Drug Interactions between aliskiren / valsartan and encorafenib

CONTRAINDICATED: In patients with type 2 diabetes and renal impairment, coadministration of aliskiren with ACE inhibitors or angiotensin receptor blockers (ARBs) has been associated with an increased risk of adverse events including renal complications, hyperkalemia, and hypotension. Interim review of data from the ALTITUDE study after 18 to 24 months revealed no additional benefit and a higher incidence of adverse events when aliskiren 300 mg daily, as opposed to placebo, was added to optimal cardiovascular treatment including an ACE inhibitor or ARB. Another preliminary finding was a slight excess of death or stroke in the aliskiren group; however, the relationship to aliskiren treatment has not been established. ALTITUDE was a multinational study in 8,606 patients from 36 countries evaluating the potential benefits of aliskiren to reduce the risk of cardiovascular and renal events in patients with type 2 diabetes and renal impairment, who are known to be at high risk of cardiovascular and renal events. The trial was halted in December 2011 per recommendation of the independent data monitoring committee overseeing the study.

GENERALLY AVOID: In patients without diabetes, coadministration of aliskiren with ACE inhibitors or ARBs may also be associated with increased risk of symptomatic hypotension, hyperkalemia, and changes in renal function including acute renal failure. All drugs inhibiting the renin-angiotensin system (RAS) can have these effects, which may be additive during concomitant administration. The risk of symptomatic hypotension is increased in the presence of marked volume and/or salt depletion. Elevations in serum potassium levels to greater than 5.5 mEq/L were infrequent with aliskiren alone (0.9% compared to 0.6% with placebo), but increased to 5.5% when used in combination with an ACE inhibitor in a diabetic population. Patients whose renal function may depend in part on the activity of the RAS, including those with renal artery stenosis, severe heart failure, postmyocardial infarction or volume depletion, may be at particular risk for developing acute renal failure with these drugs.

MANAGEMENT: The use of aliskiren with ACE inhibitors or ARBs is considered contraindicated in patients with diabetes and should be avoided in general, particularly in patients with moderate to severe renal impairment (i.e., creatinine clearance (CrCl) < 60 mL/min). Prescribers should not initiate aliskiren in diabetic patients who are taking an ACE inhibitor or an ARB, and should stop any aliskiren-containing treatment if these patients are already receiving the combination. Alternative antihypertensive treatment should be considered as necessary. Most patients do not obtain any additional benefit from combination therapy relative to monotherapy; therefore, the potential risks should be thoroughly assessed when aliskiren is prescribed with ACE inhibitors or ARBs for the treatment of essential hypertension in patients without diabetes. Volume or salt depletion should be corrected prior to initiation of treatment. Routine monitoring of blood pressure, electrolytes, and renal function are recommended, particularly in the elderly or patients with worsening heart failure or a risk for dehydration. Potassium supplementation should generally be avoided unless it is closely monitored, and patients should be advised to seek medical attention if they experience signs and symptoms of hyperkalemia such as weakness, listlessness, confusion, tingling of the extremities, and irregular heartbeat.

MONITOR: Coadministration with encorafenib may increase the plasma concentrations of drugs that are substrates of P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), organic cation transporter (OCT2), organic anion transporter (OAT1, OAT3), organic anion transporting polypeptide (OATP1B1, OATP1B3), or uridine diphosphate glucuronosyltransferase (UGT) 1A1. In in vivo studies, encorafenib has been shown to be an inhibitor of OATP1B1, 1B3, and BCRP. In vitro studies have demonstrated it to be an inhibitor of OCT2, OAT1, OAT3, and P-gp at expected clinical concentrations as well as a potent, reversible inhibitor of UGT1A1. Administration of a single dose of rosuvastatin, an OATP1B1, OATP1B3 and BCRP substrate, after repeated administration of encorafenib 450 mg once daily and binimetinib 45 mg twice daily, resulted in increased systemic exposure (AUC) and peak plasma concentration (Cmax) of rosuvastatin by approximately 1.6 fold and 2.7 fold respectively.

MANAGEMENT: Caution is advised if encorafenib must be used concomitantly with drugs that are substrates of the affected transporters or UGT1A1, particularly those with a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs whenever encorafenib is added to or withdrawn from therapy.

MONITOR: Coadministration with encorafenib may increase the plasma concentrations of drugs that are substrates of P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), organic cation transporter (OCT2), organic anion transporter (OAT1, OAT3), organic anion transporting polypeptide (OATP1B1, OATP1B3), or uridine diphosphate glucuronosyltransferase (UGT) 1A1. In in vivo studies, encorafenib has been shown to be an inhibitor of OATP1B1, 1B3, and BCRP. In vitro studies have demonstrated it to be an inhibitor of OCT2, OAT1, OAT3, and P-gp at expected clinical concentrations as well as a potent, reversible inhibitor of UGT1A1. Administration of a single dose of rosuvastatin, an OATP1B1, OATP1B3 and BCRP substrate, after repeated administration of encorafenib 450 mg once daily and binimetinib 45 mg twice daily, resulted in increased systemic exposure (AUC) and peak plasma concentration (Cmax) of rosuvastatin by approximately 1.6 fold and 2.7 fold respectively.

MANAGEMENT: Caution is advised if encorafenib must be used concomitantly with drugs that are substrates of the affected transporters or UGT1A1, particularly those with a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs whenever encorafenib is added to or withdrawn from therapy.