Antiemetic neurokinin-1 antagonist aprepitant and ifosfamide-induced encephalopathy

Population pharmacokinetic analysis reveals no impact of aprepitant on the pharmacokinetics of ifosfamide, 2-dechloroifosfamide, and 3-dechloroifosfamide

PURPOSE

Several case reports and retrospective series have clearly pointed to the role of aprepitant, an antiemetic drug, in the development of encephalopathy when used with ifosfamide. Described as an inhibitor of several CYP metabolic pathways, aprepitant is suspected of drug-drug-interaction on ifosfamide pharmacokinetics. The pharmacokinetics of ifosfamide and two of its metabolites (2-dechloroifosfamide and 3-dechloroifosfamide) was studied in patients with soft tissue sarcomas to evaluate the impact of aprepitant administration.

METHODS

A population pharmacokinetic approach was applied to analyze data obtained in 42 patients at cycle 1 (without aprepitant) and cycle 2 (with aprepitant for 34 of them).

RESULTS

A previously published pharmacokinetic model including a time-dependency process well fit the data. Aprepitant had no impact on ifosfamide or its two metabolite pharmacokinetic parameters.

CONCLUSION

This study suggests that aprepitant does not lead to a significant modification of ifosfamide metabolization, even though other metabolites such as 4 hydroxyifosfamide and chloroacetaldehyde were not monitored in this study.

Ifosfamide - History, efficacy, toxicity and encephalopathy

In this review we trace the passage of fundamental ideas through 20^th century cancer research that began with observations on mustard gas toxicity in World War I. The transmutation of these ideas across scientific and national boundaries, was channeled from chemical carcinogenesis labs in London via Yale and Chicago, then ultimately to the pharmaceutical industry in Bielefeld, Germany. These first efforts to checkmate cancer with chemicals led eventually to the creation of one of the most successful groups of cancer chemotherapeutic drugs, the oxazaphosphorines, first cyclophosphamide (CP) in 1958 and soon thereafter its isomer ifosfamide (IFO). The giant contributions of Professor Sir Alexander Haddow, Dr. Alfred Z. Gilman & Dr. Louis S. Goodman, Dr. George Gomori and Dr. Norbert Brock step by step led to this breakthrough in cancer chemotherapy. A developing understanding of the metabolic disposition of ifosfamide directed efforts to ameliorate its side-effects, in particular, ifosfamide-induced encephalopathy (IIE). This has resulted in several candidates for the encephalopathic metabolite, including 2-chloroacetaldehyde, 2-chloroacetic acid, acrolein, 3-hydroxypropionic acid and S-carboxymethyl-L-cysteine. The pros and cons for each of these, together with other IFO metabolites, are discussed in detail. It is concluded that IFO produces encephalopathy in susceptible patients, but CP does not, by a "perfect storm," involving all of these five metabolites. Methylene blue (MB) administration appears to be generally effective in the prevention and treatment of IIE, in all probability by the inhibition of monoamine oxidase in brain potentiating serotonin levels that modulate the effects of IFO on GABAergic and glutamatergic systems. This review represents the authors' analysis of a large body of published research.

Incidence of ifosfamide induced encephalopathy in patients receiving concomitant fosaprepitant

INTRODUCTION

The incidence of Ifosfamide-induced encephalopathy (IIE) ranges from 5-30%. Aprepitant and fosaprepitant may increase the risk of IIE; however, data is limited. The objective of this study was to characterize the incidence of IIE in patients receiving concomitant fosaprepitant.

METHODS

This single-center, retrospective chart review included adult patients diagnosed with sarcoma who received at least one administration of high dose ifosfamide (≥1800mg/m²) and fosaprepitant between January 2017 and June 2018. The primary endpoint was the percentage of patient cycles in which IIE was experienced. Secondary endpoints included characterization of IIE management strategies, time to IIE resolution, and the incidence of IIE upon ifosfamide re-challenge. Subgroup analyses were performed to assess whether the following variables predisposed a patient to neurotoxicity: elevated serum creatinine, hypoalbuminemia, metabolic acidosis, hyperbilirubinemia, shorter infusion time, and higher body mass index. The role of CYP2B6 inhibitors and prior cisplatin use were also examined.

RESULTS

Fifty-one patients who received 215 total cycles of ifosfamide were included. Twenty (9.3%) patient cycles included documented evidence of IIE. The most common management strategies were to prolong the infusion time and administer methylene blue. The mean time to resolution of IIE was 2.58 days. The incidence of secondary IIE upon re-challenge was 26.3%. Baseline albumin <3.5 g/dL (p<0.001) was statistically associated with the development of IIE.

CONCLUSION

Co-administration of fosaprepitant and ifosfamide in sarcoma appears to be safe. Hypoalbuminemia was a notable risk factor confirmed in this study. Further research is needed to delineate IIE risk factors.

Pharmacotherapy in Children and Adolescents: Oncology

Pharmacotherapy in paediatric oncology is a difficult task. It is challenging to determine the optimal dose in children of different age groups. In addition, anticancer drugs display severe side effects reducing the quality of life. Late effects like secondary tumours and cardiotoxicity can be apparent years after treatment and must be taken into account when planning treatment schedules. Classical cytoreducing agents are still of great importance in treating children with leukaemia and solid tumours. In addition, drugs developed by rational drug design (targeted drugs) are a very important part of many treatment protocols, and newer drugs are emerging in several types of cancer. Unfortunately, there is only limited experience with newer drugs in children, because new drugs are mostly developed for adults. Complicated therapy regimens require a solid knowledge of the pharmacology of the drugs applied. This chapter attempts to introduce some pharmacological knowledge for the most important anticancer drugs in children with a focus on side effects and age-specific considerations.

Efficacy, Tolerability and Pharmacokinetic Impact of Aprepitant in Sarcoma Patients Receiving Ifosfamide and Doxorubicin Chemotherapy: A Randomized Controlled Trial

INTRODUCTION

Aprepitant, a selective neurokinin-1 receptor antagonist approved for prevention of chemotherapy-induced nausea and vomiting (CINV), is an inhibitor of the cytochrome P450 3A4 (CYP3A4) enzyme, which is involved in the clearance of several chemotherapeutic agents. Here we evaluated the efficacy and toxicity of a combination of aprepitant, palonosetron, and dexamethasone as antiemetic prophylaxis in sarcoma patients receiving ifosfamide and doxorubicin chemotherapy, and examined the potential of aprepitant to affect the pharmacokinetics of ifosfamide, which is primarily metabolized by CYP3A4.

METHODS

A total of 108 sarcoma patients were randomly assigned to either the aprepitant group (antiemetic regimen: aprepitant, palonosetron, and dexamethasone) or the control group (antiemetic regimen: palonosetron and dexamethasone). Data on nausea, vomiting, and use of rescue medication were collected, and the primary efficacy end point was the proportion of patients with complete response (CR), defined as no vomiting and no use of rescue therapy during 120 h after initiation of chemotherapy. Tolerability was evaluated on the basis of reported adverse events and laboratory assessments. Blood samples for ifosfamide pharmacokinetic analysis were collected in ten patients.

RESULTS

The percentage of patients achieving CR was significantly higher in the aprepitant group compared with that in the control group in the acute, delay, and overall phase (78.4% vs. 59.3%, 74.5% vs. 48.1%, and 68.6% vs. 37.0%, p < 0.05, respectively). No significant differences of adverse events or hematological toxicity were detected between the two groups. Concomitant administration of aprepitant did not cause any statistically significant changes in ifosfamide pharmacokinetics. Values for aprepitant group vs. control group were as follows: geometric mean of C_max was 119 vs. 120 ng/mL, AUC_0-last was 648 vs. 635 ng h/mL, AUC_0-inf was 681 vs. 668 ng h/mL, plasma clearance was 4.40 vs. 4.49 (L/h/m²), respectively; harmonic means of t_1/2 was 2.11 vs. 2.25 h.

CONCLUSIONS

This study showed that aprepitant in combination with palonosetron and dexamethasone was safe and effectively controlled CINV in sarcoma patients receiving ifosfamide and doxorubicin chemotherapy. Aprepitant may have a low potential to affect the pharmacokinetics of chemotherapeutic agents metabolized by CYP3A4.

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.

Ifosfamide-induced Encephalopathy Precipitated by Aprepitant: A Rarely Manifested Side Effect of Drug Interaction

Central nervous system (CNS) toxicity has been reported in approximately 10%-30% of patients receiving intravenous infusions of ifosfamide. Encephalopathy is a rare but serious CNS adverse reaction in these patients, and although usually transient and reversible, may cause persistent neurological dysfunction or death. Clinical features range from fatigue and confusion to coma and death. Ifosfamide forms backbone of various treatment regimens including curative treatment and palliative chemotherapy regimen. Precipitation of ifosfamide-induced encephalopathy (IIE) by aprepitant has been reported in the literature rarely. Ifosfamide is moderately emetogenic; hence, aprepitant is used to prevent emesis induced by ifosfamide. We here report a case where a patient of recurrent B-cell Philadelphia-negative acute lymphoblastic lymphoma was given aprepitant to prevent ifosfamide-induced emesis. After 24 h of ifosfamide infusion, the patient developed symptoms of encephalopathy, i.e., headache, vomiting, and one episode of seizure which was followed by disoriented behavior. After doing all routine investigations and neuroimaging, the diagnosis of IIE was kept on clinical grounds, and after looking for the various factors, we came across injection fosaprepitant as the precipitating factor. On the clinical grounds, the patient was treated with hydration and injection methylene blue for above complaints, and the patient recovered without any residual deficit within 48-72 h. Hence, in the presence of causative agent, i.e., ifosfamide and precipitating agent injection fosaprepitant with negative imaging and normal laboratory parameters as well as the early and good response to methylene blue, the diagnosis of IIE precipitated by aprepitant was confirmed.

Drug interactions with aprepitant or fosaprepitant: Review of literature and implications for clinical practice

Purpose Aprepitant and its parenteral formulation fosaprepitant are widely used for the prevention of chemotherapy-induced nausea and vomiting. Aprepitant exerts modest inhibitory effect on CYP3A4 and modest inductive effect on CYP2C9 substrates such as some antineoplastics and multiple other medications. This article is aimed to provide pharmacists and other healthcare professionals with an updated summary of drug-drug interactions of aprepitant/fosaprepitant and implications for clinical practice. Method We reviewed publications reporting drug-drug interactions between aprepitant/fosaprepitant and other medications. Results Coadministration of aprepitant with antineoplastics or opiods may result in significant elevations in the serum levels of the agents metabolized via CYP3A4, with the best documentation for cyclophosphamide, ifosfamide, erlotinib and oxycodone. These alterations did not translate into adverse outcomes and/or necessitate dosing adjustments. The levels of warfarin were significantly decreased by aprepitant requiring prolonged monitoring after discontinuation of aprepitant. Among direct oral anticoagulants, a theoretical interaction between aprepitant and rivaroxaban or apixaban exists. Interactions between aprepitant and quetiapine or diltiazem or sirolimus required dose reductions to avoid adverse outcomes. The intravenous route had a weaker inhibitory effect on CYP3A4 than the oral pathway. Conclusion The evidence on drug interactions of aprepitant with other medications is limited, and the impact on therapeutic outcomes remains to be determined. The intravenous regimen may be a preferred option. As utilization of aprepitant is expanding, practitioners and patients need to be educated about the potential for drug interactions and a need for careful monitoring of patients concurrently receiving aprepitant and CYP2C9 or CYP3A4 substrates, especially those with a narrow therapeutic window.

Two cases of fatal encephalopathy related to Ifosfamide: an adverse role of aprepitant?

Ifosfamide is used in the treatment of sarcomas and other tumors. It sometimes provokes encephalopathy, which is a serious complication even if it is usually reversible within 48-72 h after drug cessation. Ifosfamide is required to be activated by hepatic cytochrome P450 (CYP), especially the 3A4 subtype, leading to 4-hydroxy-ifosfamide. Ifosfamide is also converted by CYP3A4 to inactive but neurotoxic metabolites. Aprepitant is a neurokinin-1 receptor antagonist that is a potent antiemetic used in combination with 5-HT3 antagonists and corticosteroids. Aprepitant has an inhibitory effect, as well as a possible inductive effect, on CYP3A4. Since ifosfamide and aprepitant are both substrates of CYP3A4, a pharmacokinetic interaction could result in secondary effects such as the potentialization of neurological side effects. In this report, we describe 2 cases of fatal encephalopathy in patients who have received both ifosfamide and aprepitant, and we discuss the mechanisms that could be involved. Our observations draw attention to the fact that aprepitant must be avoided, or at least used with caution, in patients who are receiving ifosfamide due to the risk of severe neurological side effects.

Safety of neurokinin-1 receptor antagonists

INTRODUCTION

The substance P (SP)/neurokinin (NK)-1 receptor system is involved in many pathological processes. NK-1 receptor antagonists have many promising therapeutic indications. However, the only NK-1 receptor antagonist used in clinical practice is the drug aprepitant and its intravenously administered prodrug, fosaprepitant. In general, NK-1 receptor antagonists are safe and well tolerated.

AREAS COVERED

A search was carried out in Medline using the following terms: adverse events, aprepitant, casopitant, clinical trials, CP-122,721, ezlopitant, fosaprepitant, NK-1 receptor antagonists, randomized, safety, side effects, tolerability and vofopitant.

EXPERT OPINION

Most clinical trials have focused on the antiemetic action of aprepitant in cancer patients treated with chemotherapy. However, the efficacy and safety of aprepitant have not been fully tested in other diseases in which the SP/NK-1 receptor system is involved (e.g., cancer, HIV, alcoholism); thus, clinical trials are required. The use of NK-1 receptor antagonists in oncology therapy is quite promising, but to date pharmacological therapy has not exploited the many possible therapies offered by such antagonists.

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.

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.

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.

Characterization of the occurrence of ifosfamide-induced neurotoxicity with concomitant aprepitant

Purpose. Ifosfamide is metabolized by the cytochrome P450 system to its active form, ifosforamide mustard. A potential side effect is neurotoxicity, often manifesting as confusion, hallucination, or seizure. Aprepitant, a neurokinin-1 inhibitor, is recommended for highly and moderately emetogenic chemotherapy regimens and may interfere with the metabolism of ifosfamide as it inhibits CYP3A4. The objective of the study is to identify if an increase in the incidence of neurotoxicity may be associated with the use of aprepitant with concomitant ifosfamide.

Methods. A retrospective study of inpatients with sarcoma who received a two or four-day regimen of MAI (mesna, doxorubicin, and ifosfamide) between January 1, 2004 and December 31, 2006 was conducted. Data collection focused on characterizing neurotoxicity of patients receiving ifosfamide with or without aprepitant. Correlation between serum creatinine, albumin, liver function tests, age, gender, and total doses of ifosfamide was examined.

Results. A total of 45 patients received ifosfamide of which 23 (51%) were male and 24 (53%) received aprepitant. All baseline characteristics were similar for those who received aprepitant versus those who did not. No significant differences were noted between patients with or without neurotoxicity for age, gender, or liver enzymes. Eight patients (18%) of 45 developed neurotoxicity of which six (75%) of those patients also received aprepitant. A trend of increased occurrence of neurotoxicity was noted with aprepitant administration (6 vs. 2 patients respectively, p = 0.176), although a statistical difference was not observed. A relative risk of 2.6 (95% CI, 0.47—26.6) was associated with the addition of aprepitant.

Conclusions. An increased risk was identified for ifosfamide-induced neurotoxicity associated with aprepitant use; however, the observed difference was not statistically significant. The necessity of aprepitant given in association with ifosfamide may need to be reconsidered due to this risk. J Oncol Pharm Practice (2008) 14: 157—162.

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.

Case reports and the fight against cancer

Some of the earliest case reports describing individual patients afflicted with cancer can be traced all the way back to the papyrus records of Ancient Egyptian medicine of approximately 1600 B.C.. Throughout the centuries physicians have continued the practice of writing case reports. Case reporting has provided significant advances in the knowledge of cancer on several fronts. It is without question that case reports do not replace well designed randomized clinical trials in advancing medical knowledge about cancerous diseases. However, case reports have their unique role in evidence-based medicine and often constitute the first line of evidence. This editorial reviews the many useful aspects of case reports and describes specific reports known to have revolutionized cancer management. Journal of Medical Case Reports is committed to publish well written case reports from around the world and be a source of inspiration for clinicians and scientists about newer research directions.