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

Health-related quality of life in patients treated with pembrolizumab for microsatellite instability–high/mismatch repair–deficient advanced solid tumours: Results from the KEYNOTE-158 study

Background: In the KEYNOTE-158 study (NCT02628067), pembrolizumab showed a high objective response rate and durable clinical benefit for patients with previously treated, unresectable/metastatic microsatellite instability−high (MSI-H)/mismatch repair‒deficient (dMMR) non-colorectal solid tumours. We present health-related quality of life (HRQoL) results from the MSI-H/dMMR population (cohort K). Patients and methods: Eligible patients had previously treated MSI-H/dMMR advanced non-colorectal solid tumours, measurable disease per RECIST v1.1, and ECOG performance status ≤1. Patients received pembrolizumab 200 mg Q3W for 35 cycles (2 years). The EORTC Quality of Life Questionnaire (QLQ-C30) and EQ-5D-3L were administered at baseline, at regular intervals throughout treatment, and 30 days after treatment discontinuation. Prespecified analyses (exploratory endpoints) included the magnitude of change from baseline to post-baseline timepoints in all patients and by the best overall response for QLQ-C30 global health status (GHS)/QoL, QLQ-C30 functional/symptom scales/items, and EQ-5D-3L visual analogue scale (VAS) score. Results: At data cutoff (October 5, 2020), 351 patients were enrolled, of whom 311 and 315 completed baseline QLQ-C30 and EQ-5D-3L questionnaires, respectively. QLQ-C30 GHS/QoL scores improved from baseline to week 9 (mean [95% CI] change, 3.07 [0.19–5.94]), then remained stable or improved by week 111, with greater improvements observed in patients with a best response of complete response (CR) or partial response (PR) (10.85 [6.36–15.35]). Patients with CR/PR showed improvements in physical (5.58 [1.91–9.25]), role (9.88 [3.80–15.97]), emotional (5.62 [1.56–9.68]), and social (8.33 [2.70–13.97]) functioning, and stable cognitive functioning (1.74 [−1.45 to 4.94]). Conclusions: Pembrolizumab generally improved or preserved HRQoL in patients with previously treated MSI-H/dMMR advanced non-colorectal solid tumours

Induction of Bcl-2 Expression by Hepatitis B Virus Pre-S2 Mutant Large Surface Protein Resistance to 5-Fluorouracil Treatment in Huh-7 Cells

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide with poor prognosis due to resistance to conventional chemotherapy and limited efficacy of radiotherapy. Our previous studies have indicated that expression of Hepatitis B virus pre-S2 large mutant surface antigen (HBV pre-S2Δ) is associated with a significant risk of developing HCC. However, the relationship between HBV pre-S2Δ protein and the resistance of chemotherapeutic drug treatment is still unclear. METHODOLOGY/PRINCIPAL FINDINGS: Here, we show that the expression of HBV pre-S2Δ mutant surface protein in Huh-7 cell significantly promoted cell growth and colony formation. Furthermore, HBV pre-S2Δ protein increased both mRNA (2.7±0.5-fold vs. vehicle, p=0.05) and protein (3.2±0.3-fold vs. vehicle, p=0.01) levels of Bcl-2 in Huh-7 cells. HBV pre-S2Δ protein also enhances Bcl-2 family, Bcl-xL and Mcl-1, expression in Huh-7 cells. Meanwhile, induction of NF-κB p65, ERK, and Akt phosphorylation, and GRP78 expression, an unfolded protein response chaperone, were observed in HBV pre-S2Δ and HBV pre-S-expressing cells. Induction of Bcl-2 expression by HBV pre-S2Δ protein resulted in resistance to 5-fluorouracil treatment in colony formation, caspase-3 assay, and cell apoptosis, and can enhance cell death by co-incubation with Bcl-2 inhibitor. Similarly, transgenic mice showed higher expression of Bcl-2 in liver tissue expressing HBV pre-S2Δ large surface protein in vivo. CONCLUSION/SIGNIFICANCE: Our result demonstrates that HBV pre-S2Δ increased Bcl-2 expression which plays an important role in resistance to 5-fluorouracil-caused cell death. Therefore, these data provide an important chemotherapeutic strategy in HBV pre-S2Δ-associated tumor