitant group 50.8% vs 42.5% (p=0.015). Complete responses were reported in more patients taking aprepitant in both the acute (76% vs 69%, p=0.034) and delayed (55% vs 49%, p=0.064) phases of vomiting. There were no clinically relevant differences in toxicity by adding aprepitant and improvements in the quality of life of patients on chemotherapy were recorded.