A Study of Trastuzumab Emtansine (T-DM1) Plus Pertuzumab/Pertuzumab Placebo Versus Trastuzumab [Herceptin] Plus a Taxane in Participants With Metastatic Breast Cancer (MARIANNE)

Percentage of Participants Who Died Prior to Clinical Cutoff

The percentage of participants who died prior to clinical cutoff was calculated as \[number of participants with event divided by the number analyzed\] multiplied by 100.

Time frame: Up to 70 months from randomization until clinical cutoff of 15-May-2016 (every 3 months until death, loss to follow-up, withdrawal, or study termination)

Overall Survival (OS) at Clinical Cutoff

OS was defined as the time from randomization to death from any cause. Median duration of OS was estimated using Kaplan-Meier analysis, and corresponding CIs were computed using the Brookmeyer-Crowley method.

Time frame: Up to 70 months from randomization until clinical cutoff of 15-May-2016 (every 3 months until death, loss to follow-up, withdrawal, or study termination)

Percentage of Participants With Death or Disease Progression According to Investigator Assessment

Tumor assessments were performed by the investigator according to RECIST version 1.1. Disease progression was defined as a ≥20% and 5-mm increase in sum of diameters of target lesions, taking as reference the smallest sum obtained during the study, or appearance of new lesion(s). The percentage of participants with death or disease progression was calculated as \[number of participants with event divided by the number analyzed\] multiplied by 100.

Time frame: Up to 48 months from randomization until clinical cutoff of 16-Sept-2014 (at Screening, every 9 weeks for 81 weeks, then every 12 weeks thereafter and/or up to 42 days after last dose)

PFS According to Investigator Assessment

Tumor assessments were performed by the investigator according to RECIST version 1.1. PFS was defined as the time from randomization to first documented disease progression or death from any cause. Disease progression was defined as a ≥20% and 5-mm increase in sum of diameters of target lesions, taking as reference the smallest sum obtained during the study, or appearance of new lesion(s). Median duration of PFS was estimated using Kaplan-Meier analysis, and corresponding CIs were computed using the Brookmeyer-Crowley method.

Time frame: Up to 48 months from randomization until clinical cutoff of 16-Sept-2014 (at Screening, every 9 weeks for 81 weeks, then every 12 weeks thereafter and/or up to 42 days after last dose)

Percentage of Participants Experiencing Treatment Failure

Treatment failure was defined as the discontinuation of all study medications in the treatment arm for any reason including disease progression, treatment toxicity, death, physician decision, or participant withdrawal. The percentage of participants with treatment failure was calculated as \[number of participants with event divided by the number analyzed\] multiplied by 100.

Time frame: Up to 48 months from randomization until clinical cutoff of 16-Sept-2014

Time to Treatment Failure (TTF)

Treatment failure was defined as the discontinuation of all study medications in the treatment arm for any reason including disease progression, treatment toxicity, death, physician decision, or participant withdrawal. TTF was defined as the time from randomization to treatment failure. Median TTF was estimated using Kaplan-Meier analysis, and corresponding CIs were computed using the Brookmeyer-Crowley method.

Time frame: Up to 48 months from randomization until clinical cutoff of 16-Sept-2014

One-Year Survival Rate

The percentage of participants alive at 1 year after randomization was estimated as the one-year survival rate using Kaplan-Meier analysis, and corresponding CIs were computed using Greenwood's estimate of the standard error.

Time frame: From randomization until 1 year

Percentage of Participants With Grade ≥3 Adverse Events

Adverse events were graded according to National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Grade 3: Severe or medically significant but not immediately life-threatening; hospitalization or prolongation of hospitalization indicated; disabling; limiting self care activity of daily living with inability to perform bathing, dressing and undressing, feeding self, using the toilet, taking medications but not bedridden. Grade 4: An immediate threat to life. Urgent medical intervention is required in order to maintain survival. Grade 5: Death.

Time frame: Up to 50 months from randomization until clinical cutoff of 16-Sept-2014 (continuously until 28 days after last dose

Percentage of Participants Who Died at 2 Years

Time frame: From randomization until 2 years

Overall Survival Truncated at 2 Years

Overall Survival truncated at 2 years was defined as the percentage of participants alive at 2 years.

Time frame: From randomization until 2 years

Percentage of Participants With Grade 5 Adverse Events

Adverse events were graded according to NCI CTCAE version 4.0. Grade 5 adverse events are those events which led to death.

Time frame: Up to 50 months from randomization until clinical cutoff of 16-Sept-2014 (continuously until 28 days after last dose)

Percentage of Participants With Grade 3-4 Laboratory Parameters

Laboratory results were graded according to NCI CTCAE version 4.0. Grade 3: Severe or medically significant but not immediately life-threatening; hospitalization or prolongation of hospitalization indicated; disabling; limiting self care activity of daily living with inability to perform bathing, dressing and undressing, feeding self, using the toilet, taking medications but not bedridden. Grade 4: An immediate threat to life. Urgent medical intervention is required in order to maintain survival.

Time frame: Day 1, 8, and 15 of Cycle 1-3 and on Day 1 of each subsequent cycle up to 50 months from randomization until clinical cutoff of 16-Sept-2014

Percentage of Participants With Decline of ≥2 Points From Baseline in Eastern Cooperative Oncology Group (ECOG) Performance Status

The ECOG performance status is a scale used to quantify cancer participants' general well-being and activities of daily life. The scale ranges from 0 to 5, with 0 denoting perfect health and 5 indicating death. The 6 categories are 0=Asymptomatic (Fully active, able to carry on all predisease activities without restriction), 1=Symptomatic but completely ambulatory (Restricted in physically strenuous activity but ambulatory and able to carry out work of a light or sedentary nature), 2=Symptomatic, \< 50% in bed during the day (Ambulatory and capable of all self-care but unable to carry out any work activities. Up and about more than 50% of waking hours), 3=Symptomatic, \> 50% in bed, but not bedbound (Capable of only limited self-care, confined to bed or chair 50% or more of waking hours), 4=Bedbound (Completely disabled. Cannot carry on any self-care. Totally confined to bed or chair), 5=Death.

Time frame: Baseline, Day 1 of every Cycle up to Clinical Data Cut (up to 48 months)

Hospitalization Days

Hospitalization was defined as a non-administration-related hospitalization due to serious adverse event, while on study treatment. Reported values represent number of days admitted per participants.

Time frame: Up to 48 months from randomization until clinical cutoff of 16-Sept-2014

Percentage of Participants With Hospitalization

Hospitalization was defined as a non-administration-related hospitalization due to serious adverse event, while on study treatment.

Time frame: Up to 48 months from randomization until clinical cutoff of 16-Sept-2014

Percentage of Participants With Objective Response According to IRF Assessment

Objective response was defined as having complete response (CR) or partial response (PR), assessed according to RECIST version 1.1, using radiographic images submitted to the IRF up to and including the confirmatory tumor assessment 4 to 6 weeks after study drug discontinuation. CR was defined as the disappearance of all target and non-target lesions and short-axis reduction in pathological lymph nodes to \<10 mm. PR was defined as a ≥30% decrease in sum of diameters of target lesions, taking as reference the Baseline sum. Response was determined using 2 consecutive tumor assessments at least 4 weeks apart. The percentage of participants with a best overall response of CR or PR (ie, the objective response rate \[ORR\]) was calculated as \[number of participants meeting the respective criteria divided by the number analyzed\] multiplied by 100. Corresponding CIs were computed using the Blyth-Still-Casella exact method.

Time frame: Up to 46 months from randomization until clinical cutoff of 16-Sept-2014 (at Screening, every 9 weeks for 81 weeks, then every 12 weeks thereafter and/or up to 42 days after last dose)

Percentage of Participants With Objective Response According to Investigator Assessment

Objective response was defined as having CR or PR, assessed according to RECIST version 1.1, by investigator. CR was defined as the disappearance of all target and non-target lesions and short-axis reduction in pathological lymph nodes to \<10 mm. PR was defined as a ≥30% decrease in sum of diameters of target lesions, taking as reference the Baseline sum. Response was determined using 2 consecutive tumor assessments at least 4 weeks apart. The percentage of participants with a best overall response of CR or PR (ie, the ORR) was calculated as \[number of participants meeting the respective criteria divided by the number analyzed\] multiplied by 100. Corresponding CIs were computed using the Blyth-Still-Casella exact method.

Time frame: Up to 46 months from randomization until clinical cutoff of 16-Sept-2014 (at Screening, every 9 weeks for 81 weeks, then every 12 weeks thereafter and/or up to 42 days after last dose)

Duration of Response According to IRF Assessment

Tumor assessments were performed according to RECIST version 1.1, using radiographic images submitted to the IRF up to and including the confirmatory tumor assessment 4 to 6 weeks after study drug discontinuation. Duration of response was defined as the time from confirmed PR or CR to first documented disease progression or death from any cause. CR was defined as the disappearance of all target lesions and non-target lesions and short-axis reduction in pathological lymph nodes to \<10 mm. PR was defined as a ≥30% decrease in sum of diameters of target lesions, taking as reference the Baseline sum. Response was determined using 2 consecutive tumor assessments at least 4 weeks apart. Median duration of response was estimated using Kaplan-Meier analysis, and corresponding CIs were computed using the Brookmeyer-Crowley method.

Time frame: Up to 46 months from randomization until clinical cutoff of 16-Sept-2014 (at Screening, every 9 weeks for 81 weeks, then every 12 weeks thereafter and/or up to 42 days after last dose)

Percentage of Participants With a Best Overall Response of CR, PR, or Stable Disease (SD) According to IRF Assessment

Tumor assessments were performed according to RECIST version 1.1, using radiographic images submitted to the IRF up to and including the confirmatory tumor assessment 4 to 6 weeks after study drug discontinuation. CR was defined as the disappearance of all target and non-target lesions and short-axis reduction in pathological lymph nodes to \<10 mm. PR was defined as a ≥30% decrease in sum of diameters of target lesions, taking as reference the Baseline sum. SD was defined as neither sufficient shrinkage to quality for PR nor sufficient (20%) increase to qualify for disease progression. Response was determined using 2 consecutive tumor assessments at least 4 weeks apart. The percentage of participants with a best overall response of CR, PR, or SD was calculated as \[number of participants meeting the respective criteria divided by the number analyzed\] multiplied by 100.

Time frame: Up to 46 months from randomization until clinical cutoff of 16-Sept-2014 (at Screening, every 9 weeks for 81 weeks, then every 12 weeks thereafter and/or up to 42 days after last dose)

Percentage of Participants Experiencing a Clinically Significant Increase in Taxane-Related Treatment Symptoms as Measured by Taxane Subscale of the Functional Assessment of Cancer Therapy (FACT) Taxane (FACT-TaxS) Score

The FACT-Taxane is a self-reported instrument which measures the health-related quality of life (HRQOL) of participants receiving taxane-containing chemotherapy. The FACT-TaxS consists of 16 items including 11 neurotoxicity-related questions and 5 additional questions assessing arthralgia, myalgia, and skin discoloration. Items are rated from 0 (not at all) to 4 (very much) and a total score is inversely derived. Scores may range from 0 to 64, with higher scores indicating fewer/no symptoms. A minimally clinically important difference in treatment-related symptoms was defined as a ≥5% decrease (ie, 3.2 points) in FACT-TaxS score from Baseline. The percentage of participants with treatment-related symptoms was calculated using following formula: \[number of participants meeting the above threshold divided by the number analyzed\] multiplied by 100. Corresponding CIs were computed using the Blyth-Still-Casella exact method.

Time frame: Up to 39 months from randomization until clinical cutoff of 16-Sept-2014 (at Baseline, on Day 1 of Cycles 2 to 8 and every even-numbered cycle thereafter and/or up to 42 days after last dose)

Percentage of Participants Reporting Nausea According to the Relevant Single Items of The FACT Colorectal Cancel (FACT-C) Module

The FACT-C is a self-reported instrument which measures HRQOL pertaining to colorectal cancer. Response options on each question may range from 0 (not at all) to 4 (very much). The percentage of participants with nausea was calculated using following formula: \[number of participants with any level of either symptom divided by the number analyzed\] multiplied by 100.

Time frame: At Baseline, Day 8 of Cycle 1, and Days 1 and 8 of Cycle 2

Percentage of Participants Reporting Diarrhea According to the Relevant Single Items of The FACT-C Module

The FACT-C is a self-reported instrument which measures HRQOL pertaining to colorectal cancer. Response options on each question may range from 0 (not at all) to 4 (very much). The percentage of participants with diarrhea was calculated using following formula: \[number of participants with any level of either symptom divided by the number analyzed\] multiplied by 100.

Time frame: At Baseline, Day 8 of Cycle 1, and Days 1 and 8 of Cycle 2

Percentage of Participants With a Clinically Significant Deterioration in Health Related Quality of Life (HRQoL) as Measured by FACT Breast (FACT-B) Trial Outcome Index-Physical Function Breast (TOI-PFB) Score

The FACT-B is a self-reported instrument which measures HRQOL of participants with breast cancer. It consists of 5 subscales including physical well-being (PWB), social well-being (SWB), emotional well-being (EWB), functional well-being (FWB), and a breast cancer subscale (BCS). The TOI-PFB score is taken by adding the scores from the PWB (7 items), FWB (7 items), and BCS (9 items) subscales. Items are rated from 0 (not at all) to 4 (very much) and a total score is derived. Scores may range from 0 to 92, with higher scores indicating better HRQOL. A 5 point change has been identified as the clinically minimal important difference (CMID) on the FACT-TOI-PFB scale. The percentage of participants with deterioration was calculated as \[number of participants meeting the above threshold divided by the number analyzed\] multiplied by 100.

Time frame: Up to 39 months from randomization until clinical cutoff of 16-Sept-2014 (at Baseline, on Day 1 of Cycles 2 to 8 and every even-numbered cycle thereafter and/or up to 42 days after last dose)

Time to Deterioration in HRQoL as Assessed by FACT-B TOI-PFB Score

The FACT-B is a self-reported instrument which measures HRQOL of participants with breast cancer. It consists of 5 subscales including PWB, SWB, EWB, FWB, and BCS. The TOI-PFB score is taken by adding the scores from the PWB (7 items), FWB (7 items), and BCS (9 items) subscales. Items are rated from 0 (not at all) to 4 (very much) and a total score is derived. Scores may range from 0 to 92, with higher scores indicating better HRQOL. A 5 point change has been identified as the clinically minimal important difference (CMID) on the FACT-TOI-PFB scale. Time to deterioration was defined as the time from Baseline until the first decrease in FACT-B TOI-PFB score. Median time to deterioration was estimated using Kaplan-Meier analysis, and corresponding CIs were computed using the Brookmeyer-Crowley method.

Time frame: Baseline up to 39 months from randomization until clinical cutoff of 16-Sept-2014

Change From Baseline in Rotterdam Symptom Checklist (RSCL) Activity Level Scale Score

The RSCL is a self-reported instrument which consists of 4 domains including physical symptom distress, psychological distress, activity level, and overall global life quality. Only the activity level scale was collected and assessed. Scores may range from 0 to 100, with higher scores indicating increased burden of disease. Mean RSCL activity scale score changes were calculated as \[mean score at the assessment visit minus mean score at Baseline\]. The higher the score, the higher the level of impairment or burden.

Time frame: Baseline, Cycle 7 (Week 18)

Change From Baseline in Work Productivity According to Work Productivity and Activity Impairment (WPAI) Questionnaire Score

The WPAI is a patient-reported measure which assesses the effect of general health and symptom severity on work productivity and regular activities. The General Health questionnaire asks participants to estimate the number of hours missed from work due to reasons related and unrelated to their health problems, as well as the total number of hours actually worked in the preceding 7-day period. The percentage of participants reporting that they were employed (working for pay) was assessed at baseline was assessed along with Absenteeism (work time missed), Presenteeism (impairment at work / reduced on-the-job effectiveness), Work productivity loss (overall work impairment / absenteeism plus presenteeism), and Activity Impairment. The reported changes represent change from baseline at Cycle 7. The score range for the scales of the WPAI is between 0 (no effect) to 100% (max effect)

Time frame: Baseline, Cycle 7 (Week 18)

Change From Baseline in Activity Impairment According to Work Productivity and Activity Impairment (WPAI) Questionnaire Score

The WPAI is a patient-reported measure which assesses the effect of general health and symptom severity on work productivity and regular activities. The General Health questionnaire asks participants to estimate the number of hours missed from work due to reasons related and unrelated to their health problems, as well as the total number of hours actually worked in the preceding 7-day period. The percentage of participants reporting that they were employed (working for pay) was assessed at baseline was assessed along with Absenteeism (work time missed), Presenteeism (impairment at work / reduced on-the-job effectiveness), Work productivity loss (overall work impairment / absenteeism plus presenteeism), and Activity Impairment. The reported changes represent change from baseline at Cycle 7. The score range for the scales of the WPAI is between 0 (no effect) to 100% (max effect).

Time frame: Baseline, Cycle 7 (Week 18)

Percentage of Participants With a Best Overall Response of CR or PR According to IRF Assessment Among Those With High Human Epidermal Growth Factor Receptor 2 (HER2) Messenger Ribonucleic Acid (mRNA) Levels

Tumor assessments were performed according to RECIST version 1.1, using radiographic images submitted to the IRF up to and including the confirmatory tumor assessment 4 to 6 weeks after study drug discontinuation. CR was defined as the disappearance of all target and non-target lesions and short-axis reduction in pathological lymph nodes to \<10 mm. PR was defined as a ≥30% decrease in sum of diameters of target lesions, taking as reference the Baseline sum. Response was determined using 2 consecutive tumor assessments at least 4 weeks apart. The percentage of participants with a best overall response of CR or PR (ie, the ORR) was calculated as \[number of participants meeting the respective criteria divided by the number analyzed\] multiplied by 100.

Time frame: Up to 46 months from randomization until clinical cutoff of 16-Sept-2014 (at Screening, every 9 weeks for 81 weeks, then every 12 weeks thereafter and/or up to 42 days after last dose)

Percentage of Participants With a Best Overall Response of CR or PR According to IRF Assessment Among Those With Low HER2 mRNA Levels

Tumor assessments were performed according to RECIST version 1.1, using radiographic images submitted to the IRF up to and including the confirmatory tumor assessment 4 to 6 weeks after study drug discontinuation. CR was defined as the disappearance of all target and non-target lesions and short-axis reduction in pathological lymph nodes to \<10 mm. PR was defined as a ≥30% decrease in sum of diameters of target lesions, taking as reference the Baseline sum. Response was determined using 2 consecutive tumor assessments at least 4 weeks apart. The percentage of participants with a best overall response of CR or PR (ie, the ORR) was calculated as \[number of participants meeting the respective criteria divided by the number analyzed\] multiplied by 100.

Time frame: Up to 46 months from randomization until clinical cutoff of 16-Sept-2014 (at Screening, every 9 weeks for 81 weeks, then every 12 weeks thereafter and/or up to 42 days after last dose)

Percentage of Participants With Death or Disease Progression According to IRF Assessment Among Those With High HER2 mRNA Levels

Tumor assessments were performed according to RECIST version 1.1, using radiographic images submitted to the IRF up to and including the confirmatory tumor assessment 4 to 6 weeks after study drug discontinuation. Disease progression was defined as a ≥20% and 5-mm increase in sum of diameters of target lesions, taking as reference the smallest sum obtained during the study, or appearance of new lesion(s). The percentage of participants with death or disease progression was calculated as \[number of participants with event divided by the number analyzed\] multiplied by 100.

Time frame: Up to 48 months from randomization until clinical cutoff of 16-Sept-2014 (at Screening, every 9 weeks for 81 weeks, then every 12 weeks thereafter and/or up to 42 days after last dose)

PFS According to IRF Assessment Among Those With High HER2 mRNA Levels

Tumor assessments were performed according to RECIST version 1.1, using radiographic images submitted to the IRF up to and including the confirmatory tumor assessment 4 to 6 weeks after study drug discontinuation. PFS was defined as the time from randomization to first documented disease progression or death from any cause. Disease progression was defined as a ≥20% and 5-mm increase in sum of diameters of target lesions, taking as reference the smallest sum obtained during the study, or appearance of new lesion(s). Median duration of PFS was estimated using Kaplan-Meier analysis.

Time frame: Up to 48 months from randomization until clinical cutoff of 16-Sept-2014 (at Screening, every 9 weeks for 81 weeks, then every 12 weeks thereafter and/or up to 42 days after last dose)

Percentage of Participants With Death or Disease Progression According to IRF Assessment Among Those With Low HER2 mRNA Levels

Tumor assessments were performed according to RECIST version 1.1, using radiographic images submitted to the IRF up to and including the confirmatory tumor assessment 4 to 6 weeks after study drug discontinuation. Disease progression was defined as a ≥20% and 5-mm increase in sum of diameters of target lesions, taking as reference the smallest sum obtained during the study, or appearance of new lesion(s). The percentage of participants with death or disease progression was calculated as \[number of participants with event divided by the number analyzed\] multiplied by 100.

Time frame: Up to 48 months from randomization until clinical cutoff of 16-Sept-2014 (at Screening, every 9 weeks for 81 weeks, then every 12 weeks thereafter and/or up to 42 days after last dose)

PFS According to IRF Assessment Among Those With Low HER2 mRNA Levels

Tumor assessments were performed according to RECIST version 1.1, using radiographic images submitted to the IRF up to and including the confirmatory tumor assessment 4 to 6 weeks after study drug discontinuation. PFS was defined as the time from randomization to first documented disease progression or death from any cause. Disease progression was defined as a ≥20% and 5-mm increase in sum of diameters of target lesions, taking as reference the smallest sum obtained during the study, or appearance of new lesion(s). Median duration of PFS was estimated using Kaplan-Meier analysis.

Time frame: Up to 48 months from randomization until clinical cutoff of 16-Sept-2014 (at Screening, every 9 weeks for 81 weeks, then every 12 weeks thereafter and/or up to 42 days after last dose)

Percentage of Participants Who Died Prior to Clinical Cutoff Among Those With High HER2 mRNA Levels

The percentage of participants who died prior to clinical cutoff was calculated as \[number of participants with event divided by the number analyzed\] multiplied by 100.

Time frame: Up to 70 months from randomization until clinical cutoff of 15-May-2016 (every 3 months until death, loss to follow-up, withdrawal, or study termination)

OS at Clinical Cutoff Among Those With High HER2 mRNA Levels

OS was defined as the time from randomization to death from any cause. Median duration of OS was estimated using Kaplan-Meier analysis.

Time frame: Up to 70 months from randomization until clinical cutoff of 15-May-2016 (every 3 months until death, loss to follow-up, withdrawal, or study termination)

Percentage of Participants Who Died Prior to Clinical Cutoff Among Those With Low HER2 mRNA Levels

The percentage of participants who died prior to clinical cutoff was calculated as \[number of participants with event divided by the number analyzed\] multiplied by 100.

Time frame: Up to 70 months from randomization until clinical cutoff of 15-May-2016 (every 3 months until death, loss to follow-up, withdrawal, or study termination)

OS at Clinical Cutoff Among Those With Low HER2 mRNA Levels

OS was defined as the time from randomization to death from any cause. Median duration of OS was estimated using Kaplan-Meier analysis. Reported upper bound of confidence interval for "Trastuzumab Emtansine + Placebo" and confidence interval values for "Trastuzumab + Taxane" and "Trastuzumab Emtansine + Pertuzumab" are censored values.

Time frame: Up to 70 months from randomization until clinical cutoff of 15-May-2016 (every 3 months until death, loss to follow-up, withdrawal, or study termination)