The firm will combine dabrafenib, its BRAF inhibitor, and trametinib, its
MEK inhibitor, in patients with BRAF mutation-positive metastatic cutaneous
melanoma. There will be two Phase III trials: COMBI-d and COMBI-v, which will be
looking at the combinations.
COMBI-d will combine its trametinib and dabrafenib, in patients with BRAF
V600E or V600K mutation-positive metastatic cutaneous melanoma. This trial will evaluate whether combining the two drugs is better than
dabrafenib as a single-agent therapy in stopping or slowing the progression of
metastatic melanoma (Progression-Free Survival).
The second study will combine GSK’s drugs and pit them against Roche’s Zelboraf
(vemurafenib). Zelboraf is currently the only licensed drug to treat BRAF positive
melanoma patients and is the first drug to increase overall survival in this
patient population.
COMBI-v will evaluate whether combining GSK’s two drugs can increase
overall survival at a higher level compared to patients taking Zelboraf on its
own.
GSK will be hoping that its drug can beat Zelboraf in the head-to-head
study, which could help it take market share away from Roche should it be
approved. Analysts predict peak annual sales for dabrafenib and trametinib to reach
£1.5 billion ($2.4 billion) by 2020.
GSK said that further data would be released at the ASCO cancer conference
this weekend in Chicago. Dr Rafael Amado, head of oncology R&D for GlaxoSmithKline, said: “While
recent clinical findings with BRAF inhibitors in melanoma have shown
significant improvement over chemotherapy, eventually tumours become resistant
to these inhibitors leading to disease relapse.
“Recent scientific advances have led us to the hypothesis that the
combination of BRAF and MEK inhibitors may delay resistance.
“Guided by promising results from an early phase study, we are launching
this Phase III programme and will continue discussions with regulators about
the future regulatory pathway for the combination.”