A distinct cortical code for socially learned threat.

Animals can learn about sources of danger while minimizing their own risk by observing how others respond to threats. However, the distinct neural mechanisms by which threats are learned through social observation (known as observational fear learning1-4 (OFL)) to generate behavioural responses specific to such threats remain poorly understood. The dorsomedial prefrontal cortex (dmPFC) performs several key functions that may underlie OFL, including processing of social information and disambiguation of threat cues5-11. Here we show that dmPFC is recruited and required for OFL in mice. Using cellular-resolution microendoscopic calcium imaging, we demonstrate that dmPFC neurons code for observational fear and do so in a manner that is distinct from direct experience. We find that dmPFC neuronal activity predicts upcoming switches between freezing and moving state elicited by threat. By combining neuronal circuit mapping, calcium imaging, electrophysiological recordings and optogenetics, we show that dmPFC projections to the midbrain periaqueductal grey (PAG) constrain observer freezing, and that amygdalar and hippocampal inputs to dmPFC opposingly modulate observer freezing. Together our findings reveal that dmPFC neurons compute a distinct code for observational fear and coordinate long-range neural circuits to select behavioural responses.

Dupilumab in children aged 6 months to younger than 6 years with uncontrolled atopic dermatitis: a randomised, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: Current systemic treatments for children younger than 6 years with moderate-to-severe atopic dermatitis that is uncontrolled with topical therapies might have suboptimal efficacy and safety. Dupilumab is approved for older children and adults with atopic dermatitis and for other type 2 inflammatory conditions. We aimed to evaluate efficacy and safety of dupilumab with concomitant low-potency topical corticosteroids in children aged 6 months to younger than 6 years with moderate-to-severe atopic dermatitis. METHODS: This randomised, double-blind, placebo-controlled, parallel-group, phase 3 trial was conducted in 31 hospitals, clinics, and academic institutions in Europe and North America. Eligible patients were aged 6 months to younger than 6 years, with moderate-to-severe atopic dermatitis (Investigator's Global Assessment [IGA] score 3-4) diagnosed according to consensus criteria of the American Academy of Dermatology, and an inadequate response to topical corticosteroids. Patients were randomly assigned (1:1) to subcutaneous placebo or dupilumab (bodyweight ≥5 kg to <15 kg: 200 mg; bodyweight ≥15 kg to <30 kg: 300 mg) every 4 weeks plus low-potency topical corticosteroids (hydrocortisone acetate 1% cream) for 16 weeks. Randomisation was stratified by age, baseline bodyweight, and region. Patient allocation was done via a central interactive web response system, and treatment allocation was masked. The primary endpoint at week 16 was the proportion of patients with IGA score 0-1 (clear or almost clear skin). The key secondary endpoint (coprimary endpoint for the EU and EU reference market) at week 16 was the proportion of patients with at least a 75% improvement from baseline in Eczema Area and Severity Index (EASI-75). Primary analyses were done in the full analysis set (ie, all randomly assigned patients, as randomly assigned) and safety analyses were done in all patients who received any study drug. This study was registered with ClinicalTrials.gov, NCT03346434. FINDINGS: Between June 30, 2020, and Feb 12, 2021, 197 patients were screened for eligibility, 162 of whom were randomly assigned to receive dupilumab (n=83) or placebo (n=79) plus topical corticosteroids. At week 16, significantly more patients in the dupilumab group than in the placebo group had IGA 0-1 (23 [28%] vs three [4%], difference 24% [95% CI 13-34]; p<0·0001) and EASI-75 (44 [53%] vs eight [11%], difference 42% [95% CI 29-55]; p<0·0001). Overall prevalence of adverse events was similar in the dupilumab group (53 [64%] of 83 patients) and placebo group (58 [74%] of 78 patients). Conjunctivitis incidence was higher in the dupilumab group (four [5%]) than the placebo group (none). No dupilumab-related adverse events were serious or led to treatment discontinuation. INTERPRETATION: Dupilumab significantly improved atopic dermatitis signs and symptoms versus placebo in children younger than 6 years. Dupilumab was well tolerated and showed an acceptable safety profile, similar to results in older children and adults. FUNDING: Sanofi and Regeneron Pharmaceuticals.

Safety and efficacy of amlitelimab, a fully human nondepleting, noncytotoxic anti-OX40 ligand monoclonal antibody, in atopic dermatitis: results of a phase IIa randomized placebo-controlled trial.

BACKGROUND: Atopic dermatitis (AD) is an inflammatory skin disease with significant unmet need. Blockade of the OX40-OX40 ligand (OX40L) costimulation pathway by targeting OX40L on antigen-presenting cells (APCs) with a fully human noncytotoxic, nondepleting anti-OX40L monoclonal antibody (amlitelimab; SAR445229; KY1005) is a novel way to modulate persistent inflammation. OBJECTIVES: To assess the safety and efficacy of amlitelimab over 16 weeks in adults with AD in a phase IIa double-blind placebo-controlled study. METHODS: The study was conducted at 19 hospitals in Germany, Poland, Spain and the UK. Eligible patients with moderate-to-severe AD were randomized (1 : 1 : 1) to low-dose intravenous (IV) amlitelimab (200 mg), high-dose IV amlitelimab (500 mg) or placebo, followed by three maintenance doses (50% of loading dose) at 4, 8 and 12 weeks, with safety follow-up to week 36. The co-primary endpoints were the incidence of treatment-emergent adverse events (all patients who received ≥ 1 dose of the study drug) and mean percentage change in Eczema Area and Severity Index (EASI) to week 16 (full analysis set). RESULTS: Between 13 December 2018 and 12 May 2020, 89 patients were randomly assigned to low- (n = 29) or high-dose amlitelimab (n = 30) or placebo (n = 29), of whom 88 proceeded to treatment [37 women (42%), 51 (58%) men; mean (SD) age 33.6 (11.9) years]. Amlitelimab was generally well tolerated with an unremarkable safety profile; no hypersensitivity events were reported. For the primary endpoint, the least square mean percentage change in EASI from baseline to week 16 was -80.12% [95% confidence interval (CI) -95.55 to -64.68; P = 0.009 vs. placebo] and -69.97% (95% CI -85.04 to -54.60; P = 0.07 vs. placebo) for the low- (n = 27) and high-dose (n = 27) amlitelimab groups, respectively, vs. -49.37% (95% CI -66.02 to -32.72) for placebo (n = 24). Numerically greater reductions in EASI were observed for amlitelimab vs. placebo from weeks 2 to 16. CONCLUSIONS: Novel targeting of OX40L-expressing APCs with amlitelimab was well tolerated and resulted in clinically meaningful improvements in AD.

Survival of tissue-resident memory T cells requires exogenous lipid uptake and metabolism.

Tissue-resident memory T (TRM) cells persist indefinitely in epithelial barrier tissues and protect the host against pathogens. However, the biological pathways that enable the long-term survival of TRM cells are obscure. Here we show that mouse CD8+ TRM cells generated by viral infection of the skin differentially express high levels of several molecules that mediate lipid uptake and intracellular transport, including fatty-acid-binding proteins 4 and 5 (FABP4 and FABP5). We further show that T-cell-specific deficiency of Fabp4 and Fabp5 (Fabp4/Fabp5) impairs exogenous free fatty acid (FFA) uptake by CD8+ TRM cells and greatly reduces their long-term survival in vivo, while having no effect on the survival of central memory T (TCM) cells in lymph nodes. In vitro, CD8+ TRM cells, but not CD8+ TCM cells, demonstrated increased mitochondrial oxidative metabolism in the presence of exogenous FFAs; this increase was not seen in Fabp4/Fabp5 double-knockout CD8+ TRM cells. The persistence of CD8+ TRM cells in the skin was strongly diminished by inhibition of mitochondrial FFA ß-oxidation in vivo. Moreover, skin CD8+ TRM cells that lacked Fabp4/Fabp5 were less effective at protecting mice from cutaneous viral infection, and lung Fabp4/Fabp5 double-knockout CD8+ TRM cells generated by skin vaccinia virus (VACV) infection were less effective at protecting mice from a lethal pulmonary challenge with VACV. Consistent with the mouse data, increased FABP4 and FABP5 expression and enhanced extracellular FFA uptake were also demonstrated in human CD8+ TRM cells in normal and psoriatic skin. These results suggest that FABP4 and FABP5 have a critical role in the maintenance, longevity and function of CD8+ TRM cells, and suggest that CD8+ TRM cells use exogenous FFAs and their oxidative metabolism to persist in tissue and to mediate protective immunity.

TRPM4 Conductances in Thalamic Reticular Nucleus Neurons Generate Persistent Firing during Slow Oscillations.

During sleep, neurons in the thalamic reticular nucleus (TRN) participate in distinct types of oscillatory activity. While the reciprocal synaptic circuits between TRN and sensory relay nuclei are known to underlie the generation of sleep spindles, the mechanisms regulating slow (<1 Hz) forms of thalamic oscillations are not well understood. Under in vitro conditions, TRN neurons can generate slow oscillations in a cell-intrinsic manner, with postsynaptic Group 1 metabotropic glutamate receptor activation triggering long-lasting plateau potentials thought to be mediated by both T-type Ca2+ currents and Ca2+-activated nonselective cation currents (ICAN). However, the identity of ICAN and the possible contribution of thalamic circuits to slow rhythmic activity remain unclear. Using thalamic slices derived from adult mice of either sex, we recorded slow forms of rhythmic activity in TRN neurons, which were driven by fast glutamatergic thalamoreticular inputs but did not require postsynaptic Group 1 metabotropic glutamate receptor activation. For a significant fraction of TRN neurons, synaptic inputs or brief depolarizing current steps led to long-lasting plateau potentials and persistent firing (PF), and in turn, resulted in sustained synaptic inhibition in postsynaptic relay neurons of the ventrobasal thalamus (VB). Pharmacological approachesindicated that plateau potentials were triggered by Ca2+ influx through T-type Ca2+ channels and mediated by Ca2+- and voltage-dependent transient receptor potential melastatin 4 (TRPM4) channels. Together, our results suggest that thalamic circuits can generate slow oscillatory activity, mediated by an interplay of TRN-VB synaptic circuits that generate rhythmicity and TRN cell-intrinsic mechanisms that control PF and oscillation frequency.SIGNIFICANCE STATEMENT Slow forms of thalamocortical rhythmic activity are thought to be essential for memory consolidation during sleep and the efficient removal of potentially toxic metabolites. In vivo, thalamic slow oscillations are regulated by strong bidirectional synaptic pathways linking neocortex and thalamus. Therefore, in vitro studies in the isolated thalamus offer important insights about the ability of individual neurons and local circuits to generate different forms of rhythmic activity. We found that circuits formed by GABAergic neurons in the thalamic reticular nucleus and glutamatergic relay neurons in the ventrobasal thalamus generated slow oscillatory activity, which was accompanied by persistent firing in thalamic reticular nucleus neurons. Our results identify both cell-intrinsic and synaptic mechanisms that mediate slow forms of rhythmic activity in thalamic circuits.

Efficacy and safety of dupilumab with concomitant topical corticosteroids in children 6 to 11 years old with severe atopic dermatitis: A randomized, double-blinded, placebo-controlled phase 3 trial.

BACKGROUND: Children with severe atopic dermatitis (AD) have limited treatment options. OBJECTIVE: We report the efficacy and safety of dupilumab + topical corticosteroids (TCS) in children aged 6-11 years with severe AD inadequately controlled with topical therapies. METHODS: In this double-blind, 16-week, phase 3 trial (NCT03345914), 367 patients were randomized 1:1:1 to 300 mg dupilumab every 4 weeks (300 mg q4w), a weight-based regimen of dupilumab every 2 weeks (100 mg q2w, baseline weight <30 kg; 200 mg q2w, baseline weight ≥30 kg), or placebo; with concomitant medium-potency TCS. RESULTS: Both the q4w and q2w dupilumab + TCS regimens resulted in clinically meaningful and statistically significant improvement in signs, symptoms, and quality of life (QOL) versus placebo + TCS in all prespecified endpoints. For q4w, q2w, and placebo, 32.8%, 29.5%, and 11.4% of patients, respectively, achieved Investigator's Global Assessment scores of 0 or 1; 69.7%, 67.2%, and 26.8% achieved ≥75% improvement in Eczema Area and Severity Index scores; and 50.8%, 58.3%, and 12.3% achieved ≥4-point reduction in worst itch score. Response to therapy was weight-dependent: optimal dupilumab doses for efficacy and safety were 300 mg q4w in children <30 kg and 200 mg q2w in children ≥30 kg. Conjunctivitis and injection-site reactions were more common with dupilumab + TCS than with placebo + TCS. LIMITATIONS: Short-term 16-week treatment period; severe AD only. CONCLUSION: Dupilumab + TCS is efficacious and well tolerated in children with severe AD, significantly improving signs, symptoms, and QOL.

Staged development of long-lived T-cell receptor αß TH17 resident memory T-cell population to Candida albicans after skin infection.

BACKGROUND: Candida albicans is a dimorphic fungus to which human subjects are exposed early in life, and by adulthood, it is part of the mycobiome of skin and other tissues. Neonatal skin lacks resident memory T (TRM) cells, but in adults the C albicans skin test is a surrogate for immunocompetence. Young adult mice raised under specific pathogen-free conditions are naive to C albicans and have been shown recently to have an immune system resembling that of neonatal human subjects. OBJECTIVE: We studied the evolution of the adaptive cutaneous immune response to Candida species. METHODS: We examined both human skin T cells and the de novo and memory immune responses in a mouse model of C albicans skin infection. RESULTS: In mice the initial IL-17-producing cells after C albicans infection were dermal γδ T cells, but by day 7, αß TH17 effector T cells were predominant. By day 30, the majority of C albicans-reactive IL-17-producing T cells were CD4 TRM cells. Intravital microscopy showed that CD4 effector T cells were recruited to the site of primary infection and were highly motile 10 days after infection. Between 30 and 90 days after infection, these CD4 T cells became increasingly sessile, acquired expression of CD69 and CD103, and localized to the papillary dermis. These established TRM cells produced IL-17 on challenge, whereas motile migratory memory T cells did not. TRM cells rapidly clear an infectious challenge with C albicans more effectively than recirculating T cells, although both populations participate. We found that in normal human skin IL-17-producing CD4+ TRM cells that responded to C albicans in an MHC class II-restricted fashion could be identified readily. CONCLUSIONS: These studies demonstrate that C albicans infection of skin preferentially generates CD4+ IL-17-producing TRM cells, which mediate durable protective immunity.

Influenza B virus infection and Stevens-Johnson syndrome.

A 2-year-old boy with influenza B infection and rapidly worsening targetoid skin lesions with mucosal involvement was diagnosed with Stevens-Johnson syndrome (SJS) and treated with oseltamivir and intravenous immunoglobulin, with resolution of illness. Subsequent quadrivalent inactivated influenza vaccine was well tolerated. This case highlights the rarity of SJS in the setting of influenza B infection and addresses the safety of administering subsequent influenza vaccines to such individuals.

Phototherapy Restores Deficient Type I IFN Production and Enhances Antitumor Responses in Mycosis Fungoides.

Transcriptional profiling demonstrated markedly reduced type I IFN gene expression in untreated mycosis fungoides (MF) skin lesions compared with that in healthy skin. Type I IFN expression in MF correlated with antigen-presenting cell-associated IRF5 before psoralen plus UVA therapy and epithelial ULBP2 after therapy, suggesting an enhancement of epithelial type I IFN. Immunostains confirmed reduced baseline type I IFN production in MF and increased levels after psoralen plus UVA treatment in responding patients. Effective tumor clearance was associated with increased type I IFN expression, enhanced recruitment of CD8+ T cells into skin lesions, and expression of genes associated with antigen-specific T-cell activation. IFNk, a keratinocyte-derived inducer of type I IFNs, was increased by psoralen plus UVA therapy and expression correlated with upregulation of other type I IFNs. In vitro, deletion of keratinocyte IFNk decreased baseline and UVA-induced expression of type I IFN and IFN response genes. In summary, we find a baseline deficit in type I IFN production in MF that is restored by psoralen plus UVA therapy and correlates with enhanced antitumor responses. This may explain why MF generally develops in sun-protected skin and suggests that drugs that increase epithelial type I IFNs, including topical MEK and EGFR inhibitors, may be effective therapies for MF.

Persistent serpentine supravenous hyperpigmentation--a possible cutaneous manifestation of HIV infection or a normal racial variant: a report of 3 cases.

Persistent serpentine supravenous hyperpigmentation (PSSH) describes a hyperpigmentation of the skin overlying peripheral veins. This cutaneous finding is typically seen in association with systemic chemotherapy or collagen vascular diseases such as progressive systemic sclerosis, systemic lupus erythematosus, and rheumatoid arthritis. Three dark-skinned patients with idiopathic serpentine supravenous hyperpigmentation (ISSH) without collagen vascular disease or prior intravenous cytotoxic treatments were reported. All 3 patients were dark-skinned men with symmetric, uniform hyperpigmentation of the supravenous network of the bilateral lower extremities that had been present for years. The serpentine supravenous hyperpigmentation on the lower extremities was uniform in width and color, which contrasts with the darker discoloration near the site of infusion seen with PSSH associated with chemotherapy. Interestingly, 2 of the patients had advanced human immunodeficiency virus (HIV) disease in association with their ISSH while the HIV status of the third patient was unknown. Thus, we contend that ISSH be considered a normal racial variant or a possible cutaneous manifestation of HIV disease.

Neurons in the caudal ventrolateral medulla mediate descending pain control.

Supraspinal brain regions modify nociceptive signals in response to various stressors including stimuli that elevate pain thresholds. The medulla oblongata has previously been implicated in this type of pain control, but the neurons and molecular circuits involved have remained elusive. Here we identify catecholaminergic neurons in the caudal ventrolateral medulla that are activated by noxious stimuli in mice. Upon activation, these neurons produce bilateral feed-forward inhibition that attenuates nociceptive responses through a pathway involving the locus coeruleus and norepinephrine in the spinal cord. This pathway is sufficient to attenuate injury-induced heat allodynia and is required for counter-stimulus induced analgesia to noxious heat. Our findings define a component of the pain modulatory system that regulates nociceptive responses.

Dupilumab in patients with prurigo nodularis: two randomized, double-blind, placebo-controlled phase 3 trials.

Prurigo nodularis (PN) is a chronic inflammatory skin disease with intensely pruritic nodules. The LIBERTY-PN PRIME and PRIME2 phase 3 trials enrolled adults with PN with ≥20 nodules and severe itch uncontrolled with topical therapies. Dupilumab, a fully human monoclonal antibody, blocks the shared receptor component for interleukin (IL)-4 and IL-13. Patients were randomized 1:1 to 300 mg dupilumab or placebo subcutaneously every 2 weeks for 24 weeks. The primary endpoint was pruritus improvement, measured by proportion of patients with a ≥4-point reduction in Worst Itch Numeric Rating Scale (WI-NRS) from baseline at week 24 (PRIME) or week 12 (PRIME2). Key secondary endpoints included nodule number reduction to ≤5 at week 24. PRIME and PRIME2 enrolled 151 and 160 patients, respectively. Both trials met all the pre-specified primary and key secondary endpoints. A ≥4-point WI-NRS reduction at week 24 in the dupilumab and placebo arms was achieved by 60.0% and 18.4% of patients, respectively, in PRIME (95% confidence interval (CI), 27.8-57.7 for the difference, P < 0.001) and at week 12 by 37.2% and 22.0% of patients, respectively, in PRIME2 (95% CI, 2.3-31.2; P = 0.022). Dupilumab demonstrated clinically meaningful and statistically significant improvements in itch and skin lesions versus placebo in PN. Safety was consistent with the known dupilumab safety profile.ClinicalTrials.gov identifiers: NCT04183335 and NCT04202679 .

Central memory T cells are the most effective precursors of resident memory T cells in human skin.

The circulating precursor cells that give rise to human resident memory T cells (TRM) are poorly characterized. We used an in vitro differentiation system and human skin-grafted mice to study TRM generation from circulating human memory T cell subsets. In vitro TRM differentiation was associated with functional changes, including enhanced IL-17A production and FOXP3 expression in CD4+ T cells and granzyme B production in CD8+ T cells, changes that mirrored the phenotype of T cells in healthy human skin. Effector memory T cells (TEM) had the highest conversion rate to TRM in vitro and in vivo, but central memory T cells (TCM) persisted longer in the circulation, entered the skin in larger numbers, and generated increased numbers of TRM. In summary, TCM are highly efficient precursors of human skin TRM, a feature that may underlie their known association with effective long-term immunity.

Dupilumab Provides Acceptable Safety and Sustained Efficacy for up to 4 Years in an Open-Label Study of Adults with Moderate-to-Severe Atopic Dermatitis.

BACKGROUND: Moderate-to-severe atopic dermatitis (AD) often requires long-term management with systemic therapies. OBJECTIVE: Our objective was to report the safety and efficacy of dupilumab treatment up to 4 years in adults with moderate-to-severe AD and efficacy in a subgroup of patients who transitioned from dupilumab once-weekly (qw) to administration every other week (q2w). METHODS: This interim analysis of the open-label extension study (NCT01949311) evaluated dupilumab 300 mg qw or q2w in adults previously enrolled in dupilumab trials for moderate-to-severe AD. Patients switched from qw to q2w following protocol amendment. The primary outcome was safety; efficacy was also assessed. RESULTS: Of 2677 patients enrolled and treated, 352 (13.1%) completed week 204 (end of efficacy assessments) and 202 (7.5%) completed safety follow-up through week 244. Self-reported compliance was 98.1%. Dupilumab's safety profile was consistent with previous reports. Common treatment-emergent adverse events (≥5%) included nasopharyngitis, AD, upper respiratory tract infection, oral herpes, conjunctivitis, injection-site reaction, and headache. At week 204, mean ± standard deviation (SD) Eczema Area and Severity Index was 2.46 ± 3.98, and mean percent change from parent study baseline (PSBL) was -91.07%; mean ± SD Pruritus Numerical Rating Scale score was 2.10 ± 1.83, and mean percent change from PSBL was -68.74%. Efficacy was maintained in patients (n = 226) who transitioned from qw to q2w dosing. Limitations of this study included its open-label design, the lack of control arm, and smaller subsets of patients at later timepoints and receiving the approved q2w regimen. CONCLUSION: These results support dupilumab as continuous long-term treatment for adults with moderate-to-severe AD; efficacy was sustained following transition from qw to q2w dosing. TRIAL REGISTRATION CLINICALTRIALS.GOV: NCT01949311.

Atopic dermatitis is a chronic skin disease associated with inflamed skin and intense itching. People with moderate-to-severe atopic dermatitis often need long-term treatment, but many available treatments do not have demonstrated long-term safety data. In multiple clinical trials, dupilumab treatment resulted in significant improvements in signs and symptoms of atopic dermatitis. This study examined the safety and efficacy of up to 4 years of dupilumab treatment in adults with moderate-to-severe atopic dermatitis, and whether dupilumab continued to be effective in patients who switched from receiving treatment each week to treatment every other week. To address these questions, we collected data from adults who received 300 milligrams of dupilumab every week or every other week. In this study, safety findings were consistent with the known dupilumab safety profile. Patients' signs and symptoms were evaluated before and during treatment with evaluation tools including the Eczema Area and Severity Index (EASI), which indicates the extent and severity of disease, and the Pruritus Numerical Rating Scale (NRS), which indicates the intensity of itching. Reductions of 91% in EASI scores and 69% in Pruritus NRS scores showed that the improvement in signs and symptoms persisted for 204 weeks (almost 4 years) of treatment, and these effects were sustained following the switch from weekly treatment to the approved every other week treatment with dupilumab. The safety and efficacy data presented here support the use of dupilumab as a continuous, long-term treatment for up to 4 years for adults with moderate-to-severe atopic dermatitis. Video abstract: What is the long-term safety and efficacy profile of dupilumab in adults with moderate-to-severeatopic dermatitis for up to 4 years? (MP4 102515 KB).

Long-Term Efficacy and Safety of Dupilumab in Adolescents with Moderate-to-Severe Atopic Dermatitis: Results Through Week 52 from a Phase III Open-Label Extension Trial (LIBERTY AD PED-OLE).

BACKGROUND: For adolescent patients (aged ≥ 12 to < 18 years) with uncontrolled moderate-to-severe atopic dermatitis (AD), 16 weeks of treatment with dupilumab resulted in substantial clinical benefit compared with placebo, with an acceptable safety profile. However, long-term data on the approved dose regimens of dupilumab in adolescents with AD are lacking. OBJECTIVES: This open-label extension study (LIBERTY AD PED-OLE, NCT02612454) reports the long-term safety, efficacy, and pharmacokinetics of dupilumab in adolescents with moderate-to-severe AD who had participated in dupilumab parent trials. METHODS: Patients enrolled under the original study protocol received subcutaneous dupilumab according to a weight-based regimen (2 or 4 mg/kg every week). Following protocol amendment, patients were switched to subcutaneous dupilumab 300 mg every 4 weeks (q4w) irrespective of weight, and newly enrolled patients were started on dupilumab 300 mg q4w. Patients with an inadequate clinical response (Investigator's Global Assessment [IGA] score of 0/1 was not reached) to the q4w regimen could be uptitrated to the approved dupilumab dose regimens of 200 or 300 mg every 2 weeks (body weight < 60 or ≥ 60 kg, respectively). Patients whose IGA score of 0/1 was maintained continuously for a 12-week period after week 40 were discontinued from dupilumab, monitored for relapse, and re-initiated on dupilumab if required. RESULTS: Data for 294 patients (mean age 14.7 years) were analyzed, 102 (34.7%) of whom had completed the 52-week visit at the database lock. The dupilumab long-term safety profile was comparable to that seen in adults and consistent with the known safety profile. Most treatment-emergent adverse events were mild/moderate. By week 52, 42.7% of patients had an IGA score of 0/1 (clear/almost clear), and 93.1%, 81.2%, and 56.4%, respectively, had at least a 50%, 75%, or 90% improvement in Eczema Area and Severity Index (EASI). Most (70.9%) patients required uptitration to the approved dupilumab dose regimen. The proportions of uptitrated patients with an IGA score of 0/1 or 75% improvement in EASI increased over time, reaching 35.7% and 51.9%, respectively, 48 weeks after the first uptitration visit. By week 52, 29.4% of patients had clear/almost clear skin sustained for 12 weeks and had stopped medication; 56.7% relapsed and were subsequently re-initiated on treatment, with a mean time to re-initiation of 17.5 (± standard deviation 17.3) weeks. CONCLUSIONS: Consistent with results seen with short-term treatment, long-term treatment with dupilumab showed an acceptable safety profile while providing incremental clinical benefit with continued treatment over time. The high proportion of patients who needed uptitration because of inadequate response to q4w dosing supports the q2w dose regimen as optimal for this age group. Finally, the majority of patients who stopped medication after having clear/almost clear skin sustained over 12 weeks experienced disease recurrence, suggesting the need for continued dupilumab dosing to maintain efficacy. TRIAL REGISTRATION: ClinicalTrials.gov Identifiers: NCT02612454, NCT02407756, NCT03054428, and NCT03050151. INFOGRAPHIC: Video abstract: What is the long-term safety and efficacy profile in adolescents with moderate-to-severe atopic dermatitis treated with the approved dupilumab dose regimen? (MP4 40,966 KB).

Atopic dermatitis, or eczema, is a common chronic skin disease that can cause intense and persistent itching and rashes. Atopic dermatitis remains a problem for many adolescent patients, even if they use a number of different treatments. Dupilumab is a newer treatment for atopic dermatitis. In short-term clinical studies, dupilumab improved the disease with acceptable safety. In this study, adolescents with moderate-to-severe atopic dermatitis who had completed one of the short-term studies continued dupilumab treatment for 1 year. The patients started treatment with dupilumab once every 4 weeks. But if their atopic dermatitis did not improve sufficiently, they were given dupilumab every 2 weeks. Through a year of treatment, there were no unexpected side effects. The side effects that did occur were mild or moderate in severity and in most cases did not lead to interruption of treatment. Almost half of the patients achieved skin that was clear or almost clear of atopic dermatitis during the study. But their atopic dermatitis often returned if they stopped being treated, and about half of them needed to start treatment again. Most patients needed to be treated every 2 weeks. The positive effects of dupilumab generally increased the longer patients were treated.

Preclinical and clinical experience with dupilumab on the correlates of live attenuated vaccines.

Background: The safety and tolerability of live attenuated vaccines in patients administered dupilumab for moderate-to-severe asthma have not been previously evaluated. During the LIBERTY ASTHMA TRAVERSE open-label extension study (ClinicalTrials.gov identifier NCT02134028), a yellow fever outbreak in Brazil required administration of a live attenuated vaccine to at-risk individuals. Objective: Our aim was to evaluate immune response to a live attenuated vaccine in the context of IL-4 receptor blockade (REGN1103, a dupilumab surrogate) in mice and in dupilumab-treated patients with moderate-to-severe asthma who participated in TRAVERSE. Methods: In the preclinical study, mice were coadministered REGN1103/isotype control and live attenuated influenza vaccine/control, followed by influenza virus challenge. During TRAVERSE, 37 patients discontinued dupilumab treatment and were administered 17D live attenuated yellow fever vaccine (YFV). Safety and tolerability data, dupilumab serum concentrations, and plaque reduction neutralization titers before and after vaccination were collected. Results: In the preclinical study, there was no impact of REGN1103 on vaccine efficacy in mice. In TRAVERSE, all 37 patients who received YFV achieved seroprotection despite most having therapeutic levels of dupilumab, with the magnitude of response appearing unrelated to prevaccination dupilumab concentrations. No instances of vaccine-related adverse events or vaccine hypersensitivity were reported in 36 patients; 1 patient reported nonserious body ache, malaise, and dizziness 7 days after vaccination but recovered fully. Conclusion: The preclinical model suggested that dupilumab does not affect the efficacy of live attenuated influenza vaccine. The live attenuated YFV did not raise safety concerns and appeared to be well tolerated in patients with asthma who recently discontinued dupilumab treatment, and dupilumab concentrations had no apparent impact on immunologic response to the vaccine.

Temporal induction pattern of STAT4 target genes defines potential for Th1 lineage-specific programming.

STAT4 is a critical component in the development of inflammatory adaptive immune responses. It has been extensively characterized as a lineage-determining factor in Th1 development. However, the genetic program activated by STAT4 that results in an inflammatory cell type is not well defined. In this report, we use DNA isolated from STAT4-chromatin immunoprecipitation to perform chromatin immunoprecipitation-on-chip analysis of over 28,000 mouse gene promoters to identify STAT4 targets. We demonstrate that STAT4 binds multiple gene-sets that program distinct components of the Th1 lineage. Although many STAT4 target genes display STAT4-dependent IL-12-inducible expression, other genes displayed IL-12-induced histone modifications but lack induction, possibly due to high relative basal expression. In the subset of genes that STAT4 programs for expression in Th1 cells, IL-12-induced mRNA levels remain increased for a longer time than mRNA from genes that are not programmed. This suggests that STAT4 binding to target genes, while critical, is not the only determinant for STAT4-dependent gene programming during Th1 differentiation.

Laboratory Safety of Dupilumab in Patients Aged 6-11 Years with Severe Atopic Dermatitis: Results from a Phase III Clinical Trial.

BACKGROUND: Previous studies of dupilumab in adolescents and adults with moderate-to-severe atopic dermatitis (AD) showed no clinically meaningful adverse changes in laboratory parameters. OBJECTIVE: The aim of this study was to assess laboratory outcomes in children aged 6-11 years with severe AD in a randomized, placebo-controlled, phase III trial of dupilumab. METHODS: Children aged 6-11 years with severe AD were randomized 1:1:1 to 16 weeks of dupilumab 300 mg every 4 weeks, 100 or 200 mg every 2 weeks, or matching placebo, all with concomitant topical corticosteroids (TCS). Blood samples were collected at baseline and Weeks 4, 8, and 16; urine samples were collected at baseline and Weeks 4 and 16. RESULTS: Of 367 patients enrolled in the study, 362 were included in the safety analysis, 351 completed study treatment, and 4 withdrew due to treatment-emergent adverse events not related to laboratory abnormalities. Both dupilumab + TCS groups showed overall trends toward increases in mean blood levels of eosinophils and alkaline phosphatase, and decreases in mean blood levels of platelets, neutrophils, and lactate dehydrogenase levels, without corresponding mean changes in the placebo + TCS group. None of these changes were associated with symptoms or clinically meaningful adverse outcomes, and none led to treatment modification. No clinically significant changes or trends were observed for other measured laboratory parameters. CONCLUSION: There were no clinically meaningful adverse changes in routine laboratory parameters attributable to treatment with dupilumab + TCS. Changes in platelet counts and lactate dehydrogenase levels likely reflect reduced inflammation. These results confirm similar findings in adults and adolescents, and suggest that there is no need for routine laboratory monitoring of children aged 6-11 years treated with dupilumab + TCS for severe AD. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03345914. Does treatment with dupilumab require routine laboratory monitoring in 6- to 11-year-old children with severe atopic dermatitis? (MP4 180482 kb).

Stat4 isoforms differentially regulate inflammation and demyelination in experimental allergic encephalomyelitis.

Experimental allergic encephalomyelitis (EAE) is a T cell-mediated autoimmune disease model of multiple sclerosis. Signal transducer and activator of transcription 4 (Stat4) is a transcription factor activated by IL-12 and IL-23, two cytokines known to play important roles in the pathogenesis of EAE by inducing T cells to secrete IFN-gamma and IL-17, respectively. We and others have previously shown that therapeutic intervention or targeted disruption of Stat4 was effective in ameliorating EAE. Recently, a splice variant of Stat4 termed Stat4beta has been characterized that lacks 44 amino acids at the C terminus of the full-length Stat4alpha. In this study we examined whether T cells expressing either isoform could affect the pathogenesis of EAE. We found that transgenic mice expressing Stat4beta on a Stat4-deficient background develop an exacerbated EAE compared with wild-type mice following immunization with myelin oligodendrocyte glycoprotein peptide 35-55, while Stat4alpha transgenic mice have greatly attenuated disease. The differential development of EAE in transgenic mice correlates with increased IFN-gamma and IL-17 in Stat4beta-expressing cells in situ, contrasting increased IL-10 production by Stat4alpha-expressing cells. This study demonstrates that Stat4 isoforms differentially regulate inflammatory cytokines in association with distinct effects on the onset and severity of EAE.

STAT4 isoforms differentially regulate Th1 cytokine production and the severity of inflammatory bowel disease.

STAT4, a critical regulator of inflammation in vivo, can be expressed as two alternative splice forms, a full-length STAT4alpha, and a STAT4beta isoform lacking a C-terminal transactivation domain. Each isoform is sufficient to program Th1 development through both common and distinct subsets of target genes. However, the ability of these isoforms to mediate inflammation in vivo has not been examined. Using a model of colitis that develops following transfer of CD4(+) CD45RB(high) T cells expressing either the STAT4alpha or STAT4beta isoform into SCID mice, we determined that although both isoforms mediate inflammation and weight loss, STAT4beta promotes greater colonic inflammation and tissue destruction. This correlates with STAT4 isoform-dependent expression of TNF-alpha and GM-CSF in vitro and in vivo, but not Th1 expression of IFN-gamma or Th17 expression of IL-17, which were similar in STAT4alpha- and STAT4beta-expressing T cells. Thus, higher expression of a subset of inflammatory cytokines from STAT4beta-expressing T cells correlates with the ability of STAT4beta-expressing T cells to mediate more severe inflammatory disease.