Drug Interactions between Qualaquin and revumenib

ADJUST DOSING INTERVAL: In pharmacokinetic studies, revumenib was administered while fasting or with a low fat meal. Revumenib has not been studied with meals of higher fat content and the impact on its pharmacokinetic parameters is unknown.

MONITOR: Grapefruit, grapefruit juice, grapefruit hybrids, pomelos, star-fruit, and Seville oranges may increase the plasma concentrations of revumenib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. The extent and clinical significance are unknown. In pharmacokinetic studies in patients with relapsed or refractory acute leukemia, revumenib area under the concentration-time curve (AUC) and peak plasma concentration (Cmax) increased 2-fold following concomitant use with the potent CYP450 3A4 inhibitors posaconazole, itraconazole, and voriconazole, and 2.5-fold following concomitant use with the potent CYP450 3A4 inhibitor cobicistat. However, clinically significant differences in revumenib pharmacokinetics were not observed when used concomitantly with the moderate CYP450 3A4 inhibitors fluconazole and isavuconazole. In general the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. Moreover, pharmacokinetic alterations associated with interactions involving grapefruit juice are often subject to a high degree of interpatient variability. Increased exposure to revumenib may increase the risk of QT interval prolongation, which has been associated with ventricular arrhythmias including torsade de pointes and sudden death.

MANAGEMENT: Due to the potential impact of high fat content meals on revumenib absorption and exposure, it is recommended that revumenib be administered while fasting or with a low fat meal (approximately 400-500 calories, with 25% of calories from fat). In addition, if grapefruit, grapefruit juice, grapefruit hybrids, pomelos, star-fruit, or Seville oranges are consumed during treatment with revumenib, assess patient tolerability and monitor for serious adverse effects (e.g., QT prolongation and torsade de pointes arrhythmia, differentiation syndrome, neutropenia, thrombocytopenia).

Coadministration with grapefruit juice does not appear to affect the pharmacokinetics of quinine in a clinically relevant manner. Although grapefruit juice is an inhibitor of CYP450 3A4 and quinine is metabolized by this pathway to its major metabolite, 3-hydroxyquinine, a study of ten healthy volunteers found no significant differences in quinine peak plasma concentration (Cmax), time to reach Cmax (Tmax), terminal elimination half-life, systemic exposure (AUC), or apparent oral clearance (Cl/F) when a single 600 mg oral dose of quinine sulfate was administered in combination with 200 mL of orange juice (control), half-strength grapefruit juice, and full-strength grapefruit juice twice daily for 6 days each, separated by a 2-week washout period. Relative to the control period, the apparent renal clearance of quinine was markedly increased by 81% during treatment with half-strength grapefruit juice. However, since renal clearance accounts for approximately 6% of the total clearance of quinine, this change would likely have minimal clinical impact. The lack of a significant interaction is probably due to the fact that grapefruit juice primarily inhibits intestinal rather than hepatic CYP450 3A4, and quinine is not known to undergo significant presystemic metabolism as evidenced by its relatively high oral bioavailability (76% to 88%). Nevertheless, excessive consumption of grapefruit juice and tonic water (which contains quinine) was suspected as the cause of torsade de pointes arrhythmia in a patient with a history of asymptomatic long QT syndrome. Treatment with magnesium sulfate and metoprolol had no effect, but the arrhythmia resolved spontaneously 48 hours after discontinuation of the drinks. Based on current data, moderate grapefruit juice consumption is probably safe for the majority of patients taking quinine.