Lapatinib

1 INDICATIONS AND USAGE Lapatinib tablets are indicated in combination with: capecitabine for the treatment of patients with advanced or metastatic breast cancer whose tumors overexpress human epidermal growth factor receptor 2 (HER2) and who have received prior therapy, including an anthracycline, a taxane, and trastuzumab. Limitations of Use : Patients should have disease progression on trastuzumab prior to initiation of treatment with lapatinib tablets in combination with capecitabine. letrozole for the treatment of postmenopausal women with hormone receptor-positive metastatic breast cancer that overexpresses the HER2 receptor for whom hormonal therapy is indicated. Lapatinib tablets in combination with an aromatase inhibitor has not been compared to a trastuzumab-containing chemotherapy regimen for the treatment of metastatic breast cancer. Lapatinib tablets are a kinase inhibitor indicated in combination with: ( 1 ) capecitabine for the treatment of patients with advanced or metastatic breast cancer whose tumors overexpress human epidermal growth factor receptor 2 (HER2) and who have received prior therapy, including an anthracycline, a taxane, and trastuzumab. Limitations of Use : Patients should have disease progression on trastuzumab prior to initiation of treatment with lapatinib tablets in combination with capecitabine. letrozole for the treatment of postmenopausal women with hormone receptor-positive metastatic breast cancer that overexpresses the HER2 receptor for whom hormonal therapy is indicated. Lapatinib tablets in combination with an aromatase inhibitor has not been compared to a trastuzumab-containing chemotherapy regimen for the treatment of metastatic breast cancer.

12.1 Mechanism of Action Lapatinib is a 4-anilinoquinazoline kinase inhibitor of the intracellular tyrosine kinase domains of both Epidermal Growth Factor Receptor (EGFR [ErbB1]) and of Human Epidermal Receptor Type 2 (HER2 [ErbB2]) receptors (estimated Ki app values of 3nM and 13nM, respectively) with a dissociation half-life of greater than or equal to 300 minutes. Lapatinib inhibits ErbB-driven tumor cell growth in vitro and in various animal models. An additive effect was demonstrated in an in vitro study when lapatinib and 5-FU (the active metabolite of capecitabine) were used in combination in the 4-tumor cell lines tested. The growth inhibitory effects of lapatinib were evaluated in trastuzumab-conditioned cell lines. Lapatinib retained significant activity against breast cancer cell lines selected for long-term growth in trastuzumab-containing medium in vitro . These in vitro findings suggest non-cross-resistance between these two agents. Hormone receptor-positive breast cancer cells (with ER [Estrogen Receptor] and/or PgR [Progesterone Receptor]) that coexpress the HER2 tend to be resistant to established endocrine therapies. Similarly, hormone receptor-positive breast cancer cells that initially lack EGFR or HER2 upregulate these receptor proteins as the tumor becomes resistant to endocrine therapy.

2 DOSAGE AND ADMINISTRATION The recommended dosage of lapatinib tablets for advanced or metastatic breast cancer is 1,250 mg (5 tablets) given orally once daily on Days 1 to 21 continuously in combination with capecitabine 2,000 mg/m 2 /day (administered orally in 2 doses approximately 12 hours apart) on Days 1 to 14 in a repeating 21-day cycle. ( 2.1 ) The recommended dose of lapatinib tablets for hormone receptor-positive, HER2-positive metastatic breast cancer is 1,500 mg (6 tablets) given orally once daily continuously in combination with letrozole. When lapatinib tablets are coadministered with letrozole, the recommended dose of letrozole is 2.5 mg once daily. ( 2.1 ) Lapatinib tablets should be taken at least one hour before or one hour after a meal. However, capecitabine should be taken with food or within 30 minutes after food. ( 2.1 ) Lapatinib tablets should be taken once daily. Do not divide daily doses of lapatinib tablets. ( 2.1 , 12.3 ) Modify dose for cardiac and other toxicities, severe hepatic impairment, diarrhea, and CYP3A4 drug interactions. ( 2.2 ) 2.1 Recommended Dosing HER2-Positive Metastatic Breast Cancer : The recommended dose of lapatinib tablets is 1,250 mg given orally once daily on Days 1 to 21 continuously in combination with capecitabine 2,000 mg/m 2 /day (administered orally in 2 doses approximately 12 hours apart) on Days 1 to 14 in a repeating 21-day cycle. Lapatinib tablets should be taken at least one hour before or one hour after a meal. The dose of lapatinib tablets should be once daily (5 tablets administered all at once); dividing the daily dose is not recommended [see Clinical Pharmacology (12.3)] . Capecitabine should be taken with food or within 30 minutes after food. If a day’s dose is missed, the patient should not double the dose the next day. Treatment should be continued until disease progression or unacceptable toxicity occurs. Hormone Receptor-Positive, HER2-Positive Metastatic Breast Cancer : The recommended dose of lapatinib tablets is 1,500 mg given orally once daily continuously in combination with letrozole. When coadministered with lapatinib tablets, the recommended dose of letrozole is 2.5 mg once daily. Lapatinib tablets should be taken at least one hour before or one hour after a meal. The dose of lapatinib tablets should be once daily (6 tablets administered all at once); dividing the daily dose is not recommended [see Clinical Pharmacology (12.3)] . 2.2 Dose Modification Guidelines Cardiac Events : Lapatinib tablets should be discontinued in patients with a decreased left ventricular ejection fraction (LVEF) that is Grade 2 or greater by National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE v3.0), and in patients with an LVEF that drops below the institution’s lower limit of normal (LLN) [see Warnings and Precautions (5.1) and Adverse Reactions (6.1)] . Lapatinib tablets in combination with capecitabine may be restarted at a reduced dose (1,000 mg/day) and in combination with letrozole may be restarted at a reduced dose of 1,250 mg/day after a minimum of 2 weeks if the LVEF recovers to normal and the patient is asymptomatic. Hepatic Impairment : Patients with severe hepatic impairment (Child-Pugh Class C) should have their dose of lapatinib tablets reduced. A dose reduction from 1,250 mg/day to 750 mg/day (HER2-positive metastatic breast cancer indication) or from 1,500 mg/day to 1,000 mg/day (hormone receptor-positive, HER2-positive breast cancer indication) in patients with severe hepatic impairment is predicted to adjust the area under the curve (AUC) to the normal range and should be considered. However, there are no clinical data with this dose adjustment in patients with severe hepatic impairment. Diarrhea : Lapatinib tablets should be interrupted in patients with diarrhea which is NCI CTCAE Grade 3 or Grade 1 or 2 with complicating features (moderate to severe abdominal cramping, nausea or vomiting greater than or equal to NCI CT

6 ADVERSE REACTIONS The most common (greater than 20%) adverse reactions during treatment with lapatinib plus capecitabine were diarrhea, palmar-plantar erythrodysesthesia, nausea, rash, vomiting, and fatigue. The most common (greater than or equal to 20%) adverse reactions during treatment with lapatinib plus letrozole were diarrhea, rash, nausea, and fatigue. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact AvKARE at 1-855-361-3993 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials 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. HER2-Positive Metastatic Breast Cancer : The safety of lapatinib has been evaluated in more than 12,000 patients in clinical trials. The efficacy and safety of lapatinib in combination with capecitabine in breast cancer was evaluated in 198 patients in a randomized, Phase 3 trial [see Clinical Studies ( 14.1 )] . Adverse reactions, which occurred in at least 10% of patients in either treatment arm and were higher in the combination arm, are shown in Table 1. The most common adverse reactions (greater than 20%) during therapy with lapatinib plus capecitabine were gastrointestinal (diarrhea, nausea, and vomiting), dermatologic (palmar-plantar erythrodysesthesia and rash), and fatigue. Diarrhea was the most common adverse reaction resulting in discontinuation of study medication. The most common Grades 3 and 4 adverse reactions (NCI CTCAE v3.0) were diarrhea and palmar-plantar erythrodysesthesia. Selected laboratory abnormalities are shown in Table 2. Table 1. Adverse Reactions Occurring in Greater Than or Equal to 10% of Patients a NCI CTCAE v3.0. b Grade 3 dermatitis acneiform was reported in less than 1% of patients in the group receiving lapatinib plus capecitabine. Lapatinib 1,250 mg/day + Capecitabine 2,000 mg/m 2 /day Capecitabine 2,500 mg/m 2 /day (N = 198) (N = 191) All Grades a Grade 3 Grade 4 All Grades a Grade 3 Grade 4 Reactions % % % % % % Gastrointestinal disorders Diarrhea 65 13 1 40 10 0 Nausea 44 2 0 43 2 0 Vomiting 26 2 0 21 2 0 Stomatitis 14 0 0 11 < 1 0 Dyspepsia 11 < 1 0 3 0 0 Skin and subcutaneous tissue disorders Palmar-plantar erythrodysesthesia 53 12 0 51 14 0 Rash b 28 2 0 14 1 0 Dry skin 10 0 0 6 0 0 General disorders and administration site conditions Mucosal inflammation 15 0 0 12 2 0 Musculoskeletal and connective tissue disorders Pain in extremity 12 1 0 7 < 1 0 Back pain 11 1 0 6 < 1 0 Respiratory, thoracic, and mediastinal disorders Dyspnea 12 3 0 8 2 0 Psychiatric disorders Insomnia 10 < 1 0 6 0 0 Table 2. Selected Laboratory Abnormalities Abbreviations: ALT, alanine aminotransferase; AST, aspartate aminotransferase. a NCI CTCAE v3.0. Lapatinib 1,250 mg/day + Capecitabine 2,000 mg/m 2 /day Capecitabine 2,500 mg/m 2 /day All Grades a Grade 3 Grade 4 All Grades a Grade 3 Grade 4 Parameters % % % % % % Hematologic Hemoglobin 56 < 1 0 53 1 0 Platelets 18 < 1 0 17 < 1 < 1 Neutrophils 22 3 < 1 31 2 1 Hepatic Total Bilirubin 45 4 0 30 3 0 AST 49 2 < 1 43 2 0 ALT 37 2 0 33 1 0 Hormone Receptor-Positive, Metastatic Breast Cancer : In a randomized, Phase 3 clinical trial of patients (N = 1,286) with hormone receptor-positive, metastatic breast cancer, who had not received chemotherapy for their metastatic disease, patients received letrozole with or without lapatinib. In this trial, the safety profile of lapatinib was consistent with previously reported results from trials of lapatinib in the advanced or metastatic breast cancer population. Adverse reactions, which occurred in at least 10% of patients in either treatment arm and were higher in the combination arm are shown in Table 3. Selected laboratory abnormalities are shown in Table 4. Table 3. Adverse Reactions Occurring in Greater Than or Equal to 10% of Patients a NCI CTCAE

5 WARNINGS AND PRECAUTIONS Decreases in left ventricular ejection fraction (LVEF) have been reported. Confirm normal LVEF before starting lapatinib and continue evaluations during treatment. ( 5.1 ) Lapatinib has been associated with hepatotoxicity. Monitor liver function tests before initiation of treatment, every 4 to 6 weeks during treatment, and as clinically indicated. Discontinue and do not restart lapatinib if patients experience severe changes in liver function tests. ( 5.2 ) Dose reduction in patients with severe hepatic impairment should be considered. ( 2.2 , 5.3 , 8.7 ) Diarrhea, including severe diarrhea, has been reported during treatment. Manage with antidiarrheal agents, and replace fluids and electrolytes if severe. ( 5.4 ) Lapatinib has been associated with interstitial lung disease and pneumonitis. Discontinue lapatinib if patients experience severe pulmonary symptoms. ( 5.5 ) Lapatinib may prolong the QT interval in some patients. Consider electrocardiogram (ECG) and electrolyte monitoring. ( 5.6, 12.2 ) Severe cutaneous reactions have been reported. Discontinue lapatinib if life-threatening reactions are suspected. ( 5.7 ) Lapatinib can cause fetal harm. Advise patients of the potential risk to the fetus and to use effective contraception. ( 5.8 , 8.1 , 8.3 ) 5.1 Decreased Left Ventricular Ejection Fraction Lapatinib has been reported to decrease LVEF [see Adverse Reactions ( 6.1 )] . In clinical trials, the majority (greater than 57%) of LVEF decreases occurred within the first 12 weeks of treatment; however, data on long-term exposure are limited. Caution should be taken if lapatinib is to be administered to patients with conditions that could impair left ventricular function. LVEF should be evaluated in all patients prior to initiation of treatment with lapatinib to ensure that the patient has a baseline LVEF that is within the institution’s normal limits. LVEF should continue to be evaluated during treatment with lapatinib to ensure that LVEF does not decline below the institution’s normal limits [see Dosage and Administration ( 2.2 )] . 5.2 Hepatotoxicity Hepatotoxicity [alanine aminotransferase (ALT) or aspartate aminotransferase (AST) greater than 3 times the upper limit of normal (ULN) and total bilirubin greater than 2 times the ULN] has been observed in clinical trials (less than 1% of patients) and postmarketing experience. The hepatotoxicity may be severe and deaths have been reported. Causality of the deaths is uncertain. The hepatotoxicity may occur days to several months after initiation of treatment. Liver function tests (transaminases, bilirubin, and alkaline phosphatase) should be monitored before initiation of treatment, every 4 to 6 weeks during treatment, and as clinically indicated. If changes in liver function are severe, therapy with lapatinib should be discontinued and patients should not be retreated with lapatinib [see Adverse Reactions ( 6.1 )] . 5.3 Patients With Severe Hepatic Impairment If lapatinib is to be administered to patients with severe preexisting hepatic impairment, dose reduction should be considered [see Dosage and Administration (2.2 ) and Use in Specific Populations ( 8.7 )] . In patients who develop severe hepatotoxicity while on therapy, lapatinib should be discontinued and patients should not be retreated with lapatinib [see Warnings and Precautions ( 5.2 )] . 5.4 Diarrhea Diarrhea has been reported during treatment with lapatinib [see Adverse Reactions ( 6.1 )] . The diarrhea may be severe, and deaths have been reported. Diarrhea generally occurs early during treatment with lapatinib, with almost half of those patients with diarrhea first experiencing it within 6 days. This usually lasts 4 to 5 days. Lapatinib-induced diarrhea is usually low-grade, with severe diarrhea of NCI CTCAE Grades 3 and 4 occurring in less than 10% and less than 1% of patients, respectively. Early identification and intervention is critical for the optimal management of diarrhea. Pat

4 CONTRAINDICATIONS Lapatinib tablets are contraindicated in patients with known severe hypersensitivity (e.g., anaphylaxis) to this product or any of its components. Known severe hypersensitivity (e.g., anaphylaxis) to this product or any of its components. ( 4 )

10 OVERDOSAGE There is no known antidote for overdoses of lapatinib. The maximum oral doses of lapatinib that have been administered in clinical trials are 1,800 mg once daily. More frequent ingestion of lapatinib could result in serum concentrations exceeding those observed in clinical trials and could result in increased toxicity. Therefore, missed doses should not be replaced and dosing should resume with the next scheduled daily dose. Asymptomatic and symptomatic cases of overdose have been reported. The doses ranged from 2,500 to 9,000 mg daily and where reported, the duration varied between 1 and 17 days. Symptoms observed include lapatinib-associated events [see Adverse Reactions (6.1)] and in some cases sore scalp, sinus tachycardia (with otherwise normal ECG), and/or mucosal inflammation. Because lapatinib is not significantly renally excreted and is highly bound to plasma proteins, hemodialysis would not be expected to be an effective method to enhance the elimination of lapatinib. Treatment of overdose with lapatinib should consist of general supportive measures.