GSK reports 45% survival rate in phase III study of Tafinlar in BRAF V600E mutant metastatic melanoma

GSK today announced updated results for Tafinlar^® (dabrafenib) from a planned analysis of the phase III BREAK-3 study in 250 patients with BRAF V600E mutant metastatic melanoma. These results, which include new survival data, showed 45 per cent of patients treated with dabrafenib were still alive at two years. The data were presented at the European Society for Medical Oncology (ESMO) 2014 Congress in Madrid.

Analysis of the study’s primary endpoint, progression free survival (PFS), was reported in 2012. Today’s results relate to a secondary endpoint from this study, with a final analysis of the overall survival (OS) endpoint expected in 2016.

45 per cent of patients treated with dabrafenib only, were alive at two years compared to 32 per cent of patients who began treatment with dacarbazine (DTIC).  59 per cent of patients on DTIC treatment whose disease progressed subsequently received dabrafenib treatment and are included in the DTIC control arm results. While allowing this treatment cross over means patients in the control arm get the potential benefit of an active experimental drug, this can impact the comparative study findings as patients who received both medicines are included in the DTIC arm results. At the planned two year follow up, the study showed a median OS of 20.0 months for the dabrafenib arm (95% CI 16.8-24.4) compared to 15.6 months for the DTIC arm (95% CI 12.7-21.2) [Hazard Ratio (HR) 0.77 (95% CI 0.52-1.13) – not statistically significant.]

“We are encouraged by the 45 per cent survival rate with dabrafenib at two years” said Dr. Paolo Paoletti, President of Oncology, GSK. “Treatments for melanoma have come a long way in recent years and we’re now seeing the benefits precision medicines can bring to the right patients.”

The safety profile of dabrafenib observed in this analysis was consistent with that observed at the primary analysis of BREAK-3. The five most common adverse events (AEs) in patients treated with dabrafenib were hyperkeratosis (a condition causing benign skin thickening or lesions) (41%), arthralgia (joint pain) (37%), headache (36%), pyrexia (fever) (33%) and alopecia (hair loss) (29%). Serious adverse events (SAEs) in ≥5 per cent of patients treated with dabrafenib included cutaneous squamous-cell carcinoma/keratoacanthoma (10%) and pyrexia (5%). Non cutaneous malignancies occurred in four patients (2%) on dabrafenib, two patients (5%) who crossed over and in no patients treated with DTIC.