Project description:Approximately 30 years ago, endoglin was identified as a transforming growth factor (TGF)-β coreceptor with a crucial role in developmental biology and tumor angiogenesis. Its selectively high expression on tumor vessels and its correlation with poor survival in cancer patients led to the exploration of endoglin as a therapeutic target for cancer. The endoglin neutralizing antibody TRC105 (Carotuximab®, Tracon Pharmaceuticals (San Diego, CA, USA) was subsequently tested in a wide variety of preclinical cancer models before being tested in phase I-III clinical studies in cancer patients as both a monotherapy and in combination with other chemotherapeutic and anti-angiogenic therapies. The combined data of these studies have revealed new insights into the role of endoglin in angiogenesis and its expression and functional role on other cells in the tumor microenvironment. In this review, we will summarize the preclinical work, clinical trials and biomarker studies of TRC105 and explore what these studies have enabled us to learn and what questions remain unanswered.
Project description:SummaryThis case report describes a 65-year-old man with a Rendu-Osler-Weber syndrome with secondary chronic anaemia, who received multiple intravenous (IV) iron infusions and sustained diffuse bone pain secondary to multiple insufficiency fractures. Laboratory study confirmed fibroblast growth factor 23 (FGF-23)-mediated hypophosphatemia as the main cause of a severe osteomalacia induced by ferric carboxymaltose (FCM).After 3 months or oral phosphate replacement and switching to iron sucrose, serum phosphate levels were normalized and patient improved clinically.IntroductionSome drugs can induce asymptomatic hypophosphatemia, which if sustained, can lead to a severe osteomalacia with multiple skeletal fractures. This complication has also been described with IV iron therapy.MethodsThis case report describes a patient with Rendu-Osler-Weber syndrome with chronic iron deficiency anaemia, recurrently treated with FCM, who developed a severe osteomalacia with multiple skeletal fractures.ResultsLaboratory study showed hypophosphatemia, with high ALP and high FGF-23. Images studies confirmed bone mass loss and multiple insufficiency fractures. A Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT) did not show hidden tumor, so a diagnosis of FCM-induced hypophosphatemic osteomalacia was performed. Phosphate replacement improved clinical symptoms of the patient.ConclusionIntravenous iron therapy, mainly FCM form, can cause hypophosphatemia, and in some cases induce a severe osteomalacia with multiple fractures, so it seems advisable to monitor serum phosphate levels in high risk patients, as those who receive repeated dose.
Project description:Localized renal cell carcinoma (RCC) is primarily managed with nephrectomy, which is performed with curative intent. However, disease recurs in ~20% of patients. Treatment with adjuvant therapies is used after surgery with the intention of curing additional patients by disrupting the establishment, maturation or survival of micrometastases, processes collectively referred to as the metastatic cascade. Immune checkpoint inhibitors and vascular endothelial growth factor receptor (VEGFR)-targeting tyrosine kinase inhibitors (TKIs) have shown efficacy in the treatment of metastatic RCC, increasing the interest in the utility of these agents in the adjuvant setting. Pembrolizumab, an inhibitor of the immune checkpoint PD1, is now approved by the FDA and is under review by European regulatory agencies for the adjuvant treatment of patients with localized resected clear cell RCC based on the results of the KEYNOTE-564 trial. However, the optimal use of immunotherapy and VEGFR-targeting TKIs for adjuvant treatment of RCC is not completely understood. These agents disrupt the metastatic cascade at multiple steps, providing biological rationale for further investigating the applications of these therapeutics in the adjuvant setting. Clinical trials to evaluate adjuvant therapeutics in RCC are ongoing, and clinical considerations must guide the practical use of immunotherapy and TKI agents for the adjuvant treatment of localized resected RCC.
Project description:A spotlight has been shone on endoglin in recent years due to that fact of its potential to serve as both a reliable disease biomarker and a therapeutic target. Indeed, endoglin has now been assigned many roles in both physiological and pathological processes. From a molecular point of view, endoglin mainly acts as a co-receptor in the canonical TGFβ pathway, but also it may be shed and released from the membrane, giving rise to the soluble form, which also plays important roles in cell signaling. In cancer, in particular, endoglin may contribute to either an oncogenic or a non-oncogenic phenotype depending on the cell context. The fact that endoglin is expressed by neoplastic and non-neoplastic cells within the tumor microenvironment suggests new possibilities for targeted therapies. Here, we aimed to review and discuss the many roles played by endoglin in different tumor types, as well as the strong evidence provided by pre-clinical and clinical studies that supports the therapeutic targeting of endoglin as a novel clinical strategy.
Project description:BackgroundTRC105 is an IgG1 endoglin monoclonal antibody that potentiates VEGF inhibitors in preclinical models. We assessed safety, pharmacokinetics, and antitumor activity of TRC105 in combination with axitinib in patients with metastatic renal cell carcinoma (mRCC).Subjects, materials, and methodsHeavily pretreated mRCC patients were treated with TRC105 weekly (8 mg/kg and then 10 mg/kg) in combination with axitinib (initially at 5 mg b.i.d. and then escalated per patient tolerance to a maximum of 10 mg b.i.d.) until disease progression or unacceptable toxicity using a standard 3 + 3 phase I design.ResultsEighteen patients (median number of prior therapies = 3) were treated. TRC105 dose escalation proceeded to 10 mg/kg weekly without dose-limiting toxicity. Adverse event characteristics of each drug were not increased in frequency or severity when the two drugs were administered concurrently. TRC105 and axitinib demonstrated preliminary evidence of activity, including partial responses (PR) by RECIST in 29% of patients, and median progression-free survival (11.3 months). None of the patients with PR had PR to prior first-line treatment. Lower baseline levels of osteopontin and higher baseline levels of TGF-β receptor 3 correlated with overall response rate.ConclusionTRC105 at 8 and 10 mg/kg weekly was well tolerated in combination with axitinib, with encouraging evidence of activity in patients with mRCC. A multicenter, randomized phase II trial of TRC105 and axitinib has recently completed enrollment (NCT01806064).Implications for practiceTRC105 is a monoclonal antibody to endoglin (CD105), a receptor densely expressed on proliferating endothelial cells and also on renal cancer stem cells that is implicated as a mediator of resistance to inhibitors of the VEGF pathway. In this Phase I trial, TRC105 combined safely with axitinib at the recommended single agent doses of each drug in patients with renal cell carcinoma. The combination demonstrated durable activity in a VEGF inhibitor-refractory population and modulated several angiogenic biomarkers. A randomized Phase II trial testing TRC105 in combination with axitinib in clear cell renal cell carcinoma has completed accrual.
Project description:Immunostimulatory therapies have been a cornerstone of treatment for metastatic renal cell carcinoma (RCC) since the 1990s. However, the use of traditional immunotherapeutic approaches for RCC, such as high-dose interleukin-2 and interferon-α, has been limited by significant systemic toxicities and the need to deliver these therapies at centers of expertise. Furthermore, in spite of the success of these immunostimulatory therapies for some patients with RCC, it is clear that most patients fail to respond to cytokine therapy. More effective immune therapy for RCC has therefore been necessary. The interaction between programmed death-1 (PD-1, present on T cells), and one of its ligands (PD-L1, present on antigen-presenting cells and tumor cells) constitutes an immune checkpoint through which tumors can induce T-cell tolerance and avoid immune destruction. Monoclonal antibodies that disrupt the PD-1/PD-L1 interaction serve as inhibitors of this immune checkpoint, and have demonstrated favorable activity in RCC as monotherapy and in combination with other active agents. This review summarizes the current landscape of anti-PD-1/PD-L1 therapy for RCC, and highlights challenges for the future development of this promising approach.
Project description:Growing evidence indicates that clear cell renal cell carcinoma (ccRCC) is a metabolism-related disease. Changes in fatty acid (FA) and cholesterol metabolism play important roles in ccRCC development. As a nuclear transcription factor receptor, Liver X receptor (LXR) regulates a variety of key molecules associated with FA synthesis and cholesterol transport. Therefore, targeting LXR may provide new therapeutic targets for ccRCC. However, the potential regulatory effect and molecular mechanisms of LXR in ccRCC remain unknown. In the present study, we found that both an LXR agonist and an XLR inverse agonist could inhibit proliferation and colony formation and induce apoptosis in ccRCC cells. We observed that the LXR agonist LXR623 downregulated the expression of the low-density lipoprotein receptor (LDLR) and upregulated the expression of ABCA1, which resulted in reduced intracellular cholesterol and apoptosis. The LXR inverse agonist SR9243 downregulated the FA synthesis proteins sterol regulatory element-binding protein 1c (SREBP-1c), fatty acid synthase (FASN) and stearoyl-coA desaturase 1 (SCD1), causing a decrease in intracellular FA content and inducing apoptosis in ccRCC cells. SR9243 and LXR623 induced apoptosis in ccRCC cells but had no killing effect on normal renal tubular epithelial HK2 cells. We also found that SRB1-mediated high-density lipoprotein (HDL) in cholesterol influx is the cause of high cholesterol in ccRCC cells. In conclusion, our data suggest that an LXR inverse agonist and LXR agonist decrease the intracellular FA and cholesterol contents in ccRCC to inhibit tumour cells but do not have cytotoxic effects on non-malignant cells. Thus, LXR may be a safe therapeutic target for treating ccRCC patients.
Project description:Targeted agents have revolutionized the management of metastatic renal cell carcinoma (RCC). Axitinib, an inhibitor of vascular endothelial growth factor receptor (VEGFR), has been an important addition to currently available therapies for advanced RCC. Its ability to inhibit VEGFRs at nanomolar concentrations distinguishes it as a potent tyrosine kinase inhibitor, with increased selectivity for VEGFR-1, 2, and 3 at clinically applicable concentrations. The phase 3 AXIS trial has established its superiority in prolonging progression-free survival (PFS) in previously treated RCC patients (median PFS 6.7 months for axitinib vs. 4.7 months for sorafenib). Common toxicities of axitinib include hypertension, diarrhea, nausea, hand-foot syndrome, fatigue, and hypothyroidism. Axitinib-induced diastolic blood pressure elevation may be associated with improved clinical outcome, likely reflecting the "on-target" effect of axitinib. Dose escalation to achieve therapeutic plasma drug levels is of considerable clinical interest. Although axitinib has established efficacy in patients treated with one previous agent, its use in the frontline setting is currently the subject of ongoing research.
Project description:The purpose of the study was to identify a comprehensive prognostic system of pretreatment clinical parameters in 425 patients (pts) with metastatic renal-cell carcinoma treated with different subcutaneous (s.c.) recombinant cytokine-based home therapies in consecutive trials. Treatment consisted of (A) s.c. interferon-alpha 2a (INF-alpha), s.c. interleukin-2 (IL-2) (n=102 pts), (B) s.c. IFN-alpha 2a, s.c. IL-2, and i.v. 5-fluorouracil (5-FU) (n=235 pts) or (C) s.c. IFN-alpha 2a, s.c. IL-2, and i.v. 5-FU combined with p.o. 13-cis-retinoic acid (13cRA) (n=88 pts). Kaplan-Meier survival analysis, log-rank statistics, and Cox regression analysis were employed to identify risk factors and to create a multiple risk factor model. The following pretreatment risk factors were identified by univariate analysis: (1) three and more metastatic sites, (2) presence of liver, lymph node or bone metastases, (3) neutrophil count > or = 6500 cells microl(-1), (4) serum lactate dehydrogenase level (LDH) > or = 220 U l(-1), and (5) serum C-reactive protein level (CRP) > or = 11 mg l(-1). Cox regression analysis with forward stepwise variable selection identified neutrophil count as the major prognostic factor (hazard ratio=1.9, P<0.001), while serum levels of LDH and CRP, time between diagnosis of tumour and onset of metastatic disease, number of metastatic sites, and bone metastases were significant but somewhat less important prognostic variables within the multiple risk factor model (hazard ratio < or = 1.5). Patients were assigned to one of the three risk groups according to cumulative risk defined as the sum of simplified risk s.c.ores for six pretreatment variables. Low-, intermediate-, and high-risk patients achieved a median overall survival of 32+ months (95% CI 24, 43; 5-year survival of 27%), 18+ months (95% CI 15, 20; 5-year survival of 11%), and 8+ months (95% CI 6, 10; 5-year survival of 5%), respectively. These prognostic categories are helpful both in individual patient care and in the assessment of patients entering prospective clinical trials.
Project description:Bariatric surgery procedures, such as Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG), are the most effective interventions available for sustained weight loss and improved glucose metabolism. Bariatric surgery alters the enterohepatic bile acid circulation, resulting in increased plasma bile levels as well as altered bile acid composition. While it remains unclear why both VSG and RYGB can alter bile acids, it is possible that these changes are important mediators of the effects of surgery. Moreover, a molecular target of bile acid synthesis, the bile acid-activated transcription factor FXR, is essential for the positive effects of VSG on weight loss and glycemic control. This Perspective examines the relationship and sequence of events between altered bile acid levels and composition, FXR signaling, and gut microbiota after bariatric surgery. We hypothesize that although bile acids and FXR signaling are potent mediators of metabolic function, unidentified downstream targets are the main mediators behind the benefits of weight-loss surgery. One of these targets, the gut-derived peptide FGF15/19, is a potential molecular and therapeutic marker to explain the positive metabolic effects of bariatric surgery. Focusing research efforts on identifying these complex molecular mechanisms will provide new opportunities for therapeutic strategies to treat obesity and metabolic dysfunction.