Statement: cohort 1 of the secondary trial had a much longer median PFS than cohort 1 of the primary trial.
Primary_evidence: Outcome Measurement:    Number of Participants With Progression Free Survival (PFS) in the Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Advanced or Metastatic Breast Cancer as Assessed by the Investigator   PFS is defined as the time from randomization until the earliest date of disease progression (PD) or death due to any cause, if sooner. The date of documented PD is defined as the date of radiological PD as assessed by the investigator based on imaging data and also by the clinical assessment of symptomatic progression. Per Response Evaluation Criteria in Solid Tumors (RECIST 1.0), PD is defined as a 20% increase in the sum of the longest diameter (LD) of target lesions, taking as a reference the smallest sum LD recorded since the treatment started, or the appearance of 1 or more new lesions.   Time frame: From the date of randomization until the date of the first documented progression or date of death from any cause, whichever came first, assessed for up to 46 months Results 1:    Arm/Group Title: Placebo + Letrozole 2.5 mg   Arm/Group Description: Participants received 6 tablets of placebo, identical in appearance to lapatinib tablets, orally daily (approximately at the same time each day), either 1 hour (or more) before breakfast or 1 hour (or more) after breakfast. Participants also received 1 tablet of letrozole 2.5 milligrams (mg) orally daily, preferably with the daily dose of lapatinib.   Overall Number of Participants Analyzed: 108   Measure Type: Count of Participants   Unit of Measure: Participants  89  82.4% Results 2:    Arm/Group Title: Lapatinib 1500 mg + Letrozole 2.5 mg   Arm/Group Description: Participants received 6 tablets of Lapatinib orally daily (250 mg lapatinib/tablet for a total of 1500 mg of lapatinib/day; approximately at the same time each day), either 1 hour (or more) before breakfast or 1 hour (or more) after breakfast. Participants also received 1 tablet of letrozole 2.5 mg orally daily, preferably with the daily dose of lapatinib.   Overall Number of Participants Analyzed: 111   Measure Type: Count of Participants   Unit of Measure: Participants  88  79.3%
Secondary_evidence: Outcome Measurement:    Time to Disease Progression (Initial Treatment)   Time to disease progression (TTDP) at initial treatment was defined as the number of months between date of randomization and the date of first documented disease progression or the date of death due to disease under study, whichever came first. TTDP censored at earliest of: 1) date of death not due to disease; or 2) date of last contact for participants alive without disease progression; or 3) start date of other anti-tumor therapy; or 4) first dose date of crossover treatment.   Time frame: Randomization date to the earliest date of first documented disease progression date or the date of death if the participant died due to study disease (up to 82 months) Results 1:    Arm/Group Title: Gemcitabine Plus Docetaxel   Arm/Group Description: gemcitabine 1000 milligrams per meter squared (mg/m2) intravenous, days 1 and 8 every 21 days plus docetaxel 75 mg/m2, intravenous, day 1 every 21 days.   Treatment continues until progression of disease at which time crossover treatment begins.   Overall Number of Participants Analyzed: 239   Median (95% Confidence Interval)   Unit of Measure: months  9.28        (7.73 to 10.79) Results 2:    Arm/Group Title: Docetaxel Plus Capecitabine   Arm/Group Description: docetaxel 75 mg/m2, intravenous, day 1 every 21 days plus capecitabine 1000 mg/m2, by mouth twice a day, days 1-14 every 21 days. Treatment continues until progression of disease, at which time crossover treatment begins.   Overall Number of Participants Analyzed: 236   Median (95% Confidence Interval)   Unit of Measure: months  8.88        (7.37 to 11.05)