Intramuscular AZD7442 (Tixagevimab-Cilgavimab) for Prevention of Covid-19.

BACKGROUND: The monoclonal-antibody combination AZD7442 is composed of tixagevimab and cilgavimab, two neutralizing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that have an extended half-life and have been shown to have prophylactic and therapeutic effects in animal models. Pharmacokinetic data in humans indicate that AZD7442 has an extended half-life of approximately 90 days. METHODS: In an ongoing phase 3 trial, we enrolled adults (≥18 years of age) who had an increased risk of an inadequate response to vaccination against coronavirus disease 2019 (Covid-19), an increased risk of exposure to SARS-CoV-2, or both. Participants were randomly assigned in a 2:1 ratio to receive a single dose (two consecutive intramuscular injections, one containing tixagevimab and the other containing cilgavimab) of either 300 mg of AZD7442 or saline placebo, and they were followed for up to 183 days in the primary analysis. The primary safety end point was the incidence of adverse events after a single dose of AZD7442. The primary efficacy end point was symptomatic Covid-19 (SARS-CoV-2 infection confirmed by means of reverse-transcriptase-polymerase-chain-reaction assay) occurring after administration of AZD7442 or placebo and on or before day 183. RESULTS: A total of 5197 participants underwent randomization and received one dose of AZD7442 or placebo (3460 in the AZD7442 group and 1737 in the placebo group). The primary analysis was conducted after 30% of the participants had become aware of their randomized assignment. In total, 1221 of 3461 participants (35.3%) in the AZD7442 group and 593 of 1736 participants (34.2%) in the placebo group reported having at least one adverse event, most of which were mild or moderate in severity. Symptomatic Covid-19 occurred in 8 of 3441 participants (0.2%) in the AZD7442 group and in 17 of 1731 participants (1.0%) in the placebo group (relative risk reduction, 76.7%; 95% confidence interval [CI], 46.0 to 90.0; P<0.001); extended follow-up at a median of 6 months showed a relative risk reduction of 82.8% (95% CI, 65.8 to 91.4). Five cases of severe or critical Covid-19 and two Covid-19-related deaths occurred, all in the placebo group. CONCLUSIONS: A single dose of AZD7442 had efficacy for the prevention of Covid-19, without evident safety concerns. (Funded by AstraZeneca and the U.S. government; PROVENT ClinicalTrials.gov number, NCT04625725.).

IL4I1 augments CNS remyelination and axonal protection by modulating T cell driven inflammation.

SEE PLUCHINO AND PERUZZOTTI-JAMETTI DOI101093/AWW266 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: Myelin regeneration (remyelination) is a spontaneous process that occurs following central nervous system demyelination. However, for reasons that remain poorly understood, remyelination fails in the progressive phase of multiple sclerosis. Emerging evidence indicates that alternatively activated macrophages in central nervous system lesions are required for oligodendrocyte progenitor differentiation into remyelinating oligodendrocytes. Here, we show that an alternatively activated macrophage secreted enzyme, interleukin-four induced one (IL4I1), is upregulated at the onset of inflammation resolution and remyelination in mouse central nervous system lesions after lysolecithin-induced focal demyelination. Focal demyelination in mice lacking IL4I1 or interleukin 4 receptor alpha (IL4Rα) results in increased proinflammatory macrophage density, remyelination impairment, and axonal injury in central nervous system lesions. Conversely, recombinant IL4I1 administration into central nervous system lesions reduces proinflammatory macrophage density, enhances remyelination, and rescues remyelination impairment in IL4Rα deficient mice. We find that IL4I1 does not directly affect oligodendrocyte differentiation, but modulates inflammation by reducing interferon gamma and IL17 expression in lesioned central nervous system tissues, and in activated T cells from splenocyte cultures. Remarkably, intravenous injection of IL4I1 into mice with experimental autoimmune encephalomyelitis at disease onset significantly reversed disease severity, resulting in recovery from hindlimb paralysis. Analysis of post-mortem tissues reveals reduced axonal dystrophy in spinal cord, and decreased CD4+ T cell populations in spinal cord and spleen tissues. These results indicate that IL4I1 modulates inflammation by regulating T cell expansion, thereby permitting the formation of a favourable environment in the central nervous system tissue for remyelination. Therefore, IL4I1 is a potentially novel therapeutic for promoting central nervous system repair in multiple sclerosis.

Time to onset of clinical response to anifrolumab in patients with SLE: pooled data from the phase III TULIP-1 and TULIP-2 trials.

OBJECTIVES: To evaluate the time course of clinical response following anifrolumab treatment in patients with SLE. METHODS: A post hoc analysis was conducted using pooled data from phase III, randomised, 52-week, placebo-controlled, Treatment of Uncontrolled Lupus via the Interferon Pathway (TULIP)-1 and TULIP-2 trials of intravenous anifrolumab (every 4 weeks, 48 weeks) in patients with moderate-to-severe SLE receiving standard therapy. Anifrolumab 300 mg and placebo groups were compared for British Isles Lupus Assessment Group-based Composite Lupus Assessment (BICLA) response over time, time to sustained BICLA response, SLE Responder Index ≥4 (SRI(4)) response over time, time to sustained Cutaneous Lupus Erythematosus Disease Area and Severity Index Activity (CLASI-A) response and change in glucocorticoid dosage over time. All p values for comparisons were nominal. RESULTS: Of the 726 evaluated patients (anifrolumab 300 mg, n=360; placebo, n=366), a greater proportion attained a BICLA response in the anifrolumab versus the placebo group from Week 8 (p<0.001); treatment group differentiation was maintained at all subsequent visits to Week 52. Consistently, more patients achieved a BICLA response sustained to Week 52 in the anifrolumab versus placebo group (HR=1.73, 95% CI 1.37 to 2.20). More patients attained SRI(4) response with anifrolumab than placebo from Week 12 (p=0.005). As early as Week 8, more patients achieved CLASI-A skin response sustained to Week 52 with anifrolumab versus placebo (HR=1.72, 95% CI 1.17 to 2.55). Glucocorticoid dosage reductions from baseline were greater in anifrolumab-treated versus placebo-treated patients from Week 20 (p=0.010) through Week 52. CONCLUSIONS: Anifrolumab treatment was associated with sustained improvements in overall SLE disease activity and skin responses versus placebo from Week 8, which likely led to greater glucocorticoid reductions in the anifrolumab versus placebo groups from Week 20. These findings provide insights to physicians and patients on when to expect potential clinical responses following anifrolumab treatment.

Indirect treatment comparison of anifrolumab efficacy versus belimumab in adults with systemic lupus erythematosus.

Aim: Assess the comparative efficacy of anifrolumab 300 mg versus belimumab 10 mg/kg in adults with moderate-to-severe systemic lupus erythematosus (SLE) receiving standard therapy. Patients and methods: Population-adjusted simulated treatment comparisons (primary analyses) and matching-adjusted indirect comparisons (supporting analyses) were conducted using individual patient data from TULIP-1/TULIP-2 and summary-level data from BLISS-52/BLISS-76. Results: Compared with belimumab-treated patients, anifrolumab-treated patients were more than twice as likely to achieve a reduction of four or more points in SLE Disease Activity Index 2000 score (simulated treatment comparison odds ratio: 2.47; 95% CI: 1.16-5.25) and SLE Responder Index-4 response (odds ratio: 2.61; 95% CI: 1.22-5.58) at 52 weeks. Conclusion: Patients with moderate-to-severe SLE are more likely to achieve an improvement in disease activity with anifrolumab than with belimumab.

Design of FLAIR: a Phase 2b Study of the 5-Lipoxygenase Activating Protein Inhibitor AZD5718 in Patients With Proteinuric CKD.

INTRODUCTION: Patients with chronic kidney disease (CKD) remain at risk for kidney and cardiovascular events resulting from residual albuminuria, despite available treatments. Leukotrienes are proinflammatory and vasoconstrictive lipid mediators implicated in the etiology of chronic inflammatory diseases. AZD5718 is a potent, selective, and reversible 5-lipoxygenase activating protein (FLAP) inhibitor that suppresses leukotriene production. METHODS: FLAIR (FLAP Inhibition in Renal disease) is an ongoing phase 2b, randomized, double-blind, placebo-controlled, multicenter study to evaluate the efficacy and safety of AZD5718 in patients with proteinuric CKD with or without type 2 diabetes. Participants receive AZD5718 at 3 different doses or placebo once daily for 12 weeks, followed by an 8-week extension in which they also receive dapagliflozin (10 mg/d) as anticipated future standard of care. The planned sample size is 632 participants, providing 91% power to detect 30% reduction in urinary albumin-to-creatinine ratio (UACR) between the maximum dose of AZD5718 and placebo. The dose-response effect of AZD5718 on UACR after the dapagliflozin extension is the primary efficacy objective. Key secondary objectives are the dose-response effect of AZD5718 plus current standard of care on UACR and acute effects of treatment on the estimated glomerular filtration rate. Safety, tolerability, AZD5718 pharmacokinetics, and analyses of biomarkers that may predict or reflect response to AZD5718 are additional objectives. CONCLUSION: FLAIR will provide data on the effects of 5-lipoxygenase pathway inhibition in patients with proteinuric CKD with or without type 2 diabetes, and will form the basis for future clinical trials (ClinicalTrials.gov: NCT04492722).

Oligodendrocyte regeneration: Its significance in myelin replacement and neuroprotection in multiple sclerosis.

Oligodendrocytes readily regenerate and replace myelin membranes around axons in the adult mammalian central nervous system (CNS) following injury. The ability to regenerate oligodendrocytes depends on the availability of neural progenitors called oligodendrocyte precursor cells (OPCs) in the adult CNS that respond to injury-associated signals to induce OPC expansion followed by oligodendrocyte differentiation, axonal contact and myelin regeneration (remyelination). Remyelination ensures the maintenance of axonal conduction, and the oligodendrocytes themselves provide metabolic factors that are necessary to maintain neuronal integrity. Recent advances in oligodendrocyte regeneration research are beginning to shed light on critical intrinsic signals, as well as extrinsic, environmental factors that regulate the distinct steps of oligodendrocyte lineage progression and myelin replacement under CNS injury. These studies may offer novel pharmacological targets for regenerative medicine in inflammatory demyelinating disorders in the CNS such as multiple sclerosis. This article is part of the Special Issue entitled 'Oligodendrocytes in Health and Disease'.

Oligodendrocyte dynamics in the healthy adult CNS: evidence for myelin remodeling.

Oligodendrocyte precursors (OPs) continue to proliferate and generate myelinating oligodendrocytes (OLs) well into adulthood. It is not known whether adult-born OLs ensheath previously unmyelinated axons or remodel existing myelin. We quantified OP division and OL production in different regions of the adult mouse CNS including the 4-month-old optic nerve, in which practically all axons are already myelinated. Even there, all OPs were dividing and generating new OLs and myelin at a rate higher than can be explained by first-time myelination of naked axons. We conclude that adult-born OLs in the optic nerve are engaged in myelin remodeling, either replacing OLs that die in service or intercalating among existing myelin sheaths. The latter would predict that average internode length should decrease with age. Consistent with that, we found that adult-born OLs elaborated much shorter but many more internodes than OLs generated during early postnatal life.

Cell cycle dynamics of NG2 cells in the postnatal and ageing brain.

Oligodendrocyte precursors (OLPs or 'NG2 cells') are abundant in the adult mouse brain, where they continue to proliferate and generate new myelinating oligodendrocytes. By cumulative BrdU labelling, we estimated the cell cycle time TC and the proportion of NG2 cells that is actively cycling (the growth fraction) at approximately postnatal day 6 (P6), P60, P240 and P540. In the corpus callosum, TC increased from <2 days at P6 to approximately 9 days at P60 to approximately 70 days at P240 and P540. In the cortex, TC increased from approximately 2 days to >150 days over the same period. The growth fraction remained relatively invariant at approximately 50% in both cortex and corpus callosum - that is, similar numbers of mitotically active and inactive NG2 cells co-exist at all ages. Our data imply that a stable population of quiescent NG2 cells appears before the end of the first postnatal week and persists throughout life. The mitotically active population acts as a source of new oligodendrocytes during adulthood, while the biological significance of the quiescent population remains to be determined. We found that the mitotic status of adult NG2 cells is unrelated to their developmental site of origin in the ventral or dorsal telencephalon. We also report that new oligodendrocytes continue to be formed at a slow rate from NG2 cells even after P240 (8 months of age).

PDGFRA/NG2 glia generate myelinating oligodendrocytes and piriform projection neurons in adult mice.

Platelet-derived growth factor alpha receptor (PDGFRA)/NG2-expressing glia are distributed throughout the adult CNS. They are descended from oligodendrocyte precursors (OLPs) in the perinatal CNS, but it is not clear whether they continue to generate myelinating oligodendrocytes or other differentiated cells during normal adult life. We followed the fates of adult OLPs in Pdgfra-creER(T2)/Rosa26-YFP double-transgenic mice and found that they generated many myelinating oligodendrocytes during adulthood; >20% of all oligodendrocytes in the adult mouse corpus callosum were generated after 7 weeks of age, raising questions about the function of the late-myelinating axons. OLPs also produced some myelinating cells in the cortex, but the majority of adult-born cortical cells did not appear to myelinate. We found no evidence for astrocyte production in gray or white matter. However, small numbers of projection neurons were generated in the forebrain, especially in the piriform cortex, which is the main target of the olfactory bulb.