Drug Interactions between nirogacestat and ropivacaine / sufentanil

GENERALLY AVOID: Coadministration with nirogacestat may increase the plasma concentrations and therapeutic effects of drugs that are substrates of CYP450 3A4. The interaction may be significant for sensitive CYP450 3A4 substrates or those that demonstrate a narrow therapeutic index. The proposed mechanism is decreased clearance due to nirogacestat-mediated inhibition of CYP450 3A4. Concomitant use of the sensitive CYP450 3A4 substrate midazolam with multiple doses of nirogacestat (150 mg twice daily) is predicted to increase the systemic exposure (AUC) and peak plasma concentration (Cmax) of midazolam by 2.07-fold and 1.77-fold, respectively.

MANAGEMENT: According to the manufacturer, concomitant use of nirogacestat with sensitive CYP450 3A4 substrates or those that demonstrate a narrow therapeutic index (e.g., ergot alkaloids, colchicine, fentanyl, macrolide immunosuppressants, midazolam, triazolam, vinca alkaloids) is not recommended.

Coadministration with inhibitors of CYP450 3A4 may modestly increase the plasma concentrations of ropivacaine. Although ropivacaine is primarily metabolized by CYP450 1A2, it has been shown to undergo some metabolism via CYP450 3A4. In eight healthy volunteers, pretreatment with the 3A4 inhibitor erythromycin (500 mg three times a day for 6 days) was found to have only minor effects on the pharmacokinetics of a single dose of ropivacaine (0.6 mg/kg IV over 30 minutes) compared to placebo. However, in combination with the potent 1A2 inhibitor fluvoxamine (100 mg daily), erythromycin further increased the area under the plasma concentration-time curve (AUC) of ropivacaine by 50% compared to fluvoxamine alone, which increased the ropivacaine AUC by 3.7-fold. Fluvoxamine alone prolonged the elimination half-life of ropivacaine from 2.3 to 7.4 hours, while the addition of erythromycin further increased the half-life to 11.9 hours. In another study, pretreatment with the potent 3A4 inhibitor ketoconazole (100 mg twice daily for 2 days) decreased the mean total plasma clearance of ropivacaine (40 mg IV over 20 minutes) by just 15% in 12 healthy volunteers. Thus, it appears that CYP450 3A4 inhibitors may only have a significant effect on the pharmacokinetics of ropivacaine in the presence of a CYP450 1A2 inhibitor such as fluvoxamine, ciprofloxacin, or mexiletine.