Systemic and Intracranial Outcomes With First-Line Nivolumab Plus Ipilimumab in Patients With Metastatic NSCLC and Baseline Brain Metastases From CheckMate 227 Part 1.

INTRODUCTION: In CheckMate 227 Part 1, nivolumab plus ipilimumab prolonged overall survival (OS) versus chemotherapy in patients with metastatic NSCLC, regardless of tumor programmed death-ligand 1 (PD-L1) expression. Here, we report post hoc exploratory systemic and intracranial efficacy outcomes and safety by baseline brain metastasis status at 5 years' minimum follow-up. METHODS: Treatment-naive adults with stage IV or recurrent NSCLC without EGFR or ALK alterations, including asymptomatic patients with treated brain metastases, were enrolled. Patients with tumor PD-L1 greater than or equal to 1% were randomized to nivolumab plus ipilimumab, nivolumab, or chemotherapy; patients with tumor PD-L1 less than 1% were randomized to nivolumab plus ipilimumab, nivolumab plus chemotherapy, or chemotherapy groups. Assessments included OS, systemic and intracranial progression-free survival per blinded independent central review, new brain lesion development, and safety. Brain imaging was performed at baseline (all randomized patients) and approximately every 12 weeks thereafter (patients with baseline brain metastases only). RESULTS: Overall, 202 of 1739 randomized patients had baseline brain metastases (nivolumab plus ipilimumab: 68; chemotherapy: 66). At 61.3 months' minimum follow-up, nivolumab plus ipilimumab prolonged OS versus chemotherapy in patients with baseline brain metastases (hazard ratio = 0.63; 95% confidence interval: 0.43-0.92) and in those without (hazard ratio = 0.76; 95% confidence interval: 0.66-0.87). In patients with baseline brain metastases, 5-year systemic and intracranial progression-free survival rates were higher with nivolumab plus ipilimumab (12% and 16%, respectively) than chemotherapy (0% and 6%). Fewer patients with baseline brain metastases developed new brain lesions with nivolumab plus ipilimumab (4%) versus chemotherapy (20%). No new safety signals were observed. CONCLUSIONS: With all patients off immunotherapy for more than or equal to 3 years, nivolumab plus ipilimumab continued to provide a long-term, durable survival benefit in patients with or without brain metastases. Intracranial efficacy outcomes favored nivolumab plus ipilimumab versus chemotherapy. These results further support nivolumab plus ipilimumab as an efficacious first-line treatment for patients with metastatic NSCLC, regardless of baseline brain metastasis status.

Long-term comparative efficacy and safety of nivolumab plus ipilimumab relative to other first-line therapies for advanced non-small-cell lung cancer: A systematic literature review and network meta-analysis.

OBJECTIVES: To quantify the long-term comparative efficacy and safety of nivolumab in combination with ipilimumab (NIVO + IPI) relative to other immunotherapy (IO)-based regimens and chemotherapy in patients with first-line advanced non-small cell lung cancer (aNSCLC). METHODS: Phase 3 randomized controlled-trials (RCTs) with minimum 3-year follow-up evaluating IO-based regimens approved for first-line aNSCLC were identified via systematic literature review. Analytic populations were defined by levels of PD-L1 expression and histology. Due to presence of proportional hazards violations, time-varying hazard ratios (HRs) of overall survival (OS) and progression-free survival (PFS) were estimated via Bayesian fractional polynomial network meta-analysis. For safety endpoints, odds ratios (ORs) were estimated using indirect treatment comparisons (ITCs). RESULTS: CheckMate 227, KEYNOTE-189, KEYNOTE-407, KEYNOTE-024, KEYNOTE-042, and IMpower150 were included in the base case analysis. For OS and PFS, HRs of NIVO + IPI relative to other IO-based regimens trended downward over time across analytic populations. The 36-month OS HRs of NIVO + IPI versus comparators were: 0.69 (95 % credible interval: 0.47, 1.00) versus pembrolizumab + chemotherapy and 0.65 (0.45, 0.93) versus atezolizumab + bevacizumab + chemotherapy in the non-squamous and PD-L1 all-comers population; 0.73 (0.53, 1.02) versus pembrolizumab + chemotherapy in the squamous and PD-L1 all-comers population; and 1.05 (0.83, 1.32) versus pembrolizumab in the mixed histology and PD-L1 ≥ 50 % population. For PFS, 36-month HR point estimates ranged from 0.46 to 0.85 (only statistically significant versus pembrolizumab + chemotherapy in the squamous population; 0.46 [0.31, 0.69]). Adverse events (AEs) leading to discontinuation were not statistically significantly different between NIVO + IPI and pembrolizumab + chemotherapy, nor between NIVO + IPI and pembrolizumab monotherapy, although treatment-related grade ≥ 3 AEs were higher with NIVO + IPI than pembrolizumab monotherapy (OR = 2.21 [1.30, 3.75]). CONCLUSIONS: This study indicates trends towards long-term benefit with NIVO + IPI compared with other IO-based combinations, with manageable toxicities.

Five-Year Survival Outcomes With Nivolumab Plus Ipilimumab Versus Chemotherapy as First-Line Treatment for Metastatic Non-Small-Cell Lung Cancer in CheckMate 227.

PURPOSE: We present 5-year results from CheckMate 227 Part 1, in which nivolumab plus ipilimumab improved overall survival (OS) versus chemotherapy in patients with metastatic non-small-cell lung cancer, regardless of tumor programmed death ligand 1 (PD-L1) status. METHODS: Adults with stage IV/recurrent non-small-cell lung cancer without EGFR mutations or ALK alterations and with tumor PD-L1 ≥ 1% or < 1% (n = 1739) were randomly assigned. Patients with tumor PD-L1 ≥ 1% were randomly assigned to first-line nivolumab plus ipilimumab, nivolumab alone, or chemotherapy. Patients with tumor PD-L1 < 1% were randomly assigned to nivolumab plus ipilimumab, nivolumab plus chemotherapy, or chemotherapy. End points included exploratory 5-year results for efficacy, safety, and quality of life. RESULTS: At a minimum follow-up of 61.3 months, 5-year OS rates were 24% versus 14% for nivolumab plus ipilimumab versus chemotherapy (PD-L1 ≥ 1%) and 19% versus 7% (PD-L1 < 1%). The median duration of response was 24.5 versus 6.7 months (PD-L1 ≥ 1%) and 19.4 versus 4.8 months (PD-L1 < 1%). Among patients surviving 5 years, 66% (PD-L1 ≥ 1%) and 64% (PD-L1 < 1%) were off nivolumab plus ipilimumab without initiating subsequent systemic anticancer treatment by the 5-year time point. Survival benefit continued after nivolumab plus ipilimumab discontinuation because of treatment-related adverse events, with a 5-year OS rate of 39% (combined PD-L1 ≥ 1% and < 1% populations). Quality of life in 5-year survivors treated with nivolumab plus ipilimumab was similar to that in the general US population through the 5-year follow-up. No new safety signals were observed. CONCLUSION: With all patients off immunotherapy treatment for ≥ 3 years, nivolumab plus ipilimumab increased 5-year survivorship versus chemotherapy, including long-term, durable clinical benefit regardless of tumor PD-L1 expression. These data support nivolumab plus ipilimumab as an effective first-line treatment for patients with metastatic non-small-cell lung cancer.

Inhibition of non-homologous end joining in Fanconi Anemia cells results in rescue of survival after interstrand crosslinks but sensitization to replication associated double-strand breaks.

When Fanconi Anemia (FA) proteins were depleted in human U2OS cells with integrated DNA repair reporters, we observed decreases in homologous recombination (HR), decreases in mutagenic non-homologous end joining (m-NHEJ) and increases in canonical NHEJ, which was independently confirmed by measuring V(D)J recombination. Furthermore, depletion of FA proteins resulted in reduced HR protein foci and increased NHEJ protein recruitment to replication-associated DSBs, consistent with our observation that the use of canonical NHEJ increases after depletion of FA proteins in cycling cells. FA-depleted cells and FA-mutant cells were exquisitely sensitive to a DNA-PKcs inhibitor (DNA-PKi) after sustaining replication-associated double strand breaks (DSBs). By contrast, after DNA interstrand crosslinks, DNA-PKi resulted in increased survival in FA-deficient cells, implying that NHEJ is contributing to lethality after crosslink repair. Our results suggest FA proteins inhibit NHEJ, since repair intermediates from crosslinks are rendered lethal by NHEJ. The implication is that bone marrow failure in FA could be triggered by naturally occurring DNA crosslinks, and DNA-PK inhibitors would be protective. Since some sporadic cancers have been shown to have deficiencies in the FA-pathway, these tumors should be vulnerable to NHEJ inhibitors with replication stress, but not with crosslinking agents, which could be tested in future clinical trials.

Efficient cleavage of single and clustered AP site lesions within mono-nucleosome templates by CHO-K1 nuclear extract contrasts with retardation of incision by purified APE1.

Clustered DNA damage is a unique characteristic of radiation-induced DNA damage and the formation of these sites poses a serious challenge to the cell's repair machinery. Within a cell DNA is compacted, with nucleosomes being the first order of higher level structure. However, few data are reported on the efficiency of clustered-lesion processing within nucleosomal DNA templates. Here, we show retardation of cleavage of a single AP site by purified APE1 when contained in nucleosomal DNA, compared to cleavage of an AP site in non-nucleosomal DNA. This retardation seen in nucleosomal DNA was alleviated by incubation with CHO-K1 nuclear extract. When clustered DNA damage sites containing bistranded AP sites were present in nucleosomal DNA, efficient cleavage of the AP sites was observed after treatment with nuclear extract. The resultant DSB formation led to DNA dissociating from the histone core and nucleosomal dispersion. Clustered damaged sites containing bistranded AP site/8-oxoG residues showed no retardation of cleavage of the AP site but retardation of 8-oxoG excision, compared to isolated lesions, thus DSB formation was not seen. An increased understanding of processing of clustered DNA damage in a nucleosomal environment may lead to new strategies to enhance the cytotoxic effects of radiotherapeutics.

Delayed repair of radiation induced clustered DNA damage: friend or foe?

A signature of ionizing radiation exposure is the induction of DNA clustered damaged sites, defined as two or more lesions within one to two helical turns of DNA by passage of a single radiation track. Clustered damage is made up of double strand breaks (DSB) with associated base lesions or abasic (AP) sites, and non-DSB clusters comprised of base lesions, AP sites and single strand breaks. This review will concentrate on the experimental findings of the processing of non-DSB clustered damaged sites. It has been shown that non-DSB clustered damaged sites compromise the base excision repair pathway leading to the lifetime extension of the lesions within the cluster, compared to isolated lesions, thus the likelihood that the lesions persist to replication and induce mutation is increased. In addition certain non-DSB clustered damaged sites are processed within the cell to form additional DSB. The use of E. coli to demonstrate that clustering of DNA lesions is the major cause of the detrimental consequences of ionizing radiation is also discussed. The delayed repair of non-DSB clustered damaged sites in humans can be seen as a "friend", leading to cell killing in tumour cells or as a "foe", resulting in the formation of mutations and genetic instability in normal tissue.

Hierarchy of lesion processing governs the repair, double-strand break formation and mutability of three-lesion clustered DNA damage.

Ionising radiation induces clustered DNA damage sites which pose a severe challenge to the cell's repair machinery, particularly base excision repair. To date, most studies have focussed on two-lesion clusters. We have designed synthetic oligonucleotides to give a variety of three-lesion clusters containing abasic sites and 8-oxo-7, 8-dihydroguanine to investigate if the hierarchy of lesion processing dictates whether the cluster is cytotoxic or mutagenic. Clusters containing two tandem 8-oxoG lesions opposing an AP site showed retardation of repair of the AP site with nuclear extract and an elevated mutation frequency after transformation into wild-type or mutY Escherichia coli. Clusters containing bistranded AP sites with a vicinal 8-oxoG form DSBs with nuclear extract, as confirmed in vivo by transformation into wild-type E. coli. Using ung1 E. coli, we propose that DSBs arise via lesion processing rather than stalled replication in cycling cells. This study provides evidence that it is not only the prompt formation of DSBs that has implications on cell survival but also the conversion of non-DSB clusters into DSBs during processing and attempted repair. The inaccurate repair of such clusters has biological significance due to the ultimate risk of tumourigenesis or as potential cytotoxic lesions in tumour cells.