Drug Interactions between pirtobrutinib and Symfi Lo

GENERALLY AVOID: Coadministration with potent or moderate inducers of CYP450 3A4 may significantly decrease the plasma concentrations of pirtobrutinib, which is primarily metabolized by the isoenzyme. When pirtobrutinib (200 mg single dose) was administered with rifampin, a potent CYP450 3A4 inducer, pirtobrutinib systemic exposure (AUC) decreased by 71%. Concomitant use of bosentan or efavirenz, moderate CYP450 3A4 inducers, is predicted to decrease pirtobrutinib AUC by 27% and 49%, respectively. Reduced effectiveness of pirtobrutinib may result.

MANAGEMENT: Coadministration of pirtobrutinib and potent or moderate CYP450 3A4 inducers should be avoided. If concomitant use of a moderate CYP450 3A4 inducer is unavoidable and the current dosage of pirtobrutinib is 200 mg once daily, increase the dose to 300 mg. If the current dosage of pirtobrutinib is 50 mg or 100 mg once daily, increase the dose by 50 mg.

MONITOR: Coadministration of efavirenz with other agents known to induce hepatotoxicity may potentiate the risk of liver injury. Efavirenz has been associated with hepatotoxicity during postmarketing use. Among reported cases of hepatic failure, a few occurred in patients with no preexisting hepatic disease or other identifiable risk factors.

MANAGEMENT: The risk of hepatic injury should be considered when efavirenz is used in combination with other agents that are potentially hepatotoxic (e.g., acetaminophen; alcohol; androgens and anabolic steroids; antituberculous agents; azole antifungal agents; ACE inhibitors; cyclosporine (high dosages); disulfiram; endothelin receptor antagonists; interferons; ketolide and macrolide antibiotics; kinase inhibitors; minocycline; nonsteroidal anti-inflammatory agents; other HIV reverse transcriptase inhibitors; proteasome inhibitors; retinoids; sulfonamides; tamoxifen; thiazolidinediones; tolvaptan; vincristine; zileuton; anticonvulsants such as carbamazepine, hydantoins, felbamate, and valproic acid; lipid-lowering medications such as fenofibrate, lomitapide, mipomersen, niacin, and statins; herbals and nutritional supplements such as black cohosh, chaparral, comfrey, DHEA, kava, pennyroyal oil, and red yeast rice). Patients should be advised to seek medical attention if they experience potential signs and symptoms of hepatotoxicity such as fever, rash, itching, anorexia, nausea, vomiting, fatigue, malaise, right upper quadrant pain, dark urine, pale stools, and jaundice. Monitoring of liver function tests should occur before and during treatment, especially in patients with underlying hepatic disease (including hepatitis B or C coinfection) or marked transaminase elevations. The benefit of continued therapy with efavirenz should be considered against the unknown risks of significant liver toxicity in patients who develop persistent elevations of serum transaminases greater than five times the upper limit of normal.

MONITOR: Coadministration of efavirenz with other agents known to induce hepatotoxicity may potentiate the risk of liver injury. Efavirenz has been associated with hepatotoxicity during postmarketing use. Among reported cases of hepatic failure, a few occurred in patients with no preexisting hepatic disease or other identifiable risk factors.

MANAGEMENT: The risk of hepatic injury should be considered when efavirenz is used in combination with other agents that are potentially hepatotoxic (e.g., acetaminophen; alcohol; androgens and anabolic steroids; antituberculous agents; azole antifungal agents; ACE inhibitors; cyclosporine (high dosages); disulfiram; endothelin receptor antagonists; interferons; ketolide and macrolide antibiotics; kinase inhibitors; minocycline; nonsteroidal anti-inflammatory agents; other HIV reverse transcriptase inhibitors; proteasome inhibitors; retinoids; sulfonamides; tamoxifen; thiazolidinediones; tolvaptan; vincristine; zileuton; anticonvulsants such as carbamazepine, hydantoins, felbamate, and valproic acid; lipid-lowering medications such as fenofibrate, lomitapide, mipomersen, niacin, and statins; herbals and nutritional supplements such as black cohosh, chaparral, comfrey, DHEA, kava, pennyroyal oil, and red yeast rice). Patients should be advised to seek medical attention if they experience potential signs and symptoms of hepatotoxicity such as fever, rash, itching, anorexia, nausea, vomiting, fatigue, malaise, right upper quadrant pain, dark urine, pale stools, and jaundice. Monitoring of liver function tests should occur before and during treatment, especially in patients with underlying hepatic disease (including hepatitis B or C coinfection) or marked transaminase elevations. The benefit of continued therapy with efavirenz should be considered against the unknown risks of significant liver toxicity in patients who develop persistent elevations of serum transaminases greater than five times the upper limit of normal.

MONITOR: Coadministration with pirtobrutinib may increase the plasma concentrations of drugs that are substrates of CYP450 2C8, 2C19, 3A4, P-glycoprotein (P-gp), and/or breast cancer resistance protein (BCRP). The peak plasma concentration (Cmax) and systemic exposure (AUC) of repaglinide, a CYP450 2C8 substrate, increased by 98% and 130%, respectively, and the Cmax and AUC of omeprazole, a CYP450 2C19 substrate, increased by 49% and 56%, respectively, when administered with pirtobrutinib. The Cmax and AUC of oral midazolam, a CYP450 3A4 substrate, increased by 58% and 70%, respectively, while exposure to IV midazolam was not significantly affected, when administered with pirtobrutinib. The Cmax and AUC of digoxin, a P-gp substrate, increased by 51% and 17%, respectively, when administered with a single pirtobrutinib dose (200 mg), and 55% and 35%, respectively, when administered with multiple pirtobrutinib doses (200 mg daily). The Cmax and AUC of rosuvastatin, a BCRP substrate, increased by 146% and 140%, respectively, when administered with pirtobrutinib. The risk of adverse reactions related to these substrates may be increased.

MANAGEMENT: Caution is advised if pirtobrutinib is used concomitantly with substrates of CYP450 2C8, 2C19, 3A4, P-gp, and/or BCRP, particularly sensitive substrates or those with a narrow therapeutic range. The prescribing information for concomitant medications should be consulted to assess the benefits versus risks of coadministration and for any dosage adjustments that may be required.