Continued HER2 Suppression With Lapatinib Plus Trastuzumab Versus Trastuzumab Alone

Study Overview
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Brief Summary
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This was a randomized, open-label, multi-center Phase III study evaluating the efficacy and safety of lapatinib in combination with trastuzumab versus trastuzumab alone as continued HER2 suppression therapy in women with HER2-positive metastatic breast cancer (MBC). Eligible subjects should have completed 12 to 24 weeks of first- or second-line treatment with trastuzumab plus chemotherapy, experienced either complete disappearance of all metastatic lesions, or persistence of metastatic disease (stable disease) without unequivocal progression or the occurrence of new lesions, and been indicated to continue to receive trastuzumab alone as maintenance therapy. Eligible subjects who entered the LPT112515 study on first-line treatment should not have known history of central nervous system (CNS) metastases; subjects who entered the study on second-line treatment should not have known history of CNS metastases or have stable (asymptomatic and off steroids ≥3 months) CNS metastases. The primary objective of this study was to compare progression-free survival (PFS) in subjects with HER2-positive MBC randomized to receive treatment with lapatinib plus trastuzumab versus those randomized to receive trastuzumab alone. The secondary objectives included overall survival, clinical benefit response rate (CR, PR or SD ≥24 weeks) and the qualitative and quantitative adverse event profile of the 2 treatment arms. It was estimated that 280 subjects (140 per group) would be required to observe 193 PFS events.

Official Title
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A Randomized, Phase III, Open-label Study of Lapatinib Plus Trastuzumab Versus Trastuzumab as Continued HER2 Suppression Therapy After Completion of First- or Second-line Trastuzumab Plus Chemotherapy in Subjects With HER2-positive Metastatic Breast Cancer

Conditions
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Cancer

Intervention / Treatment
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* Drug: Lapatinib
* Biological: Trastuzumab


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Signed the informed consent form (ICF) Female, ≥18 years of age Histologically verified breast cancer with distant metastases (metastatic breast cancer) Documentation of HER2 overexpression or gene amplification in the invasive component of either the primary tumor or metastatic disease site defined as: 3+ by IHC and/or HER2/neu gene amplification by fluorescence, chromogenic or silver in situ hybridization [FISH, CISH or SISH; >6 HER2/neu gene copies per nucleus or a FISH, CISH or SISH HER2 gene copies to chromosome 17 signal ratio of ≥2.0] Completed 12 to 24 weeks of first- or second-line treatment with trastuzumab in combination with chemotherapy Either complete disappearance of all lesions, or persistence of metastatic disease (stable disease) without unequivocal progression or the occurrence of new lesions Documentation of lesion response during the course of therapy received prior to randomization (i.e., improvement or no worsening of tumor burden; the absence of new lesions) Measurable disease is not required for study participation No known or suspected (associated neurological signs and symptoms) brain metastases (including leptomeningeal involvement) Stable brain metastasis (defined as asymptomatic and off steroids ≥3 months) are permitted in subjects on second-line treatment (completed 12-24 weeks of second-line treatment with trastuzumab plus chemotherapy) Baseline of Left Ventricular Ejection Fraction (LVEF) ≥50% measured by echocardiography (ECHO) or multi-gated acquisition scan (MUGA) Completion of screening assessments Have adequate marrow and organ function Exclusion Criteria: History of other malignancy. Subjects who have been disease-free for 5 years or subjects with a history of completely resected non-melanoma skin cancer (basal or squamous) are eligible Eastern Cooperative Oncology Group (ECOG) Performance Status >2 Concurrent anti-cancer treatment, except anti-hormonal therapy for subjects with hormone receptor positive breast cancer Concurrent treatment with an investigational agent Prior treatment with anti-HER2 therapy, except trastuzumab or lapatinib Concurrent treatment with protocol-defined prohibited medications (refer to protocol for details) Serious cardiac illness or medical condition including but not confined to: Uncontrolled arrhythmias Uncontrolled or symptomatic angina History of congestive heart failure (CHF) Myocardial infarction <6 months from study entry Acute or current active (requiring anti-viral therapy) hepatic or biliary disease (with the exception of subjects with Gilbert's syndrome, asymptomatic gallstones, liver metastases or stable chronic liver disease per investigator assessment) Concurrent disease or condition that may interfere with study participation, or any serious medical disorder that would interfere with the subject's safety (for example, active or uncontrolled infection or any psychiatric condition prohibiting understanding or rendering of informed consent) Women of childbearing potential, including women whose last menstrual period was <12 months ago (unless surgically sterile) who are unable or unwilling to use adequate contraceptive measures during the study treatment period. Adequate contraception includes intra-uterine device, barrier methods with spermicide, or oral contraceptives (unless clinically contraindicated for the subject population or per local practice, refer to protocol for further details) Pregnant or lactating females Any clinically significant gastrointestinal abnormalities that may alter absorption such as malabsorption syndrome or major resection of the stomach or bowels. Known immediate or delayed hypersensitivity reaction or idiosyncrasy to drugs chemically related to any of the study agents or their excipients that, in the opinion of the Investigator or GSK medical monitor , contra-indicates participation

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Arm 1: Lapatinib plus Trastuzumab<br> | Drug: Lapatinib<br>* Oral Lapatinib 1000 mg once daily. Lapatinib was a small molecule, reversible inhibitor targeting HER2 tyrosine kinase receptor.<br>Biological: Trastuzumab<br>* IV Trastuzumab 6 mg/kg every three weeks. Trastuzumab was a humanized, monoclonal antibody directed against the extracellular domain of the HER2 tyrosine kinase receptor.<br>|
| Active Comparator: Arm 2: Trastuzumab<br> | Biological: Trastuzumab<br>* IV Trastuzumab 6 mg/kg every three weeks. Trastuzumab was a humanized, monoclonal antibody directed against the extracellular domain of the HER2 tyrosine kinase receptor.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Progression-free Survival | Progression-free survival (PFS) with lapatinib plus trastuzumab versus trastuzumab alone. Progression-free survival (PFS) is defined as the time from randomization to the earliest date of disease progression (with radiological evidence) or death from any cause, or to last contact date up to 21Feb2014. Disease Progression was defined using Response Evaluation Criteria In Solid Tumors (RECIST v1.1), a 20% increase in the sum of the diameters of target lesions, taking as a reference, the smallest sum diameters recorded since the treatment started (the sum must have an absolute increase from nadir of 5mm), or an unequivocal progression of existing non-target lesions, or the appearance of new lesions. | Time from randomization until disease progression or death, approximately 4 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Overall Survival | Overall Survival is defined as the interval of time (in months) between the date of randomization and the date of death due to any cause. | Time from randomization until death, approximately 4 years | 
| Best Overall Response | The best overall response was the best response from the start of the treatment until disease progression/recurrence and was determined programmatically using investigators assessment of responses of target lesion, non-target lesion and new lesions based on RECIST v1.1. Complete Response (CR) = disappearance of all target lesion and non-target lesions if applicable, and no new lesion; Partial Response (PR) = ≥30% decrease in the sum of the longest diameter of target lesions and non-target lesion was neither complete response nor progressive disease (Non-CR/Non-PD) or not evaluable (NE); SD = Neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD; PD = ≥ 20% increase from nadir of the target lesions or appearance of new lesion. CR and PR were confirmed responses. Confirmed CR - at least two determinations of CR at least 4 weeks apart before PD; Confirmed PR - at least two determinations of PR or better at least 4 weeks apart before PD. | approximately 4 years | 
| Clinical Benefit Response Rate (CR, PR or SD ≥24 Weeks) | Clinical Benefit Rate (CBR) was defined as the percentage of patients achieving either a confirmed CR or PR at any time or maintaining SD for at least 24 weeks while on study, according to the investigator assessment of response per RECIST 1.1 criteria. Confirmed CR - at least two determinations of CR at least 4 weeks apart before PD; Confirmed PR - at least two determinations of PR or better at least 4 weeks apart before PD. | approximately 4 years | 
| Adverse Event Profile of the Two Treatment Arms |  | From first dose of study treatment until 30 days after the last dose of study treatment, approximately 8 years. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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carcinoma, breast lump, Pagets disease, breast cancer positive for human epidermal growth factor receptor 2, breast cancer progression, estrogen-receptor