Standard first-line chemotherapy results in disease progression and death within one year in most patients with human epidermal growth factor receptor 2 (HER2)-negative gastro-oesophageal adenocarcinoma1–4. Nivolumab plus chemotherapy demonstrated superior overall survival versus chemotherapy at 12-month follow-up in gastric, gastro-oesophageal junction or oesophageal adenocarcinoma in the randomized, global CheckMate 649 phase 3 trial5 (programmed death ligand-1 (PD-L1) combined positive score ≥5 and all randomized patients). On the basis of these results, nivolumab plus chemotherapy is now approved as a first-line treatment for these patients in many countries6. Nivolumab and the cytotoxic T-lymphocyte antigen-4 (CTLA-4) inhibitor ipilimumab have distinct but complementary mechanisms of action that contribute to the restoration of anti-tumour T-cell function and induction of de novo anti-tumour T-cell responses, respectively7–11. Treatment combining 1 mg kg−1 nivolumab with 3 mg kg−1 ipilimumab demonstrated clinically meaningful anti-tumour activity with a manageable safety profile in heavily pre-treated patients with advanced gastro-oesophageal cancer12. Here we report both long-term follow-up results comparing nivolumab plus chemotherapy versus chemotherapy alone and the first results comparing nivolumab plus ipilimumab versus chemotherapy alone from CheckMate 649. After the 24.0-month minimum follow-up, nivolumab plus chemotherapy continued to demonstrate improvement in overall survival versus chemotherapy alone in patients with PD-L1 combined positive score ≥5 (hazard ratio 0.70; 95% confidence interval 0.61, 0.81) and all randomized patients (hazard ratio 0.79; 95% confidence interval 0.71, 0.88). Overall survival in patients with PD-L1 combined positive score ≥ 5 for nivolumab plus ipilimumab versus chemotherapy alone did not meet the prespecified boundary for significance. No new safety signals were identified. Our results support the continued use of nivolumab plus chemotherapy as standard first-line treatment for advanced gastro-oesophageal adenocarcinoma.

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1000 Background: Pembrolizumab (pembro) monotherapy showed promising antitumor activity and manageable safety in patients (pts) with metastatic TNBC in KEYNOTE-012, -086 and -119. KEYNOTE-355 (ClinicalTrials.gov, NCT02819518) compared pembro + chemotherapy (chemo) vs placebo (pbo) + chemo for previously untreated locally recurrent inoperable or metastatic TNBC. Methods: Pts with ≥6 mo DFI were randomized 2:1 to pembro + chemo (nab-paclitaxel; paclitaxel; or gemcitabine/carboplatin) or pbo + chemo for up to 35 administrations of pembro/pbo or until progression/intolerable toxicity. Pts were stratified by chemo type (taxane vs gemcitabine/carboplatin), PD-L1 status (CPS ≥1 vs <1), and prior (neo)adjuvant treatment with same-class chemo (yes vs no). Dual primary endpoints are PFS (RECIST v1.1, blinded independent central review) and OS by tumor PD-L1 expression (CPS ≥10 and ≥1) and in all pts. PFS was estimated using the Kaplan-Meier method. Stratified log-rank tests were used to assess treatment group differences. HR and 95% CIs were based on a stratified Cox regression model. AEs were monitored throughout the study and graded per NCI CTCAE v4.0. Results: As of Dec 11 2019, median follow-up was 17.5 mo for pembro + chemo (n=566) and 15.5 mo for chemo (n=281). Pembro + chemo significantly improved PFS vs chemo alone in pts with CPS ≥10 tumors (Table), meeting one of the protocol-defined primary objectives. Although the boundary for a statistically significant benefit of pembro + chemo in pts with CPS ≥1 tumors was not met and formal testing in ITT was not performed, the pembro treatment effect increased with PD-L1 enrichment (Table). OS follow-up is ongoing. Grade 3-5 treatment-related AE rates were 68.1% with pembro + chemo (2 deaths) vs 66.9% with chemo (0 deaths); rates of grade 3-4 immune-mediated AEs and infusion reactions were 5.5% vs 0%. Clinical trial information: NCT02819518 . Conclusion: Pembro combined with several chemo partners showed a statistically significant and clinically meaningful improvement in PFS vs chemo alone in pts with previously untreated locally recurrent inoperable or metastatic TNBC whose tumors expressed PD-L1 (CPS ≥10). Pembro + chemo was generally well tolerated, with no new safety concerns. [Table: see text]

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BackgroundFluorescent nanoparticles or quantum dots (QDs) have been intensely studied for basic and applied research due to their unique size-dependent properties. There is an increasing interest in developing ecofriendly methods to synthesize these nanoparticles since they improve biocompatibility and avoid the generation of toxic byproducts. The use of biological systems, particularly prokaryotes, has emerged as a promising alternative. Recent studies indicate that QDs biosynthesis is related to factors such as cellular redox status and antioxidant defenses. Based on this, the mixture of extreme conditions of Antarctica would allow the development of natural QDs producing bacteria.ResultsIn this study we isolated and characterized cadmium and tellurite resistant Antarctic bacteria capable of synthesizing CdS and CdTe QDs when exposed to these oxidizing heavy metals. A time dependent change in fluorescence emission color, moving from green to red, was determined on bacterial cells exposed to metals. Biosynthesis was observed in cells grown at different temperatures and high metal concentrations. Electron microscopy analysis of treated cells revealed nanometric electron-dense elements and structures resembling membrane vesicles mostly associated to periplasmic space. Purified biosynthesized QDs displayed broad absorption and emission spectra characteristic of biogenic Cd nanoparticles.ConclusionsOur work presents a novel and simple biological approach to produce QDs at room temperature by using heavy metal resistant Antarctic bacteria, highlighting the unique properties of these microorganisms as potent natural producers of nano-scale materials and promising candidates for bioremediation purposes.