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Nonclinical safety and pharmacokinetic data for monomethyl auristatin E (MMAE) and 14 vedotin antibody-drug conjugates (ADC) were evaluated to determine patterns of toxicity, consistency of pharmacokinetic results, and species differences between rats and monkeys. Most nonclinical toxicities were antigen-independent, common across ADCs, and included hematologic, lymphoid, and reproductive toxicity related to MMAE pharmacology. Hematologic toxicity was the dose-limiting toxicity (DLT) or predominant toxicity for the majority of vedotin ADCs in both species. Tissue expression of the targeted antigen of an ADC rarely correlated with DLT; only two ADCs had antigen-dependent skin DLTs. For two additional ADCs, antigen-dependent delivery of MMAE in the bone marrow may have exacerbated the antigen-independent hematologic DLT. The highest tolerated doses and pharmacokinetics were similar within a given species, with rats tolerating higher doses than monkeys. Studies longer than 1 month in duration detected the same or fewer toxicities than 1-month studies and had no additional findings that affected the human risk assessment. These data support opportunities to streamline ADC toxicity assessments without compromising human starting dose selection or target organ identification., (©2024 The Authors; Published by the American Association for Cancer Research.)

Objective: Systemic sclerosis is an autoimmune disease characterized by fibrosis of the skin and internal organs including the lung. Mucosal-associated invariant T cells are innate-like T lymphocytes able to produce various cytokines and cytotoxic mediators such as granzyme B. A large body of evidence supports a role of mucosal-associated invariant T cells in autoimmune disease but more recent reports suggest also a potential role in fibrotic conditions. Therefore, we herein addressed the question as whether mucosal-associated invariant T cells may have an altered profile in systemic sclerosis., Methods: Mucosal-associated invariant T cell frequency was analyzed by flow cytometry, using fresh peripheral blood from 74 consecutive systemic sclerosis patients who were compared to 44 healthy donors. In addition, in-depth mucosal-associated invariant T cell phenotype and function were analyzed in unselected 29 women with systemic sclerosis who were compared to 23 healthy women donors., Results: Proportion of circulating mucosal-associated invariant T cells was significantly reduced by 68% in systemic sclerosis compared to healthy donors (0.78% in systemic sclerosis vs 2.5%, p < 0.0001). Within systemic sclerosis subsets, mucosal-associated invariant T cells were reduced in patients with interstitial lung disease (systemic sclerosis-interstitial lung disease) (0.56% vs 0.96% in patients without interstitial lung disease, p = 0.04). Moreover, in systemic sclerosis patients, mucosal-associated invariant T cells displayed an activated phenotype indicated by markedly increased CD69 + mucosal-associated invariant T cell frequency (20% mucosal-associated invariant T cell CD69 + compared to 9.4% in healthy donors, p = 0.0014). Interestingly, mucosal-associated invariant T cells from systemic sclerosis-interstitial lung disease patients had a more pronounced altered phenotype compared to systemic sclerosis without interstitial lung disease with a correlation between mucosal-associated invariant T cells expressing CCR6 + and mucosal-associated invariant T cell frequency (r = 0.8, p = 0.006)., Conclusion: Circulating mucosal-associated invariant T cells were reduced and exhibited an activated phenotype in systemic sclerosis patients. This peripheral mucosal-associated invariant T cell deficiency may be related to enhanced apoptosis and/or homing in inflamed tissue, particularly in systemic sclerosis-interstitial lung disease patients., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2023.)

Integrin beta-6, a component of the heterodimeric adhesion receptor alpha-v/beta-6, is overexpressed in numerous solid tumors. Its expression has been shown by multiple investigators to be a negative prognostic indicator in diverse cancers including colorectal, non-small cell lung, gastric, and cervical. We developed SGN-B6A as an antibody-drug conjugate (ADC) directed to integrin beta-6 to deliver the clinically validated payload monomethyl auristatin E (MMAE) to cancer cells. The antibody component of SGN-B6A is specific for integrin beta-6 and does not bind other alpha-v family members. In preclinical studies, this ADC has demonstrated activity in vivo in models derived from non-small cell lung, pancreatic, pharyngeal, and bladder carcinomas spanning a range of antigen expression levels. In nonclinical toxicology studies in cynomolgus monkeys, doses of up to 5 mg/kg weekly for four doses or 6 mg/kg every 3 weeks for two doses were tolerated. Hematologic toxicities typical of MMAE ADCs were dose limiting, and no significant target-mediated toxicity was observed. A phase I first-in-human study is in progress to evaluate the safety and antitumor activity of SGN-B6A in a variety of solid tumors known to express integrin beta-6 (NCT04389632)., (©2023 The Authors; Published by the American Association for Cancer Research.)

Background: SGN-B7H4V is a novel investigational vedotin antibody-drug conjugate (ADC) comprising a B7-H4-directed human monoclonal antibody conjugated to the cytotoxic payload monomethyl auristatin E (MMAE) via a protease-cleavable maleimidocaproyl valine citrulline (mc-vc) linker. This vedotin linker-payload system has been clinically validated in multiple Food and Drug Administration approved agents including brentuximab vedotin, enfortumab vedotin, and tisotumab vedotin. B7-H4 is an immune checkpoint ligand with elevated expression on a variety of solid tumors, including breast, ovarian, and endometrial tumors, and limited normal tissue expression. SGN-B7H4V is designed to induce direct cytotoxicity against target cells by binding to B7-H4 on the surface of target cells and releasing the cytotoxic payload MMAE upon internalization of the B7-H4/ADC complex., Methods: B7-H4 expression was characterized by immunohistochemistry across multiple solid tumor types. The ability of SGN-B7H4V to kill B7-H4-expressing tumor cells in vitro and in vivo in a variety of xenograft tumor models was also evaluated. Finally, the antitumor activity of SGN-B7H4V as monotherapy and in combination with an anti-programmed cell death-1 (PD-1) agent was evaluated using an immunocompetent murine B7-H4-expressing Renca tumor model., Results: Immunohistochemistry confirmed B7-H4 expression across multiple solid tumors, with the highest prevalence in breast, endometrial, and ovarian tumors. In vitro, SGN-B7H4V killed B7-H4-expressing tumor cells by MMAE-mediated direct cytotoxicity and antibody-mediated effector functions including antibody-dependent cellular cytotoxicity and antibody-dependent cellular phagocytosis. In vivo, SGN-B7H4V demonstrated strong antitumor activity in multiple xenograft models of breast and ovarian cancer, including xenograft tumors with heterogeneous B7-H4 expression, consistent with the ability of vedotin ADCs to elicit a bystander effect. In an immunocompetent murine B7-H4-expressing tumor model, SGN-B7H4V drove robust antitumor activity as a monotherapy that was enhanced when combined with an anti-PD-1 agent., Conclusion: The immune checkpoint ligand B7-H4 is a promising molecular target expressed by multiple solid tumors. SGN-B7H4V demonstrates robust antitumor activity in preclinical models through multiple potential mechanisms. Altogether, these preclinical data support the evaluation of SGN-B7H4V as a monotherapy in the ongoing phase 1 study of SGN-B7H4V in advanced solid tumors (NCT05194072) and potential future clinical combinations with immunotherapies., Competing Interests: Competing interests: EG, MU, AE, PY, DS, KH, SA, L-YH, JH, KG, PMT, EST, JJG, RT, SW, KS, EJH, KSn, DM, MP, AJS, CF, JPS, NN, and SJG were employees of and had equity ownership in Seagen Inc. at the time of this work., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: Polyarticular juvenile idiopathic arthritis (pJIA) is a subset of juvenile idiopathic arthritis (JIA), divided into two subtypes according to the presence of rheumatoid factor: pJIA without rheumatoid factor (pJIA RF-) and pJIA with positive rheumatoid factor (pJIA RF+), this latter is characterised with more structural damage. Anti-citrullinated peptide antibodies (ACPA) are often associated with RF. The respective performance of ACPA versus RF in structural outcome in pJIA, and in particular in adulthood pJIA remains unknown. Therefore, the aim of this study was to determine whether ACPA could be of value to assess structural damage in pJIA persisting in adulthood., Methods: Patients with pJIA and available data for ACPA, RF and X-ray were included retrospectively. Structural damage was assessed by two independent blinded investigators using Sharp Van Der Heijde scores., Results: 56 pJIA adult patients were included: 62% (35/56) had pJIA RF+ and 38% (21/56) pJIA RF-. ACPA positivity in pJIA was significantly associated with presence of RF (96% vs 26%, P<0.001). RF positivity was significantly associated with higher Sharp van Der Heijde erosion and total scores (respectively P<0.01 and P<0.05). There were higher Sharp Van Der Heijde erosion, joint space narrowing and total scores in the pJIA ACPA+ subgroup than in the pJIA ACPA- subgroup, although there was no statistical significance. However, when adjusted on disease duration, pJIA ACPA+ patients had significantly higher erosion and total scores than pJIA ACPA- patients (P<0.05), and pJIA ACPA+ patients required more bDMARDs than pJIA ACPA- patients (P<0.05). Moreover, pJIA patients with high Sharp van Der Heijde joint space narrowing and total scores had significantly higher ACPA levels (P<0.01). A correlation was identified between ACPA levels and Sharp van Der Heijde total score (r=0.54, P<0.05). In the pJIA RF+ subgroup the presence of ACPA was associated with additional structural damage compared to no ACPA: sharp Van Der Heijde erosion, joint space narrowing and total scores were higher in the pJIA RF+ ACPA+ subgroup than in the pJIA RF+ ACPA- subgroup although these results did not reach significance., Conclusion: Our results suggest that pJIA RF+ ACPA+ adult patients may have a more severe articular phenotype than pJIA RF+ ACPA- patients. ACPA could bring an additional value to RF for pJIA patients regarding structural damage. Altogether our results show that RF and ACPA are associated with structural damage measured by Sharp Van Der Heijde score in pJIA persisting in adulthood., (Copyright © 2022 Société française de rhumatologie. Published by Elsevier Masson SAS. All rights reserved.)

Objective: To describe which variables were collected by rheumatologists to monitor patients with rheumatoid arthritis (RA) during teleconsultation and identify which ones have more impact on clinician intervention., Methods: Retrospective monocentric, routine care cross-sectional study including patients with RA seen in teleconsultation between March and September 2020. Available variables assessing disease status were collected in teleconsultation files. Clinician intervention was defined by treatment escalation and/or the need for a rapid face-to-face consultation or day hospitalization., Results: One hundred forty-three patients with RA were included (116 females, mean age of 58 [SD 16] yrs, mean disease duration of 14 [SD 11] yrs). The presence or absence of patient self-reported RA flares was mentioned in all medical files, followed by the presence and/or the number of tender joints (76%), the duration of morning stiffness (66%), the number of pain-related nocturnal awakenings (66%) and the C-reactive protein (CRP) value (54%). Teleconsultation led to a clinician intervention in 22/143 patients (15%), representing 51% of patients with self-reported flares (22/43 patients). Therapeutic escalation was necessary in 13 patients and/or face-to-face consultation or day hospitalization were organized for 10 patients. Multivariate analysis identified RA flares (odds ratio [OR] 15.6, 95% CI 3.37-68.28) and CRP values > 10 mg/L (OR 3.32, 95% CI % 1.12-13.27) as the variables independently associated with clinician intervention., Conclusion: Our study identified patient-reported RA flares and increased CRP values as 2 red flags in teleconsultation, independently associated with therapeutic modification and/or the need for a rapid face-to-face consultation. These indicators may help clinicians' decision making in teleconsultation., (Copyright © 2022 by the Journal of Rheumatology.)

Objective: Systemic sclerosis (SSc) is a debilitating autoimmune disease characterized by severe lung outcomes resulting in reduced life expectancy. Fra-2-transgenic mice offer the opportunity to decipher the relationships between the immune system and lung fibrosis. This study was undertaken to investigate whether the Fra-2-transgenic mouse lung phenotype may result from an imbalance between the effector and regulatory arms in the CD4+ T cell compartment., Methods: We first used multicolor flow cytometry to extensively characterize homeostasis and the phenotype of peripheral CD4+ T cells from Fra-2-transgenic mice and control mice. We then tested different treatments for their effectiveness in restoring CD4+ Treg cell homeostasis, including adoptive transfer of Treg cells and treatment with low-dose interleukin-2 (IL-2)., Results: Fra-2-transgenic mice demonstrated a marked decrease in the proportion and absolute number of peripheral Treg cells that preceded accumulation of activated, T helper cell type 2-polarized, CD4+ T cells. This defect in Treg cell homeostasis was derived from a combination of mechanisms including impaired generation of these cells in both the thymus and the periphery. The impaired ability of peripheral conventional CD4+ T cells to produce IL-2 may greatly contribute to Treg cell deficiency in Fra-2-transgenic mice. Notably, adoptive transfer of Treg cells, low-dose IL-2 therapy, or combination therapy changed the phenotype of Fra-2-transgenic mice, resulting in a significant reduction in pulmonary parenchymal fibrosis and vascular remodeling in the lungs., Conclusion: Immunotherapies for restoring Treg cell homeostasis could be relevant in SSc. An intervention based on low-dose IL-2 injections, as is already proposed in other autoimmune diseases, could be the most suitable treatment modality for restoring Treg cell homeostasis for future research., (© 2022 American College of Rheumatology.)

Objectives: To estimate the seroprevalence of SARS-CoV-2 infection in patients with rheumatic diseases and to specify the proportion of asymptomatic and symptomatic forms of COVID-19., Methods: We screened for SARS-CoV-2 infection among spondyloarthritis (SpA, n=143) or rheumatoid arthritis (RA, n=140) patients in our outpatient clinic at Cochin Hospital in Paris between June and August 2020. We performed a qualitative SARS-CoV-2 serological test which detects IgG directed against the N nucleocapsid protein (anti-N) and, for some patients, against the Spike protein (anti-S). Descriptive analyses were managed., Results: During June-August 2020, the SARS-CoV-2 seroprevalence rate in our population was 2.83% (8/283 patients) without significant difference between RA and SpA patients (2.14% and 3.5%, respectively). We report 11 out of 283 patients (3.8%) with a diagnosis of SARS-CoV-2 infection. Among these 11 patients, 1 patient was asymptomatic (9%) with a confirmed diagnosis of COVID-19 by anti-S serology. Of the 283 patients, 85% were under bDMARDs, mainly on rituximab (RTX) (n=44) and infliximab (IFX) (n=136)., Conclusions: The seroprevalence of SARS-CoV-2 in patients with rheumatic diseases, mainly under bDMARDs treatments, was 2.83%. Among infected patients, 9% were asymptomatic. Detecting SARS-CoV-2 infections could be based on the strategy using patients' interview and anti-N serology., (Copyright © 2021 Société française de rhumatologie. Published by Elsevier Masson SAS. All rights reserved.)