PURPOSE:To explore why PD-L1 scores in metastatic gastro-esophageal adenocarcinomas (GEAs) were significantly lower in a real-world cohort compared with the CheckMate 649 (CM649) trial. METHODS:PD-L1 combined positive scores (CPS) were evaluated using validated assays in 100 consecutive patients with advanced/metastatic GEA at St Bartholomew's Hospital (SBH) and compared with CM649 (n = 1567). Clinicopathological factors and biopsy site were analysed to assess their impact on PD-L1 results. RESULTS:CPS ≥ 5 was substantially less frequent in SBH patients (30%) compared with CM649 (61%). Older age ( ≥ 65 years), non-diffuse histology, and MMR deficiency were associated with CPS ≥ 5 across both cohorts, yet these factors were more common at SBH and therefore did not explain the lower positivity rate. Metastatic biopsies were more frequent in CM649 (21% vs. 9%), but CPS ≥ 5 was lower in metastases (50%) than in primary tumors (60%). Importantly, PD-L1 positivity varied by metastatic site: lymph node metastases showed the highest rate (80%), while liver (50%) and other sites (44%) were significantly lower than primaries (60%). CONCLUSION:PD-L1 CPS is shaped by clinicopathological context and biopsy site. The persistently lower CPS ≥ 5 prevalence at SBH despite validated testing highlights assay variability and reinforces the urgent need for assay standardisation. Preferential use of primary tumor tissue may help reduce metastasis-specific bias.

Abstract Pancreatic ductal adenocarcinoma (PDAC) is highly aggressive and profoundly resistant to immunotherapy, driven by a dense, desmoplastic, and immunosuppressive stroma dominated by cancer-associated fibroblasts (CAFs). CAFs are genetically stable and abundant, making them attractive targets for epigenetic reprogramming to overcome immune exclusion.We hypothesized that epigenetic modulators could reshape CAF-cancer cell interactions, reduce immunosuppression, and enhance responsiveness to immunotherapies, including immune checkpoint blockade and CAR-T cells. Using a 3D PDAC co-culture spheroid model, we screened a panel of clinically relevant epigenetic agents. Transcriptomic profiling revealed drug-induced changes in both tumor and stromal compartments, focusing on CAF subtype reprogramming, stroma-epithelial crosstalk, tumor growth and invasion, immunosuppression, and matrisome remodeling.The CDK7 inhibitor CT7001 emerged as a promising candidate, profoundly altering CAF phenotype, reprogramming CAF subtypes, and modulating stromal gene expression, while reducing epithelial-mesenchymal transition and cell cycle pathways in cancer cells. In an orthotopic PDAC mouse model, CT7001 combined with Gemcitabine significantly extended survival. Notably, treated tumors exhibited increased T-cell infiltration into the otherwise immunologically “cold” PDAC microenvironment, highlighting its potential to sensitize tumors to immunotherapy. Ongoing spatial multiplex imaging and RNA-seq analyses aim to correlate in vivo immune and stromal changes with in vitro findings, supporting rational combination strategies. This epigenetic screening platform provides a predictive framework to evaluate compounds that overcome CAF-mediated immune exclusion and modulate the tumor microenvironment, offering new avenues to enhance PDAC responsiveness to diverse immunotherapies. Citation Format: Celia Martín-Otal, Daire Hanna, Kairbaan Hodivala-Dilke, Angus J. M. Cameron, Oliver Pearce, David Propper. Epigenetic reprogramming of stromal-epithelial crosstalk to improve immunotherapy response in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 7936.

Adjuvant chemotherapy for colorectal cancer (CRC) with oxaliplatin and fluoropyrimidine was traditionally given for 6 months but is associated with cumulative peripheral neuropathy. The SCOT study (ISRCTN59757862) was an international, randomized, phase III, noninferiority trial investigating treatment reduction from 6 to 3 months. It originally reported noninferior disease-free survival with reduced toxicity and improved quality of life for 3 months of treatment in 6,088 patients. Here, we report overall survival (OS) with 38 months of additional follow-up. Patients with high-risk stage II and stage III CRC were assigned (1:1) to receive 3 or 6 months of either capecitabine and oxaliplatin (CAPOX) or infusional fluorouracil, leucovorin, and oxaliplatin (FOLFOX; bolus and infused fluorouracil with oxaliplatin) that were selected before random assignment. With a median of 113 months follow-up and 1,255 OS events, 5-year OS for 3 versus 6 months of treatment was 82.4% in both groups (hazard ratio, 0.96; 95% CI, 0.8 to 1.07), proving noninferiority of 3 months of treatment. Noninferiority of 3 months of treatment for OS was also shown in 1,087 patients with rectal cancer. The duration effect is regimen-dependent with noninferiority shown for CAPOX but not for FOLFOX. In summary, SCOT has shown noninferiority for OS with 3 months of adjuvant chemotherapy treatment, which should be recommended for most patients.

Abstract Background Pancreatic cancer (PDAC: pancreatic ductal adenocarcinoma, the commonest form), a lethal disease, is best treated with surgical excision but is feasible in less than a fifth of patients. Around a third of patients presentlocally advanced, inoperable, non-metastatic (laPDAC), whose stadrd of care is palliative chemotherapy; a small minority are down-sized sufficiently to enable surgical excision. We propose a phase II clinical trial to test whether a combination of standard chemotherapy (gemcitabine & nab-Paclitaxel: GEM-NABP) and repurposing All Trans Retinoic Acid (ATRA) to target the stroma may extend progression-free survival and enable successful surgical resection for patients with laPDAC, since data from phase IB clinical trial demonstrate safety of GEM-NABP-ATRA combination to patients with advanced PDAC with potential therapeutic benefit. Methods Patients with laPDAC will receive at least six cycles of GEM-NABP with 1:1 randomisation to receive this with or without ATRA to assess response, until progression or intolerance. Those with stable/responding disease may undergo surgical resection. Primary endpoint is progression free survival (PFS) defined as the time from the date of randomisation to the date of first documented tumour progression (response evaluation criteria in solid tumours [RECIST] v1.1) or death from any cause, whichever occurs first. Secondary endpoints include objective response rate (ORR), overall survival (OS), safety and tolerability, surgical resection rate, R0 surgical resection rate and patient reported outcome measures (PROMS) as measured by questionnaire EQ-5D-5L. Exploratory endpoints include a decrease or increase in CA19-9 and serum Vitamin A over time correlated with ORR, PFS, and OS. Discussion STARPAC2 aims to assess the role of stromal targeting in laPDAC. Trial registration EudraCT: 2019–004231-23; NCT04241276; ISRCTN11503604.

BACKGROUND:Preclinical studies suggest that cancer cells take up oxidized vitamin C (dehydroascorbate, DHA) via the GLUT1 transporter, leading to oxidative stress and glutathione depletion. This mechanism may offer a therapeutic strategy for KRAS-mutated cancers. This Phase IB trial evaluated high-dose intravenous ascorbic acid (AA) combined with nab-paclitaxel, cisplatin, and gemcitabine (NABPLAGEM) in patients with untreated metastatic pancreatic ductal adenocarcinoma (PDAC). METHODS:Eligible patients (≥18 years, ECOG 0-1, measurable PDAC, adequate organ function) received AA (25, 37.5, or 56.25 g/m2 twice weekly) plus NABPLAGEM on Days 1 and 8 of 21-day cycles. The primary endpoint was determining the maximum tolerated dose (MTD) of AA. RESULTS:Seventeen patients were enrolled (median age 63.9; 70.6 % female; 82.4 % white). No MTD was reached; AA up to 56.25 g/m2 twice weekly was feasible. Patients on the lowest AA dose remained on treatment longer. Grade ≥3 treatment-related adverse events (TRAEs) included thrombocytopenia (82.4 %), anemia (35.3 %), neutropenia (29.4 %), hypokalemia (29.4 %), diarrhea (11.8 %), and colitis (11.8 %), with no significant differences between dose groups. Peak AA levels >20 mM were achieved in 57 % of patients at the highest dose. Median progression-free survival (PFS) and overall survival (OS) were 7.1 and 14.2 months, respectively, with no significant differences by AA dose. Textural imaging showed decreased liver fat in 3 of 4 patients with baseline steatosis. CONCLUSION:High-dose AA with NABPLAGEM was tolerable in patients with advanced PDAC but did not improve disease response compared to historical data for chemotherapy alone. A separate study suggests AA may enhance gemcitabine and nab-paclitaxel efficacy without cisplatin. AA and cisplatin may have overlapping DNA-damaging effects, or differences in AA dosing frequency and exposure may influence outcomes - variables to consider in future trials. TRIAL REGISTRATION:NCT03410030.

Abstract Background Vitamin D agonism has been shown in preclinical studies to decrease the production of collagen, decrease myeloid derived suppressor cells, and decrease regulatory T cells in pancreatic ductal adenocarcinoma (PDAC). Paricalcitol is a vitamin D analog used for vitamin D replacement for those with secondary hyperparathyroidism. Two individuals with PDAC who had been developed resistance gemcitabine based combination therapy had shown clinical benefit with the addition of paricalcitol. This clinical study was done to study the effect of adding paricalcitol to individuals with metastatic PDAC receiving gemcitabine based combination therapy (NCT04054362, NCT03415854) . Methods Adults with a histologically- or cytologically-confirmed diagnosis of metastatic PDAC and who were previously untreated were eligible. Individuals received gemcitabine based combination- either gemcitabine plus nab-paclitaxel or gemcitabine plus nab-paclitaxel and cisplatin and had to either demonstrate progressive or stable disease. Paricalcitol was given at a fixed dose of 25 mcg IV three days a week. The combination continued until either disease progression or poor tolerance. The primary objective was to determine the clinical benefit of adding paricalcitol to gemcitabine based combination therapy for metastatic PDAC. Secondary objectives included assessing safety and pharmacodynamic through patient biopsies. Results A total of 34 patients were enrolled across two sites. 16 patients received paricalcitol. The overall response rate was 0% ( CR, PR). Disease control rate at 9 weeks was 21.4% (CR+PR+ SD). PFS upon addition of paricalcitol was 1.6 months. OS upon addition of paricalcitol was 4.8 months. Grade 3/4 AE's attributed to paricalcitol include 13% thrombocytopenia; 19% anemia; 6% transaminitis; 6% pleural effusion; 6% ascites- all grade 3. Conclusions The addition of paricalcitol demonstrated evidence of limited clinical benefit in individuals with metastatic PDAC receiving front-line gemcitabine based therapy. Paricalcitol was generally well tolerated. Tumor analysis is ongoing. Addition studies utilizing prospective treatment of paricalcitol for front line treatment of mPDAC are ongoing (NCT03520790). Trial funding provided by SU2C, CRUK, Lustgarten Foundation, and AACR. Citation Format: David Propper, Gayle Jameson, Denise Roe, Betsy Wertheim, Dan Von Hoff, Erkut H. Borazanci. Paricalcitol addition to chemotherapy in patients with previously untreated metastatic pancreatic ductal adenocarcinoma (PINBALL) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT214.

696 Background: Advanced PDAC has limited therapeutic options. BPM31510-IV, a novel nano formulation of Ubidecarenone was evaluated in Phase 2 in patients with advanced PDAC. In addition to response and safety, the study included FDG-PET and omics as exploratory analyses. Multi-omics analyses from longitudinally collected patient samples including a subset of Adequately Treated Analysis Set (ATAS) (n=19) were performed to determine potential biomarkers associated with clinical outcomes. Methods: Metastatic PDAC patients (N=45) who had previously received between one and three lines of prior therapy were enrolled in this study. Omics analyses including proteomic, structural lipidomic, signaling lipidomic, and metabolomic measurements were performed on patient buffy coat and plasma samples. Biomolecules with significant association to patient outcome (PFS, OS & TTP) were identified by linear regression analysis. Additional analysis with mixed effect linear modeling approach was used to relate omic values during ten weeks of treatment and patient ATAS status and time on study. Previous analysis of proteomics from patients in a phase 1 solid tumor study was mapped onto a similar omics output for phase 2 to reveal predictive biomarkers for disease status. Results: Proteomics analysis on patient buffy coats revealed enrichment of dicarboxylic and tricarboxylic metabolic processes, mitochondrial membrane space proteins, pyruvate metabolism, and malate/aspartate shuttle pathway with a positive correlation with TTP in the model, demonstrating an integrated connectivity to Ubidecarenone’s functional effects on metabolism. Medium chain acyl carnitines and c-reactive protein (CRP) were identified as having the most significant differences in trajectories between patient ATC status by mixed effect linear modeling. Medium chain acyl carnitines differences could likely be the result of an integrated adaptation of liver homeostasis and physiological activity impacted by treatment. Analysis of RECIST1.1 evaluated in Phase 1 clinical trial and subsequently validated in Phase 2 trial identified 4 proteins with predictive utility at the start of treatment (t=0) (SERPINA5, Vitronectin, Lumican, Proteosome 20S subunit alpha 4), 5 lipid molecular species, and 1 metabolite (2-keto-isovalerate). These markers exhibited differential expression in both clinical trials related to clinical outcome, thus demonstrating a biological relevance to BPM31510 treatment. Conclusions: Our results point to biomarkers associated with (a) length on trial, (b) outcome and (c) involvement of mitochondrial biology in the mechanism of BPM31510-IV in the adequately treated PDAC population. The data herein supports further study of these biomarkers in late-stage trials to confirm the biological mechanism of BPM31510 in PDAC patients. Clinical trial information: NCT02650804 .

Background: Triptolide and its water-soluble prodrug, Minnelide™, have shown promising activity against pancreatic ductal adenocarcinoma (PDAC) in both in vitro and in vivo experiments. Triptolide induces apoptosis in pancreatic cancer cells by different pathways, including caspase-dependent apoptotic death and caspase -independent autophagic death. It inhibits the activity of the TFIIH general transcription factor complex and modulates the transcriptional landscape of both the stroma and cancer cell compartments. In the epithelial tumour compartment, triptolide down-regulates key transcription factors such as c-MYC. Preclinical investigations indicate significant activity against super enhancer targets. In the phase I clinical trial of Minnelide™ activity in highly refractory metastatic pancreatic carcinoma was observed. Hence, we undertook this study in patients with chemotherapy refractory metastatic PDAC. Our aims were to determine clinical anticancer effects, and to define effects of the drug on super enhancer expression and downstream effects. Methods: Eligibility criteria included stage IV PDAC progressing on standard chemotherapy, Karnofsky performance status ≥ 70%, and measurable disease by RECIST 1.1. Planned sample size was up to 35 patients with interim analysis after the first 18 evaluable patients, aiming for at least a 20% difference in DCR (10% v 30%). Minnelide™ 0.67 mg/m2 was administered intravenously over 30 minutes on days 1-21, followed by a 7-day rest period in a 28-day cycle. Exploratory objectives included: analyses of paired tumour biopsies for changes in immune cell infiltration, stromal activation, chromatin accessibility, proteomics and metabolism. Results: 17 patients were treated. There were no RECIST responses or stable disease. However, evidence of activity was observed in 4 of 15 evaluable patients. This activity included progression after 117 days treatment in 1 patient and reductions in CT tumour size or FDG-PET uptake and/or significant decreases in circulating CA19.9 levels in 3 others. Minnelide was generally well tolerated. Treatment related toxicities > 3 were: neutropenia 4 patients and cerebellar ataxia 1 patient.Exploratory analyses included ATAC-Seq on paired biopsies where gene ontology analyses showed downregulation of genes negatively regulating cell cycle and upregulation of genes controlling cell cycle checkpoints. Other exploratory analyses will be presented. Conclusions: The study identified a tolerable drug dose and evidence of activity in a highly chemotherapy-refractory population which provides encouraging proof for the principle of targeting TFIIH in human PDAC. Supported by SU2C, Cancer Research UK, Lustgarten Foundation Citation Format: David Propper, Erkut Borazanci, Peter J. O'Dwyer, Daniel Von Hoff, Joseph Hartlebury, Corina E. Antal, Gerard I. Evan, HaiYong Han, Michael Downes, Ronald Evans, Joshua Rabinowitz, Emmanuel Petricoin, Ashok Saluja, Mohana Velagapudi, Hitendra Patel. Phase II open label trial of Minnelide™ in patients with chemotherapy refractory metastatic pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT218.

Importance:The timing of adjuvant chemotherapy after surgery for colorectal cancer and its association with long-term outcomes have been investigated in national cohort studies, with no consensus on the optimal time from surgery to adjuvant chemotherapy. Objective:To analyze the association between the timing of adjuvant chemotherapy after surgery for colorectal cancer and disease-free survival. Design, Setting, and Participants:This is a post hoc analysis of the phase 3 SCOT randomized clinical trial, from 244 centers in 6 countries, investigating the noninferiority of 3 vs 6 months of adjuvant chemotherapy. Patients with high-risk stage II or stage III nonmetastatic colorectal cancer who underwent curative-intended surgery were randomized to either 3 or 6 months of adjuvant chemotherapy consisting of fluoropyrimidine and oxaliplatin regimens. Those with complete information on the date of surgery, treatment type, and long-term follow-up were investigated for the primary and secondary end points. Data were analyzed from May 2022 to February 2024. Intervention:In the post hoc analysis, patients were grouped according to the start of adjuvant chemotherapy being less than 6 weeks vs greater than 6 weeks after surgery. Main Outcomes and Measures:The primary end point was disease-free survival. The secondary end points were adverse events in the total treatment period or the first cycle of adjuvant chemotherapy. Results:A total of 5719 patients (2251 [39.4%] female; mean [SD] age, 63.4 [9.3] years) were included in the primary analysis after data curation; among them, 914 were in the early-start group and 4805 were in the late-start group. Median (IQR) follow-up was 72.0 (47.3-88.1) months, with a median (IQR) of 56 (41-66) days from surgery to chemotherapy. Five-year disease-free survival was 78.0% (95% CI, 75.3%-80.8%) in the early-start group and 73.2% (95% CI, 72.0%-74.5%) in the late-start group. In an adjusted Cox regression analysis, the start of adjuvant chemotherapy greater than 6 weeks after surgery was associated with worse disease-free survival (hazard ratio, 1.24; 95% CI, 1.06-1.46; P = .01). In adjusted logistic regression models, there was no association with adverse events in the total treatment period (odds ratio, 0.82; 95% CI, 0.65-1.04; P = .09) or adverse events in the first cycle of treatment (odds ratio, 0.77; 95% CI, 0.56-1.09; P = .13). Conclusions and Relevance:In this international population of patients with high-risk stage II and stage III colorectal cancer, starting adjuvant chemotherapy more than 6 weeks after surgery was associated with worse disease-free survival, with no difference in adverse events between the groups. Trial Registration:isrctn.org Identifier: ISRCTN59757862.

Gegen Ende der 2. Entwicklungswoche bildet sich mit dem Entstehen des Axialfortsatzes (Initialstadium für die Chorda dorsalis) die sog. morphologische Mittellinie. Dabei unterscheiden wir nach Blechschmidt entwicklungsdynamische Prozesse nach antiapikal (kranial) für das Gesamtei und nach apikal bei der Bildung des Axialfortsatzes. Asymmetrie ist von Beginn an für alle Entwicklungsstadien das vorherrschende Prinzip. Wir unterscheiden die sog. morphologische Mittellinie, kurz Mittellinie, vom osteopathischen Konzept der sog. Midline.Towards the end of the 2nd week of development, the so-called morphological midline is formed with the emergence of the axial process (precursor of the notochord). According to Blechschmidt, for the development of the axial process, we must distinguish between developmental processes in the entire ovum that are anti-apical (cranial) and apical. Asymmetry in growth is the predominant principle from the beginning, for all stages of development. We distinguish the so-called morphological middle line, or median line, from the osteopathic concept of the so-called midline.

Supplementary Figure from A Therapeutically Actionable Protumoral Axis of Cytokines Involving IL-8, TNFα, and IL-1β

ObjectivesSubjective reports of cognitive impairment following chemotherapy are frequent in cancer patients. Objective cognitive impairment has been observed in cancer patients regardless of treatment regimen suggesting the relationship between cognitive impairment and chemotherapy is not clear cut. Little research has explored the effects of chemotherapy on cognition following surgery in colorectal cancer (CRC). The present study explored the effects of chemotherapy on cognitive performance in a sample of CRC patients. Methods136 participants were recruited into a prospective cohort study: 78 CRC patients undergoing surgery and adjuvant chemotherapy, 58 CRC patients undergoing surgery only. A battery of neuropsychological tests was administered to participants 4 weeks post-surgery (T1), 12 weeks after first chemotherapy (T2) and 3 months after last chemotherapy (T3) or equivalent time-points. ResultsUsing the criterion of scoring at least two standard-deviations below the group norm on at least one neuropsychological test, 45%-55% of all CRC patients showed cognitive deficits 10 months after surgery (T3) and 14% on at least 3 tests. However, cognition did not significantly differ between patients who had chemotherapy and those who did not. A time by group interaction effect was found on the composite cognition score using multi-level modelling suggesting a greater improvement in cognition in the surgery only group over time (p < 0.05). ConclusionsCRC patients display cognitive impairment 10 months after surgery. Chemotherapy did not worsen cognitive impairment but did appear to slow cognitive recovery relative to those undergoing surgery only. The findings demonstrate a clear need for supportive cognitive interventions for all CRC patients following treatment.

Tibial malunion and nonunion are complications that may follow the repair of traumatic tibial shaft fractures. Management may sometime require osteotomy and bone transport. In recent years, there has been a paradigm shift in the management of intercalary tibial defects away from bone transport via external fixation towards intramedullary lengthening nails. This shift necessitates a re-evaluation of the approach to infection and soft tissue defects.We describe the case of a young man with a two-year history of infected tibial nonunion who underwent osteotomy and debridement before requiring free tissue transfer and eventual bone transport. Second, we present the case of a middle-aged man with a 30-year history of infected tibial malunion. Prior to placement of the intramedullary nail, debridement and osteotomy were performed, followed by two free anterolateral thigh flaps and tissue rearrangement.The use of free tissue transfers and emphasis on achieving an anatomically correct lower extremity prior to the initiation of bone transport resulted in minimal external fixation time, treatment compliance, and satisfactory clinical outcomes. Although multiple treatments can produce successful bone transport, no cohesive treatment algorithm exists that addresses infection, external fixation time, healing, and psychological burden.The paradigm shift towards intramedullary bone transport devices requires the use of antibiotic implants and prioritization of the soft tissue envelope prior to device implantation to prevent hardware infection and reoperation. An algorithmic management approach by an orthoplastic surgical team that includes an orthopedic surgeon and microsurgeon is recommended.

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy in need of new therapeutic options. Using unbiased analyses of super-enhancers (SEs) as sentinels of core genes involved in cell-specific function, here we uncover a druggable SE-mediated RNA-binding protein (RBP) cascade that supports PDAC growth through enhanced mRNA translation. This cascade is driven by a SE associated with the RBP heterogeneous nuclear ribonucleoprotein F, which stabilizes protein arginine methyltransferase 1 (PRMT1) to, in turn, control the translational mediator ubiquitin-associated protein 2-like. All three of these genes and the regulatory SE are essential for PDAC growth and coordinately regulated by the Myc oncogene. In line with this, modulation of the RBP network by PRMT1 inhibition reveals a unique vulnerability in Myc-high PDAC patient organoids and markedly reduces tumor growth in male mice. Our study highlights a functional link between epigenetic regulation and mRNA translation and identifies components that comprise unexpected therapeutic targets for PDAC.

During the past 40 years, cytokines and cytokine receptors have been extensively investigated as either cancer targets or cancer treatments. A strong preclinical rationale supports therapeutic strategies to enhance the growth inhibitory and immunostimulatory effects of interferons and interleukins, including IL-2, IL-7, IL-12 and IL-15, or to inhibit the inflammatory and tumour-promoting actions of cytokines such as TNF, IL-1β and IL-6. This rationale is underscored by the discovery of altered and dysregulated cytokine expression in all human cancers. These findings prompted clinical trials of several cytokines or cytokine antagonists, revealing relevant biological activity but limited therapeutic efficacy. However, most trials involved patients with advanced-stage disease, which might not be the optimal setting for cytokine-based therapy. The advent of more effective immunotherapies and an increased understanding of the tumour microenvironment have presented new approaches to harnessing cytokine networks in the treatment of cancer, which include using cytokine-based therapies to enhance the activity or alleviate the immune-related toxicities of other treatments as well as to target early stage cancers. Many challenges remain, especially concerning delivery methods, context dependencies, and the pleiotropic, redundant and often conflicting actions of many cytokines. Herein, we discuss the lessons learnt from the initial trials of single-agent cytokine-based therapies and subsequent efforts to better exploit such agents for the treatment of solid tumours.

Background Epidermal growth factor receptor (EGFR) is a therapeutic target to which HER2/HER3 activation may contribute resistance. This Phase I/II study examined the toxicity and efficacy of high-dose pulsed AZD8931, an EGFR/HER2/HER3 inhibitor, combined with chemotherapy, in metastatic colorectal cancer (CRC). Methods Treatment-naive patients received 4-day pulses of AZD8931 with irinotecan/5-FU (FOLFIRI) in a Phase I/II single-arm trial. Primary endpoint for Phase I was dose limiting toxicity (DLT); for Phase II best overall response. Samples were analysed for pharmacokinetics, EGFR dimers in circulating exosomes and Comet assay quantitating DNA damage. Results Eighteen patients received FOLFIRI and AZD8931. At 160 mg bd, 1 patient experienced G3 DLT; 160 mg bd was used for cohort expansion. No grade 5 adverse events (AE) reported. Seven (39%) and 1 (6%) patients experienced grade 3 and grade 4 AEs, respectively. Of 12 patients receiving 160 mg bd, best overall response rate was 25%, median PFS and OS were 8.7 and 21.2 months, respectively. A reduction in circulating HER2/3 dimer in the two responding patients after 12 weeks treatment was observed. Conclusions The combination of pulsed high-dose AZD8931 with FOLFIRI has acceptable toxicity. Further studies of TKI sequencing may establish a role for pulsed use of such agents rather than continuous exposure. Trial registration number ClinicalTrials.gov number: NCT01862003.

Abstract Interleukin-8 (CXCL8) produced in the tumor microenvironment correlates with poor response to checkpoint inhibitors and is known to chemoattract and activate immunosuppressive myeloid leukocytes. In human cancer, IL8 mRNA levels correlate with IL1B and TNF transcripts. Both cytokines induced IL-8 functional expression from a broad variety of human cancer cell lines, primary colon carcinoma organoids, and fresh human tumor explants. Although IL8 is absent from the mouse genome, a similar murine axis in which TNFα and IL-1β upregulate CXCL1 and CXCL2 in tumor cells was revealed. Furthermore, intratumoral injection of TNFα and IL-1β induced IL-8 release from human malignant cells xenografted in immunodeficient mice. In all these cases, the clinically used TNFα blockers infliximab and etanercept or the IL-1β inhibitor anakinra was able to interfere with this pathogenic cytokine loop. Finally, in paired plasma samples of patients with cancer undergoing TNFα blockade with infliximab in a clinical trial, reductions of circulating IL-8 were substantiated. Significance: IL-8 attracts immunosuppressive protumor myeloid cells to the tumor microenvironment, and IL-8 levels correlate with poor response to checkpoint inhibitors. TNFα and IL-1β are identified as major inducers of IL-8 expression on malignant cells across cancer types and models in a manner that is druggable with clinically available neutralizing agents. This article is highlighted in the In This Issue feature, p. 2007

319 Background: The efficacy of SARS-COV-2 vaccination has been demonstrated in healthy individuals. Immune responses are less well characterised in cancer patient groups, especially those receiving anticancer therapy (e.g. immune therapy, chemotherapy and targeted therapies. We aim to assess the immune response to the SARS-COV-2 vaccination in patients with solid organ cancer on different systemic anti-cancer therapies. Methods: All patients received 2 doses of COVID-19 mRNA vaccination as part of the UK National vaccination programme; with the second booster dose administered within 12 weeks of the first dose. All patients received either BNT162b2 (Pfizer/BioNTech) or ChAdOx1 S (AstraZeneca) vaccines. Sequential serum samples were collected pre-booster dose vaccination (baseline/within -30 days) and after second dose SARS-COV-2 vaccination, at 14-35 days and 36-63 days. Presence and titres of serum Anti-SARS-CoV-2 Spike protein (S) antibody titres were measured. Seroconversion is defined as a response ≥0.8 U/ml, and maximum response to Anti-S is defined as ≥250 U/ml. Responses were measured in 3 patient groups according to the type of anti-cancer therapy: chemotherapy (CHT group), immune therapy (IO group) and targeted therapies, mainly VEGF TKI (TT group). Results: Overall, 61 patients were recruited: 45.9%(28/61) in CHT group, 32.8% (20/61) in IO group and 21.3% (13/61) in the TT group. Baseline characteristics were comparable between patient groups. In response to the booster dose vaccination at 14-35 days, the number of patients who seroconverted was 79.3% (23/29), 94.7% (18/19) and 84.6% (11/13) in the CHT, IO and TT groups, respectively. At this same time point, 51.7% (15/29) in the CHT group achieved maximum anti-S titre levels (≥250 U/ml), compared with 78.9% (15/19) of patients in IO group and 69.2% (9/13) of patients in TT group. All 3 groups demonstrated a significant increase in Anti-S antibodies at 14-35 days after second dose vaccine when compared to pre-booster serum levels, with the largest increase seen in the IO group with a mean Anti-S increase of 149.1 U/ml (SD±105.0, p < 0.0001) followed by the TT group mean increase 120.2 U/ml (SD ±110.8, p < 0.01) and the CHT group, mean increase 83.0 U/ml (SD ±108.4, p < 0.001). Anti-S antibody levels were sustained at 36-63 days post-booster across all groups. However only IO patients had a sustained immune response to vaccination, with median Anti-S titres level of ≥250 U/ml and a significant drop was seen in the CHT group (median Anti-S level 138, p < 0.05). Conclusions: Anti-S titres increase following vaccination in all 3 groups but remain most sustained in the IO group at 36-63 days post-vaccination. Chemotherapy and other targeted therapy treated patients may benefit from early COVID-19 vaccine boosters, compared to patients receiving immune therapy.