Study to Determine the Effectiveness of GSK1120212 in BRAF Mutation-positive Melanoma Previously Treated With or Without a BRAF Inhibitor

Best confirmed response was assessed by the Investigator per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Best response was measured either as a complete response (CR), defined as the disappearance of all target lesions and pathological lymph nodes <10 millimeters (mm), or a partial response (PR), defined as at least a 30% decrease in the sum of the diameters of target lesions. To be assigned a status of confirmed CR or PR, a confirmatory disease assessment was required no less than 28 days after the criteria for response were first met.

The number of participants with best confirmed response was analyzed for the following subgroups of participants previously treated with standard therapy but not BRAF inhibitors: (1) participants with prior (before the start of this study) brain metastases (mets); (2) participants without prior brain mets; (3) participants with BRAF mutation V600E; (4) participants with BRAF mutation V600E and no prior brain mets; and (5) participants with BRAF mutation V600K. Objective response was assessed per RECIST version 1.1. Objective response was measured either as CR, defined as the disappearance of all target lesions and pathological lymph nodes <10 mm, or PR, defined as at least a 30% decrease in the sum of the diameters of target lesions. To be assigned a status of confirmed CR or PR, a confirmatory disease assessment was required no less than 28 days after the criteria for response were first met. Brain metastasis is a cancer that has spread to the brain from another location of the body.

An interim analysis was performed using data collected approximately 12 and 13 weeks after the 30th participant was enrolled in the prior BRAF inhibitor and prior standard therapy groups, respectively. The best unconfirmed response by the investigator per RECIST version 1.1 was assessed. The study design permitted stopping the study for futility if <3 best confirmed responses were observed in the first 30 participants of each treatment arm after completing the first post-dose assessment at Week 8. Best response was measured as either a CR, defined as the disappearance of all target lesions and pathological lymph nodes <10 millimeters, or a PR, defined as at least a 30% decrease in the sum of the diameters of target lesions.

Human plasma samples were analyzed for trametinib using a validated analytical method.

An AE is defined as any untoward medical occurrence in a subject or clinical investigation subject, temporally associated with the use of a medicinal product, whether or not considered to be related to the medicinal product. AE and serious AE (SAE) data were collected from the start of the investigational product and continued until the End of Treatment Visit. Refer to the general Adverse AE/SAE module for a complete list of AEs and SAEs.

Duration of tumor response is defined as the time from the first documented evidence of a CR or PR to disease progression (at least a 20 percent increase in the sum of diameters of target lesions, taking as reference the smallest sum on study; unequivocal progression of non-target lesions, or the appearance of a new lesion) or death due to any cause. No participants who were previously treated with BRAF inhibitors had a CR, defined as the disappearance of all target lesions and pathological lymph nodes <10 millimeters, or a PR, defined as at least a 30% decrease in the sum of the diameters of target lesions; thus, no duration of response data can be presented.

PFS is defined as the interval between the treatment start date and the earliest date of disease progression (at least a 20 percent increase in the sum of diameters of target lesions, taking as reference the smallest sum on study; unequivocal progression of non-target lesions, or the appearance of a new lesion) or death due to any cause, whichever occurred first. Participants who had not progressed or died were censored at the date of the last adequate tumor assessment at the time of the cut-off.

PFS was analyzed for the following subgroups of participants previously treated with standard therapy but not BRAF inhibitors: (1) participants with prior (before the start of this study) brain metastases (mets); (2) participants without prior brain mets; (3) participants with BRAF mutation V600E; (4) participants with BRAF mutation V600E and no prior brain mets; and (5) participants with BRAF mutation V600K. Per RECIST version 1.1, PFS is defined as the interval between the treatment start date and the earliest date of disease progression (at least a 20 percent increase in the sum of diameters of target lesions, taking as reference the smallest sum on study; unequivocal progression of non-target lesions, or the appearance of a new lesion) or death due to any cause, whichever occurred earliest. Brain metastasis is a cancer that has spread to the brain from another location of the body.

Overall survival is defined as the time from the treatment start date until death due to any cause. Participants who had not died were censored at the date of the last adequate tumor assessment at the time of the cut-off.

Overall survival (defined as the time from the treatment start date until death due to any cause) data data are presented as the number of participants who were alive 6 months, 12 months and 24 months after Baseline. Participants who had not died were censored at the date of the last adequate tumor assessment at the time of the cut-off.

Tumor progression was assessed as disease progression (DP), defined as at least a 20 percent increase in the sum of diameters of target lesions (representative of all involved organs), taking as reference the smallest sum on study; unequivocal progression of non-target lesions; or the appearance of a new lesion. Because melanoma often progresses to the brain/central nervous system (CNS) and this study enrolled approximately 20% participants with prior brain metastases, tumor progression in the brain/CNS was summarized. Paticipants could have been included in more than one category.