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Pancreatic ductal adenocarcinoma (PDAC) is expected to be the second most deadly cancer by 2040, owing to the high incidence of metastatic disease and limited responses to treatment1,2. Less than half of all patients respond to the primary treatment for PDAC, chemotherapy3,4, and genetic alterations alone cannot explain this5. Diet is an environmental factor that can influence the response to therapies, but its role in PDAC is unclear. Here, using shotgun metagenomic sequencing and metabolomic screening, we show that the microbiota-derived tryptophan metabolite indole-3-acetic acid (3-IAA) is enriched in patients who respond to treatment. Faecal microbiota transplantation, short-term dietary manipulation of tryptophan and oral 3-IAA administration increase the efficacy of chemotherapy in humanized gnotobiotic mouse models of PDAC. Using a combination of loss- and gain-of-function experiments, we show that the efficacy of 3-IAA and chemotherapy is licensed by neutrophil-derived myeloperoxidase. Myeloperoxidase oxidizes 3-IAA, which in combination with chemotherapy induces a downregulation of the reactive oxygen species (ROS)-degrading enzymes glutathione peroxidase 3 and glutathione peroxidase 7. All of this results in the accumulation of ROS and the downregulation of autophagy in cancer cells, which compromises their metabolic fitness and, ultimately, their proliferation. In humans, we observed a significant correlation between the levels of 3-IAA and the efficacy of therapy in two independent PDAC cohorts. In summary, we identify a microbiota-derived metabolite that has clinical implications in the treatment of PDAC, and provide a motivation for considering nutritional interventions during the treatment of patients with cancer.

Supplementary Figure 1 shows Nanobody 7D12 block of different EGFR ligands; Supplementary Figure 2 shows EGFR expression and EGF stimulated growth of mutated EGFR variants; Supplementary Figure 3 shows phage display experiments; Supplementary Table 1 shows EGFR primers.

Epidermal growth factor receptor (EGFR) ectodomain variants mediating primary resistance or secondary treatment failure in cancer patients treated with cetuximab or panitumumab support the need for more resistance-preventive or personalized ways of targeting this essential pathway. Here, we tested the hypothesis that the EGFR nanobody 7D12 fused to an IgG1 Fc portion (7D12-hcAb) would overcome EGFR ectodomain–mediated resistance because it targets a very small binding epitope within domain III of EGFR. Indeed, we found that 7D12-hcAb bound and inhibited all tested cell lines expressing common resistance-mediating EGFR ectodomain variants. Moreover, we assessed receptor functionality and binding properties in synthetic mutants of the 7D12-hcAb epitope to model resistance to 7D12-hcAb. Because the 7D12-hcAb epitope almost completely overlaps with the EGF-binding site, only position R377 could be mutated without simultaneous loss of receptor functionality, suggesting a low risk of developing secondary resistance toward 7D12-hcAb. Our binding data indicated that if 7D12-hcAb resistance mutations occurred in position R377, which is located within the cetuximab and panitumumab epitope, cells expressing these receptor variants would retain sensitivity to these antibodies. However, 7D12-hcAb was equally ineffective as cetuximab in killing cells expressing the cetuximab/panitumumab-resistant aberrantly N-glycosylated EGFR R521K variant. Yet, this resistance could be overcome by introducing mutations into the Fc portion of 7D12-hcAb, which enhanced immune effector functions and thereby allowed killing of cells expressing this variant. Taken together, our data demonstrate a broad range of activity of 7D12-hcAb across cells expressing different EGFR variants involved in primary and secondary EGFR antibody resistance.

BackgroundKRAS circulating tumor DNA (ctDNA) has shown biomarker potential for pancreatic ductal adenocarcinoma (PDAC) but has not been applied in clinical routine yet. We aim to improve clinical applicability of ctDNA detection in PDAC and to study the impact of blood-draw site and time point on the detectability and prognostic role of KRAS mutations.Methods221 blood samples from 108 PDAC patients (65 curative, 43 palliative) were analyzed. Baseline peripheral and tumor-draining portal venous (PV), postoperative, and follow-up blood were analyzed and correlated with prognosis.ResultsSignificantly higher KRAS mutant detection rates and copy numbers were observed in palliative compared to curative patients baseline blood (58.1% vs 24.6%; P = 0.002; and P < 0.001). Significantly higher KRAS mutant copies were found in PV blood compared to baseline (P < 0.05) samples. KRAS detection in pre- and postoperative and PV blood were significantly associated with shorter recurrence-free survival (all P < 0.015) and identified as independent prognostic markers. KRAS ctDNA status was also an independent unfavorable prognostic factor for shorter overall survival in both palliative and curative cohorts (hazard ratio [HR] 4.9, P = 0.011; HR 6.9, P = 0.008).ConclusionsKRAS ctDNA detection is an independent adverse prognostic marker in curative and palliative PDAC patients—at all sites of blood draw and a strong follow-up marker. The most substantial prognostic impact was seen for PV blood, which could be an effective novel tool for identifying prognostic borderline patients—guiding future decision-making on neoadjuvant treatment despite anatomical resectability. In addition, higher PV mutant copy numbers contribute to an improved technical feasibility.

Aim: To determine a recommended Phase II dose of the oral fluoropyrimidine trifluridine/tipiracil (FTD/TPI) combined with the multi-kinase inhibitor regorafenib (REG) in refractory metastatic colorectal cancer patients. Materials & methods: A conventional 3 + 3 dose finding design was used. FTD/TPI was administered on days 1–5 and 8–12 of a 28-day cycle, REG on days 2–22. Two dose levels were used: FTD/TPI 25 mg/m2 b.i.d. + REG 120 mg/d, then escalated to FTD/TPI 35 mg/m2 b.i.d. + REG 120 mg/d. Results: In total, 12 patients were treated at two dose levels. Three dose-limiting toxicities were observed; all were grade 3 hypertension causally attributed to REG. Recommended Phase II dose is FTD/TPI 25 mg/m2 b.i.d. + REG 120 mg/d. Median progression-free survival was 3.81 months (95% CI: 1.51–5.29), median OS 11.1 months (95% CI: 2.3–18.2). Conclusion: The combination of REG and FTD/TPI is feasible and safe. Efficacy signals exceed that of the single agents at acceptable toxicity levels and are clinically meaningful.

In metastatic esophagogastric adenocarcinoma (EGA), the addition of programmed cell death 1 (PD-1) inhibitors to chemotherapy has improved outcomes in selected patient populations.To investigate the efficacy of trastuzumab and PD-1 inhibitors with cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) inhibitors or FOLFOX in first-line treatment of advanced ERBB2-positive EGA.This phase 2 multicenter, outpatient, randomized clinical trial with 2 experimental arms compared with historical control individually was conducted between March 2018 and May 2020 across 21 German sites. The reported results are based on a median follow-up of 14.3 months. Patients with previously untreated, metastatic ERBB2-positive (local immunohistochemistry score of 3+ or 2+/in situ hybridization amplification positive) EGA, adequate organ function, and eligibility for immunotherapy were included. Data analysis was performed from June to September 2021.Patients were randomized to trastuzumab and nivolumab (1 mg/kg × 4/240 mg for up to 12 months) in combination with mFOLFOX6 (FOLFOX arm) or ipilimumab (3 mg/kg × 4 for up to 12 weeks) (ipilimumab arm).The primary end point was survival improvement with a targeted increase of the 12-month overall survival rate from 55% (trastuzumab/chemotherapy-ToGA regimen) to 70% in each arm.A total of 97 patients were enrolled, and 88 were randomized (18 women, 70 men; median [range] age, 61 [41-80] years). Baseline Eastern Cooperative Oncology Group performance status was 0 in 54 patients (61%) and 1 in 34 patients (39%); 66 patients (75%) had EGA localized in the esophagogastric junction and 22 in the stomach (25%). Central post hoc biomarker analysis (84 patients) showed PD-1 ligand 1 (PD-L1) combined positive score of 1 or greater in 59 patients (72%) and 5 or greater in 46 patients (56%) and confirmed ERBB2 positivity in 76 patients. The observed overall survival rate at 12 months was 70% (95% CI, 54%-81%) with FOLFOX and 57% (95% CI, 41%-71%) with ipilimumab. Treatment-related grade 3 or greater adverse events (AEs) and serious AEs occurred in 29 and 15 patients in the FOLFOX arm and in 20 and 17 patients in the ipilimumab arm, respectively, with a higher incidence of autoimmune-related AEs in the ipilimumab arm and neuropathy in the FOLFOX arm. Liquid biopsy analyses showed strong correlation of early cell-free DNA increase with shorter progression-free and overall survival and emergence of truncating and epitope-loss ERBB2 resistance sequence variations with trastuzumab treatment.In this randomized clinical trial, trastuzumab, nivolumab, and FOLFOX showed favorable efficacy compared with historical data and trastuzumab, nivolumab, and ipilimumab in ERBB2-positive EGA. The ipilimumab arm yielded similar OS compared with the ToGA regimen.ClinicalTrials.gov Identifier: NCT03409848.

Background Esophagogastric adenocarcinoma (EGA) currently represents a main cause of cancer related death. Despite an intensified treatment for locally advanced or metastatic EGA with a doublet chemotherapy consisting of a platinum compound and a fluoropyrimidine in combination with trastuzumab for HER2-positive disease or in selected cases with docetaxel, survival remains poor. Recently, immune-oncology based strategies relevantly improved the treatment of different solid tumors and showed some promise in late or later stage trials in EGA. Notably, the combination of immunotherapy with trastuzumab to enhance anti-tumor immunity through activation of innate and adaptive immunity was beneficial in preclinical studies or clinical studies in breast cancer. Methods The INTEGA study is an open-label, randomized, multicenter, exploratory phase II trial designed to assess clinical performance, safety and tolerability of ipilimumab or 5-FU/folinic acid and oxaliplatin (FOLFOX) in combination with nivolumab and trastuzumab in patients with previously untreated HER2-positive, locally advanced or metastatic EGA. The primary objective is to determine the clinical performance of ipilimumab or FOLFOX in combination with nivolumab and trastuzumab in terms of overall survival. Secondary objectives are safety and tolerability, efficacy in terms of progression-free survival and objective response rate and blood-based signatures (e.g. immune response or suppression of anti-HER2 resistance) that may correlate with treatment response. Discussion Recent evidence from the phase II NCT02954536 study (oxaliplatin, capecitabine, trastuzumab and pembrolizumab) suggests the clinical feasibility of combining chemotherapy, trastuzumab and checkpoint inhibition in EGA. However, evidence for a chemotherapy-free regimen is also mounting in HER2-positive disease (NCT02689284) i.e. margetuximab and Pembrolizumab. Both studies excelled with high overall response rates and manageable toxicities. The INTEGA study aims to comparatively assess these results and select a promising new 1st line regimen which then needs to be confirmed in a randomized phase III trial. Further, the translational part of the study might help to better stratify patients and tailor treatment of either arm. Trial registration NCT03409848 24.01.2018.

In contrast to other tumor types, immunotherapy has not yet become a relevant part of the treatment landscape of unselected colorectal cancer. Beside the small subgroup of deficient mismatch repair or microsatellite instable tumors (about 5%) as a surrogate for high mutational burden and subsequently high neoantigen load and immunogenicity, inhibitors of programmed death 1 (PD-1), programmed death ligand 1 (PD-L1) and/or cytotoxic T lymphocyte-associated antigen-4 were not or only modestly effective in metastatic colorectal cancer. Thus, a variety of combination approaches with chemotherapy, targeted therapy, toll-like receptor agonists, local ablation or oncolytic viruses is currently being evaluated in different disease settings. Despite several encouraging single arm data already presented or published, available randomized data are unimpressive. Adding PD-1/PD-L1 inhibitors to fluoropyrimidines and bevacizumab maintenance showed no beneficial impact on delaying progression. In refractory disease, the combination of PD-1/PD-L1 and MEK inhibitor was not different from regorafenib, whereas a PD-1/PD-L1 and cytotoxic T lymphocyte-associated antigen-4 inhibitor combination demonstrated better overall survival compared to supportive care alone. Clinical trials in all disease settings applying different combination approaches are ongoing and may define the role of immunotherapy in colorectal cancer.

Epidermal growth factor receptor (EGFR) ectodomain variants mediating primary resistance or secondary treatment failure in cancer patients treated with cetuximab or panitumumab support the need for more resistance-preventive or personalized ways of targeting this essential pathway. Here, we tested the hypothesis that the EGFR nanobody 7D12 fused to an IgG1 Fc portion (7D12-hcAb) would overcome EGFR ectodomain–mediated resistance because it targets a very small binding epitope within domain III of EGFR. Indeed, we found that 7D12-hcAb bound and inhibited all tested cell lines expressing common resistance-mediating EGFR ectodomain variants. Moreover, we assessed receptor functionality and binding properties in synthetic mutants of the 7D12-hcAb epitope to model resistance to 7D12-hcAb. Because the 7D12-hcAb epitope almost completely overlaps with the EGF-binding site, only position R377 could be mutated without simultaneous loss of receptor functionality, suggesting a low risk of developing secondary resistance toward 7D12-hcAb. Our binding data indicated that if 7D12-hcAb resistance mutations occurred in position R377, which is located within the cetuximab and panitumumab epitope, cells expressing these receptor variants would retain sensitivity to these antibodies. However, 7D12-hcAb was equally ineffective as cetuximab in killing cells expressing the cetuximab/panitumumab-resistant aberrantly N-glycosylated EGFR R521K variant. Yet, this resistance could be overcome by introducing mutations into the Fc portion of 7D12-hcAb, which enhanced immune effector functions and thereby allowed killing of cells expressing this variant. Taken together, our data demonstrate a broad range of activity of 7D12-hcAb across cells expressing different EGFR variants involved in primary and secondary EGFR antibody resistance.

Checkpoint inhibitors (e.g., PD1, PD-L1, or CTLA 4) have revolutionized the treatment algorithm of mismatch repair-deficient (dMMR) or microsatellite instability-high (MSI-H) metastatic colorectal cancer (MCRC). In 2017, two phase ll studies revealed extraordinarily high overall response rates for single-agent PD1-antibodies in treatment-refractory colorectal cancer. Apart from treatment response, PD1-treatment resulted in a remarkable overall survival of 31.4 months. Recently, the phase III KN-177 study set the new standard for first line MCRC treatment by proving immunotherapy with pembrolizumab superior to investigators choice chemotherapy (doublet chemotherapy of FOLFIRI or FOLFOX with or without Bevacizumab or Cetuximab). The progression-free survival at 12 months was almost doubled compared to the former chemotherapy standard. In addition to this, checkpoint inhibitor combinations like PD1/PD-L1 and CTLA 4 showed promising early results in metastatic or resectabel colorectal cancer. Several studies are currently evaluating the benefit of checkpoint inhibitor combinations, checkpoint inhibitor chemotherapy combinations and/or the combination with other agents like anti-angiogenic antibodies. Only randomized controlled trials will tell us whether these combinations will even increase the efficacy of single agent immunotherapy in first line dMMR or MSI-H mCRC.

Skin-migratory dendritic cells (migDCs) are pivotal antigen-presenting cells that continuously transport antigens to draining lymph nodes and regulate immune responses. However, identification of migDCs is complicated by the lack of distinguishing markers, and it remains unclear which molecules determine their migratory capacity during inflammation. We show that, in the skin, the neuronal plasticity molecule activity-regulated cytoskeleton-associated protein/activity-regulated gene 3.1 (Arc/Arg3.1) was strictly confined to migDCs. Mechanistically, Arc/Arg3.1 was required for accelerated DC migration during inflammation because it regulated actin dynamics through nonmuscle myosin II. Accordingly, Arc/Arg3.1-dependent DC migration was critical for mounting T cell responses in experimental autoimmune encephalomyelitis and allergic contact dermatitis. Thus, Arc/Arg3.1 was restricted to migDCs in the skin and drove fast DC migration by exclusively coordinating cytoskeletal changes in response to inflammatory challenges. These findings commend Arc/Arg3.1 as a universal switch in migDCs that may be exploited to selectively modify immune responses.