Interactions : אינטראקציות

4.5 Interaction with other medicinal products and other forms of interaction

When netupitant/palonosetron capsules are used concomitantly with another CYP3A4 inhibitor, netupitant plasma concentrations could be elevated. When this medicinal product is used concomitantly with medicinal products that induce CYP3A4 activity, netupitant plasma concentrations could be reduced and this may result in decreased efficacy. This medicinal product can increase plasma concentrations of concomitantly administered medicinal products that are metabolised via CYP3A4.
In humans, netupitant is eliminated mainly by hepatic metabolism mediated by CYP3A4 with a marginal renal excretion. At a dose of 300 mg in humans, netupitant is a substrate and moderate inhibitor of CYP3A4. Palonosetron is eliminated from the body through both renal excretion and metabolic pathways, with the latter mediated via multiple CYP enzymes. Palonosetron is mainly metabolised by CYP2D6, with minor contribution by CYP3A4 and CYP1A2 isoenzymes. Based on in vitro studies, palonosetron does not inhibit or induce cytochrome P450 isoenzyme at clinically relevant concentrations.

Interaction between oral netupitant and oral palonosetron:

No clinically relevant pharmacokinetic interactions have been observed between oral netupitant and oral palonosetron.

Interaction with CYP3A4 substrates:

Dexamethasone
Co-administration of a single dose of 300 mg netupitant with a dexamethasone regimen (20 mg on Day 1, followed by 8 mg twice daily from Day 2 to Day 4) significantly increased the exposure to dexamethasone in a time and dose dependent manner. The AUC0-24 (Day 1), the AUC24-36 (Day 2) and the AUC84-108 and AUC84-∞ (Day 4) of dexamethasone increased 2.4-fold, with co-administration of 300 mg netupitant. The pharmacokinetic profile of netupitant was unchanged when administered in combination with dexamethasone.
As such, the oral dexamethasone dose should be reduced by approximately 50% when co-administered with netupitant/palonosetron capsules (see section 4.2).

Chemotherapeutic medicinal products (docetaxel, etoposide, cyclophosphamide) Exposure to docetaxel and etoposide was increased 37% and 21%, respectively, when co-administered with netupitant/palonosetron capsules. No consistent effect was seen with cyclophosphamide after netupitant co-administration.

Oral contraceptives
Netupitant/palonosetron capsules, when given with a single oral dose of 60 μg ethinylestradiol and 300 μg levonorgestrel had no significant effect on the AUC of ethinylestradiol and increased the AUC of levonorgestrel by 1.4-fold; clinical effects on the efficacy of hormonal contraception are unlikely.
No relevant changes of netupitant and palonosetron pharmacokinetics were observed.

Erythromycin and Midazolam
Exposure to erythromycin and midazolam was increased approximately 1.3 and 2.4 fold, respectively, when each was co-administered with netupitant. These effects were not considered clinically important. The pharmacokinetic profile of netupitant was unaffected by the concomitant administration of either midazolam or erythromycin. The potential effects of increased plasma concentrations of midazolam or other benzodiazepines metabolized via CYP3A4 (alprazolam, triazolam) should be considered when coadministering these active substances with netupitant/palonosetron capsules.



Serotonergic medicinal products (e.g. SSRIs and SNRIs)

There have been reports of serotonin syndrome following concomitant use of 5-HT3 antagonists and other serotonergic medicinal products (including SSRIs such as fluoxetine, paroxetine, sertraline, fluvoxamine, citalopram or escitalopram and SNRIs such as venlafaxine or duloxetine) (see section 4.4).

Effect of other medicinal products on the pharmacokinetics of Akynzeo 
Netupitant is mainly metabolized by CYP3A4; therefore, co-administration with medicinal products that inhibit or induce CYP3A4 activity may influence plasma concentrations of netupitant.

Consequently, concomitant administration with strong CYP3A4 inhibitors (e.g., ketoconazole) should be approached with caution and concomitant administration with strong CYP3A4 inducers (e.g., rifampicin) should be avoided. Moreover, this medicinal product should be used with caution in patients receiving concomitant orally administered active substances with a narrow therapeutic range that are primarily metabolized by CYP3A4, such as cyclosporine, tacrolimus, sirolimus, everolimus, alfentanil, diergotamine, ergotamine, fentanyl, and quinidine.

Effect of ketoconazole and rifampicin

Administration of the CYP3A4 inhibitor ketoconazole with netupitant/palonosetron capsules increased the AUC of netupitant 1.8 fold and Cmax 1.3 fold when compared to the administration of netupitant/palonosetron capsules alone. Co-administration with ketoconazole did not affect the pharmacokinetics of palonosetron.
Administration of the CYP3A4 inducer rifampicin with Akynzeo alone decreased the AUC of netupitant 5.2 fold and Cmax 2.6 fold. Co-administration of rifampicin did not affect the pharmacokinetics of palonosetron. Consequently, concomitant administration with strong CYP3A4 inhibitors (e.g., ketoconazole) should be approached with caution and concomitant administration with strong CYP3A4 inducers (e.g. rifampicin) should be avoided.

Additional interactions

Netupitant/palonosetron capsules are unlikely to interact with medicinal products which are P-gp substrates. Netupitant is not a substrate for P-gp. When netupitant was administered on Day 8 of a 12-day regimen of digoxin, no changes in digoxin pharmacokinetics were observed.
Inhibition of the efflux transported BCRP and glucuronidation isozyme UGT2B7 by netupitant and its metabolites is unlikely and, if it occurs, of scarce clinical relevance.
In vitro data shows that netupitant inhibits UGT2B7, the magnitude of such an effect in the clinical setting is not established. Caution is recommended when netupitant is combined with an oral substrate of this enzyme (e.g.zidovudine, valproic acid, morphine).
In vitro data suggests that netupitant inhibits the efflux of transporter BCRP. The clinical relevance of this effect is not established.
In vitro data show that netupitant is a P-gp inhibitor. In a study performed in healthy volunteers, netupitant does not affect the exposure of digoxin, a P-gp substrate, whereas it increases its Cmax by 1.09 fold [90%CI 0.9-1.31]. It is not excluded that this effect may be more marked, and then clinically relevant, in cancer patients, notably those having abnormal renal function. Therefore, caution is recommended when netupitant is combined with digoxin or with other P-gp substrates such as dabigatran, or colchicine.