Pembrolizumab in microsatellite instability high or mismatch repair deficient cancers: updated analysis from the phase II KEYNOTE-158 study.

BACKGROUND: Pembrolizumab demonstrated durable antitumor activity in 233 patients with previously treated advanced microsatellite instability high (MSI-H) or mismatch repair deficient (dMMR) advanced solid tumors in the phase II multicohort KEYNOTE-158 (NCT02628067) study. Herein, we report safety and efficacy outcomes with longer follow-up for more patients with previously treated advanced MSI-H/dMMR noncolorectal cancers who were included in cohort K of the KEYNOTE-158 (NCT02628067) study. PATIENTS AND METHODS: Eligible patients with previously treated advanced noncolorectal MSI-H/dMMR solid tumors, measurable disease as per RECIST v1.1, and Eastern Cooperative Oncology Group performance status of 0 or 1 received pembrolizumab 200 mg Q3W for 35 cycles or until disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR) as per RECIST v1.1 by independent central radiologic review. RESULTS: Three hundred and fifty-one patients with various tumor types were enrolled in KEYNOTE-158 cohort K. The most common tumor types were endometrial (22.5%), gastric (14.5%), and small intestine (7.4%). Median time from first dose to database cut-off (5 October 2020) was 37.5 months (range, 0.2-55.6 months). ORR among 321 patients in the efficacy population (patients who received ≥1 dose of pembrolizumab enrolled ≥6 months before the data cut-off date) was 30.8% [95% confidence interval (CI) 25.8% to 36.2%]. Median duration of response was 47.5 months (range, 2.1+ to 51.1+ months; '+' indicates no progressive disease by the time of last disease assessment). Median progression-free survival was 3.5 months (95% CI 2.3-4.2 months) and median overall survival was 20.1 months (95% CI 14.1-27.1 months). Treatment-related adverse events (AEs) occurred in 227 patients (64.7%). Grade 3-4 treatment-related AEs occurred in 39 patients (11.1%); 3 (0.9%) had grade 5 treatment-related AEs (myocarditis, pneumonia, and Guillain-Barre syndrome, n = 1 each). CONCLUSIONS: Pembrolizumab demonstrated clinically meaningful and durable benefit, with a high ORR of 30.8%, long median duration of response of 47.5 months, and manageable safety across a range of heavily pretreated, advanced MSI-H/dMMR noncolorectal cancers, providing support for use of pembrolizumab in this setting.

First-line chemotherapy with liposomal doxorubicin plus cisplatin for patients with advanced malignant pleural mesothelioma: phase II trial.

BACKGROUND: Chemotherapy based on platinum is the standard treatment for unresectable malignant pleural mesothelioma (MPM). Liposomal doxorubicin (LD) consists of pegylated phospholipid vesicles that encapsulate doxorubicin-enhancing liposome deposition in the tumour. We evaluated the toxicity profile and anti-tumour activity of cisplatin plus LD in untreated patients with MPM, as well as (99m)Tc-LD distribution in MPM lesions after chemotherapy administration. METHODS: A total of 38 patients with non-resectable MPM received LD 40 mg m(-2) and cisplatin 60 mg m(-2) every 21 days. Gamma camera images of (99m)Tc-LD were acquired to evaluate LD accumulation in measurable tumour tissue. The study was registered in Clinical Trials (NCT00886028). RESULTS: In all, 72% of patients were stage III and 28% were stage IV. Eighty four percent and 16% have high and low risk acording EORTC respectively. The median time to progression was 4.6 months (95% confidence interval (95% CI: 3.4-5.9 months), and median overall survival (OS) was 19.6 months (15.2-37.2 months). Patients that responded to chemotherapy treatment had better survival than patients who did not. Functional physical scales, dysnea, cough, and chest/arm pain demonstrated improvement. The accumulation ratio of LD in tumour and soft tissues vs liver was 0.78±0.16 and 0.29±0.09, respectively. After 1 h of administration, LD uptake in tumour tissue was higher than in soft tissue (P< 0.001). CONCLUSION: The combination of LD and cisplatin results in an active therapeutic regimen for unresectable MPM, with an acceptable toxicity profile and improvement in quality of life. (99m)Tc-LD showed higher levels of tumour uptake as compared with surrounding tissues.