A Study of a Combination of Trastuzumab and Capecitabine With or Without Pertuzumab in Patients With HER2-positive Metastatic Breast Cancer (PHEREXA)

Progression Free Survival (PFS) was defined as the time from randomization to first documented disease progression (PD), as determined by an Independent Review Facility (IRF) using Response Evaluation Criteria in Solid Tumors (RECIST) version 1.0, or death from any cause, whichever occurred first. PD was defined as at least a 20% increase in the sum of the longest diameter (LD) of target lesions taking as reference the smallest sum LD recorded since the treatment started or the appearance of one or more new lesions; or the appearance of one or more new lesions and/or unequivocal progression of existing non-target lesions. IRF review of tumor assessment ceased after the primary PFS analysis. The primary endpoint was analyzed after approximately 337 IRF-assessed PFS events were observed.

Time frame: Tumor assessments every 9 weeks from randomization until Week 27, then every 12 weeks thereafter, until IRF-determined PD, initiation of alternative anticancer medication, or death (up to 5.5 years).

Population: All randomized participants.

Clinical Benefit Rate is based upon Independent Review Facility (IRF) assessments; defined as the percentage of participants a complete response (CR), partial response (PR), or stable disease for at least 8 cycles or 6 months.

Time frame: Tumor assessments every 9 weeks from randomization until Week 27, then every 12 weeks thereafter, until IRF-determined PD, initiation of alternative anticancer medication, or death (up to 5.5 years).

Population: Participants without a post-baseline tumor assessment were considered to be non-responders and were not included in this outcome measure.

Duration of Objective Response was defined for the subpopulation of responders as time from first Independent Review Facility (IRF)-assessed complete response (CR) or partial response (PR) to subsequent first documented, IRF-confirmed evidence of disease progression. Only participants with an objective response were included in the analysis of duration of objective response.

Time frame: Tumor assessments every 9 weeks from randomization until Week 27, then every 12 weeks thereafter, until IRF-determined PD, initiation of alternative anticancer medication, or death (up to 5.5 years).

Investigator Assessment Progression-Free Survival (PFS) was defined as the time from randomization to the first documented progressive disease, as determined by the investigator using Response Evaluation Criteria in Solid Tumors (RECIST) v1.0, or death from any cause, whichever occurred first. PD is defined as at least a 20% increase in the sum of the longest diameter (LD) of target lesions taking as reference the smallest sum LD recorded since the treatment started or the appearance of one or more new lesions; or the appearance of one or more new lesions and/or unequivocal progression of existing non-target lesions.

Time frame: Tumor assessments every 9 weeks from randomization until Week 27, then every 12 weeks thereafter, until IRF-determined PD, initiation of alternative anticancer medication, or death (up to 7.5 years).

Population: All randomized participants.

Overall Objective Response Rate is based upon investigator and IRF assessments. Objective Response Rate (ORR) was defined as the percentage of participants with a confirmed complete response (CR) or partial response (PR) among those who had measurable disease at baseline. CR was defined as the disappearance of all target lesions. PR was defined as at least a 30% decrease in the sum of the longest diameter (LD) of target lesions, taking as reference the baseline sum LD.

Time frame: Tumor assessments every 9 weeks from randomization until Week 27, then every 12 weeks thereafter, until IRF-determined PD, initiation of alternative anticancer medication, or death (up to 5.5 years).

Population: Participants without a post-baseline tumor assessment were considered to be non-responders and were not included in this outcome measure.

Overall Survival (OS) was defined as the time from the date of randomization to the date of death from any cause. The results of the final OS analysis are presented here. Participants who were alive or lost to follow-up at the time of the analysis were censored at the last known alive date. Participants with no postbaseline information were censored at the time of randomization plus 1 day. Prior to the final data analysis cut-off, it was ensured that all participants who were in survival follow-up had been contacted as recently as possible within the last 3 months to confirm current survival status.

Time frame: From randomization until death from any cause (up to 7.5 years).

Population: All randomized participants.

The Overall Survival (OS) 2-year truncated analysis is the Kaplan-Meier estimate of the percentage of participants who were surviving at 2 years. OS is defined as the time from the date of randomization to the date of death from any cause, with censoring of all events and follow-up beyond the end of the second year.

Time frame: From randomization until death from any cause (up to 2 years)

Population: All randomized participants.

Time to Progression (TTP) was defined as time between randomization and the first occurrence of progressive disease (PD), based on IRF assessment.

Time frame: Tumor assessments every 9 weeks from randomization until Week 27, then every 12 weeks thereafter, until IRF-determined PD, initiation of alternative anticancer medication, or death (up to 5.5 years).

Population: All randomized participants.

Time to Treatment Failure (TTF) was defined as time between randomization and date of disease progression based on independent review, death, or withdrawal of treatment due to adverse events, withdrawn informed consent, refusal of treatment/failure to cooperate, or failure to return, whichever occurred first.

Time frame: Tumor assessments every 9 weeks from randomization until Week 27, then every 12 weeks thereafter, until IRF-determined PD, initiation of alternative anticancer medication, or death (up to 5.5 years).

Population: All randomized participants.