GlaxoSmithKline and Pfizer have joined forces to test a combination of their respective melanoma compounds.

A Phase I/II study will explore the efficacy and safety of Pfizer's investigational drug palbociclib with GlaxoSmithKline's already-marketed Mekinist (trametinib). The trials will also evaluate the effect of the combo on tumour biomarkers, safety and anti-cancer activity in patients with BRAFV600 wild type melanoma, including those with NRAS mutations.

The two companies will collaborate on the study, which GSK will conduct. Financial terms of the agreement have not been disclosed.

Garry Nicholson, head of Pfizer's oncology business unit, spoke of maximising the value of the firm's portfolio through the study of novel combinations and "this includes combining our own cancer medicines with each other, as well as with those of other companies where there is strong scientific rationale". He added that "emerging data suggest the potential for trametinib and palbociclib to work together to treat melanoma".

Mekinist, a reversible inhibitor of MEK1 and MEK2, was approved by the US Food and Drug Administration in May, on the same day as another GSK melanoma drug Tafinlar (dabrafenib). A combination of those two treatments was granted a priority review by the FDA in September.

As for palbociclib, Pfizer has high hopes for the selective inhibitor of cyclin dependent kinases (CDK) 4 and 6. It received breakthrough therapy designation from the FDA for breast cancer in April this year.