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Marija Ivanovic
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P2.09 - Pathology (ID 174)
- Event: WCLC 2019
- Type: Poster Viewing in the Exhibit Hall
- Track: Pathology
- Presentations: 1
- Now Available
- Moderators:
- Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall
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P2.09-30 - PD-L1 Testing and Clinical Benefit in Patients Treated with CPI (Now Available) (ID 1672)
10:15 - 18:15 | Author(s): Marija Ivanovic
- Abstract
Background
PD-L1 expression in tumor cells should predict better response rate in lung carcinoma patients treated with immune checkpoint inhibitors.
Method
Retrospective analysis of 46 NSCLC lung cancer patients with cytology/pathology samples from primary tumor/metastasis tested for PD-L1 expression and comparing the PD-L1 testing results with clinical benefit. Follow-up period was 6 to 24 months. Samples were stained with PD-L1 mouse monoclonal antibody (clone 22C3, DAKO, Denmark) or with rabbit monoclonal antibody (clone SP263, Ventana/Roche, USA) on an automated staining platform (Benchmark ultra, Ventana/Roche, USA). Samples were divided into four categories: Cytology, histology, primary tumor and metastasis. Number of positive tumor cells was assessed semiquantitatively and divided into three categories: 0%, 1 to 49% and 50 to 100%. We compared PD-L1 expression with clinical course of patients treated with immune checkpoint inhibitors (nivolumab, pembrolizumab and atezolizumab), considering complete response, partial response and stable disease (RECIST criteria) as clinical benefit. Progress of the disease was considered as no clinical benefit.
Result
We had 37% cytological and 63% histological samples. Overall PD-L1 expression was present in 76% of all samples (1 to 49% and 50 to 100% categories, 13% and 63%, respectfully). We observed clinical benefit in 33 patients (5, 5 and 23 with 0%, 1 to 49% and 50 to 100%, respectively). Progress of the disease was observed in 13 patients (6, 1 and 6 with 0%, 1 to 49% and 50 to 100%, respectively). Out of 29 patients with histological samples, 22 had clinical benefit (2, 5 and 15 with 0%, 1 to 49% and 50 to 100%, respectively). Progress of the disease was observed in 7 patients (5, 0 and 2 with 0%, 1 to 49% and 50 to 100%, respectively). Out of 17 patients with cytological samples 11 had clinical benefit (3, 0 and 8 with 0%, 1 to 49% and 50 to 100%, respectively). Progress of the disease was observed in 6 patients (1, 1 and 4 with 0%, 1 to 49% and 50 to 100%, respectively). We had 29 samples from primary tumor and 17 samples from metastasis. 23 patients with primary tumor sample (2, 4 and 16 with 0%, 1 to 49% and 50 to 100%, respectively) and 10 with metastasis sample (3, 0 and 7 with 0%, 1 to 49% and 50 to 100%, respectively) had clinical benefit. Progress of the disease was observed in 6 patients with primary tumor sample (4, 0 and 2 with 0%, 1 to 49% and 50 to 100%, respectively) and in 7 patients with metastasis sample (2, 1 and 4 with 0%, 1 to 49% and 50 to 100%, respectively) .
Conclusion
Histological samples from primary tumors seem to have the best, while cytological samples from metastases the poorest predictive value for assessment of clinical benefit for NSCLC patients treated with immunotherapy.
