IVACAFTOR Drug Interactions: What You Need to Know

5.7 Drug Interactions Substrates of CYP3A Lumacaftor is a strong inducer of CYP3A. Administration of ORKAMBI may decrease systemic exposure of medicinal products that are substrates of CYP3A, which may decrease therapeutic effect. Co-administration with sensitive CYP3A substrates or CYP3A substrates with a narrow therapeutic index is not recommended. ORKAMBI may substantially decrease hormonal contraceptive exposure, reducing their effectiveness and increasing the incidence of menstruation-associated adverse reactions, e.g., amenorrhea, dysmenorrhea, menorrhagia, menstrual irregular (27% in women using hormonal contraceptives compared with 3% in women not using hormonal contraceptives). Hormonal contraceptives, including oral, injectable, transdermal, and implantable, should not be relied upon as an effective method of contraception when co-administered with ORKAMBI [see Adverse Reactions (6.1) , Drug Interactions (7.3 , 7.11) , and Clinical Pharmacology (12.3) ] . Strong CYP3A Inducers Ivacaftor is a substrate of CYP3A4 and CYP3A5 isoenzymes. Use of ORKAMBI with strong CYP3A inducers, such as rifampin, significantly reduces ivacaftor exposure, which may reduce the therapeutic effectiveness of ORKAMBI. Therefore, co-administration with strong CYP3A inducers (e.g., rifampin, St. John's wort [ Hypericum perforatum ]) is not recommended [see Drug Interactions (7.2) and Clinical Pharmacology (12.3) ] .

7 DRUG INTERACTIONS See Full Prescribing Information for a complete list. ( 2.3 , 7 , 12.3 ) Potential for Other Drugs to Affect Lumacaftor/Ivacaftor

7.1 Inhibitors of CYP3A Co-administration of lumacaftor/ivacaftor with itraconazole, a strong CYP3A inhibitor, did not impact the exposure of lumacaftor, but increased ivacaftor exposure by 4.3-fold. Due to the induction effect of lumacaftor on CYP3A, at steady-state, the net exposure of ivacaftor is not expected to exceed that when given in the absence of lumacaftor at a dose of 150 mg every 12 hours (the approved dose of ivacaftor monotherapy). Therefore, no dosage adjustment is necessary when CYP3A inhibitors are initiated in patients currently taking ORKAMBI. However, when initiating ORKAMBI in patients taking strong CYP3A inhibitors, reduce the ORKAMBI dosage as recommended for the first week of treatment to allow for the steady-state induction effect of lumacaftor. Following this period, continue with the recommended daily dose <span class="opacity-50 text-xs">[see Dosage and Administration (2.3) ]</span> . Examples of strong CYP3A inhibitors include: ketoconazole, itraconazole, posaconazole, and voriconazole. telithromycin, clarithromycin. No dosage adjustment is recommended when used with moderate or weak CYP3A inhibitors.

7.2 Inducers of CYP3A Co-administration of lumacaftor/ivacaftor with rifampin, a strong CYP3A inducer, had minimal effect on the exposure of lumacaftor, but decreased ivacaftor exposure (AUC) by 57%. This may reduce the effectiveness of ORKAMBI. Therefore, co-administration with strong CYP3A inducers, such as rifampin, rifabutin, phenobarbital, carbamazepine, phenytoin, and St. John&apos;s wort ( Hypericum perforatum ), is not recommended <span class="opacity-50 text-xs">[see Warnings and Precautions (5.7) and Clinical Pharmacology (12.3) ]</span> . No dosage adjustment is recommended when used with moderate or weak CYP3A inducers. Potential for Lumacaftor/Ivacaftor to Affect Other Drugs

7.3 CYP3A Substrates Lumacaftor is a strong inducer of CYP3A. Co-administration of lumacaftor with ivacaftor, a sensitive CYP3A substrate, decreased ivacaftor exposure by approximately 80%. Administration of ORKAMBI may decrease systemic exposure of medicinal products which are substrates of CYP3A, thereby decreasing the therapeutic effect of the medicinal product. Co-administration of ORKAMBI is not recommended with sensitive CYP3A substrates or CYP3A substrates with a narrow therapeutic index <span class="opacity-50 text-xs">[see Warnings and Precautions (5.7) and Clinical Pharmacology (12.3) ]</span> such as: Benzodiazepines : midazolam, triazolam (consider an alternative to these benzodiazepines). Immunosuppressants : cyclosporine, everolimus, sirolimus, and tacrolimus (avoid the use of ORKAMBI).

7.4 CYP2B6 and CYP2C Substrates In vitro studies suggest that lumacaftor has the potential to induce CYP2B6, CYP2C8, CYP2C9, and CYP2C19; inhibition of CYP2C8 and CYP2C9 has also been observed in vitro . Additionally, in vitro studies suggest that ivacaftor may inhibit CYP2C9. Therefore, concomitant use of ORKAMBI with CYP2B6, CYP2C8, CYP2C9, and CYP2C19 substrates may alter the exposure of these substrates.

7.5 Digoxin and Other P-gp Substrates Based on in vitro results which showed P-gp inhibition and pregnane-X-receptor (PXR) activation, lumacaftor has the potential to both inhibit and induce P-gp. Additionally, a clinical study with ivacaftor monotherapy showed that ivacaftor is a weak inhibitor of P-gp. Therefore, concomitant use of ORKAMBI with P-gp substrates may alter the exposure of these substrates. Monitor the serum concentration of digoxin and titrate the digoxin dose to obtain the desired clinical effect.

7.6 Anti-allergics and Systemic Corticosteroids ORKAMBI may decrease the exposure of montelukast, which may reduce its efficacy. No dosage adjustment for montelukast is recommended. Employ appropriate clinical monitoring, as is reasonable, when co-administered with ORKAMBI. Concomitant use of ORKAMBI may reduce the exposure and effectiveness of prednisone and methylprednisolone. A higher dose of these systemic corticosteroids may be required to obtain the desired clinical effect.

7.7 Antibiotics Concomitant use of ORKAMBI may decrease the exposure of clarithromycin, erythromycin, and telithromycin, which may reduce the effectiveness of these antibiotics. Consider an alternative to these antibiotics, such as ciprofloxacin, azithromycin, and levofloxacin.

7.8 Antifungals Concomitant use of ORKAMBI may reduce the exposure and effectiveness of itraconazole, ketoconazole, posaconazole, and voriconazole. Concomitant use of ORKAMBI with these antifungals is not recommended. Monitor patients closely for breakthrough fungal infections if such drugs are necessary. Consider an alternative such as fluconazole.

7.9 Anti-inflammatories Concomitant use of ORKAMBI may reduce the exposure and effectiveness of ibuprofen. A higher dose of ibuprofen may be required to obtain the desired clinical effect.

7.10 Antidepressants Concomitant use of ORKAMBI may reduce the exposure and effectiveness of citalopram, escitalopram, and sertraline. A higher dose of these antidepressants may be required to obtain the desired clinical effect.

7.11 Hormonal Contraceptives ORKAMBI may decrease hormonal contraceptive exposure, reducing the effectiveness. Hormonal contraceptives, including oral, injectable, transdermal, and implantable, should not be relied upon as an effective method of contraception when co-administered with ORKAMBI. Concomitant use of ORKAMBI with hormonal contraceptives increased the menstrual abnormality events <span class="opacity-50 text-xs">[see Adverse Reactions (6.1) ]</span> . Avoid concomitant use unless the benefit outweighs the risks.

7.12 Oral Hypoglycemics Concomitant use of ORKAMBI may reduce the exposure and effectiveness of repaglinide and may alter the exposure of sulfonylurea. A dosage adjustment may be required to obtain the desired clinical effect. No dosage adjustment is recommended for metformin.

7.13 Proton Pump Inhibitors, H 2 Blockers, Antacids ORKAMBI may reduce the exposure and effectiveness of proton pump inhibitors such as omeprazole, esomeprazole, and lansoprazole, and may alter the exposure of ranitidine. A dose adjustment may be required to obtain the desired clinical effect. No dose adjustment is recommended for calcium carbonate antacid.

7.14 Warfarin ORKAMBI may alter the exposure of warfarin. Monitor the international normalized ratio (INR) when warfarin co-administration with ORKAMBI is required.

7.15 Concomitant Drugs That Do Not Need Dosage Adjustment No dosage adjustment of ORKAMBI or concomitant drug is recommended when ORKAMBI is given with the following: azithromycin, aztreonam, budesonide, ceftazidime, cetirizine, ciprofloxacin, colistimethate, colistin, dornase alfa, fluticasone, ipratropium, levofloxacin, pancreatin, pancrelipase, salbutamol, salmeterol, sulfamethoxazole, trimethoprim, tiotropium, and tobramycin. Based on the metabolism and route of elimination, ORKAMBI is not expected to impact the exposure of these drugs.

None. None. ( 4 )

AND PRECAUTIONS Use in patients with advanced liver disease: ORKAMBI should be used with caution in these patients and only if the benefits are expected to outweigh the risks. If ORKAMBI is used in these patients, they should be closely monitored after the initiation of treatment and the dosage should be reduced. Liver function decompensation, including liver failure leading to death, has been reported in CF patients with pre-existing cirrhosis with portal hypertension. ( 2.2 , 5.1 , 6.1 ) Liver-related events: Elevated transaminases (ALT/AST) have been observed in some cases associated with elevated bilirubin. Measure serum transaminases and bilirubin before initiating ORKAMBI, every 3 months during the first year of treatment, and annually thereafter. For patients with a history of ALT, AST, or bilirubin elevations, more frequent monitoring should be considered. Interrupt dosing in patients with ALT or AST >5 × upper limit of normal (ULN), or ALT or AST >3 × ULN with bilirubin >2 × ULN. Following resolution, consider the benefits and risks of resuming dosing. ( 5.2 , 6.1 ) Hypersensitivity reactions: Angioedema and anaphylaxis have been reported with ORKAMBI in the postmarketing setting. Initiate appropriate therapy in the event of a hypersensitivity reaction. ( 5.3 ) Intracranial hypertension: Intracranial hypertension (IH) has been reported in the postmarketing setting with the use of ORKAMBI. If an unusual headache or visual disturbances occur during treatment, and IH is suspected, interrupt ORKAMBI and refer for prompt medical evaluation. ( 5.4 ) Respiratory events: Chest discomfort, dyspnea, and respiration abnormal were observed more commonly during initiation of ORKAMBI. Clinical experience in patients with percent predicted FEV 1 (ppFEV 1 ) <40 is limited, and additional monitoring of these patients is recommended during initiation of therapy. ( 5.5 , 6.1 ) Blood pressure: Increased blood pressure has been observed in some patients. Periodically monitor blood pressure in all patients. ( 5.6 , 6.1 ) Drug interactions: Use with sensitive CYP3A substrates or CYP3A substrates with a narrow therapeutic index may decrease systemic exposure of the medicinal products and co-administration is not recommended. Hormonal contraceptives should not be relied upon as an effective method of contraception and their use is associated with increased menstruation-related adverse reactions. Use with strong CYP3A inducers may diminish exposure of ivacaftor, which may diminish its effectiveness; therefore, co-administration is not recommended. ( 5.7 , 6.1 , 7 , 12.3 ) Cataracts: Non-congenital lens opacities/cataracts have been reported in pediatric patients treated with ORKAMBI and ivacaftor, a component of ORKAMBI. Baseline and follow-up examinations are recommended in pediatric patients initiating ORKAMBI. ( 5.8 )

5.1 Use in Patients with Advanced Liver Disease Worsening of liver function, including hepatic encephalopathy, in patients with advanced liver disease has been reported. Liver function decompensation, including liver failure leading to death, has been reported in CF patients with pre-existing cirrhosis with portal hypertension while receiving ORKAMBI. Use ORKAMBI with caution in patients with advanced liver disease and only if the benefits are expected to outweigh the risks. If ORKAMBI is used in these patients, they should be closely monitored after the initiation of treatment and the dosage should be reduced <span class="opacity-50 text-xs">[see Dosage and Administration (2.2) and Adverse Reactions (6.1) ]</span> .

5.2 Liver-related Events Serious adverse reactions related to elevated transaminases have been reported in patients with CF receiving ORKAMBI. In some instances, these elevations have been associated with concomitant elevations in total serum bilirubin. It is recommended that ALT, AST, and bilirubin be assessed prior to initiating ORKAMBI, every 3 months during the first year of treatment, and annually thereafter. For patients with a history of ALT, AST, or bilirubin elevations, more frequent monitoring should be considered. Patients who develop increased ALT, AST, or bilirubin should be closely monitored until the abnormalities resolve. Dosing should be interrupted in patients with ALT or AST &gt;5 × upper limit of normal (ULN) when not associated with elevated bilirubin. Dosing should also be interrupted in patients with ALT or AST elevations &gt;3 × ULN when associated with bilirubin elevations &gt;2 × ULN. Following resolution of transaminase elevations, consider the benefits and risks of resuming dosing <span class="opacity-50 text-xs">[see Adverse Reactions (6.1) ]</span> .

5.3 Hypersensitivity Reactions, Including Anaphylaxis Hypersensitivity reactions, including cases of angioedema and anaphylaxis, have been reported in the postmarketing setting <span class="opacity-50 text-xs">[see Adverse Reactions (6.2) ]</span> . If signs or symptoms of serious hypersensitivity reactions develop during treatment, discontinue ORKAMBI and institute appropriate therapy. Consider the benefits and risks for the individual patient to determine whether to resume treatment with ORKAMBI.

5.4 Intracranial Hypertension Cases of intracranial hypertension (IH) have been reported in the postmarketing setting with the use of ORKAMBI <span class="opacity-50 text-xs">[see Adverse Reactions (6.2) ]</span> . Clinical manifestations of IH include headache, blurred vision, diplopia, and potential vision loss; papilledema can be found on fundoscopy. If an unusual headache or visual disturbances occur during treatment, and IH is suspected, interrupt ORKAMBI and refer for prompt medical evaluation. Consider the benefits and risks for the individual patient to determine whether to resume treatment with ORKAMBI. Patients should be monitored until IH resolution and for recurrence. Patients with elevated vitamin A levels may be at increased risk.

5.5 Respiratory Events Respiratory events (e.g., chest discomfort, dyspnea, and respiration abnormal) were observed more commonly in patients during initiation of ORKAMBI compared to those who received placebo. These events have led to drug discontinuation and can be serious, particularly in patients with advanced lung disease (percent predicted FEV 1 &lt;40). Clinical experience in patients with ppFEV 1 &lt;40 is limited, and additional monitoring of these patients is recommended during initiation of therapy <span class="opacity-50 text-xs">[see Adverse Reactions (6.1) ]</span> .

5.6 Effect on Blood Pressure Increased blood pressure has been observed in some patients treated with ORKAMBI. Blood pressure should be monitored periodically in all patients being treated with ORKAMBI <span class="opacity-50 text-xs">[see Adverse Reactions (6.1) ]</span> .

5.7 Drug Interactions Substrates of CYP3A Lumacaftor is a strong inducer of CYP3A. Administration of ORKAMBI may decrease systemic exposure of medicinal products that are substrates of CYP3A, which may decrease therapeutic effect. Co-administration with sensitive CYP3A substrates or CYP3A substrates with a narrow therapeutic index is not recommended. ORKAMBI may substantially decrease hormonal contraceptive exposure, reducing their effectiveness and increasing the incidence of menstruation-associated adverse reactions, e.g., amenorrhea, dysmenorrhea, menorrhagia, menstrual irregular (27% in women using hormonal contraceptives compared with 3% in women not using hormonal contraceptives). Hormonal contraceptives, including oral, injectable, transdermal, and implantable, should not be relied upon as an effective method of contraception when co-administered with ORKAMBI <span class="opacity-50 text-xs">[see Adverse Reactions (6.1) , Drug Interactions (7.3 , 7.11) , and Clinical Pharmacology (12.3) ]</span> . Strong CYP3A Inducers Ivacaftor is a substrate of CYP3A4 and CYP3A5 isoenzymes. Use of ORKAMBI with strong CYP3A inducers, such as rifampin, significantly reduces ivacaftor exposure, which may reduce the therapeutic effectiveness of ORKAMBI. Therefore, co-administration with strong CYP3A inducers (e.g., rifampin, St. John&apos;s wort [ Hypericum perforatum ]) is not recommended <span class="opacity-50 text-xs">[see Drug Interactions (7.2) and Clinical Pharmacology (12.3) ]</span> .

5.8 Cataracts Cases of non-congenital lens opacities have been reported in pediatric patients treated with ORKAMBI and ivacaftor, a component of ORKAMBI. Although other risk factors were present in some cases (such as corticosteroid use and exposure to radiation), a possible risk attributable to ivacaftor cannot be excluded <span class="opacity-50 text-xs">[see Use in Specific Populations (8.4) ]</span> . Baseline and follow-up ophthalmological examinations are recommended in pediatric patients initiating ORKAMBI treatment.