Start Your Search
OA08 - Mesothelioma: Immunotherapy and microRNA for Diagnosis and Treatment (ID 907)
- Event: WCLC 2018
- Type: Oral Abstract Session
- Track: Mesothelioma
- Presentations: 1
- Coordinates: 9/24/2018, 15:15 - 16:45, Room 201 BD
OA08.03 - Phase II Trial of Pembrolizumab (NCT02399371) In Previously-Treated Malignant Mesothelioma (MM): Final Analysis (ID 12045)
15:35 - 15:45 | Author(s): Theodore Karrison
We conducted a phase II trial to assess the activity of pembrolizumab in a non-selected population of mesothelioma patients and determine a PD-L1 expression threshold.a9ded1e5ce5d75814730bb4caaf49419 Method
Eligible patients had histologically-confirmed pleural or peritoneal MM, PS 0-1, prior pemetrexed/platin, disease progression on ≤2 prior regimens. Pembrolizumab 200 mg was administered Q21 days; CT scans were obtained Q9 weeks. The primary endpoints determined: 1) the objective response rate (ORR) in an unselected and a PD-L1 positive population; 2) the optimal threshold for PD-L1 expression using the 22C3 IHC tumor cell/tumor proportion score (TPS) assay. Proceeding to a second stage required ≥3 responses in 35 PD-L1 unselected patients in Part A. Part B would PD-L1 preselect only if a threshold was determined in Part A. At WCLC 2016, we reported 7 responses in Part A, and no PD-L1 threshold was identified (ROC 0.62). Thus, Part B enrolled 30 additional patients without biomarker enrichment.
65 patients enrolled 5/15-2/18; 1 withdrew. PS 0: 53%; male: 77%; median age: 68 (range 26-85); 1 prior chemotherapy 61%; pleural 87.5%; epithelioid 76.6%, biphasic 15.6%, sarcomatoid 7.8%. Mean cycles: 9 (range 1-34). Partial response: 19%, stable disease: 47%, disease control rate: 66%. ORR by histology: epithelioid 16%, biphasic 10%, sarcomatoid 40%. ORR by disease site: pleural 20%, peritoneal 12.5%. Median progression-free survival: 4.5 months (95% CI: 2.3, 6.2). Median overall survival: 11.5 months (95% CI: 7.6, 14). Grade ¾ toxicity: adrenal insufficiency 3%, pneumonitis 3%, rash 3%, colitis 1.6%, confusion 1.6%, hepatitis 1.6%, hyperglycemia 1.6%. Grade 5: hepatitis 1.6%, unknown 1.6%. PD-L1 expression by TPS (N = 62): none (< 1%) 45%; low (1-49%) 32%; high (≥50%) 23%. ORR by TPS: none 7%, low 26%, high 31%. PD-L1 did not correlate with RR as a continuous metric (ROC area 0.65; 95% CI: 0.48, 0.82), though there was a trend towards a higher ORR in PD-L1 ≥1% (28%) compared with PD-L1 <1% (7%). Median PFS by TPS: none 3.1 months, low 6.2 months, high 6.1 months; 1-year PFS by TPS: none 7%; low 7%; high 31%.8eea62084ca7e541d918e823422bd82e Conclusion
Single-agent pembrolizumab has robust activity in PD-L1 unselected, previously-treated mesothelioma. There were no unexpected toxicities. Responses were more frequent in pleural and sarcomatoid MM. Although an optimal PD-L1 threshold could not be identified, a trend towards a higher response rate and more durable PFS with increasing PD-L1 expression was observed. Funded in part by a Mesothelioma Foundation grant.6f8b794f3246b0c1e1780bb4d4d5dc53
Only Active Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login or select "Add to Cart" and proceed to checkout.