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2 DOSAGE AND ADMINISTRATION Select patients for treatment with VITRAKVI based on the presence of a NTRK gene fusion ( 2.1 , 14 ). Recommended Dosage in Adult and Pediatric Patients with Body Surface Area of 1 Meter-Squared or greater: 100 mg orally twice daily ( 2.2 ) Recommended Dosage in Pediatric Patients with Body Surface Area of Less Than 1 Meter-Squared: 100 mg/m 2 orally twice daily ( 2.2 ) 2.1 Patient Selection Select patients for treatment with VITRAKVI based on the presence of a NTRK gene fusion in tumor specimens [see Clinical Studies (14) ] . In patients with secretory breast cancer, mammary analogue secretory cancer (MASC), congenital mesoblastic nephroma (CMN), or infantile fibrosarcoma, consider treatment without confirmation of NTRK rearrangements in tumor specimens. Information on FDA-approved tests is available at http://www.fda.gov/companiondiagnostics. 2.2 Recommended Dosage Recommended Dosage in Adult and Pediatric Patients with Body Surface Area of 1 Meter-Squared or greater The recommended dosage of VITRAKVI is 100 mg orally twice daily, with or without food, until disease progression or until unacceptable toxicity. Recommended Dosage in Pediatric Patients with Body Surface Area Less Than 1 Meter-Squared The recommended dosage of VITRAKVI is 100 mg/m 2 orally twice daily, with or without food, until disease progression or until unacceptable toxicity. 2.3 Dosage Modifications for Adverse Reactions For Grade 2 and higher liver function test abnormalities, refer to Section 2.4, Table 2, Dosage Modifications for Hepatotoxicity. For all other Grade 3 or 4 adverse reactions: Withhold VITRAKVI until adverse reaction resolves or improves to baseline or Grade 1. Resume at the next dosage modification if resolution occurs within 4 weeks. Permanently discontinue VITRAKVI if an adverse reaction does not resolve within 4 weeks. The recommended dosage reductions for VITRAKVI for adverse reactions are provided in Table 1. Table 1 Recommended Dosage Reductions for VITRAKVI for Adverse Reactions Dosage Reduction Adult and Pediatric Patients with Body Surface Area of 1 m 2 or Greater Pediatric Patients with Body Surface Area Less Than 1 m 2 First 75 mg orally twice daily 75 mg/m 2 orally twice daily Second 50 mg orally twice daily 50 mg/m 2 orally twice daily Third 100 mg orally once daily 25 mg/m 2 orally twice daily Pediatric patients on 25 mg/m 2 orally twice daily should remain on this dosage even if body surface area becomes greater than 1 m 2 during the treatment. Maximum dose should be 25 mg/m 2 orally twice daily at the third dosage modification. Permanently discontinue VITRAKVI in patients who are unable to tolerate VITRAKVI after three dose modifications. 2.4 Dosage Modifications for Hepatotoxicity The recommended dosage modifications for VITRAKVI liver function test abnormalities are provided in Table 2. For CTCAE Grade 2 ALT and/or AST elevation, monitor liver function frequently as clinically indicated, to establish whether a dose interruption or reduction is required [see Warnings and Precautions (5.2) ] . Table 2 Recommended Dosage Modifications for VITRAKVI for Hepatotoxicity Severity Grading defined by National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) version 4.03 Dosage Modification ALT = alanine aminotransferase; AST = aspartate aminotransferase; ULN = upper limit of normal AST or ALT ≥ 5 × ULN with bilirubin ≤ 2 × ULN [see Warnings and Precautions (5.2) ] Withhold VITRAKVI until recovery to ≤ Grade 1 or return to baseline. Resume VITRAKVI at the next lower dose level. Permanently discontinue if a Grade 4 AST and/or ALT elevation occurs after resuming VITRAKVI. AST or ALT > 3 × ULN with total bilirubin > 2 × ULN in the absence of alternative causes Permanently discontinue VITRAKVI. 2.5 Dosage Modifications for Coadministration with Strong CYP3A4 Inhibitors Avoid coadministration of strong CYP3A4 inhibitors with VITRAKVI. If coadministration of a strong CYP3A4 inhibitor cannot be avoided, reduce the VITRAKVI dose by 50%. After the inhibitor has been discontinued for 3 to 5 elimination half-lives, resume the VITRAKVI dose that was used prior to initiating the CYP3A4 inhibitor [see Drug Interactions (7.1) , Clinical Pharmacology (12.3) ]. 2.6 Dosage Modifications for Coadministration with Strong or Moderate CYP3A4 Inducers Avoid coadministration of strong CYP3A4 inducers with VITRAKVI. If coadministration of a strong CYP3A4 inducer cannot be avoided, double the VITRAKVI dose. Additionally, for coadministration with a moderate CYP3A4 inducer, double the VITRAKVI dose. After the inducer has been discontinued for 3 to 5 elimination half-lives, resume the VITRAKVI dose that was used prior to initiating the CYP3A4 inducer [see Drug Interactions (7.1) , Clinical Pharmacology (12.3) ]. 2.7 Dosage Modifications for Patients with Hepatic Impairment Reduce the starting dose of VITRAKVI by 50% in patients with moderate (Child-Pugh B) to severe (Child-Pugh C) hepatic impairment [see Use in Specific Populations (8.6) , Clinical Pharmacology (12.3) ] . 2.8 Administration VITRAKVI capsule or oral solution may be used interchangeably. Do not make up a missed dose within 6 hours of the next scheduled dose. If vomiting occurs after taking a dose of VITRAKVI, take the next dose at the scheduled time. Capsules Swallow capsules whole with water. Do not chew or crush the capsules. Oral Solution packaged in one bottle containing 100 mL Store the glass bottle of VITRAKVI oral solution in the refrigerator. Discard any unused VITRAKVI oral solution remaining after 90 days of first opening the bottle. Prior to preparing an oral dose for administration, refer to the Instructions for Use. Oral Solution packaged in two bottles each containing 50 mL Store the glass bottles of VITRAKVI oral solution in the refrigerator. Discard any unused VITRAKVI oral solution remaining after 31 days of first opening the bottle. Prior to preparing an oral dose for administration, refer to the Instructions for Use.
Side Effects Overview
6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: Central Nervous System Effects [see Warnings and Precautions (5.1) ] Hepatotoxicity [see Warnings and Precautions (5.2) ] The most common (≥ 20%) adverse reactions, including laboratory abnormalities, with VITRAKVI were increased AST, increased ALT, anemia, hypoalbuminemia, musculoskeletal pain, increased alkaline phosphatase, leukopenia, lymphopenia, neutropenia, hypocalcemia, fatigue, vomiting, cough, constipation, pyrexia, diarrhea, nausea, abdominal pain, dizziness, and rash ( 6 ). To report SUSPECTED ADVERSE REACTIONS, contact Bayer HealthCare Pharmaceuticals Inc. at 1-888-842-2937 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trial Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Unless noted, data in WARNINGS AND PRECAUTIONS and below reflects exposure to VITRAKVI in 444 patients, including 62% patients exposed for greater than 6 months, 44% patients exposed for greater than 1 year, and 30% patients exposed for greater than 2 years. VITRAKVI was studied in one adult dose-finding trial [LOXO-TRK-14001 (n = 75)], one pediatric dose-finding trial [SCOUT (n = 154)], and one single arm trial [NAVIGATE (n = 215)]. All patients had an unresectable or metastatic solid tumor and no satisfactory alternative treatment options or disease progression following treatment. Across these 444 patients, the median age was 44 years (range: 18 days to 90 years); 35% were younger than 18 years; 53% were female; 59% were White, 24% were Asian and, 4% were Black; and 7% were Hispanic/Latino. Most adults (91%) received VITRAKVI 100 mg orally twice daily and 91% of pediatrics (< 18 years) received VITRAKVI 100 mg/m 2 twice daily up to a maximum dose of 100 mg twice daily. The dose ranged from 50 mg daily to 200 mg twice daily in adults and 9.6 mg/m 2 twice daily to 120 mg/m 2 twice daily in pediatrics [see Use in Specific Populations (8.4) ] . The most common serious adverse reactions (≥ 2%) were pneumonia, pyrexia, and dyspnea. Grade 3 or 4 adverse reactions occurred in 60% of patients; adverse reactions leading to dose interruption or modification occurred in 45% and 11% of patients, respectively, and 12% permanently discontinued VITRAKVI for adverse reactions. The most common adverse reactions (1% each) that resulted in permanent discontinuation of VITRAKVI were increased ALT and increased AST. The most common adverse reactions (≥ 3%) resulting in dose interruption were increased ALT (6%), increased AST (5%), neutrophil count decreased (4.7%), pyrexia (4.3%), and vomiting (3.2%). Most (64%) adverse reactions leading to dose interruption occurred during the first three months of exposure. The most common adverse reactions (≥ 20%), including laboratory abnormalities, in order of decreasing frequency were increased AST, increased ALT, anemia, hypoalbuminemia, musculoskeletal pain, increased alkaline phosphatase, leukopenia, lymphopenia, neutropenia, hypocalcemia, fatigue, vomiting, cough, constipation, pyrexia, diarrhea, nausea, abdominal pain, dizziness, and rash. Adverse reactions of VITRAKVI occurring in ≥ 10% of patients and laboratory abnormalities worsening from baseline in ≥ 20% of patients are summarized in Table 3 and Table 4, respectively. Table 3 Adverse Reactions Occurring in ≥ 10% of Patients Treated with VITRAKVI Adverse Reaction The adverse reaction identifies a composite term: VITRAKVI N = 444 All Grades National Cancer Institute-Common Terminology Criteria for Adverse Events (NCI-CTCAE) v 4.03. (%) Grade 3-4 Grade 4 adverse reaction: 1 of cognitive impairment, 1 of pyrexia. (%) Musculoskeletal and Connective Tissue Musculoskeletal Pain Includes: arthralgia, back pain, bone pain, flank pain, groin pain, growing pains, musculoskeletal chest pain, musculoskeletal discomfort, musculoskeletal pain, musculoskeletal stiffness, myalgia, neck pain, non-cardiac chest pain, pain in extremity, pain in jaw, and tendon pain 41 3.6 General Fatigue Includes: fatigue, asthenia 31 2.5 Pyrexia 26 2.3 Edema Includes: face edema, generalized edema, lip edema, localized edema, edema, edema genital, edema peripheral, periorbital edema, and swelling 17 0.7 Respiratory, Thoracic and Mediastinal Cough Includes: cough, productive cough, and upper-airway cough syndrome 29 0.5 Dyspnea Includes: dyspnea, and dyspnea exertional 17 2.7 Nasal congestion 10 0 Nervous System Dizziness Includes: dizziness, dizziness postural, and vertigo 22 0.9 Headache 17 0.9 Cognitive Impairment Includes: amnesia, aphasia, cognitive disorder, confusional state, delirium, disturbance in attention, hallucination, hallucination visual, memory impairment, mental impairment, mental status changes 11 2 Gastrointestinal Vomiting 30 1.1 Constipation 27 0.5 Diarrhea 26 2.9 Nausea 25 0.5 Abdominal pain Includes: abdominal discomfort, abdominal pain, abdominal pain lower, abdominal pain upper, abdominal tenderness, epigastric discomfort, and gastrointestinal pain 24 1.4 Skin and Subcutaneous Tissue Disorders Rash Includes: dermatitis, dermatitis acneiform, dermatitis bullous, dermatitis exfoliative generalized, eczema, eczema asteatotic, palmar-plantar erythrodysaesthesia syndrome, rash, rash erythematous, rash macular, rash maculo-papular, rash papular, rash pruritic, and rash pustular 21 0.2 Psychiatric Mood disorders Includes: agitation, anxiety, depression, depressed mood, euphoric mood, fear, feeling jittery, irritability, panic attack, psychomotor hyperactivity, restlessness 14 0.9 Sleep Disturbance Includes: insomnia, sleep disorder, somnolence 12 0.2 Investigations Increased weight 17 4.1 Metabolism and Nutrition Decreased appetite 14 1.1 Infections and Infestations Upper respiratory tract infection 18 0.7 Urinary tract infection Includes: cystitis, cystitis escherichia, escherichia urinary tract infection, kidney infection, pyelonephritis, pyelonephritis acute, pyelonephritis chronic, and urinary tract infection 14 1.8 Nasopharyngitis 11 0 Table 4 Laboratory Abnormalities Occurring in ≥ 20% Patients Treated with VITRAKVI Laboratory Abnormality VITRAKVI Based on NCI CTCAE v4.03 All Grades (%) Denominator for each laboratory parameter is based on the number of patients with a baseline and post-treatment laboratory value available which ranged from 416 to 442 patients. Grade 3-4 (%) Chemistry Increased AST 62 7 Increased ALT 61 8 Hypoalbuminemia 44 2.7 Increased alkaline phosphatase 40 3 Hypocalcemia 32 3.1 Hematology Anemia 45 8 Leukopenia 37 3.8 Lymphopenia 35 11 Neutropenia 34 11
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5 WARNINGS AND PRECAUTIONS Central Nervous System (CNS) Effects: Advise patients and caretakers of the risk of CNS adverse reactions including dizziness, cognitive impairment, mood disorders, and sleep disturbances. Advise patients not to drive or operate hazardous machinery if experiencing neurotoxicity. Withhold and modify dosage, or permanently discontinue VITRAKVI based on severity. ( 2.3 , 5.1 ) Hepatotoxicity: Obtain liver function tests (ALT, AST, ALP and bilirubin) before initiation of VITRAKVI and every 2 weeks during the first 2 months of treatment, then monthly thereafter or as clinically indicated. Temporarily withhold, reduce dose, or permanently discontinue VITRAKVI based on severity. ( 2.4 , 5.2 ) Embryo-Fetal Toxicity: Can cause fetal harm. Advise females with reproductive potential of potential risk to the fetus and to use effective contraception. ( 5.3 , 8.3 ) 5.1 Central Nervous System Effects Central nervous system (CNS) adverse reactions occurred in patients receiving VITRAKVI, including dizziness, cognitive impairment, mood disorders, and sleep disturbances. In patients who received VITRAKVI (n=444), all grades CNS effects including cognitive impairment, mood disorders, dizziness and sleep disorders were observed in 40.3% with Grades 3-4 in 3.8% of patients. Cognitive impairment occurred in 11% of patients. The median time to onset of cognitive impairment was 6 months (range: 2 days to 56 months). Cognitive impairment occurring in ≥ 1% of patients included memory impairment (4.1%), disturbance in attention (3.6%), confusional state (2.3%), cognitive disorder (1.6%), delirium (1.4%), and hallucination (1.1%). Grade 3 cognitive adverse reactions occurred in 1.8% of patients and Grade 4 cognitive adverse reactions in 0.2% of patients. Among the 49 patients with cognitive impairment, 6% required a dose modification, and 18% required dose interruption. Mood disorders occurred in 14% of patients. The median time to onset of mood disorders was 3.3 months (range: 1 day to 65 months). Mood disorders occurring in ≥ 1% of patients included anxiety (5%), agitation (3.2%), depression (3.2%), irritability (2.3%), and restlessness (1.1%). Grade 3 mood disorders occurred in 0.9% of patients. Among the 63 patients who experienced mood disorders, no patient required a dose modification, and 1.6% required dose interruption. Dizziness occurred in 22% of patients, and Grade 3 dizziness occurred in 0.9% of patients. Among the 96 patients who experienced dizziness, 6% of patients required a dose modification, and 5% required dose interruption. Sleep disturbances occurred in 12% of patients. Sleep disturbances included insomnia (9%), somnolence (3.4%), and sleep disorder (0.5%). Grade 3 sleep disturbances occurred in 0.2% of patients. Among the 54 patients who experienced sleep disturbances, no patient required a dose modification, and 3.7% required dose interruption. Advise patients and caretakers of these risks with VITRAKVI. Advise patients not to drive or operate hazardous machinery if they are experiencing neurologic adverse reactions. Withhold or permanently discontinue VITRAKVI based on the severity. If withheld, modify the VITRAKVI dosage when resumed [see Dosage and Administration (2.3) ] . 5.2 Hepatotoxicity Hepatotoxicity including drug-induced liver injury (DILI) has occurred in patients taking VITRAKVI. In patients who received VITRAKVI (n=444), increased AST of any grade occurred in 62% of patients and increased ALT of any grade occurred in 61%. Grade 3-4 increased AST or ALT occurred in 7% and 8% of patients, respectively [see Adverse Reactions (6.1) ] . The median time to onset of increased AST was 1.9 months (range: 4 days to 3.8 years). The median time to onset of increased ALT was 1.9 months (range: 1 day to 4.9 years). Increased AST and ALT leading to dose modifications occurred in 1.6% and 3.2% of patients, respectively. Increased AST or ALT led to permanent discontinuation in 4 (0.9%) patients. There have been reports from clinical studies and postmarketing cases of Grade ≥ 2 increases in ALT and/or AST with increases in bilirubin ≥ 2 × ULN. Obtain liver function tests (ALT, AST, ALP and bilirubin) before initiation of VITRAKVI and monitor every 2 weeks during the first 2 months of treatment, then monthly thereafter, or more frequently following the occurrence of Grade 2 or greater AST or ALT elevation. Temporarily withhold, reduce the dose, or permanently discontinue VITRAKVI based on severity [see Dosage and Administration (2.4) ] . 5.3 Embryo-Fetal Toxicity Based on literature reports in human subjects with congenital mutations leading to changes in TRK signaling, findings from animal studies, and its mechanism of action, VITRAKVI can cause fetal harm when administered to a pregnant woman. Larotrectinib resulted in malformations in rats and rabbits at maternal exposures that were approximately 11- and 0.7-times, respectively, those observed at the clinical dose of 100 mg twice daily. Advise women of the potential risk to a fetus. Advise females of reproductive potential to use an effective method of contraception during treatment and for 1 week after the last dose of VITRAKVI [see Use in Specific Populations (8.1 , 8.3) ] .
Farmakokinetik
12.3 Pharmacokinetics The pharmacokinetics of larotrectinib were studied in healthy subjects and adult and pediatric patients with locally advanced or metastatic solid tumors. In healthy subjects who received a single dose of VITRAKVI capsules, systemic exposure (C max and AUC) of larotrectinib was dose proportional over the dose range of 100 mg to 400 mg (1 to 4 times the recommended adult dose) and slightly greater than proportional at doses of 600 mg to 900 mg (6 to 9 times the recommended adult dose). In adult patients who received VITRAKVI capsules 100 mg twice daily in Study LOXO-TRK-14001, peak plasma levels (C max ) of larotrectinib were achieved at approximately 1 hour after dosing and steady-state was reached within 3 days. Mean steady-state larotrectinib [coefficient of variation (CV%)] for C max was 788 (81%) ng/mL and AUC 0-24hr was 4351 (97%) ng*h/mL. Absorption The mean absolute bioavailability of VITRAKVI capsules was 34% (range: 32% to 37%). In healthy subjects, the AUC of VITRAKVI oral solution was similar to that of the capsules and the C max was 36% higher with the oral solution. Effect of Food The AUC of larotrectinib was similar and the C max was reduced by 35% after oral administration of a single 100 mg capsule of VITRAKVI to healthy subjects taken with a high-fat meal (approximately 900 calories, 58 grams carbohydrate, 56 grams fat and 43 grams protein) compared to the C max and AUC in the fasted state. Distribution The mean (CV%) volume of distribution (V ss ) of larotrectinib is 48 (38%) L following intravenous administration of larotrectinib in healthy subjects. Larotrectinib is 70% bound to human plasma proteins in vitro and binding is independent of drug concentrations. The blood-to-plasma concentration ratio is 0.9. Elimination The mean (CV%) clearance (CL/F) of larotrectinib is 98 (44%) L/h and the half-life is 2.9 hours following oral administration of VITRAKVI in healthy subjects. Metabolism Larotrectinib is metabolized predominantly by CYP3A4. Following oral administration of a single [ 14 C] radiolabeled 100 mg dose of larotrectinib to healthy subjects, unchanged larotrectinib constituted 19% and an O-linked glucuronide constituted 26% of the major circulating radioactive drug components in plasma. Excretion Following oral administration of a single [ 14 C] radiolabeled 100 mg dose of larotrectinib to healthy subjects, 58% (5% unchanged) of the administered radioactivity was recovered in feces and 39% (20% unchanged) was recovered in urine. Specific Populations Age (range: 28 days to 82 years), sex, and body weight (range: 3.8 kg to 179 kg) had no clinically meaningful effect on the pharmacokinetics of larotrectinib. Pediatric Patients In pediatric patients, the larotrectinib geometric mean (%CV) AUC 0-24hr by age subgroup was: 3348 (66%) ng*h/mL in patients 1 month to < 2 years (n = 9), 4135 (36%) ng*h/mL in patients 2 to < 12 years (n = 15), and 3108 (69%) ng*h/mL and in patients 12 to < 18 years (n = 9). Patients with Renal Impairment Following oral administration of a single 100 mg dose of VITRAKVI capsules in subjects with end-stage renal disease (e.g., subjects who required dialysis), the AUC 0-INF of larotrectinib increased 1.5-fold and C max increased 1.3-fold as compared to that in subjects with normal renal function (creatinine clearance ≥ 90 mL/min as estimated by Cockcroft-Gault). The pharmacokinetics of VITRAKVI in patients with moderate to severe renal impairment (creatinine clearance ≤ 60 mL/min) have not been studied. Patients with Hepatic Impairment Following oral administration of a single 100 mg dose of VITRAKVI capsules, the AUC 0-INF of larotrectinib increased 1.3-fold in subjects with mild hepatic impairment (Child-Pugh A), 2-fold in subjects with moderate hepatic impairment (Child-Pugh B) and 3.2-fold in subjects with severe hepatic impairment (Child-Pugh C) as compared to that in subjects with normal hepatic function. The C max was similar in subjects with mild and moderate hepatic impairment and the C max of larotrectinib increased 1.5-fold in subjects with severe hepatic impairment as compared to that in subjects with normal hepatic function [see Dosage and Administration (2.7) , Use in Specific Populations (8.6) ]. Drug Interaction Studies Clinical Studies Effect of CYP3A Inhibitors: Coadministration of a single 100 mg dose of VITRAKVI capsules with itraconazole (strong CYP3A inhibitor) increased the AUC 0-INF of larotrectinib by 4.3-fold and the C max by 2.8-fold as compared to VITRAKVI administered alone [see Dosage and Administration (2.5) , Drug Interactions (7.1) ]. Coadministration of VITRAKVI with fluconazole (moderate CYP3A4 inhibitor) is predicted to increase VITRAKVI steady state AUC by 2.7-fold and C max by 1.9-fold. Effect of CYP3A Inducers: Coadministration of a single 100 mg dose of VITRAKVI capsules with rifampin (strong CYP3A inducer) decreased the AUC 0-INF of larotrectinib by 81% and the C max by 71% as compared to VITRAKVI administered alone [see Dosage and Administration (2.6) , Drug Interactions (7.1) ] . Coadministration of VITRAKVI with efavirenz (moderate CYP3A4 inducer) is predicted to decrease steady state AUC of VITRAKVI by approximately 72% and C max by 60% compared to VITRAKVI administered alone [see Dosage and Administration (2.6) , Drug Interactions (7.1) ]. Effect of Strong P-glycoprotein (P-gp) Inhibitors: Coadministration of a single 100 mg dose of VITRAKVI capsules with a P-gp inhibitor (rifampin) increased the AUC 0-INF of larotrectinib by 1.7-fold and the C max by 1.8-fold as compared to VITRAKVI administered alone. Effect of Larotrectinib on CYP3A4 Substrates: Coadministration of VITRAKVI capsules 100 mg twice daily with a sensitive CYP3A4 substrate (midazolam) increased both the AUC 0-INF and C max of midazolam by 1.7-fold as compared to midazolam administered alone. The AUC 0-INF and C max of 1-hydroxymidazolam, the main metabolite of midazolam, were both increased 1.4-fold as compared to when midazolam was administered alone [see Drug Interactions (7.2) ] . In Vitro Studies Effect of Transporter on Larotrectinib: Larotrectinib is a substrate for P-gp and BCRP. Larotrectinib is not a substrate of OAT1, OAT3, OCT1, OCT2, OATP1B1, or OATP1B3. Effect of Larotrectinib on Transporters: Larotrectinib is not an inhibitor of BCRP, P-gp, OAT1, OAT3, OCT1, OCT2, OATP1B1, OATP1B3, BSEP, MATE1 and MATE2-K at clinically relevant concentrations. Effect of Larotrectinib on CYP Substrates: Larotrectinib is not an inhibitor or inducer of CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, or CYP2D6 at clinically relevant concentrations.