PD-L1 expression by tumor and tumor-infiltrating immune cells is associated with higher response rates to anti–PD-1/PD-L1 antibodies among solid tumors, according to a study published in Precision Oncology.1
The role of PD-L1 testing as a biomarker for response to anti–PD-1/PD-L1 antibody treatment is not yet well-defined. This meta-analysis evaluated the predictive role PD-L1 expression by pooling data from multiple trials across several solid malignancies.
The analysis included 6664 patients from 41 distinct phase 1 to 3 clinical trials that evaluated nivolumab, pembrolizumab, atezolizumab, durvalumab, or avelumab in advanced non–small-cell lung cancer (NSCLC), renal cell carcinoma, bladder cancer, melanoma, gastroesophageal cancer, Merkel cell cancer, head and neck cancer, and small-cell lung cancer.
PD-L1 positivity by immunohistochemistry (IHC) was significantly associated with favorable response among all tumor types (odds ratio [OR], 2.26; 95% CI, 1.85-2.75; P < .001), but particularly for NSCLC (OR, 2.51; 95% CI, 1.99-3.17; P < .001), compared with PD-L1 negativity.
The favorable response to PD-1/PD-L1 inhibition in NSCLC was present among different PD-L1 expression thresholds, including 1% (OR, 2.17; 95% CI, 1.03-4.57), 5% (OR, 2.80; 95% CI, 1.56-5.02), and 10% (OR, 2.84; 1.40-5.77).
PD-L1 positivity was associated with treatment response regardless of which IHC assay was used. The ORs ranged from 2.02 to 4.42 for the 28-8, SP142, 22C3, 73-10, and SP263 assays.
The authors stated that these findings suggest that “detection of PD-L1 expression in tumor cells and tumor-infiltrating immune cells using IHC is highly accessible and has significant potential as a biomarker predictive of response to PD-1/PD-L1 axis therapies across various tumor types.”
- Khunger M, Hernandez AV, Pasupuleti V, et al. Programmed cell death 1 (PD-1) ligand (PD-L1) expression in solid tumors as predictive biomarker of benefit from PD-1/PD-L1 axis inhibitors: a systematic review and meta-analysis. Precis Oncol. 2017 May 18. doi: 10.1200/PO.16.00030 [Epub ahead of print]