Clinical Outcomes Beyond 1L EGFR-TKI Progression in mNSCLC: Final Results of the Real-World Study 'LUNGFUL'.

BACKGROUND/AIM: Real-world data on the EGFR mutational profile upon progression after first/second-generation EGFR-TKI treatment in patients with advanced non-small-cell lung cancer (NSCLC) and treatment strategies employed thereon are needed. PATIENTS AND METHODS: This observational study was conducted in 23 hospital-based lung cancer Centers in Greece (protocol code: D133FR00126). Ninety-six eligible patients were consecutively enrolled between July-2017 and September-2019. Re-biopsy was performed in 18 of 79 patients who tested T790M-negative in liquid biopsy after progression in the first-line (1L) setting. RESULTS: Of the study population, 21.9% tested T790M-positive, while 72.9% proceeded to 2L treatment, mainly comprising of a third-generation EGFR-TKI (48.6%), a switch to chemotherapy (30.0%), or chemo-immunotherapy (17.1%). The objective response rate (ORR) in 2L was 27.9% in T790M-negative and 50.0% in T790M-positive patients. Of evaluable patients, 67.2% experienced disease progression; median progression-free survival (PFS) was 5.7 and 10.0 months among T790M-negative and positive patients, respectively. Among T790M-negative patients, longer median PFS and post-progression survival were observed with third-generation EGFR-TKI treatment. CONCLUSION: Mutational status and treatment strategy were identified as critical determinants of clinical outcomes in the 2L-setting of EGFR-mutated NSCLC patients in real-world settings in Greece, with early diagnosis, appropriate molecular testing and high-efficacy treatments at first lines positively affecting ORR and PFS.

Real-world management patterns in EGFR-mutant advanced non-small-cell lung cancer before first-line adoption of osimertinib: the REFLECT study in Greece.

Aim: To retrospectively characterize real-world therapeutic strategies, clinical outcomes and attrition rates with EGFR tyrosine kinase inhibitors (TKIs), before first-line osimertinib approval, in EGFR-mutated advanced/metastatic non-small-cell lung cancer patients in Greece. Results: Among 160 patients, the discontinuation rate for first-line first- or second-generation EGFR-TKIs was 85%; among these patients, 43% did not receive any second-line therapy and 9.4% died during an 18.7-month follow-up period. Median progression-free and overall survival were 12.1 and 20.9 months, respectively. Osimertinib was offered as second- and third-line treatment in 69.6 and 21.7% of patients with the T790M mutation, respectively. Brain metastases were recorded in 10.6% of patients during treatment, with median overall survival of 4.9 months. Conclusion: Given the high attrition rates and the impact of CNS progression, offering the most appropriate first-line EGFR-TKI treatment with CNS penetration is key to maximize outcomes.

Based on the results of clinical and real-world studies, EGFR tyrosine kinase inhibitors (EGFR-TKIs) are considered the first-line standard of care for people with a type of cancer, know as EGFR-mutant advanced/metastatic non-small-cell lung cancer. However, treatment patterns and outcomes after progression are less well reported and could impact the first-line EGFR-TKI therapeutic approach. This study is part of a large European analysis of real-world evidence, known as the REFLECT study, the objective of which is to learn more about the characterization of testing and treatment patterns, as well as attrition rates, in people receiving first-line treatment with first- or second-generation EGFR-TKIs. Clinical Trial Registration: NCT04031898 (ClinicalTrials.gov) or D5162R00009.

IgA1 Protease Treatment Reverses Mesangial Deposits and Hematuria in a Model of IgA Nephropathy.

IgA nephropathy (IgAN), characterized by mesangial IgA1 deposits, is a leading cause of renal failure worldwide. IgAN pathogenesis involves circulating hypogalactosylated IgA1 complexed with soluble IgA Fc receptor I (sCD89) and/or anti-hypogalactosylated-IgA1 autoantibodies, but no specific treatment is available for IgAN. The absence of IgA1 and CD89 homologs in the mouse has precluded in vivo proof-of-concept studies of specific therapies targeting IgA1. However, the α1KI­CD89Tg mouse model of IgAN, which expresses human IgA1 and human CD89, allows in vivo testing of recombinant IgA1 protease (IgA1­P), a bacterial protein that selectively cleaves human IgA1. Mice injected with IgA1­P (1-10 mg/kg) had Fc fragments of IgA1 in both serum and urine, associated with a decrease in IgA1-sCD89 complexes. Levels of mesangial IgA1 deposits and the binding partners of these deposits (sCD89, transferrin receptor, and transglutaminase 2) decreased markedly 1 week after treatment, as did the levels of C3 deposition, CD11b(+) infiltrating cells, and fibronectin. Antiprotease antibodies did not significantly alter IgA1­P activity. Moreover, hematuria consistently decreased after treatment. In conclusion, IgA1­P strongly diminishes human IgA1 mesangial deposits and reduces inflammation, fibrosis, and hematuria in a mouse IgAN model, and therefore may be a plausible treatment for patients with IgAN.

Role of IgA receptors in the pathogenesis of IgA nephropathy.

Immunoglobulin A nephropathy (IgAN) or Berger's disease is the most common form of primary glomerulonephritis in the world and one of the first causes of end-stage renal failure. IgAN is characterized by the accumulation of immune complexes containing polymeric IgA1 in mesangial areas. The pathogenesis of this disease involves the deposition of polymeric and hypogalactosylated IgA1 (Gd-IgA1) in the mesangium. Quantitative and structural changes of Gd-IgA1 play a key role in the development of the disease due to functional abnormalities of two IgA receptors: the FcαRI (CD89) expressed by blood myeloid cells and the transferrin receptor (CD71) on mesangial cells. Abnormal Gd-IgA1 induces release of soluble CD89, which participates in the formation of circulating IgA1 complexes. These complexes are trapped by CD71 that is overexpressed on mesangial cells in IgAN patients together with the crosslinking enzyme transglutaminase 2 allowing pathogenic IgA complex formation in situ and mesangial cell activation. A humanized mouse model expressing IgA1 and CD89 develops IgAN in a similar manner as patients. In this model, a food antigen, the gliadin, was shown to be crucial for circulating IgA1 complex formation and deposition, which could be prevented by a gluten-free diet. Identification of these new partners opens new therapeutic prospects for IgAN treatment.

Gluten exacerbates IgA nephropathy in humanized mice through gliadin-CD89 interaction.

IgA1 complexes containing deglycosylated IgA1, IgG autoantibodies, and a soluble form of the IgA receptor (sCD89), are hallmarks of IgA nephropathy (IgAN). Food antigens, notably gluten, are associated with increased mucosal response and IgAN onset, but their implication in the pathology remains unknown. Here, an IgAN mouse model expressing human IgA1 and CD89 was used to examine the role of gluten in IgAN. Mice were given a gluten-free diet for three generations to produce gluten sensitivity, and then challenged for 30 days with a gluten diet. A gluten-free diet resulted in a decrease of mesangial IgA1 deposits, transferrin 1 receptor, and transglutaminase 2 expression, as well as hematuria. Mice on a gluten-free diet lacked IgA1-sCD89 complexes in serum and kidney eluates. Disease severity depended on gluten and CD89, as shown by reappearance of IgAN features in mice on a gluten diet and by direct binding of the gluten-subcomponent gliadin to sCD89. A gluten diet exacerbated intestinal IgA1 secretion, inflammation, and villous atrophy, and increased serum IgA1 anti-gliadin antibodies, which correlated with proteinuria in mice and patients. Moreover, early treatment of humanized mice with a gluten-free diet prevented mesangial IgA1 deposits and hematuria. Thus, gliadin-CD89 interaction may aggravate IgAN development through induction of IgA1-sCD89 complex formation and a mucosal immune response. Hence, early-stage treatment with a gluten-free diet could be beneficial to prevent disease.

Update on crescentic glomerulonephritis.

The recent years have seen a number of major progresses in the field of extracapillary glomerulonephritis. This entity is the final damage caused by unrelated immunological disorders such as immune complexes glomerular deposits or microvascular injury caused by proinflammatory cytokines, neutrophil extracellular traps (NET), and cell adhesion molecules in the context of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This review provides a summary of recent advances in the understanding of crescentic glomerulonephritis, focusing on interplays of local immune cells and on local mediators participating to crescent formation especially in anti-glomerular basement membrane (anti-GBM) antibody disease. The recent advances about AAV and lupus nephritis are covered by other chapters of this issue. Nevertheless, these considerations may apply to the general case of crescentic glomerulonephritis of all causes.

Transglutaminase is essential for IgA nephropathy development acting through IgA receptors.

IgA nephropathy (IgAN) is a common cause of renal failure worldwide. Treatment is limited because of a complex pathogenesis, including unknown factors favoring IgA1 deposition in the glomerular mesangium. IgA receptor abnormalities are implicated, including circulating IgA-soluble CD89 (sCD89) complexes and overexpression of the mesangial IgA1 receptor, TfR1 (transferrin receptor 1). Herein, we show that although mice expressing both human IgA1 and CD89 displayed circulating and mesangial deposits of IgA1-sCD89 complexes resulting in kidney inflammation, hematuria, and proteinuria, mice expressing IgA1 only displayed endocapillary IgA1 deposition but neither mesangial injury nor kidney dysfunction. sCD89 injection into IgA1-expressing mouse recipients induced mesangial IgA1 deposits. sCD89 was also detected in patient and mouse mesangium. IgA1 deposition involved a direct binding of sCD89 to mesangial TfR1 resulting in TfR1 up-regulation. sCD89-TfR1 interaction induced mesangial surface expression of TGase2 (transglutaminase 2), which in turn up-regulated TfR1 expression. In the absence of TGase2, IgA1-sCD89 deposits were dramatically impaired. These data reveal a cooperation between IgA1, sCD89, TfR1, and TGase2 on mesangial cells needed for disease development. They demonstrate that TGase2 is responsible for a pathogenic amplification loop facilitating IgA1-sCD89 deposition and mesangial cell activation, thus identifying TGase2 as a target for therapeutic intervention in this disease.

Gluten induces coeliac-like disease in sensitised mice involving IgA, CD71 and transglutaminase 2 interactions that are prevented by probiotics.

Coeliac disease (CD) is a malabsorptive enteropathy resulting from intolerance to gluten. Environmental factors and the microbiota are suggested to have critical roles in the onset of CD. The CD71 IgA receptor on epithelial cells is responsible for abnormal retrotranscytosis of IgA-gluten peptide complexes from the intestinal lumen into the lamina propria, inducing intestinal inflammation. However, understanding the role of gluten in the CD physiopathology has been hindered by the absence of relevant animal models. Here, we generated a mouse model for CD to study the factors controlling its pathogenesis as well as to investigate the influence of oral delivery of probiotics on disease development. Gluten sensitivity was established by feeding three generations of BALB/c mice a gluten-free diet (G-) followed by gluten challenge (G+) for 30 days. The G+ mice developed villous atrophy, crypt hyperplasia and infiltration of T cells and macrophages in the small intestine. Inflammation was associated with an overexpression of CD71 on the apical side of enterocytes and an increase of plasma cells producing IgA, which colocalised with the CD71. Moreover, IgA colocalised with the transglutaminase 2 (TG2), the production of which was increased in the lamina propria of G+ mice. These mice displayed increased production of cyclooxygenase-2 (COX-2), pro-inflammatory cytokines and IL-15, as well as anti-gliadin and anti-TG2 autoantibodies. The commensal flora-isolated presumptive probiotic Saccharomyces boulardii KK1 strain hydrolysed the 28-kDa α-gliadin fraction, and its oral delivery in G+ mice improved enteropathy development in association with decrease of epithelial cell CD71 expression and local cytokine production. In conclusion, the G+ BALB/c mouse represents a new mouse model for human CD based on histopathological features and expression of common biomarkers. The selected probiotic treatment reversing disease development will allow the study of the role of probiotics as a new therapeutic approach of CD.

Dysfunctions of the Iga system: a common link between intestinal and renal diseases.

Immunoglobulin A (Iga)-isotype antibodies play an important role in immunity owing to their structure, glycosylation, localization and receptor interactions. Dysfunctions in this system can lead to multiple types of pathology. This review describes the characteristics of Iga and discusses the involvement of abnormalities in the Iga system on the development of celiac disease and Iga nephropathy.