Pembrolizumab plus Chemotherapy for Squamous Non-Small-Cell Lung Cancer

Identification of ADAR1 adenosine deaminase dependency in a subset of cancer cells

Systematic exploration of cancer cell vulnerabilities can inform the development of novel cancer therapeutics. Here, through analysis of genome-scale loss-of-function datasets, we identify adenosine deaminase acting on RNA (ADAR or ADAR1) as an essential gene for the survival of a subset of cancer cell lines. ADAR1-dependent cell lines display increased expression of interferon-stimulated genes. Activation of type I interferon signaling in the context of ADAR1 deficiency can induce cell lethality in non-ADAR1-dependent cell lines. ADAR deletion causes activation of the double-stranded RNA sensor, protein kinase R (PKR). Disruption of PKR signaling, through inactivation of PKR or overexpression of either a wildtype or catalytically inactive mutant version of the p150 isoform of ADAR1, partially rescues cell lethality after ADAR1 loss, suggesting that both catalytic and non-enzymatic functions of ADAR1 may contribute to preventing PKR-mediated cell lethality. Together, these data nominate ADAR1 as a potential therapeutic target in a subset of cancers.

Specific cancer cell vulnerabilities can provide an opportunity for the development of novel cancer therapeutics. In this study the authors demonstrate that targeting ADAR1 represents a potential therapeutic vulnerability in cancers with activated interferon response signatures.

Pembrolizumab in combination with ipilimumab as second-line or later therapy for advanced non-small-cell lung cancer: KEYNOTE-021 cohorts D and H

OBJECTIVES

Combination immunotherapy may result in improved antitumor activity compared with single-agent treatment. We report results from dose-finding and dose-expansion cohorts of the phase 1/2 KEYNOTE-021 study that evaluated combination therapy with anti‒programmed death 1 (PD-1) antibody pembrolizumab plus anti‒cytotoxic T-lymphocyte antigen-4 (CTLA-4) antibody ipilimumab in patients with previously treated advanced non-small-cell lung cancer (NSCLC).

MATERIALS AND METHODS

Eligibility criteria stipulated histologically/cytologically confirmed advanced NSCLC and treatment failure on ≥1 prior systemic therapy (platinum-based chemotherapy or targeted therapy for patients with EGFR/ALK aberrations). In the dose-finding cohort, patients initially received pembrolizumab 10 mg/kg plus ipilimumab 1 or 3 mg/kg once every 3 weeks for 4 cycles followed by pembrolizumab 10 mg/kg monotherapy for up to 2 years. Based on emerging published data, subsequent patients received pembrolizumab 2 mg/kg plus ipilimumab 1 mg/kg. Objective response rate (ORR; primary efficacy endpoint) was assessed per RECIST version 1.1 by blinded, independent central review. Phase 2 hypothesis that ORR would be greater than the 20% rate for historical controls was evaluated using the exact binomial test.

RESULTS

Fifty-one patients were enrolled; 71% received ≥2 prior lines of therapy. No dose-limiting toxicities occurred at any dose level. Among patients who received pembrolizumab 2 mg/kg plus ipilimumab 1 mg/kg (n = 44), ORR was 30% (95% CI, 17%-45%), but not statistically significantly >20% (P = 0.0858). Median progression-free survival in this group was 4.1 (95% CI, 1.4-5.8) months; median overall survival was 10.9 (95% CI, 6.1-23.7) months. With pembrolizumab 2 mg/kg plus ipilimumab 1 mg/kg, incidences of treatment-related adverse events, grade 3-5 treatment-related adverse events, and immune-mediated adverse events and infusion reactions were 64%, 29%, and 42%, respectively.

CONCLUSIONS

In patients with heavily pretreated advanced NSCLC, pembrolizumab plus ipilimumab showed evidence of antitumor activity, but was associated with meaningful toxicity.

Effectiveness and safety of PD-1/PD-L1 or CTLA4 inhibitors combined with chemotherapy as a first-line treatment for lung cancer: A meta-analysis

Background

Immune checkpoint inhibitors (ICIs) combined with chemotherapy have been applied as a first-line treatment for lung cancer, but consistent beneficial results have not been documented. Therefore, our meta-analysis aimed to evaluate the effectiveness and safety of combination therapy to promote its application.

Methods

We searched electronic databases for studies that estimated the safety and efficacy of combined therapy. The objective response rate (ORR) and disease control response (DCR) parameters were evaluated with odds ratio (OR) values of the combination arm over the non-combination arm. Hazard ratios (HR) and its 95% confidence intervals (95% CI) were used to calculate progression-free survival (PFS) and overall survival (OS) in the combination and non-combination arms. All treatment-related adverse events (TRAEs) and 3 to 5 TRAEs were expressed as relative risk (RR) values of the combination arm over the non-combination arm.

Results

Ten eligible studies involving 4,887 patients were identified. The pooled ORs for ORR and DCR were 1.85 (95% CI: 1.30-2.63, P<0.01) and 1.14 (95% CI: 0.70-1.86, P<0.01), respectively. The pooled HRs for PFS and OS were 0.67 (95% CI: 0.58-0.79, P<0.001) and 0.76 (95% CI: 0.65-0.88, P<0.001), respectively. In subgroup analysis, ORR and DCR were significantly improved in the programmed cell death-1/L1 (PD-1/L1) blockade for non-small cell lung cancer (NSCLC) group (subgroup A), with a combined OR values of 2.36 (95% CI: 1.79-3.13, P<0.001) and 1.92 (95% CI: 1.10-3.35, P<0.001), respectively. However, no significant benefits were observed in the cytotoxic T lymphocyte antigen-4 (CTLA-4) blockade for small cell lung cancer (SCLC) (subgroup B) and CTLA-4 blockade for NSCLC groups (subgroup C). In addition, a significant improvement in PFS was observed in subgroup A, subgroup B and subgroup C, with pooled HR values of 0.58 (95% CI: 0.52-0.63, P<0.001), 0.86 (95% CI: 0.76-0.97, P<0.05) and 0.83 (95% CI: 0.68-1.00, P<0.05), respectively. Only subgroup A exhibited an OS benefit, with a combined HR value of 0.67 (95% CI: 0.55-0.81, P<0.001). Moreover, as the expression of PD-L1 increased, the PFS and OS benefits were more significantly. Furthermore, patients without central nervous system (CNS) metastasis who were treated with PD-1/L1 inhibitors had a longer OS than patients with CNS metastasis (HR: 0.67, 95% CI: 0.55-0.80, P<0.001). Finally, combined therapy was associated with 3 to 5 TRAEs (RR: 1.26, 95% CI: 1.08-1.47; P<0.01).

Conclusions

Patients treated with immunotherapy and chemotherapy in combination exhibited superior in ORR, DCR, PFS and OS as well as slightly increased TRAE levels compared with those of patients treated with either monotherapy.