Side Effects Overview
6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: • Neutropenia [see Warnings and Precautions (5.1) ] • ILD/Pneumonitis [see Warnings and Precautions (5.2) ] Most common adverse reactions (incidence ≥20%) in combination with either letrozole or fulvestrant, including laboratory abnormalities, were white blood cell count decreased, neutrophils decreased, blood creatinine increased, hemoglobin decreased, platelets decreased, infections, aspartate aminotransferase increased, alanine aminotransferase increased, fatigue, nausea, stomatitis, diarrhea, and alopecia. ( 6.1 ) The most common adverse reactions (incidence ≥20%) in combination with inavolisib and fulvestrant, including laboratory abnormalities, were neutrophils decreased, hemoglobin decreased, fasting glucose increased, platelets decreased, lymphocytes decreased, stomatitis, diarrhea, calcium decreased, fatigue, potassium decreased, creatinine increased, alanine aminotransferase (ALT) increased, nausea, sodium decreased, magnesium decreased, rash, decreased appetite, COVID-19 infection, and headache. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Pfizer Inc at 1-800-438-1985 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Studies 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. PALOMA-2: IBRANCE plus Letrozole Patients with estrogen receptor (ER)-positive, HER2-negative advanced or metastatic breast cancer for initial endocrine-based therapy The safety of IBRANCE (125 mg/day) plus letrozole (2.5 mg/day) versus placebo plus letrozole was evaluated in PALOMA-2. The data described below reflect exposure to IBRANCE in 444 out of 666 patients with ER-positive, HER2-negative advanced breast cancer who received at least 1 dose of IBRANCE plus letrozole in PALOMA-2. The median duration of treatment for IBRANCE plus letrozole was 19.8 months while the median duration of treatment for placebo plus letrozole arm was 13.8 months. Dose reductions due to an adverse reaction of any grade occurred in 36% of patients receiving IBRANCE plus letrozole. No dose reduction was allowed for letrozole in PALOMA-2. Permanent discontinuation associated with an adverse reaction occurred in 43 of 444 (10%) patients receiving IBRANCE plus letrozole and in 13 of 222 (6%) patients receiving placebo plus letrozole. Adverse reactions leading to permanent discontinuation for patients receiving IBRANCE plus letrozole included neutropenia (1.1%) and alanine aminotransferase increase (0.7%). The most common adverse reactions (≥10%) of any grade reported in patients in the IBRANCE plus letrozole arm by descending frequency were neutropenia, infections, leukopenia, fatigue, nausea, alopecia, stomatitis, diarrhea, anemia, rash, asthenia, thrombocytopenia, vomiting, decreased appetite, dry skin, pyrexia, and dysgeusia. The most frequently reported Grade ≥3 adverse reactions (≥5%) in patients receiving IBRANCE plus letrozole by descending frequency were neutropenia, leukopenia, infections, and anemia. Adverse reactions (≥10%) reported in patients who received IBRANCE plus letrozole or placebo plus letrozole in PALOMA-2 are listed in Table 4. Table 4. Adverse Reactions (≥10%) in PALOMA-2 IBRANCE plus Letrozole (N=444) Placebo plus Letrozole (N=222) Adverse Reaction All Grades % Grade 3 % Grade 4 % All Grades % Grade 3 % Grade 4 % Grading according to CTCAE 4.0. CTCAE=Common Terminology Criteria for Adverse Events; N=number of patients; N/A=not applicable; Infections and infestations Infections Infections includes all reported preferred terms (PTs) that are part of the System Organ Class Infections and infestations. 60 Most common infections (≥1%) include: nasopharyngitis, upper respiratory tract infection, urinary tract infection, oral herpes, sinusitis, rhinitis, bronchitis, influenza, pneumonia, gastroenteritis, conjunctivitis, herpes zoster, pharyngitis, cellulitis, cystitis, lower respiratory tract infection, tooth infection, gingivitis, skin infection, gastroenteritis viral, respiratory tract infection, respiratory tract infection viral, and folliculitis. 6 1 42 3 0 Blood and lymphatic system disorders Neutropenia 80 56 10 6 1 1 Leukopenia 39 24 1 2 0 0 Anemia 24 5 <1 9 2 0 Thrombocytopenia 16 1 <1 1 0 0 Metabolism and nutrition disorders Decreased appetite 15 1 0 9 0 0 Nervous system disorders Dysgeusia 10 0 0 5 0 0 Gastrointestinal disorders Stomatitis Stomatitis includes: aphthous stomatitis, cheilitis, glossitis, glossodynia, mouth ulceration, mucosal inflammation, oral pain, oral discomfort, oropharyngeal pain, and stomatitis. 30 1 0 14 0 0 Nausea 35 <1 0 26 2 0 Diarrhea 26 1 0 19 1 0 Vomiting 16 1 0 17 1 0 Skin and subcutaneous tissue disorders Alopecia 33 Grade 1 events – 30%; Grade 2 events – 3%. N/A N/A 16 Grade 1 events – 15%; Grade 2 events – 1%. N/A N/A Rash Rash includes the following PTs: rash, rash maculo-papular, rash pruritic, rash erythematous, rash papular, dermatitis, dermatitis acneiform, and toxic skin eruption. 18 1 0 12 1 0 Dry skin 12 0 0 6 0 0 General disorders and administration site conditions Fatigue 37 2 0 28 1 0 Asthenia 17 2 0 12 0 0 Pyrexia 12 0 0 9 0 0 Clinically relevant adverse reactions in <10% of patients who received IBRANCE plus letrozole in PALOMA-2 included epistaxis (9%), lacrimation increased (6%), dry eye (4.1%), vision blurred (3.6%), and febrile neutropenia (2.5%). Table 5. Laboratory Abnormalities in PALOMA-2 IBRANCE plus Letrozole (N=444) Placebo plus Letrozole (N=222) Laboratory Abnormality All Grades % Grade 3 % Grade 4 % All Grades % Grade 3 % Grade 4 % N=number of patients; WBC=white blood cells. WBC decreased 97 35 1 25 1 0 Blood creatinine increased 96 2 <1 91 0 0 Neutrophils decreased 95 56 12 20 1 1 Hemoglobin decreased 78 6 0 42 2 0 Platelets decreased 63 1 1 14 0 0 Aspartate aminotransferase increased 52 3 0 34 1 0 Alanine aminotransferase increased 43 2 <1 30 0 0 PALOMA-3: IBRANCE plus Fulvestrant Patients with HR-positive, HER2-negative advanced or metastatic breast cancer who have had disease progression on or after prior adjuvant or metastatic endocrine therapy The safety of IBRANCE (125 mg/day) plus fulvestrant (500 mg) versus placebo plus fulvestrant was evaluated in PALOMA-3. The data described below reflect exposure to IBRANCE in 345 out of 517 patients with HR-positive, HER2-negative advanced or metastatic breast cancer who received at least 1 dose of IBRANCE plus fulvestrant in PALOMA-3. The median duration of treatment for IBRANCE plus fulvestrant was 10.8 months while the median duration of treatment for placebo plus fulvestrant arm was 4.8 months. Dose reductions due to an adverse reaction of any grade occurred in 36% of patients receiving IBRANCE plus fulvestrant. No dose reduction was allowed for fulvestrant in PALOMA-3. Permanent discontinuation associated with an adverse reaction occurred in 19 of 345 (6%) patients receiving IBRANCE plus fulvestrant, and in 6 of 172 (3%) patients receiving placebo plus fulvestrant. Adverse reactions leading to discontinuation for those patients receiving IBRANCE plus fulvestrant included fatigue (0.6%), infections (0.6%), and thrombocytopenia (0.6%). The most common adverse reactions (≥10%) of any grade reported in patients in the IBRANCE plus fulvestrant arm by descending frequency were neutropenia, leukopenia, infections, fatigue, nausea, anemia, stomatitis, diarrhea, thrombocytopenia, vomiting, alopecia, rash, decreased appetite, and pyrexia. The most frequently reported Grade ≥3 adverse reactions (≥5%) in patients receiving IBRANCE plus fulvestrant in descending frequency were neutropenia and leukopenia. Adverse reactions (≥10%) reported in patients who received IBRANCE plus fulvestrant or placebo plus fulvestrant in PALOMA-3 are listed in Table 6. Table 6. Adverse Reactions (≥10%) in PALOMA-3 Adverse Reaction IBRANCE plus Fulvestrant (N=345) Placebo plus Fulvestrant (N=172) All Grades Grade 3 Grade 4 All Grades Grade 3 Grade 4 % % % % % % Grading according to CTCAE 4.0. CTCAE=Common Terminology Criteria for Adverse Events; N=number of patients; N/A=not applicable. Infections and infestations Infections Infections includes all reported preferred terms (PTs) that are part of the System Organ Class Infections and infestations. 47 Most common infections (≥1%) include: nasopharyngitis, upper respiratory infection, urinary tract infection, bronchitis, rhinitis, influenza, conjunctivitis, sinusitis, pneumonia, cystitis, oral herpes, respiratory tract infection, gastroenteritis, tooth infection, pharyngitis, eye infection, herpes simplex, and paronychia. 3 1 31 3 0 Blood and lymphatic system disorders Neutropenia 83 55 11 4 1 0 Leukopenia 53 30 1 5 1 1 Anemia 30 4 0 13 2 0 Thrombocytopenia 23 2 1 0 0 0 Metabolism and nutrition disorders Decreased appetite 16 1 0 8 1 0 Gastrointestinal disorders Nausea 34 0 0 28 1 0 Stomatitis Stomatitis includes: aphthous stomatitis, cheilitis, glossitis, glossodynia, mouth ulceration, mucosal inflammation, oral pain, oropharyngeal discomfort, oropharyngeal pain, stomatitis. 28 1 0 13 0 0 Diarrhea 24 0 0 19 1 0 Vomiting 19 1 0 15 1 0 Skin and subcutaneous tissue disorders Alopecia 18 Grade 1 events – 17%; Grade 2 events – 1%. N/A N/A 6 Grade 1 events – 6%. N/A N/A Rash Rash includes: rash, rash maculo-papular, rash pruritic, rash erythematous, rash papular, dermatitis, dermatitis acneiform, toxic skin eruption. 17 1 0 6 0 0 General disorders and administration site conditions Fatigue 41 2 0 29 1 0 Pyrexia 13 <1 0 5 0 0 Clinically relevant adverse reactions in <10% of patients who received IBRANCE plus fulvestrant in PALOMA-3 included asthenia (8%), dysgeusia (7%), epistaxis (7%), lacrimation increased (6%), dry skin (6%), vision blurred (6%), dry eye (3.8%), and febrile neutropenia (0.9%). Table 7. Laboratory Abnormalities in PALOMA-3 Laboratory Abnormality IBRANCE plus Fulvestrant (N=345) Placebo plus Fulvestrant (N=172) All Grades % Grade 3 % Grade 4 % All Grades % Grade 3 % Grade 4 % N=number of patients; WBC=white blood cells. WBC decreased 99 45 1 26 0 1 Neutrophils decreased 96 56 11 14 0 1 Blood creatinine increased 95 1 0 82 0 0 Hemoglobin decreased 78 3 0 40 2 0 Platelets decreased 62 2 1 10 0 0 Aspartate aminotransferase increased 43 4 0 48 4 0 Alanine aminotransferase increased 36 2 0 34 0 0 INAVO120: IBRANCE plus Inavolisib and Fulvestrant Adults with PIK3CA-mutated, HR-positive, HER2-negative, locally advanced or metastatic breast cancer whose disease progressed during or within 12 months of completing adjuvant endocrine therapy and who have not received prior systemic therapy for locally advanced or metastatic disease The safety of the combination of IBRANCE plus inavolisib and fulvestrant was evaluated in a randomized, double-blind, placebo-controlled study (INAVO120) in 324 patients with PIK3CA -mutated, HR-positive, HER2-negative, locally advanced or metastatic breast cancer [see Clinical Studies (14) ] . Patients received either IBRANCE 125 mg orally once daily for 21 consecutive days followed by 7 days off treatment to comprise a cycle of 28 days plus fulvestrant in combination with inavolisib (n=162) or placebo (n=162). The median duration of treatment for IBRANCE plus inavolisib and fulvestrant was 9 months (range: 0 to 39 months). Serious adverse reactions occurred in 24% of patients who received IBRANCE plus inavolisib and fulvestrant. Serious adverse reactions occurring in ≥1% of patients receiving IBRANCE plus inavolisib and fulvestrant included anemia (1.9%), diarrhea (1.2%), and urinary tract infection (1.2%). Fatal adverse reactions occurred in 3.7% of patients who received IBRANCE plus inavolisib and fulvestrant, including (0.6% each) acute coronary syndrome, cerebral hemorrhage, cerebrovascular accident, COVID-19 infection, and gastrointestinal hemorrhage. Permanent discontinuation of IBRANCE associated with an adverse reaction occurred in 8 of 162 (4.9%) patients receiving IBRANCE plus inavolisib and fulvestrant and in 0 of 162 patients receiving IBRANCE plus placebo and fulvestrant. Adverse reactions leading to discontinuation of IBRANCE in patients receiving IBRANCE plus inavolisib and fulvestrant were neutropenia, infections, alanine aminotransferase increased, gastric ulcer, intestinal perforation, hyperglycemia, type 2 diabetes mellitus, bone pain, musculoskeletal pain, transitional cell carcinoma, and acute kidney injury (0.6% each). Dose reduction of IBRANCE due to an adverse reaction occurred in 38% of patients receiving IBRANCE plus inavolisib and fulvestrant and in 30% of patients receiving IBRANCE plus placebo and fulvestrant. Adverse reactions leading to dose reductions of IBRANCE in ≥2% patients receiving IBRANCE plus inavolisib and fulvestrant were neutropenia (30%), leukopenia (6%), and thrombocytopenia (3.7%). Dose interruption of IBRANCE due to an adverse reaction occurred in 71% of patients receiving IBRANCE plus inavolisib and fulvestrant and in 61% of patients receiving IBRANCE plus placebo and fulvestrant. Adverse reactions leading to dose interruption of IBRANCE in ≥2% patients receiving IBRANCE plus inavolisib and fulvestrant were neutropenia (56%), infections (29%), leukopenia (12%), stomatitis (4.9%), anemia (6%), thrombocytopenia (4.3%), diarrhea (3.7%), pyrexia (3.1%), alanine aminotransferase increased (2.5%), hyperglycemia (2.5%), and nausea (2.5%). The most common (≥20%) adverse reactions, including laboratory abnormalities, were decreased neutrophils, decreased hemoglobin, increased fasting glucose, decreased platelets, decreased lymphocytes, stomatitis, diarrhea, decreased calcium, fatigue, decreased potassium, increased creatinine, increased alanine aminotransferase (ALT), nausea, decreased sodium, decreased magnesium, rash, decreased appetite, COVID-19 infection, and headache. Adverse reactions and laboratory abnormalities in INAVO120 are summarized in Table 8 and Table 9, respectively. Table 8. Adverse Reactions (≥10% with ≥5% [All Grades] or ≥2% [Grade 3-4] Higher Incidence in the IBRANCE plus inavolisib and fulvestrant Arm) in INAVO120 Adverse Reaction IBRANCE plus Inavolisib and Fulvestrant (N=162) IBRANCE plus Placebo and Fulvestrant (N=162) All Grades (%) Grade 3-4 (%) All Grades (%) Grade 3-4 (%) Gastrointestinal Disorders Stomatitis Includes aphthous ulcer, glossitis, glossodynia, lip ulceration, mouth ulceration, mucosal inflammation, and stomatitis. 51 6 No Grade 4 adverse reactions were observed. 27 0 Diarrhea 48 3.7 16 0 Nausea 28 0.6 17 0 Vomiting 15 0.6 4.9 1.2 General Disorders and Administration Site Conditions Fatigue 38 1.9 25 1.2 Skin and Subcutaneous Tissue Disorders Rash Includes other related terms. 26 0 19 0 Alopecia 19 0 6 0 Dry skin Includes dry skin, skin fissures, xerosis, and xeroderma. 13 0 4.3 0 Metabolism and Nutrition Disorders Decreased appetite 24 0 9 0 Infections and Infestations COVID-19 infection 23 1.9 10 0.6 Urinary tract infection 15 1.2 9 0 Nervous System Disorders Headache 22 0 14 0 Investigations Decreased weight 17 3.7 0.6 0 Clinically relevant adverse reactions occurring in <10% of patients who received the triplet combination of IBRANCE plus inavolisib and fulvestrant included abdominal pain, dry eye, dysgeusia, and dyspepsia. Table 9. Select Laboratory Abnormalities (≥10% with a ≥2% [All Grades or Grade 3-4] Higher Incidence in the IBRANCE plus Inavolisib and Fulvestrant Arm) in INAVO120 ALT=alanine aminotransferase. Laboratory Abnormality IBRANCE plus Inavolisib and Fulvestrant The denominator used to calculate the rate varied from 122 to 160 based on the number of patients with a baseline value and at least one post-treatment value. IBRANCE plus Placebo and Fulvestrant The denominator used to calculate the rate varied from 131 to 161 based on the number of patients with a baseline value and at least one post-treatment value. All Grades (%) Grade 3-4 (%) All Grades (%) Grade 3-4 (%) Hematology Neutrophils (total, absolute) decreased 95 82 97 79 Hemoglobin decreased 88 8 No Grade 4 laboratory abnormalities were observed. 85 2.5 Platelets decreased 8 16 71 3.7 Lymphocytes (absolute) decreased 72 9 68 14 Chemistry Glucose (fasting) increased Grading according to CTCAE version 4.03. 85 12 43 0 Calcium decreased 42 3.1 32 3.7 Potassium decreased 38 6 21 0.6 Creatinine increased 38 1.9 30 1.2 ALT increased 34 3.1 29 1.2 Sodium decreased 28 2.5 19 2.5 Magnesium decreased 27 0.6 21 0 Lipase (fasting) increased 16 1.4 7 0 Other Clinical Trials Experience The following adverse reaction has been reported following administration of IBRANCE: venous thromboembolism. 6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of IBRANCE. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Respiratory Disorders: Interstitial lung disease (ILD)/non-infectious pneumonitis Skin and Subcutaneous Tissue Disorders: Palmar-plantar erythrodysesthesia syndrome (PPES) Male Patients with HR-Positive, HER2-Negative Advanced or Metastatic Breast Cancer Based on limited data from postmarketing reports and electronic health records, the safety profile for men treated with IBRANCE is consistent with the safety profile in women treated with IBRANCE.
Pharmacocinétique
12.3 Pharmacokinetics The pharmacokinetics (PK) of palbociclib were characterized in patients with solid tumors including advanced breast cancer and in healthy subjects. Absorption The mean maximum observed concentration (C max ) of palbociclib is generally observed between 6 to 12 hours (time to reach maximum concentration, T max ) following oral administration. The mean absolute bioavailability of IBRANCE after an oral 125 mg dose is 46%. In the dosing range of 25 mg to 225 mg, the AUC and C max increased proportionally with dose in general. Steady state was achieved within 8 days following repeated once daily dosing. With repeated once daily administration, palbociclib accumulated with a median accumulation ratio of 2.4 (range 1.5 to 4.2). Food effect : Palbociclib absorption and exposure were very low in approximately 13% of the population under the fasted condition. Food intake increased the palbociclib exposure in this small subset of the population, but did not alter palbociclib exposure in the rest of the population to a clinically relevant extent. Therefore, food intake reduced the intersubject variability of palbociclib exposure, which supports administration of IBRANCE with food. Compared to IBRANCE given under overnight fasted conditions, the population average area under the concentration-time curve from zero to infinity (AUC INF ) and C max of palbociclib increased by 21% and 38%, respectively, when given with high-fat, high-calorie food (approximately 800 to 1000 calories with 150, 250, and 500 to 600 calories from protein, carbohydrate, and fat, respectively), by 12% and 27%, respectively, when given with low-fat, low-calorie food (approximately 400 to 500 calories with 120, 250, and 28 to 35 calories from protein, carbohydrate, and fat, respectively), and by 13% and 24%, respectively, when moderate-fat, standard calorie food (approximately 500 to 700 calories with 75 to 105, 250 to 350 and 175 to 245 calories from protein, carbohydrate, and fat, respectively) was given 1 hour before and 2 hours after IBRANCE dosing. Distribution Binding of palbociclib to human plasma proteins in vitro was approximately 85%, with no concentration dependence over the concentration range of 500 ng/mL to 5000 ng/mL. The mean fraction unbound (f u ) of palbociclib in human plasma in vivo increased incrementally with worsening hepatic function. There was no obvious trend in the mean palbociclib f u in human plasma in vivo with worsening renal function. The geometric mean apparent volume of distribution (V z /F) was 2583 L with a coefficient of variation (CV) of 26%. Metabolism In vitro and in vivo studies indicated that palbociclib undergoes hepatic metabolism in humans. Following oral administration of a single 125 mg dose of [ 14 C]palbociclib to humans, the primary metabolic pathways for palbociclib involved oxidation and sulfonation, with acylation and glucuronidation contributing as minor pathways. Palbociclib was the major circulating drug-derived entity in plasma (23%). The major circulating metabolite was a glucuronide conjugate of palbociclib, although it only represented 1.5% of the administered dose in the excreta. Palbociclib was extensively metabolized with unchanged drug accounting for 2.3% and 6.9% of radioactivity in feces and urine, respectively. In feces, the sulfamic acid conjugate of palbociclib was the major drug-related component, accounting for 26% of the administered dose. In vitro studies with human hepatocytes, liver cytosolic and S9 fractions, and recombinant SULT enzymes indicated that CYP3A and SULT2A1 are mainly involved in the metabolism of palbociclib. Elimination The geometric mean apparent oral clearance (CL/F) of palbociclib was 63.1 L/hr (29% CV), and the mean (± standard deviation) plasma elimination half-life was 29 (±5) hours in patients with advanced breast cancer. In 6 healthy male subjects given a single oral dose of [ 14 C]palbociclib, a median of 91.6% of the total administered radioactive dose was recovered in 15 days; feces (74.1% of dose) was the major route of excretion, with 17.5% of the dose recovered in urine. The majority of the material was excreted as metabolites. Specific Populations Age, Gender, and Body Weight Based on a population pharmacokinetic analysis in 183 patients with cancer (50 male and 133 female patients, age range from 22 to 89 years, and body weight range from 37.9 to 123 kg), gender had no effect on the exposure of palbociclib, and age and body weight had no clinically important effect on the exposure of palbociclib. Hepatic Impairment Data from a pharmacokinetic trial in subjects with varying degrees of hepatic impairment indicate that palbociclib unbound AUC INF decreased 17% in subjects with mild hepatic impairment (Child-Pugh class A), and increased by 34% and 77% in subjects with moderate (Child-Pugh class B) and severe (Child-Pugh class C) hepatic impairment, respectively, relative to subjects with normal hepatic function. Palbociclib unbound C max increased by 7%, 38% and 72% for mild, moderate and severe hepatic impairment, respectively, relative to subjects with normal hepatic function. In addition, based on a population pharmacokinetic analysis that included 183 patients, where 40 patients had mild hepatic impairment based on National Cancer Institute (NCI) classification (total bilirubin ≤ ULN and AST > ULN, or total bilirubin >1.0 to 1.5 × ULN and any AST), mild hepatic impairment had no effect on the exposure of palbociclib, further supporting the findings from the dedicated hepatic impairment study. Renal Impairment Data from a pharmacokinetic trial in subjects with varying degrees of renal impairment indicate that palbociclib AUC INF increased by 39%, 42%, and 31% with mild (60 mL/min ≤ CrCl <90 mL/min), moderate (30 mL/min ≤ CrCl <60 mL/min), and severe (CrCl <30 mL/min) renal impairment, respectively, relative to subjects with normal renal function. Peak palbociclib exposure (C max ) increased by 17%, 12%, and 15% for mild, moderate, and severe renal impairment, respectively, relative to subjects with normal renal function. In addition, based on a population pharmacokinetic analysis that included 183 patients where 73 patients had mild renal impairment and 29 patients had moderate renal impairment, mild and moderate renal impairment had no effect on the exposure of palbociclib. The pharmacokinetics of palbociclib have not been studied in patients requiring hemodialysis. Drug Interactions In vitro data indicate that CYP3A and SULT enzyme SULT2A1 are mainly involved in the metabolism of palbociclib. Palbociclib is a weak time-dependent inhibitor of CYP3A following daily 125 mg dosing to steady state in humans. In vitro, palbociclib is not an inhibitor of CYP1A2, 2A6, 2B6, 2C8, 2C9, 2C19, and 2D6, and is not an inducer of CYP1A2, 2B6, 2C8, and 3A4 at clinically relevant concentrations. CYP3A Inhibitors: Data from a drug interaction trial in healthy subjects (N=12) indicate that coadministration of multiple 200 mg daily doses of itraconazole with a single 125 mg IBRANCE dose increased palbociclib AUC INF and the C max by approximately 87% and 34%, respectively, relative to a single 125 mg IBRANCE dose given alone [see Drug Interactions (7.1) ] . CYP3A Inducers: Data from a drug interaction trial in healthy subjects (N=15) indicate that coadministration of multiple 600 mg daily doses of rifampin, a strong CYP3A inducer, with a single 125 mg IBRANCE dose decreased palbociclib AUC INF and C max by 85% and 70%, respectively, relative to a single 125 mg IBRANCE dose given alone. Data from a drug interaction trial in healthy subjects (N=14) indicate that coadministration of multiple 400 mg daily doses of modafinil, a moderate CYP3A inducer, with a single 125 mg IBRANCE dose decreased palbociclib AUC INF and C max by 32% and 11%, respectively, relative to a single 125 mg IBRANCE dose given alone [see Drug Interactions (7.2) ] . CYP3A Substrates: Palbociclib is a weak time-dependent inhibitor of CYP3A following daily 125 mg dosing to steady state in humans. In a drug interaction trial in healthy subjects (N=26), coadministration of midazolam with multiple doses of IBRANCE increased the midazolam AUC INF and the C max values by 61% and 37%, respectively, as compared to administration of midazolam alone [see Drug Interactions (7.3) ] . Gastric pH Elevating Medications: In a drug interaction trial in healthy subjects, coadministration of a single 125 mg dose of IBRANCE with multiple doses of the proton pump inhibitor (PPI) rabeprazole under fed conditions decreased palbociclib C max by 41%, but had limited impact on AUC INF (13% decrease), when compared to a single dose of IBRANCE administered alone. Given the reduced effect on gastric pH of H2-receptor antagonists and local antacids compared to PPIs, the effect of these classes of acid-reducing agents on palbociclib exposure under fed conditions is expected to be minimal. Under fed conditions there is no clinically relevant effect of PPIs, H2-receptor antagonists, or local antacids on palbociclib exposure. In another healthy subject study, coadministration of a single dose of IBRANCE with multiple doses of the PPI rabeprazole under fasted conditions decreased palbociclib AUC INF and C max by 62% and 80%, respectively, when compared to a single dose of IBRANCE administered alone. Effect of Palbociclib on Transporters: In vitro evaluations indicated that palbociclib has a low potential to inhibit the activities of drug transporters organic anion transporter (OAT)1, OAT3, organic cation transporter (OCT)2, and organic anion transporting polypeptide (OATP)1B1, OATP1B3 at clinically relevant concentrations. In vitro, palbociclib has the potential to inhibit OCT1 at clinically relevant concentrations, as well as the potential to inhibit P-glycoprotein (P-gp) or breast cancer resistance protein (BCRP) in the gastrointestinal tract at the proposed dose. Effect of Transporters on Palbociclib: Based on in vitro data, P-gp and BCRP mediated transport are unlikely to affect the extent of oral absorption of palbociclib at therapeutic doses.