Lapatinib
WARNING: HEPATOTOXICITY
Hepatotoxicity has been observed in clinical trials and postmarketing experience. The hepatotoxicity may be severe and deaths have been reported. Causality of the deaths is uncertain. [See WARNINGS and PRECAUTIONS]
DRUG DESCRIPTION
Lapatinib is a small molecule and a member of the 4-anilinoquinazoline class of kinase inhibitors. It is present as the monohydrate of the ditosylate salt, with chemical name N-(3 chloro-4-{[(3-fluorophenyl)methyl]oxy}phenyl)-6-[5-({[2 (methylsulfonyl)ethyl]amino}methyl)-2-furanyl]-4-quinazolinamine bis(4 methylbenzenesulfonate) monohydrate. It has the molecular formula C29H26ClFN4O4S (C7H8O3S)2 H2O and a molecular weight of 943.5. Lapatinib ditosylate monohydrate has the following chemical structure:
Lapatinib is a yellow solid, and its solubility in water is 0.007 mg/mL and in 0.1N HCl is 0.001 mg/mL at 25ยฐ C.
Each 250 mg tablet of TYKERB contains 405 mg of lapatinib ditosylate monohydrate, equivalent to 398 mg of lapatinib ditosylate or 250 mg lapatinib free base.
The inactive ingredients of TYKERB are: Tablet Core:Magnesium stearate, microcrystalline cellulose, povidone, sodium starch glycolate. Coating: Orange film-coat: FD&C yellow No. 6/sunset yellow FCF aluminum lake, hypromellose, macrogol/PEG 400, polysorbate 80, titanium dioxide.
INDICATIONS
TYKERB is indicated in combination with capecitabine for the treatment of patients with advanced or metastatic breast cancer whose tumors overexpress HER2 and who have received prior therapy including an anthracycline, a taxane, and trastuzumab.
DOSAGE AND ADMINISTRATION
Recommended Dosing
The recommended dose of TYKERB is 1,250 mg (5 tablets) given orally once daily on Days 1-21 continuously in combination with capecitabine 2,000 mg/m2/day (administered orally in 2 doses approximately 12 hours apart) on Days 1-14 in a repeating 21 day cycle. TYKERB should be taken at least one hour before or one hour after a meal. The dose of TYKERB should be once daily; dividing the daily dose is not recommended [see CLINICAL PHARMACOLOGY].
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.
Dose Modification Guidelines
Cardiac Events: TYKERB should be discontinued in patients with a decreased left ventricular ejection fraction (LVEF) that is Grade 2 or greater by NCI Common Terminology Criteria for Adverse Events (NCI CTCAE) and in patients with an LVEF that drops below the institution's lower limit of normal [see WARNINGS and PRECAUTIONS and ADVERSE REACTIONS]. TYKERB may be restarted at a reduced dose (1,000 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 TYKERB reduced. A dose reduction to 750 mg/day 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 is no clinical data with this dose adjustment in patients with severe hepatic impairment.
Concomitant Strong CYP3A4 Inhibitors: The concomitant use of strong CYP3A4 inhibitors should be avoided (e.g., ketoconazole, itraconazole, clarithromycin, atazanavir, indinavir, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, voriconazole). Grapefruit may also increase plasma concentrations of lapatinib and should be avoided. If patients must be coadministered a strong CYP3A4 inhibitor, based on pharmacokinetic studies, a dose reduction to 500 mg/day of lapatinib is predicted to adjust the lapatinib AUC to the range observed without inhibitors and should be considered. However, there are no clinical data with this dose adjustment in patients receiving strong CYP3A4 inhibitors. If the strong inhibitor is discontinued, a washout period of approximately 1 week should be allowed before the lapatinib dose is adjusted upward to the indicated dose. [See DRUG INTERACTIONS]
Concomitant Strong CYP3A4 Inducers: The concomitant use of strong CYP3A4 inducers should be avoided (e.g., dexamethasone, phenytoin, carbamazepine, rifampin, rifabutin, rifapentin, phenobarbital, St. John's Wort). If patients must be coadministered a strong CYP3A4 inducer, based on pharmacokinetic studies, the dose of lapatinib should be titrated gradually from 1,250 mg/day up to 4,500 mg/day based on tolerability. This dose of lapatinib is predicted to adjust the lapatinib AUC to the range observed without inducers and should be considered. However, there are no clinical data with this dose adjustment in patients receiving strong CYP3A4 inducers. If the strong inducer is discontinued the lapatinib dose should be reduced to the indicated dose. [See DRUG INTERACTIONS.]
Other Toxicities: Discontinuation or interruption of dosing with TYKERB may be considered when patients develop ? Grade 2 NCI CTC toxicity and can be restarted at 1,250 mg/day when the toxicity improves to Grade 1 or less. If the toxicity recurs, then TYKERB should be restarted at a lower dose (1,000 mg/day). TYKERB should be restarted at a lower dose (1,000 mg/day).
See manufacturer's prescribing information for capecitabine dosage adjustment guidelines in the event of toxicity.
SIDE EFFECTS
Clinical Trials Experience
The safety of TYKERB has been evaluated in more than 3,500 patients in clinical trials. The efficacy and safety of TYKERB in combination with capecitabine in breast cancer was evaluated in 198 patients in a randomized, Phase 3 trial. [See Clinical Studies] 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.
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.
The most common adverse reactions ( > 20%) during therapy with TYKERB plus capecitabine were gastrointestinal (diarrhea, nausea, and vomiting), dermatologic (palmarplantar erythrodysesthesia and rash), and fatigue. Diarrhea was the most common adverse reaction resulting in discontinuation of study medication.
The most common Grade 3 and 4 adverse reactions (NCI CTC v3) were diarrhea and palmar-plantar erythrodysesthesia. Selected laboratory abnormalities are shown in Table 2.
Table 1. Adverse Reactions Occurring in 10% of Patients TYKERB 1,250 mg/day + Capecitabine 2,000 mg/m2/day
(N = 198) Capecitabine
2,500 mg/m2/day
(N = 191)
Reactions All Grades* % Grade 3 % Grade 4 % All Grades* % Grade 3 % Grade 4 %
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
Skinand subcutaneous tissue disorders
Palmar-plantar erythrodysesthesia 53 12 0 51 14 0
Rashโ 28 2 0 14 1 0
Dry skin 10 0 0 6 0 0
General disorders and administrativesite 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
*National Cancer Institute Common Terminology Criteriafor Adverse Events,version3.
โ Grade 3 dermatitis acneiform was reportedin <1% of patientsin TYKERB plus capecitabine group.
Table 2. Selected Laboratory AbnormalitiesParameters TYKERB 1,250 mg/day + Capecitabine 2,000mg/m2/day Capecitabine 2,500 mg/m2/day
All Grades* % Grade 3% Grade 4% All Grades* % Grade 3% Grade 4%
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
*National Cancer Institute Common Terminology Criteriafor Adverse Events,version 3.
Decreases in Left Ventricular Ejection Fraction: Due to potential cardiac toxicity with HER2 (ErbB2) inhibitors, LVEF was monitored in clinical trials at approximately 8-week intervals. LVEF decreases were defined as signs or symptoms of deterioration in left ventricular cardiac function that are ? Grade 3 (NCI CTCAE), or a ? 20% decrease in left ventricular cardiac ejection fraction relative to baseline which is below the institution's lower limit of normal. Among 198 patients who received lapatinib/capecitabine combination treatment, 3 experienced Grade 2 and one had Grade 3 LVEF adverse reactions (NCI CTC 3.0). [See WARNINGS and PRECAUTIONS]
Hepatotoxicity: Lapatinib has been associated with hepatoxicity [see Boxed Warning and WARNINGS and PRECAUTIONS].
Interstitial Lung Disease/Pneumonitis: Lapatinib has been associated with interstitial lung disease and pneumonitis in monotherapy or in combination with other chemotherapies [see WARNINGS and PRECAUTIONS].
DRUG INTERACTIONS
Effects of Lapatinib on Drug Metabolizing Enzymes and Drug Transport Systems
Lapatinib inhibits CYP3A4 and CYP2C8 in vitro at clinically relevant concentrations. Caution should be exercised and dose reduction of the concomitant substrate drug should be considered when dosing lapatinib concurrently with medications with narrow therapeutic windows that are substrates of CYP3A4 or CYP2C8. Lapatinib did not significantly inhibit the following enzymes in human liver microsomes: CYP1A2, CYP2C9, CYP2C19, and CYP2D6 or UGT enzymes in vitro, however, the clinical significance is unknown.
Lapatinib inhibits human P-glycoprotein. If TYKERB is administered with drugs that are substrates of Pgp, increased concentrations of the substrate drug are likely, and caution should be exercised.
Drugs that Inhibit or Induce Cytochrome P450 3A4 Enzymes
Lapatinib undergoes extensive metabolism by CYP3A4, and concomitant administration of strong inhibitors or inducers of CYP3A4 alter lapatinib concentrations significantly (see Ketoconazole and Carbamazepine sections, below). Dose adjustment of lapatinib should be considered for patients who must receive concomitant strong inhibitors or concomitant strong inducers of CYP3A4 enzymes [see DOSAGE AND ADMINISTRATION].
Ketoconazole: In healthy subjects receiving ketoconazole, a CYP3A4 inhibitor, at 200 mg twice daily for 7 days, systemic exposure (AUC) to lapatinib was increased to approximately 3.6-fold of control and half-life increased to 1.7-fold of control.
Carbamazepine: In healthy subjects receiving the CYP3A4 inducer, carbamazepine, at 100 mg twice daily for 3 days and 200 mg twice daily for 17 days, systemic exposure (AUC) to lapatinib was decreased approximately 72%.
Drugs that Inhibit Drug Transport Systems
Lapatinib is a substrate of the efflux transporter P-glycoprotein (Pgp, ABCB1). If TYKERB is administered with drugs that inhibit Pgp, increased concentrations of lapatinib are likely, and caution should be exercised.
Other Chemotherapy Agents
In a separate study, concomitant administration of lapatinib with capecitabine did not meaningfully alter the pharmacokinetics of either agent (or the metabolites of capecitabine).
WARNINGS
Included as part of the PRECAUTIONS section.
PRECAUTIONS
Decreased Left Ventricular Ejection Fraction
TYKERB has been reported to decrease LVEF [see ADVERSE REACTIONS]. In the randomized clinical trial, the majority ( > 60%) of LVEF decreases occurred within the first 9 weeks of treatment; however, data on long-term exposure are limited. Caution should be taken if TYKERB 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 TYKERB 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 TYKERB to ensure that LVEF does not decline below the institution's normal limits [see DOSAGE AND ADMINISTRATION].
Hepatotoxicity
Hepatotoxicity (ALT or AST > 3 times the upper limit of normal and total bilirubin > 1.5 times the upper limit of normal) has been observed in clinical trials ( < 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 TYKERB should be discontinued and patients should not be retreated with TYKERB [see ADVERSE REACTIONS].
Patients with Severe Hepatic Impairment
If TYKERB is to be administered to patients with severe pre-existing hepatic impairment, dose reduction should be considered [see DOSAGE AND ADMINISTRATION and Use in Specific Populations]. In patients who develop severe hepatotoxicity while on therapy, TYKERB should be discontinued and patients should not be retreated with TYKERB [see WARNINGS and PRECAUTIONS].
Diarrhea
Diarrhea, including severe diarrhea, has been reported during treatment with TYKERB [see ADVERSE REACTIONS]. Proactive management of diarrhea with anti-diarrheal agents is important. Severe cases of diarrhea may require administration of oral or intravenous electrolytes and fluids, and interruption or discontinuation of therapy with TYKERB.
Interstitial Lung Disease/Pneumonitis
Lapatinib has been associated with interstitial lung disease and pneumonitis in monotherapy or in combination with other chemotherapies [see ADVERSE REACTIONS]. Patients should be monitored for pulmonary symptoms indicative of interstitial lung disease or pneumonitis. TYKERB should be discontinued in patients who experience pulmonary symptoms indicative of interstitial lung disease/pneumonitis which are ? Grade 3 (NCI CTCAE).
QT Prolongation
QT prolongation measured by automated machine-read evaluation of ECG was observed in an uncontrolled, open-label dose escalation study of lapatinib in advanced cancer patients [see CLINICAL PHARMACOLOGY]. Lapatinib should be administered with caution to patients who have or may develop prolongation of QTc. These conditions include patients with hypokalemia or hypomagnesemia, with congenital long QT syndrome, patients taking anti-arrhythmic medicines or other medicinal products that lead to QT prolongation, and cumulative high-dose anthracycline therapy. Hypokalemia or hypomagnesemia should be corrected prior to lapatinib administration. The prescriber should consider baseline and on-treatment electrocardiograms with QT measurement.
Pregnancy
Pregnancy Category D
TYKERB can cause fetal harm when administered to a pregnant woman. In a study where pregnant rats were dosed with lapatinib during organogenesis and through lactation, at a dose of 120 mg/kg/day (approximately 6.4 times the human clinical exposure based on AUC), 91% of the pups had died by the fourth day after birth, while 34% of the 60 mg/kg/day pups were dead. The highest no-effect dose for this study was 20 mg/kg/day (approximately equal to the human clinical exposure based on AUC).
Lapatinib was studied for effects on embryo-fetal development in pregnant rats and rabbits given oral doses of 30, 60, and 120 mg/kg/day. There were no teratogenic effects; however, minor anomalies (left-sided umbilical artery, cervical rib, and precocious ossification) occurred in rats at the maternally toxic dose of 120 mg/kg/day (approximately 6.4 times the human clinical exposure based on AUC). In rabbits, lapatinib was associated with maternal toxicity at 60 and 120 mg/kg/day (approximately 0.07 and 0.2 times the human clinical exposure, respectively, based on AUC) and abortions at 120 mg/kg/day. Maternal toxicity was associated with decreased fetal body weights and minor skeletal variations.
There are no adequate and well-controlled studies with TYKERB in pregnant women. Women should be advised not to become pregnant when taking TYKERB. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus.
Patient Counseling Information
See FDA-approved patient labeling
Decreased Left Ventricular Ejection Fraction
Patients should be informed that TYKERB has been reported to decrease left ventricular ejection fraction which may result in shortness of breath, palpitations, and/or fatigue. Patients should inform their physician if they develop these symptoms while taking TYKERB.
Diarrhea
Patients should be informed that TYKERB often causes diarrhea which may be severe in some cases. Patients should be told how to manage and/or prevent diarrhea and to inform their physician if severe diarrhea occurs during treatment with TYKERB.
Drug Interactions
TYKERB may interact with many drugs; therefore, patients should be advised to report to their healthcare provider the use of any other prescription or nonprescription medication or herbal products.
Food
Patients should be informed of the importance of taking TYKERB at least one hour before or one hour after a meal, in contrast to capecitabine which should be taken with food or within 30 minutes after food.
Divided Dosing
The dose of TYKERB should not be divided. Patients should be advised of the importance of taking TYKERB once daily, in contrast to capecitabine which is taken twice daily.
Nonclinical Toxicology
Carcinogenesis, Mutagenesis, Impairment of Fertility
Two-year carcinogenicity studies with lapatinib are ongoing.
Lapatinib was not clastogenic or mutagenic in the Chinese hamster ovary chromosome aberration assay, microbial mutagenesis (Ames) assay, human lymphocyte chromosome aberration assay or the in vivo rat bone marrow chromosome aberration assay at single doses up to 2,000 mg/kg. However, an impurity in the drug product (up to 4 ppm or 8 mcg/day) was genotoxic when tested alone in both in vitro and in vivo assays.
There were no effects on male or female rat mating or fertility at doses up to 120 mg/kg/day in females and 180 mg/kg/day in males (approximately 6.4 times and 2.6 times the expected human clinical exposure based on AUC, respectively). The effect of lapatinib on human fertility is unknown. However, when female rats were given oral doses of lapatinib during breeding and through the first 6 days of gestation, a significant decrease in the number of live fetuses was seen at 120 mg/kg/day and in the fetal body weights at ? 60 mg/kg/day (approximately 6.4 times and 3.3 times the expected human clinical exposure based on AUC, respectively).
Use in Specific Populations
Pregnancy
Pregnancy Category D [see WARNINGS and PRECAUTIONS].
Nursing Mothers
It is not known whether lapatinib is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from TYKERB, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Pediatric Use
The safety and effectiveness of TYKERB in pediatric patients have not been established.
Geriatric Use
Of the total number of metastatic breast cancer patients in clinical studies of TYKERB in combination with capecitabine (N = 198), 17% were 65 years of age and older, and 1% were 75 years of age and older. No overall differences in safety or effectiveness of the combination of TYKERB and capecitabine were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.
Renal Impairment
Lapatinib pharmacokinetics have not been specifically studied in patients with renal impairment or in patients undergoing hemodialysis. There is no experience with TYKERB in patients with severe renal impairment. However, renal impairment is unlikely to affect the pharmacokinetics of lapatinib given that less than 2% (lapatinib and metabolites) of an administered dose is eliminated by the kidneys.
Hepatic Impairment
The pharmacokinetics of lapatinib were examined in subjects with pre-existing moderate (n = 8) or severe (n = 4) hepatic impairment (Child-Pugh Class B/C, respectively) and in 8 healthy control subjects. Systemic exposure (AUC) to lapatinib after a single oral 100-mg dose increased approximately 14% and 63% in subjects with moderate and severe pre-existing hepatic impairment, respectively. Administration of TYKERB in patients with severe hepatic impairment should be undertaken with caution due to increased exposure to the drug. A dose reduction should be considered for patients with severe pre-existing hepatic impairment [see DOSAGE AND ADMINISTRATION]. In patients who develop severe hepatotoxicity while on therapy, TYKERB should be discontinued and patients should not be retreated with TYKERB [see WARNINGS and PRECAUTIONS].
OVERDOSE
There is no known antidote for overdoses of TYKERB. The maximum oral doses of lapatinib that have been administered in clinical trials are 1,800 mg once daily. More frequent ingestion of TYKERB 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.
There has been a report of one patient who took 3,000 mg of TYKERB for 10 days. This patient had Grade 3 diarrhea and vomiting on Day 10. The event resolved following IV hydration and interruption of treatment with TYKERB and letrozole.
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.
CONTRAINDICATIONS
None.
See manufacturer's prescribing information for capecitabine contraindications.
CLINICAL PHARMACOLOGY
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 Kiapp values of 3nM and 13nM, respectively) with a dissociation half-life of ? 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-crossresistance between these two agents.
Pharmacokinetics
Absorption: Absorption following oral administration of TYKERB is incomplete and variable. Serum concentrations appear after a median lag time of 0.25 hours (range 0 to 1.5 hour). Peak plasma concentrations (Cmax) of lapatinib are achieved approximately 4 hours after administration. Daily dosing of TYKERB results in achievement of steady state within 6 to 7 days, indicating an effective half-life of 24 hours.
At the dose of 1,250 mg daily, steady state geometric mean (95% confidence interval) values of Cmax were 2.43 mcg/mL (1.57 to 3.77 mcg/mL) and AUC were 36.2 mcg.hr/mL (23.4 to 56 mcgยทhr/mL).
Divided daily doses of TYKERB resulted in approximately 2-fold higher exposure at steady state (steady state AUC) compared to the same total dose administered once daily.
Systemic exposure to lapatinib is increased when administered with food. Lapatinib AUC values were approximately 3- and 4-fold higher (Cmax approximately 2.5- and 3-fold higher) when administered with a low fat (5% fat-500 calories) or with a high fat (50% fat-1,000 calories) meal, respectively.
Distribution: Lapatinib is highly bound ( > 99%) to albumin and alpha-1 acid glycoprotein. In vitro studies indicate that lapatinib is a substrate for the transporters breast cancer resistance protein (BCRP, ABCG2) and P-glycoprotein (Pgp, ABCB1). Lapatinib has also been shown in vitro to inhibit these efflux transporters, as well as the hepatic uptake transporter OATP 1B1, at clinically relevant concentrations.
Metabolism: Lapatinib undergoes extensive metabolism, primarily by CYP3A4 and CYP3A5, with minor contributions from CYP2C19 and CYP2C8 to a variety of oxidated metabolites, none of which accounts for more than 14% of the dose recovered in the feces or 10% of lapatinib concentration in plasma.
Elimination: At clinical doses, the terminal phase half-life following a single dose was 14.2 hours; accumulation with repeated dosing indicates an effective half-life of 24 hours.
Elimination of lapatinib is predominantly through metabolism by CYP3A4/5 with negligible ( < 2%) renal excretion. Recovery of parent lapatinib in feces accounts for a median of 27% (range 3 to 67%) of an oral dose.
Effects of Age, Gender, or Race: Studies of the effects of age, gender, or race on the pharmacokinetics of lapatinib have not been performed.
QT Prolongation
The QT prolongation potential of lapatinib was assessed as part of an uncontrolled, openlabel dose escalation study in advanced cancer patients. Eighty-one patients received daily doses of lapatinib ranging from 175 mg/day to 1,800 mg/day. Serial ECGs were collected on Day 1 and Day 14 to evaluate the effect of lapatinib on QT intervals. Thirteen of the 81 subjects were found to have either QTcF (corrected QT by the Friedericia method) > 480 msec or an increase in QTcF > 60 msec by automated machine-read evaluation of ECG. Analysis of the data suggested a relationship between lapatinib concentration and the QTc interval.
Clinical Studies
The efficacy and safety of TYKERB in combination with capecitabine in breast cancer were evaluated in a randomized, Phase 3 trial. Patients eligible for enrollment had HER2 (ErbB2) over-expressing (IHC 3+ or IHC 2+ confirmed by FISH), locally advanced or metastatic breast cancer, progressing after prior treatment that included anthracyclines, taxanes, and trastuzumab.
Patients were randomized to receive either TYKERB 1,250 mg once daily (continuously) plus capecitabine 2,000 mg/m2/day on Days 1-14 every 21 days, or to receive capecitabine alone at a dose of 2,500 mg/m2/day on Days 1-14 every 21 days. The endpoint was time to progression (TTP). TTP was defined as time from randomization to tumor progression or death related to breast cancer. Based on the results of a pre-specified interim analysis, further enrollment was discontinued. Three hundred and ninety-nine (399) patients were enrolled in this study. The median age was 53 years and 14% were older than 65 years. Ninety-one percent (91%) were Caucasian. Ninety-seven percent (97%) had stage IV breast cancer, 48% were estrogen receptor+ (ER+) or progesterone receptor+ (PR+), and 95% were ErbB2 IHC 3+ or IHC 2+ with FISH confirmation. Approximately 95% of patients had prior treatment with anthracyclines, taxanes, and trastuzumab.
Efficacy analyses four months after the interim analysis are presented in Table 3, Figure 1, and Figure 2.
Table 3. Efficacy Results Independent Assessment* Investigator Assessment
TYKERB 1,250 mg/day + Capecitabine 2,000 mg/m2/day
(N = 198) Capecitabine 2,500 mg/m2/day
(N = 201) TYKERB 1,250 mg/day + Capecitabine 2,000 mg/m2/day
(N = 198) Capecitabine 2,500 mg/m2/day
(N = 201)
Number of TTP events 82 102 121 126
Median TTP, weeks
(25th, 75th, Percentile), weeks 27.1
(17.4, 49.4) 18.6
(9.1, 36.9) 23.9
(12.0, 44.0) 18.3
(6.9, 35.7)
Hazard Ratio
(95% CI)
p value 0.57
(0.43,0.77)
0.00013 0.72
(0.56,0.92)
0.00762
Response Rate (%)
(95% CI) 23.7
(18.0, 30.3) 13.9
(9.5, 19.5) 31.8
(25.4, 38.8) 17.4
(12.4, 23.4)
TTP = Time to progression.
*The time from last tumor assessment to the data cut-off date was >100 days in approximately 30% of patients in the independent assessment. Thepre-specified assessment interval was 42 or 84 days.
At the time of updated analysis, 30% of patients had died and the data for survival analysis are not mature. Fifty-five patients (28%) in the TYKERB plus capecitabine group and 64 subjects (32%) in the capecitabine group had died.