Evaluation of the effect of aprepitant on CYP3A4 activity using midazolam as a probe

Investigating Potential Drug-Drug Interactions in Pediatric and Adolescent Patients Receiving Chemotherapy

INTRODUCTION

Pediatric and adolescent oncology patients admitted to receive chemotherapy are at risk for drug-drug interactions (DDI). While adult literature has quoted this risk to be as high as 95% of encounters, the literature in pediatrics is limited. This is a single-center, retrospective chart review of DDI in hospitalized pediatric oncology patients.

METHODS

All patients admitted to Texas Children's Hospital for chemotherapy were included. Medications ordered during the hospitalization were evaluated by Lexicomp® Drug Interactions Tool. Interactions classified as D or X or interactions rated a C including a chemotherapeutic agent were independently reviewed by three clinicians for clinical relevance. Medications associated with central nervous system (CNS) depression or QTc prolongation were counted separately.

RESULTS

Of 100 admissions evaluated, 100% had a flagged interaction. There were a total of 12 X-rated interactions, 8 D-rated interactions, and 12 C-rated interactions with a chemotherapeutic agent found to be clinically relevant. Thirty-three percent of admissions had 4 or more QTc prolonging medications ordered. Twenty-four percent of admissions had 3 or more prescribed CNS depressants. In total 49% of admissions were found to have at least 1 clinically-significant DDI.

CONCLUSIONS

This study exemplifies the risk of drug-drug interactions in children and young adults admitted to the hospital for chemotherapy. We demonstrated a high rate of flagged interactions with about half of admissions found to have a potentially clinically-significant DDI. Concomitant use of multiple QTc prolonging and CNS depressant medications was also prevalent, indicating a need to evaluate monitoring practices.

Comparison between Antiemetic Effects of Palonosetron and Granisetron on Chemotherapy-Induced Nausea and Vomiting in Japanese Patients Treated with R-CHOP

In the present study, the antiemetic effect of palonosetron, not combined with dexamethasone and aprepitant, on chemotherapy-induced nausea and vomiting was evaluated in patients with malignant lymphoma receiving first-line rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) therapy, and was compared to that of granisetron. A total of 74 patients with non-Hodgkin lymphoma were included in this study (April 2007 to December 2015). Palonosetron (0.75 mg) or granisetron (3 mg) was intravenously administered before R-CHOP therapy. The proportions of patients with complete response (CR) during the overall (0-120 h after the start of R-CHOP therapy), acute (0-24 h) and delayed (24-120 h) phases were evaluated. CR was defined as no vomiting and no use of antiemetic rescue medication. A total of 32 and 42 patients were treated with palonosetron and granisetron, respectively. The CR rate in the palonosetron group was significantly higher than that in the granisetron group during the delayed phase (90.6 and 61.9%, respectively; p=0.007). Logistic regression analysis showed that use of palonosetron improved the CR rate during the delayed phase, compared to use of granisetron. Female sex, age less than 60 years, no habitual alcohol intake, and Eastern Cooperative Oncology Group performance status (ECOG-PS) score of 1 were significant risk factors associated with non-CR. The findings of this study suggested the superiority of palonosetron to granisetron, without accompanying dexamethasone and aprepitant, for chemotherapy-induced nausea and vomiting in patients with malignant lymphoma.

Effects of aprepitant on the pharmacokinetics of ondansetron and granisetron in healthy subjects

BACKGROUND

The neurokinin-1-receptor antagonist aprepitant, when given in combination with a corticosteroid and a 5-hydroxytryptamine type 3 (5-HT(3))-receptor antagonist, has been shown to be effective for the prevention of acute and delated chemotherapy-induced nausea and vomiting (CINV).

OBJECTIVE

Two studies were conducted to determine whether concomitant administration of aprepitant altered the pharmacokinetic profiles of ondansetron and granisetron, two 5-HT(3)-receptor antagonists commonly used as antiemetic therapy for CINV.

METHODS

The 2 studies were randomized, open-label, crossover trials conducted in healthy subjects aged between 18 and 46 years. Study 1 involved the following 2 treatment regimens: aprepitant 375 mg PO, dexamethasone 20 mg PO, and ondansetron 32 mg IV on day 1, followed by aprepitant 250 mg PO and dexamethasone 8 mg PO on days 2 through 5; and dexamethasone 20 mg PO and ondansetron 32 mg IV on day 1, followed by dexamethasone 8 mg PO on days 2 through 5. Study 2 involved the following 2 treatment regimens: aprepitant 125 mg PO with granisetron 2 mg PO on day 1, followed by aprepitant 80 mg PO on days 2 and 3; and granisetron 2 mg PO on day 1 only. Individual plasma samples were used to estimate area under the plasma concentration-time curve from time zero to infinity (AUC(0- infinity )), peak plasma concentration, and apparent terminal elimination half-life (t(12)) of both ondansetron and granisetron.

RESULTS

Study 1 included 19 subjects (10 women, 9 men), and study 2 included 18 subjects (11 men, 7 women). Coadministration of aprepitant 375 mg produced a small but statistically significant increase in the AUC(0- infinity ) for intravenous ondansetron (from 1268.3 to 1456.5 ng.h/mL; P = 0.019), with no significant effect on peak concentration at the end of the infusion (360.8 ng/mL with aprepitant vs 408.4 ng/mL without) or t(12) (5.0 vs 4.5 hours, respectively). Coadministration of aprepitant 125 mg/80 mg did not alter the mean pharmacokinetic characteristics of oral granisetron (AUC(0- infinity ), 101.4 ng.h/mL with aprepitant vs 92.2 ng.h/mL without; maximum plasma concentration, 9.0 ng/mL with and without aprepitant; time to maximum plasma concentration, both 3.0 hours; t(12), 6.5 vs 6.9 hours, respectively).

CONCLUSION

Concomitant administration of aprepitant had no clinically significant effect on the mean pharmacokinetic characteristics of either ondansetron or granisetron in these healthy subjects.