Author Identifier
James Freeman
ORCID : 0000-0001-8065-8416
Ashleigh McEvoy
ORCID : 0000-0001-5692-1317
Johnny Lo
ORCID : 0000-0003-1913-5354
Mel Ziman
ORCID : 0000-0001-7527-3538
Elin Gray
ORCID : 0000-0002-8613-3570
Document Type
Journal Article
Publication Title
The oncologist
ISSN
1549-490X
PubMed ID
31806779
Publisher
Wiley
School
School of Medical and Health Sciences / School of Engineering
RAS ID
30276
Grant Number
NHMRC : 1013349
Abstract
BACKGROUND: PD-1 inhibitors are routinely used for the treatment of advanced melanoma. This study sought to determine whether PD-L1 expression on circulating tumor cells (CTCs) can serve as a predictive biomarker of clinical benefit and response to treatment with the PD-1 inhibitor pembrolizumab.
METHODS: Blood samples were collected from patients with metastatic melanoma receiving pembrolizumab, prior to treatment and 6-12 weeks after initiation of therapy. Multiparametric flow cytometry was used to identify CTCs and evaluate the expression of PD-L1.
RESULTS: CTCs were detected in 25 of 40 patients (63%). Patients with detectable PD-L1
CONCLUSION: Our results reveal the potential of CTCs as a noninvasive real-time biopsy to evaluate PD-L1 expression in patients with melanoma. PD-L1 expression on CTCs may be predictive of response to pembrolizumab and longer PFS.
IMPLICATIONS FOR PRACTICE: The present data suggest that PD-L1 expression on circulating tumor cells may predict response to pembrolizumab in advanced melanoma. This needs further validation in a larger trial and, if proven, might be a useful liquid biopsy tool that could be used to stratify patients into groups more likely to respond to immunotherapy, hence leading to health cost savings.
DOI
10.1634/theoncologist.2019-0557
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Comments
Khattak, M. A., Reid, A., Freeman, J., Pereira, M., McEvoy, A., Lo, J., ... & Amanuel, B. (2020). PD-L1 Expression on Circulating Tumor Cells May Be Predictive of Response to Pembrolizumab in Advanced Melanoma: Results from a Pilot Study. The oncologist, 25(3), e520-e527. https://doi.org/10.1634/theoncologist.2019-0557