The immune checkpoint inhibitors targeting cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) and the programmed death protein 1 (PD-1)/PD-L1 pathway have recently shown promising therapeutic results in patients with metastatic melanoma.
Sixty-four pre-treatment formalin-fixed and paraffin embedded melanoma samples from MMP treated with a BRAF inhibitor (n = 39) or BRAF and MEK inhibitors (n = 25) were assessed for presence of β-catenin, PD-L1, cluster of differentiation (CD)8, CD103 and forkhead box protein P3 (FOXP3) expression by immunohistochemistry, and results were correlated with clinical outcome.
The addition of an anti-PD-1/PD-L1 agent, such as pembrolizumab, durvalumab or atezolizumab, to combined BRAF and MEK inhibition has shown considerable promise, with several trials ongoing in metastatic melanoma.
Pembrolizumab (MK-3475, lambrolizumab, Keytruda(®)) is a PD-1 inhibitor that has shown clinical activity in a variety of solid tumors and is currently approved for the second-line treatment of PD-L1-positive non-small-cell lung cancer and for unresectable/metastatic melanoma.
New generations of immune checkpoint blockading antibodies targeting programmed cell death 1 (PD-1) and its ligand (PD-L1) are now under intense investigation in metastatic melanoma (MM) and non-small-cell lung cancer (NSCLC), and impressive clinical results are anticipated.
PD-L1 expression (cutoff 5%) was analyzed by immunohistochemistry with two different antibodies in BRAF(V600)-mutated formalin-fixed and paraffin-embedded samples from 80 consecutive MMP treated with BRAFi at a single institution.
Modern immune therapies (PD-1/PD-L1 and CTLA-4 checkpoints blockade and adoptive cell transfer) have remarkably improved the response rates of metastatic melanoma.
In this Review, we discuss the existing evidence for the newest treatments for BRAF-mutant melanoma, including combined BRAF and MEK inhibition and PD-1-PD-L1 checkpoint inhibitors, and assess future treatment strategies that could change metastatic melanoma from a rapidly fatal terminal illness to a chronic disease for most patients.
Consistent with this hypothesis, overall survival of patients with B7-H1(+) metastatic melanoma was significantly prolonged compared with that of patients with B7-H1(-) metastatic melanoma.