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.
RAS ID
30276
Document Type
Journal Article
Date of Publication
12-5-2020
ISSN
1549-490X
PubMed ID
31806779
School
School of Medical and Health Sciences / School of Engineering
Grant Number
NHMRC : 1013349
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Publisher
Wiley
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
Recommended Citation
Khattak, M. K., Reid, A. L., Freeman, J., Pereira, M., McEvoy, A., Lo, J., Frank, M., Meniawy, T., Didan, A., Spencer, I., Amanuel, B., Millward, M., Ziman, M., & Gray, E. (2020). PD-L1 expression on circulating tumor cells may be predictive of response to Pembrolizumab in advanced melanoma: Results from a pilot study. DOI: https://doi.org/10.1634/theoncologist.2019-0557
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