Impaired circulating myeloid CD1c+ dendritic cell function in human glioblastoma is restored by p38 inhibition - implications for the next generation of DC vaccines

Current treatments for glioblastoma (GBM) have limited efficacy and significant morbidity and therefore new strategies are urgently needed. Dendritic cells have the power to create anti-tumour immune responses. The greater potency of circulating dendritic cells (DC) over laboratory-generated monocyte-derived DC makes them exciting new immunotherapeutic candidates. To determine the immune status of GBM patients we initially investigated the frequency and function of circulating DC subsets. Furthermore, we tested the therapeutic potential of inhibiting the p38 mitogen-activated protein kinase pathway (p38i) in circulating DC to overcome DC dysfunction.GBM patients (n=16) had significantly reduced numbers of the major myeloid circulating dendritic cell (cDC2) and plasmacytoid DC vs healthy controls; 1736 vs 4975 (p=0.028) and 893 vs 2287 cells/mL (P

Effects of a high-dose 24-h infusion of tranexamic acid on death and thromboembolic events in patients with acute gastrointestinal bleeding (HALT-IT): an international randomised, double-blind, placebo-controlled trial

Background: Tranexamic acid reduces surgical bleeding and reduces death due to bleeding in patients with trauma. Meta-analyses of small trials show that tranexamic acid might decrease deaths from gastrointestinal bleeding. We aimed to assess the effects of tranexamic acid in patients with gastrointestinal bleeding. Methods: We did an international, multicentre, randomised, placebo-controlled trial in 164 hospitals in 15 countries. Patients were enrolled if the responsible clinician was uncertain whether to use tranexamic acid, were aged above the minimum age considered an adult in their country (either aged 16 years and older or aged 18 years and older), and had significant (defined as at risk of bleeding to death) upper or lower gastrointestinal bleeding. Patients were randomly assigned by selection of a numbered treatment pack from a box containing eight packs that were identical apart from the pack number. Patients received either a loading dose of 1 g tranexamic acid, which was added to 100 mL infusion bag of 0·9% sodium chloride and infused by slow intravenous injection over 10 min, followed by a maintenance dose of 3 g tranexamic acid added to 1 L of any isotonic intravenous solution and infused at 125 mg/h for 24 h, or placebo (sodium chloride 0·9%). Patients, caregivers, and those assessing outcomes were masked to allocation. The primary outcome was death due to bleeding within 5 days of randomisation; analysis excluded patients who received neither dose of the allocated treatment and those for whom outcome data on death were unavailable. This trial was registered with Current Controlled Trials, ISRCTN11225767, and ClinicalTrials.gov, NCT01658124. Findings: Between July 4, 2013, and June 21, 2019, we randomly allocated 12 009 patients to receive tranexamic acid (5994, 49·9%) or matching placebo (6015, 50·1%), of whom 11 952 (99·5%) received the first dose of the allocated treatment. Death due to bleeding within 5 days of randomisation occurred in 222 (4%) of 5956 patients in the tranexamic acid group and in 226 (4%) of 5981 patients in the placebo group (risk ratio [RR] 0·99, 95% CI 0·82–1·18). Arterial thromboembolic events (myocardial infarction or stroke) were similar in the tranexamic acid group and placebo group (42 [0·7%] of 5952 vs 46 [0·8%] of 5977; 0·92; 0·60 to 1·39). Venous thromboembolic events (deep vein thrombosis or pulmonary embolism) were higher in tranexamic acid group than in the placebo group (48 [0·8%] of 5952 vs 26 [0·4%] of 5977; RR 1·85; 95% CI 1·15 to 2·98). Interpretation: We found that tranexamic acid did not reduce death from gastrointestinal bleeding. On the basis of our results, tranexamic acid should not be used for the treatment of gastrointestinal bleeding outside the context of a randomised trial

Enhanced dendritic cell immunotherapy to treat glioblastoma

Introduction: Glioblastoma (GBM) patients have a poor survival and are inevitably treatment refractory. The power of enhancing the immune system to combat the chemo-radiotherapy resistant tumour, melanoma, affirms the potential for re-directing the immune response against GBM. Furthermore, immunotherapy combines anti-cancer cytotoxicity with durable memory responses. Dendritic cells (DC) orchestrate a central role in the adaptive immune response by antigen uptake, presentation and co-stimulation to effector T-cells. However, tumours have evolved mechanisms to evade immune recognition by DC. Here we focussed on the myeloid CD1c+ (cDC2) subset, the most abundant circulating DC, to assess the feasibility of adoptive transfer in the next generation of DC vaccines. We also study the novel use of p38 mitogen-activated protein kinase inhibitor (p38i) as an adjunct to improve DC dysfunction and combination therapy with immune checkpoint blockade (ICB). Method: 6-colour flow cytometry of whole blood was used to enumerate and phenotype 4 circulating DC subsets in GBM patients (n=16) and healthy controls (n=16). Following magnetic bead isolation of DC, the cytokines IL-12 and IL-10 were measured post maturation from GBM patients (n=6) and modelled using healthy DC co-cultured with dexamethasone (Dex) and GBM tumour-derived lysate (TDL). A mixed lymphocyte reaction (MLR) measured T-cell stimulatory ability and phenotype. Migration was assessed using a transwell 5M pore membrane towards a CCL21 gradient and antigen presentation measured using an autologous DC, lymphocyte and peptide co-culture expansion system. Peptide-specific responses were analysed by IFN- ELISPOT. cDC2 ability to cross present gp100 peptides was analysed using transfected gp100280-288 T-cell receptor-Jurkat cell line. The p38i, BIRB0796, was added as an adjunct prior to maturation to assess response and ICB added to determine synergy in a MLR. Results: GBM patients had reduced cDC2 and plasmacytoid DC, with an immature phenotype, compared to controls. Likewise, cDC2 isolated from patients, showed significantly suppressed IL-12 secretion. This was modelled in healthy DC by co-culture with Dex and TDL. Treatment with p38i reversed cDC2 dysfunction with increased co-stimulation expression, IL-12 secretion and allo-stimulation. In addition, IL-10 was suppressed, migration towards CCL21 improved and cross-presentation ability maintained. Patient-derived cDC2 showed improved IL-12:IL-10 ratio, similar to healthy controls. There was a superior and synergistic Th1 proliferation when combined with ICB. Conclusions: Circulating DC from GBM patients are dysfunctional and this represents a potential mechanism of immune evasion. Here we establish that p38i restores phenotype and function to activate a Th1 response. We have also shown favourable characteristics of a combination ICB treatment strategy. This is the first study in GBM patients to investigate the use of cDC2 in the next generation of vaccines with a p38i adjunct. We are in the process of establishing the first cDC2 vaccine trial in GBM patients

Enhanced dendritic cell immunotherapy to treat glioblastoma

Introduction: Glioblastoma (GBM) patients have a poor survival and are inevitably treatment refractory. The power of enhancing the immune system to combat the chemo-radiotherapy resistant tumour, melanoma, affirms the potential for re-directing the immune response against GBM. Furthermore, immunotherapy combines anti-cancer cytotoxicity with durable memory responses. Dendritic cells (DC) orchestrate a central role in the adaptive immune response by antigen uptake, presentation and co-stimulation to effector T-cells. However, tumours have evolved mechanisms to evade immune recognition by DC. Here we focussed on the myeloid CD1c+ (cDC2) subset, the most abundant circulating DC, to assess the feasibility of adoptive transfer in the next generation of DC vaccines. We also study the novel use of p38 mitogen-activated protein kinase inhibitor (p38i) as an adjunct to improve DC dysfunction and combination therapy with immune checkpoint blockade (ICB). Method: 6-colour flow cytometry of whole blood was used to enumerate and phenotype 4 circulating DC subsets in GBM patients (n=16) and healthy controls (n=16). Following magnetic bead isolation of DC, the cytokines IL-12 and IL-10 were measured post maturation from GBM patients (n=6) and modelled using healthy DC co-cultured with dexamethasone (Dex) and GBM tumour-derived lysate (TDL). A mixed lymphocyte reaction (MLR) measured T-cell stimulatory ability and phenotype. Migration was assessed using a transwell 5M pore membrane towards a CCL21 gradient and antigen presentation measured using an autologous DC, lymphocyte and peptide co-culture expansion system. Peptide-specific responses were analysed by IFN- ELISPOT. cDC2 ability to cross present gp100 peptides was analysed using transfected gp100280-288 T-cell receptor-Jurkat cell line. The p38i, BIRB0796, was added as an adjunct prior to maturation to assess response and ICB added to determine synergy in a MLR. Results: GBM patients had reduced cDC2 and plasmacytoid DC, with an immature phenotype, compared to controls. Likewise, cDC2 isolated from patients, showed significantly suppressed IL-12 secretion. This was modelled in healthy DC by co-culture with Dex and TDL. Treatment with p38i reversed cDC2 dysfunction with increased co-stimulation expression, IL-12 secretion and allo-stimulation. In addition, IL-10 was suppressed, migration towards CCL21 improved and cross-presentation ability maintained. Patient-derived cDC2 showed improved IL-12:IL-10 ratio, similar to healthy controls. There was a superior and synergistic Th1 proliferation when combined with ICB. Conclusions: Circulating DC from GBM patients are dysfunctional and this represents a potential mechanism of immune evasion. Here we establish that p38i restores phenotype and function to activate a Th1 response. We have also shown favourable characteristics of a combination ICB treatment strategy. This is the first study in GBM patients to investigate the use of cDC2 in the next generation of vaccines with a p38i adjunct. We are in the process of establishing the first cDC2 vaccine trial in GBM patients

Oncogenic osteomalacia and metastatic breast cancer: a case report and review of the literature

ObjectivesOncogenic osteomalacia is a rare paraneoplastic metabolic syndrome that is characterised by severe hypophosphataemia, hyperphosphaturia and osteomalacia secondary to renal loss of phosphate. It is commonly caused by overproduction of fibroblast growth factor-23 (FGF23) from benign tumours of mesenchymal origin. Currently, there is no clear evidence on the management of oncogenic osteomalacia in patients with metastatic solid tumours.MethodsWe report a case of breast cancer-induced oncogenic osteomalacia and discuss its diagnosis and management.ResultsA 71-year-old woman with advanced breast cancer developed symptomatic oncogenic osteomalacia with raised FGF23, severe hypophosphataemia and hypocalcaemia. The electrolytic disturbances were exacerbated after the administration of bisphosphonates in the context of her oncological treatment. Systemic chemotherapy and maintenance endocrine treatment along with phosphate and calcium supplementation reduced the activity of oncogenic osteomalacia and resolved the electrolytic imbalances.ConclusionsTo our knowledge, this is the first reported case of oncogenic osteomalacia in a patient with breast cancer. Oncogenic osteomalacia constitutes a diagnostic and therapeutic challenge. Pre-clinical and clinical evidence suggest that a possible underlying mechanism is the presence of molecular alterations in the FGF/FGFR signalling pathway leading to overexpression of FGF23. In metastatic setting, anticancer treatment can potentially lead to the normalisation of the electrolytic disturbances and reduction of the activity of oncogenic osteomalacia. The use of antiresorptive therapy in patients with bone metastases can potentially trigger FGF23 overexpression. Its use should be guided by the patients’ risk of skeletal-related events and electrolytic disturbances as well as the degree of activity of oncogenic osteomalacia.<br/

Resistance Mechanisms and Barriers to Successful Immunotherapy for Treating Glioblastoma

Glioblastoma (GBM) is inevitably refractory to surgery and chemoradiation. The hope for immunotherapy has yet to be realised in the treatment of GBM. Immune checkpoint blockade antibodies, particularly those targeting the Programme death 1 (PD-1)/PD-1 ligand (PD-L1) pathway, have improved the prognosis in a range of cancers. However, its use in combination with chemoradiation or as monotherapy has proved unsuccessful in treating GBM. This review focuses on our current knowledge of barriers to immunotherapy success in treating GBM, such as diminished pre-existing anti-tumour immunity represented by low levels of PD-L1 expression, low tumour mutational burden and a severely exhausted T-cell tumour infiltrate. Likewise, systemic T-cell immunosuppression is seen driven by tumoural factors and corticosteroid use. Furthermore, unique anatomical differences with primary intracranial tumours such as the blood-brain barrier, the type of antigen-presenting cells and lymphatic drainage contribute to differences in treatment success compared to extracranial tumours. There are, however, shared characteristics with those known in other tumours such as the immunosuppressive tumour microenvironment. We conclude with a summary of ongoing and future immune combination strategies in GBM, which are representative of the next wave in immuno-oncology therapeutics

Effects of a high-dose 24-h infusion of tranexamic acid on death and thromboembolic events in patients with acute gastrointestinal bleeding (HALT-IT): an international randomised, double-blind, placebo-controlled trial

BackgroundTranexamic acid reduces surgical bleeding and reduces death due to bleeding in patients with trauma. Meta-analyses of small trials show that tranexamic acid might decrease deaths from gastrointestinal bleeding. We aimed to assess the effects of tranexamic acid in patients with gastrointestinal bleeding.MethodsWe did an international, multicentre, randomised, placebo-controlled trial in 164 hospitals in 15 countries. Patients were enrolled if the responsible clinician was uncertain whether to use tranexamic acid, were aged above the minimum age considered an adult in their country (either aged 16 years and older or aged 18 years and older), and had significant (defined as at risk of bleeding to death) upper or lower gastrointestinal bleeding. Patients were randomly assigned by selection of a numbered treatment pack from a box containing eight packs that were identical apart from the pack number. Patients received either a loading dose of 1 g tranexamic acid, which was added to 100 mL infusion bag of 0·9% sodium chloride and infused by slow intravenous injection over 10 min, followed by a maintenance dose of 3 g tranexamic acid added to 1 L of any isotonic intravenous solution and infused at 125 mg/h for 24 h, or placebo (sodium chloride 0·9%). Patients, caregivers, and those assessing outcomes were masked to allocation. The primary outcome was death due to bleeding within 5 days of randomisation; analysis excluded patients who received neither dose of the allocated treatment and those for whom outcome data on death were unavailable. This trial was registered with Current Controlled Trials, ISRCTN11225767, and ClinicalTrials.gov, NCT01658124.FindingsBetween July 4, 2013, and June 21, 2019, we randomly allocated 12 009 patients to receive tranexamic acid (5994, 49·9%) or matching placebo (6015, 50·1%), of whom 11 952 (99·5%) received the first dose of the allocated treatment. Death due to bleeding within 5 days of randomisation occurred in 222 (4%) of 5956 patients in the tranexamic acid group and in 226 (4%) of 5981 patients in the placebo group (risk ratio [RR] 0·99, 95% CI 0·82–1·18). Arterial thromboembolic events (myocardial infarction or stroke) were similar in the tranexamic acid group and placebo group (42 [0·7%] of 5952 vs 46 [0·8%] of 5977; 0·92; 0·60 to 1·39). Venous thromboembolic events (deep vein thrombosis or pulmonary embolism) were higher in tranexamic acid group than in the placebo group (48 [0·8%] of 5952 vs 26 [0·4%] of 5977; RR 1·85; 95% CI 1·15 to 2·98).InterpretationWe found that tranexamic acid did not reduce death from gastrointestinal bleeding. On the basis of our results, tranexamic acid should not be used for the treatment of gastrointestinal bleeding outside the context of a randomised trial.</div