Safety, tolerability, and efficacy of subcutaneous efgartigimod in patients with chronic inflammatory demyelinating polyradiculoneuropathy (ADHERE): a multicentre, randomised-withdrawal, double-blind, placebo-controlled, phase 2 trial.

BACKGROUND: Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune disease of the peripheral nervous system that can lead to severe disability from muscle weakness and sensory disturbances. Around a third of patients do not respond to currently available treatments, and many patients with a partial response have residual neurological impairment, highlighting the need for effective alternatives. Efgartigimod alfa, a human IgG1 antibody Fc fragment, has demonstrated efficacy and safety in patients with generalised myasthenia gravis. We evaluated the safety, tolerability, and efficacy of subcutaneous efgartigimod PH20 in adults with CIDP. METHODS: ADHERE, a multistage, double-blind, placebo-controlled trial, enrolled participants with CIDP from 146 clinical sites from Asia-Pacific, Europe, and North America. Participants with evidence of clinically meaningful deterioration entered an open-label phase of weekly 1000 mg subcutaneous efgartigimod PH20 for no longer than 12 weeks (stage A). Those with confirmed evidence of clinical improvement (ECI; treatment responders) entered a randomised-withdrawal phase of 1000 mg subcutaneous efgartigimod PH20 weekly treatment versus placebo for a maximum of 48 weeks (stage B). Participants were randomised (1:1) through interactive response technology and stratified by their adjusted Inflammatory Neuropathy Cause and Treatment (aINCAT) score change during stage A and their most recent CIDP medication within 6 months before screening. Investigators, the clinical research organisation, and participants were masked to the treatment. The primary endpoint in stage A, evaluated in the stage A safety population, was confirmed ECI (≥1 points aINCAT decrease, ≥4 points [centile metric] Inflammatory Rasch-built Overall Disability Scale increase, or ≥8 kPa grip strength increase after four injections and two consecutive visits). The primary endpoint in stage B, evaluated in the modified intention-to-treat population, was the risk of relapse (time to first aINCAT increase of ≥1 points). ADHERE is registered with ClinicalTrials.gov (NCT04281472) and EudraCT (2019-003076-39) and is completed. FINDINGS: Between April 15, 2020, and May 11, 2023, 629 participants were screened; 322 (114 female, 208 male) entered stage A, of whom 214 (66%, 95% CI 61·0-71·6) had confirmed ECI. In stage B, 221 participants were randomised (79 female, 142 male; 111 to subcutaneous efgartigimod PH20, 110 to placebo). Subcutaneous efgartigimod PH20 significantly reduced the risk of relapse versus placebo (hazard ratio 0·39 [95% CI 0·25-0·61]; p<0·0001). 31 (27·9% [19·6-36·3]) participants given subcutaneous efgartigimod PH20 had a relapse versus 59 (53·6% [44·3-63·0]) given placebo. In stage A, treatment-emergent adverse events (TEAEs) occurred in 204 (63%) participants and serious TEAEs in 21 (7%). In stage B, TEAEs occurred in 71 (64%) participants on subcutaneous efgartigimod PH20 and 62 (56%) participants on placebo, and serious TEAEs in six (5%) on subcutaneous efgartigimod PH20 and six (5%) on placebo. Three deaths occurred: two in stage A (one non-related and one unlikely related to treatment) and one in stage B (placebo group). INTERPRETATION: ADHERE showed the efficacy of subcutaneous efgartigimod PH20 in reducing the risk of relapse versus placebo in people with CIDP who responded to treatment. Further studies are needed to provide data on the longer-term effects of efgartigimod alfa and how it compares with currently available treatment options. FUNDING: argenx.

p75ECD-Fc reverses neonatal hypoxic-ischemic encephalopathy-induced neurological deficits and inhibits apoptosis associated with Nestin.

A recent study has introduced a recombinant fusion protein, consisting of the extracellular domain (ECD) of p75 and the Fc fragment of human immunoglobulin IgG1 (p75ECD-Fc), as a multifaceted agent within the nervous system. This research aimed to assess the effects of p75ECD-Fc on neuronal growth and the restoration of neurological functions in rats afflicted with neonatal hypoxic-ischemic encephalopathy (NHIE). In vitro analyses revealed that 1 µM p75ECD-Fc treatment markedly increased cell viability and facilitated neurite outgrowth in neurons exposed to oxygen-glucose deprivation (OGD). Subsequent in vivo studies determined that a dose of 78.6 µg/3 µl of p75ECD-Fc significantly mitigated brain damage and both acute and long-term neurological impairments, outperforming the therapeutic efficacy of hypothermia, as evidenced through behavioral assessments. Additionally, in vivo immunostaining showed that p75ECD-Fc administration enhanced neuronal survival and regeneration, and reduced astrocytosis and microglia activation in the cortex and hippocampus of NHIE rats. A noteworthy shift from A1 to A2 astrocyte phenotypes and from M1 to M2 microglia phenotypes was observed after p75ECD-Fc treatment. Furthermore, a co-expression of the p75 neurotrophin receptor (p75NTR) and Nestin was identified, with an overexpression of Nestin alleviating the neurological dysfunction induced by NHIE. Mechanistically, the neuroprotective effects of p75ECD-Fc, particularly its inhibition of neuronal apoptosis post-OGD, may be attributed to Nestin. Taken together, these results highlight the neuroprotective and anti-inflammatory effects of p75ECD-Fc treatment through the modulation of glial cell phenotypes and the Nestin-mediated inhibition of neuronal apoptosis, positioning it as a viable therapeutic approach for NHIE.

Systematic analysis of Fc mutations designed to enhance binding to Fc-gamma receptors.

A critical attribute of therapeutic antibodies is their ability to engage with humoral or cellular effector mechanisms, and this depends on the ability of the Fc region to bind to complement (C1q) or Fc receptors. Investigators have sought to optimize these effects by engineering the Fc region to bind to a greater or lesser extent to individual receptors. Different approaches have been used in the clinic, but they have not been systematically compared. We have now produced a matched set of anti-CD20 antibodies representing a range of variants and compared their activity in cell-based assays for complement-dependent cytotoxicity, antibody-dependent cell-mediated cytotoxicity, and antibody-dependent phagocytosis using a range of individual Fc receptors. We have also compared the thermal stability of the variants by differential scanning fluorimetry (DSF). The results reveal a spectrum of activities which may be appropriate for different applications.

In silico mediated workflow for rapid development of downstream processing: Orthogonal product-related impurity removal for a Fc-containing therapeutic.

Therapeutic formats derived from the monoclonal antibody structure have been gaining significant traction in the biopharmaceutical market. Being structurally similar to mAbs, most Fc-containing therapeutics exhibit product-related impurities in the form of aggregates, charge variants, fragments, and glycoforms, which are inherently challenging to remove. In this work, we developed a workflow that employed rapid resin screening in conjunction with an in silico tool to identify and rank orthogonally selective processes for the removal of product-related impurities from a Fc-containing therapeutic product. Linear salt gradient screens were performed at various pH conditions on a set of ion-exchange, multimodal ion-exchange, and hydrophobic interaction resins. Select fractions from the screening experiments were analyzed by three different analytical techniques to characterize aggregates, charge variants, fragments, and glycoforms. The retention database generated by the resin screens and subsequent impurity characterization were then processed by an in silico tool that generated and ranked all possible two-step resin sequences for the removal of product-related impurities. A highly-ranked process was then evaluated and refined at the bench-scale to develop a completely flowthrough two-step polishing process which resulted in complete removal of the Man5 glycoform and aggregate impurities with a 73% overall yield. The successful implementation of the in silico mediated workflow suggests the possibility of a platformable workflow that could facilitate polishing process development for a wide variety of mAb-based therapeutics.

GLP-1 receptor agonist-induced diabetic ketoacidosis: A case report.

RATIONALE: Glucagon-like peptide-1 is an endogenous incretin that plays an active role in weight loss and hypoglycemia. Dulaglutide is a long-acting glucagon-like peptide-1 receptor agonist (GLP-1RA), which has been approved for the treatment of patients with type 2 diabetes (T2D). GLP-1RAs can increase insulin secretion and inhibit glucagon release, thereby leading to a decrease in blood glucose levels within the body. Specifically, GLP-1RAs control postprandial blood glucose levels by inhibiting hepatic glucose production and delaying gastric emptying. However, attention should be given to gastrointestinal adverse reactions. There are currently a few cases of GLP-1RA causing diabetic ketoacidosis (DKA). PATIENT CONCERNS: The following report details the case of a 50-year-old Chinese female who has been living with diabetes for 12 years. Initially diagnosed with T2D, she was subsequently identified as a patient with latent autoimmune diabetes in adults (LADA) following treatment. The patient presented severe nausea, vomiting, and fatigue 1 day after injecting dulaglutide 1 time and discontinuing insulin therapy. She was diagnosed with severe DKA in the emergency department. DIAGNOSES: LADA and DKA. INTERVENTIONS: Changed from dulaglutide to insulin therapy. OUTCOMES: After discontinuing dulaglutide and switching to insulin for blood glucose reduction, the patient's DKA was corrected, and blood glucose levels returned to normal. LESSONS: This case suggests that clinicians should be alert to patients with severe DKA in cases of severe gastrointestinal adverse reactions after the use of GLP-1RAs. In addition, in most countries, GLP-1RAs are administered to patients with T2D, but we should consider the use of GLP-1RAs in patients with type 1 diabetes and LADA.

Effects of the glucagon-like peptide-1 receptor agonist dulaglutide on sexuality in healthy men: a randomised, double-blind, placebo-controlled crossover study.

BACKGROUND: The reward-regulatory properties of GLP-1 are attracting increasing interest. Animal studies show that GLP-1 receptor agonists not only reduce consumption of addictive substances, but also influence sexual behaviour. We aimed to investigate the effect of dulaglutide versus placebo on sexual desire in humans. METHODS: In this randomised, double-blind, placebo-controlled crossover trial, healthy eugonadal men of normal weight, aged 18-50 years with active and satisfactory sex lifes were (1:1) randomly allocated to dulaglutide or placebo for four weeks. We assessed sexual desire (Massachusetts General Hospital-Sexual Functioning Questionnaire [MGH-SFQ]), hormones of the hypothalamic-pituitary-gonadal axis (total testosterone, follicle-stimulating hormone [FSH], luteinizing hormone [LH]) and sperm parameters. Changes in these parameters were compared under dulaglutide versus placebo using paired t-tests. FINDINGS: 24 out of 26 randomised participants completed the study (13 participants randomised to dulaglutide first and 13 to placebo first). No change in the MGH-SFQ was observed after four weeks of dulaglutide versus placebo (estimated difference 0.58 [95% CI -0.83 to 2.00], p-value = 0.402). Hormones of the hypothalamic-pituitary-gonadal axis (estimated differences: total testosterone (nmol/l) 0.9 [95% CI -1.5 to 3.3], FSH (IU/l) -0.2 [95% CI -0.3 to 0.0] and LH (IU/l) -0.8 [95% CI -1.5 to 0.0]) as well as sperm parameters all remained in the normal range without significant differences between the treatments. No severe adverse events occurred. INTERPRETATION: In this study of healthy men, we found no evidence of negative impacts of a four-week treatment with the widely used GLP-1 receptor agonist dulaglutide on sexual desire, hypothalamic-pituitary-gonadal axis hormones or sperm parameters. FUNDING: Swiss National Science Foundation (PZ00P3_193206), Gottfried and Julia Bangerter-Rhyner Foundation, Goldschmidt-Jacobson Foundation, Swiss Academy of Medical Sciences.

Systematic analysis of Fc mutations designed to reduce binding to Fc-gamma receptors.

Elimination of the binding of immunoglobulin Fc to Fc gamma receptors is highly desirable for the avoidance of unwanted inflammatory responses to therapeutic antibodies and fusion proteins. Many different approaches have been used in the clinic, but they have not been systematically compared. We have now produced a matched set of anti-CD20 antibodies with different Fc subclasses and variants and compared their activity for binding to C1q, Fc-gamma receptors and in cell-based assays. Most of the variants still have significant levels of activity in one or more of these assays and many of them have impaired temperature stability compared with the corresponding wild-type antibody.

Broad-spectrum coronavirus neutralization induced by hetero RBD-Fc protein vaccine.

In the landscape of infectious diseases, human coronaviruses such as SARS-CoV, MERS-CoV, and SARS-CoV-2 pose significant threats, characterized by severe respiratory illnesses and notable resistance to conventional treatments due to their rapid evolution and the emergence of diverse variants, particularly within SARS-CoV-2. This study investigated the development of broad-spectrum coronavirus vaccines using heterodimeric RBD-Fc proteins engineered through the "Knob-into-Hole" technique. We constructed various recombinant proteins incorporating the receptor-binding domains (RBDs) of different coronaviruses. Heterodimers combining RBDs from SARS-CoV-2 with those of SARS-CoV or MERS-CoV elicited superior neutralizing responses compared to homodimeric proteins in murine models. Additionally, heterotetrameric proteins, specifically D614G_Delta/BA.1_XBB.1.5-RBD and MERS_D614G/BA.1_XBB.1.5-RBD, elicited remarkable breadth and potency in neutralizing all known SARS-CoV-2 variants, SARS-CoV, related sarbecoviruses like GD-Pangolin and WIV1, and even MERS-CoV pseudoviruses. Furthermore, these heterotetrameric proteins also demonstrated enhanced cellular immune responses. These findings underscore the potential of recombinant hetero proteins as a universal vaccine strategy against current and future coronavirus threats.

Improved Clinical Outcomes with the Combination Therapy of a Glucagon-like Peptide-1 Receptor Agonists and a Sodium-glucose Cotransporter-2 Inhibitor in Overweight/Obese People with Type 2 Diabetes: Real-world Evidence from the Indian Subcontinent.

OBJECTIVE: Type 2 diabetes (T2D) mellitus is increasing exponentially in India, with overweight/obesity being prime contributors. This study aimed at assessing the clinical impact of the combination therapy of a glucagon-like peptide-1 receptor agonist (GLP-1RA) injection (inj.) and a sodium-glucose cotransporter-2 inhibitor (SGLT-2i) in overweight/obese patients from the Indian subcontinent. METHODS: In two real-world evidence (RWE) studies (RWE1 and 2), we retrospectively observed the effect of the combination therapy of a GLP-1RA, injection dulaglutide (DU) 1.5 mg/week, and an SGLT-2i, canagliflozin (CAN) 100 mg/day at weeks 16, 32, and 52 on HbA1c, body weight (weight), systolic blood pressure (SBP), lipids, change in doses of antidiabetic agents (ADA) and antihypertensive agents (AHA) in overweight/obese Asian Indian subjects with T2D, who had suboptimal glycemic control. RESULTS: A total of 95 T2D patients [51 males (M), 44 females (F)] completed the two RWE studies. In RWE 1, 40 patients (20 M/20 F), mean [standard deviation (SD)] age 49.4 (10.7) years (Y), weight 92.6 (6.6) kg, body mass index (BMI) 30.6 (2.3) kg/m2, duration of T2D 8.1 (3.2) Y, completed the study. At week 32, the mean (SD) reduction in A1c (%) was -1.3% [8.4 (0.7) to 7.1 (0.3); p < 0.01] and mean (SD) weight (kg) loss was -5.5 [92.6 (6.6) to 87.9 (7.02); p < 0.00001]. This group was then followed up until week 52. In RWE 2, 55 patients (31 M/24 F), age 51 (5.8) Y, weight 92.6 ± 3.4 kg, BMI 31.1 ± 2.1 kg/m2, SBP 142.4 ± 3.9 mm Hg, estimated glomerular filtration rate (eGFR) 62 ± 5 mL/minute/1.73 m2, with 8.4 ± 3.3 Y duration of diabetes met the inclusion criteria. In 71% of subjects, A1c decreased by -1.4% [8.5 ± 0.4 to 7.1 ± 0.2; p < 0.0001] at week 16 and was 6.8 ± 0.3 (p = 0.0002) in 18% at week 32. CONCLUSION: A statistically significant (SS) improvement in glycemic control, weight, and improvement in cardiovascular (CV) risk factors was observed with the GLP-1RA/SGLT-2i combination, which was well tolerated.

Peptibodies: Bridging the gap between peptides and antibodies.

Peptides are a very critical class of pharmaceutical compounds that can control several signaling pathways and thereby affect many physiological and biochemical processes. Previous research suggests that both peptides and antibodies may serve as potent tools for research, diagnostics, vaccination, and therapeutics across diverse domains. The distinct attributes of peptides, like their profound tissue penetration, efficient cellular internalization, reduced immunogenicity, and adaptability to chemical modification, underscore their significance in biomedical applications. However, they also possess drawbacks such as lower affinity, poor absorption, low stability to proteolytic digestion, and rapid clearance. The advent of peptibodies is a significant advance that improves the limitations of both peptides and antibodies. Peptibodies, or Peptide-Fc fusions, represent a promising therapeutic modality comprising biologically active peptides fused to an Fc domain. The stability and efficacy of the peptide are enhanced by this fusion strategy, which overcomes some of the inherent limitations. Many peptibodies have been developed to treat conditions like cancer, diabetes, and lupus. Romiplostim and Dulaglutide are the only ones approved by the EMA and FDA, respectively. Given the growing significance of peptibodies in the pharmaceutical landscape, this investigation aims to explain key aspects encompassing the intrinsic properties of peptides, the intricacies of peptibody production, and their potential therapeutic applications.

Transplacental delivery of factor IX Fc-fusion protein ameliorates bleeding phenotype of newborn hemophilia B mice.

Hemophilia B is an inherited hemorrhagic disorder characterized by a deficiency of blood coagulation factor IX (FIX) that results in abnormal blood coagulation. The blood coagulation is already evident in hemophiliacs at the fetal stage, and thus intracranial hemorrhage and other bleeding complications can occur at birth, leading to sequelae. Therefore, it is important to develop effective treatments for hemophiliacs in utero. In this study, in order to transplacentally deliver FIX from pregnant mice to their fetuses, an improved adenovirus (Ad) vector expressing human FIX fused with the IgG Fc domain (FIX Fc fusion protein), which plays a crucial role in neonatal Fc receptor (FcRn)-mediated transcytosis across the placenta, was intravenously administered to E13.5 pregnant mice. Significant levels of FIX Fc fusion protein were detected in 0-day-old newborn mice whose mothers were administered an Ad vector expressing FIX Fc fusion protein. Wild-type FIX overexpressed in the pregnant mice was not delivered to the fetuses. Plasma FIX levels in the newborn mice were relatively well correlated with those in their mothers, although transplacental delivery efficiencies of FIX Fc fusion protein were slightly reduced when the FIX Fc fusion protein was highly expressed in the mother mice. Plasma FIX levels in the newborn mice were about 3.6-6.4% of those in their mothers, Transplacental delivery of FIX Fc fusion protein to their fetuses successfully improved the blood clotting ability in the newborn mice.

Efficacy, adherence and persistence of various glucagon-like peptide-1 agonists: nationwide real-life data.

AIM: The management of type 2 diabetes mellitus has advanced in the last two decades since the introduction of glucagon-like peptide-1 receptor agonists (GLP-1RAs). However, multiple factors may interfere with achieving better glycaemic control. This study evaluated the differences between various GLP-1RAs in efficacy, adherence and persistence. MATERIALS AND METHODS: We conducted a retrospective cohort study using the electronic medical database from Clalit Health Services. Adults with type 2 diabetes mellitus who purchased any GLP-1RA between 2009 and 2021 were included. The Index Date was defined as the date of the first purchase of any GLP-1RA. We evaluated the adherence, persistence and glycaemic control after GLP-1RAs initiation. Baseline glycaemic and post-treatment glycaemic controls were analysed. RESULTS: In total, 70 654 patients were included. The mean age was 11.7 ± 60.4, and 51% were females. A significant reduction in glycated haemoglobin (HbA1c) was observed in all patients who received GLP-1RAs. However, the percentage of changes in the HbA1c was higher among weekly GLP-1RA than daily initiators (14.6% vs. 10.2%, p < 0.001). The proportion of subjects with any decrease in HbA1c was higher among the once-weekly compared with the daily dose (82.4% vs. 74.7%) and mainly patients initiated semaglutide or dulaglutide, with 16.0% and 14.7% reduction. The frequency of good adherence (the proportion of days covered ≥80%) was significantly higher among the weekly group odds ratio = 1.25 (95% confidence interval 1.21-1.28). Good adherence was reported in older age, female gender, Jewish ethnicity and high socio-economic status (p < 0.001). CONCLUSIONS: Weekly GLP-1RAs initiators were more adherent, persistent to therapy and achieved better glycaemic control. Epidemiological variables might play a role in achieving this goal.

SARS-CoV-2 infection prior to vaccination amplifies Fc-mediated humoral profiles in an age-dependent manner.

Immunity acquired by vaccination following infection, termed hybrid immunity, has been shown to confer enhanced protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by enhancing the breadth and potency of immune responses. Here, we assess Fc-mediated humoral profiles in hybrid immunity and their association with age and vaccine type. Participants are divided into three groups: infection only, vaccination only, and vaccination following infection (i.e., hybrid immunity). Using systems serology, we profile humoral immune responses against spikes and subdomains of SARS-CoV-2 variants. We find that hybrid immunity is characterized by superior Fc receptor binding and natural killer (NK) cell-, neutrophil-, and complement-activating antibodies, which is higher than what can be expected from the sum of the vaccination and infection. These differences between hybrid immunity and vaccine-induced immunity are more pronounced in aged adults, especially for immunoglobulin (Ig)G1, IgG2, and Fcγ receptor-binding antibodies. Our findings suggest that vaccination strategies that aim to mimic hybrid immunity should consider age as an important modifier.

Dulaglutide rescues the elevated testicular dysfunction in a mouse model of high-fat diet-induced obesity.

Obesity is a well-known risk factor for testicular function; however, dulaglutide's effect on the testis in obesity has received little attention. Currently, clinicians prescribe the antidiabetic drug dulaglutide only off-label for weight management in non-diabetics. Investigating the impact of this novel compound on obesity is critical for determining whether it has any disruptive effects on testicular cells. We used a well-known animal model of high-fat diet-induced obesity in this investigation, and testicular dysfunction was determined by sperm DNA damage, spermatocyte chromosomal abnormalities, and spermiogram analysis. Following a 12-week high-fat diet challenge, mice were randomly assigned to dulaglutide (0.6 mg/kg/day) or saline treatments for five weeks. Testes and sperm cells were collected 24 h after the last dulaglutide injection. Untreated obese mice had a lower testes/body weight ratio, more sperm DNA damage, diakinesis-metaphase I chromosomal abnormalities, a lower sperm count/motility, more cell morphological defects, and an altered testicular redox balance. In obese mice, dulaglutide injection efficiently restored all disturbed parameters to their control levels. Dulaglutide injection into healthy mice exhibited no significant harmful effects at the applied regimen. As a result, we infer that dulaglutide therapy might bring obese men additional benefits by recovering testicular dysfunction induced by obesity.

Engineering and Characterization of a Long-Half-Life Relaxin Receptor RXFP1 Agonist.

Relaxin-2 is a peptide hormone with important roles in human cardiovascular and reproductive biology. Its ability to activate cellular responses such as vasodilation, angiogenesis, and anti-inflammatory and antifibrotic effects has led to significant interest in using relaxin-2 as a therapeutic for heart failure and several fibrotic conditions. However, recombinant relaxin-2 has a very short serum half-life, limiting its clinical applications. Here, we present protein engineering efforts targeting the relaxin-2 hormone in order to increase its serum half-life while maintaining its ability to activate the G protein-coupled receptor RXFP1. To achieve this, we optimized a fusion between relaxin-2 and an antibody Fc fragment, generating a version of the hormone with a circulating half-life of around 3 to 5 days in mice while retaining potent agonist activity at the RXFP1 receptor both in vitro and in vivo.

Fc-engineered antibodies promote neutrophil-dependent control of Mycobacterium tuberculosis.

Mounting evidence indicates that antibodies can contribute towards control of tuberculosis (TB). However, the underlying mechanisms of humoral immune protection and whether antibodies can be exploited in therapeutic strategies to combat TB are relatively understudied. Here we engineered the receptor-binding Fc (fragment crystallizable) region of an antibody recognizing the Mycobacterium tuberculosis (Mtb) capsule, to define antibody Fc-mediated mechanism(s) of Mtb restriction. We generated 52 Fc variants that either promote or inhibit specific antibody effector functions, rationally building antibodies with enhanced capacity to promote Mtb restriction in a human whole-blood model of infection. While there is likely no singular Fc profile that universally drives control of Mtb, here we found that several Fc-engineered antibodies drove Mtb restriction in a neutrophil-dependent manner. Single-cell RNA sequencing analysis showed that a restrictive Fc-engineered antibody promoted neutrophil survival and expression of cell-intrinsic antimicrobial programs. These data show the potential of Fc-engineered antibodies as therapeutics able to harness the protective functions of neutrophils to promote control of TB.

Deciphering GB1's Single Mutational Landscape: Insights from MuMi Analysis.

Mutational changes that affect the binding of the C2 fragment of Streptococcal protein G (GB1) to the Fc domain of human IgG (IgG-Fc) have been extensively studied using deep mutational scanning (DMS), and the binding affinity of all single mutations has been measured experimentally in the literature. To investigate the underlying molecular basis, we perform in silico mutational scanning for all possible single mutations, along with 2 µs-long molecular dynamics (WT-MD) of the wild-type (WT) GB1 in both unbound and IgG-Fc bound forms. We compute the hydrogen bonds between GB1 and IgG-Fc in WT-MD to identify the dominant hydrogen bonds for binding, which we then assess in conformations produced by Mutation and Minimization (MuMi) to explain the fitness landscape of GB1 and IgG-Fc binding. Furthermore, we analyze MuMi and WT-MD to investigate the dynamics of binding, focusing on the relative solvent accessibility of residues and the probability of residues being located at the binding interface. With these analyses, we explain the interactions between GB1 and IgG-Fc and display the structural features of binding. In sum, our findings highlight the potential of MuMi as a reliable and computationally efficient tool for predicting protein fitness landscapes, offering significant advantages over traditional methods. The methodologies and results presented in this study pave the way for improved predictive accuracy in protein stability and interaction studies, which are crucial for advancements in drug design and synthetic biology.

Pharmacokinetics, pharmacodynamics, and safety of GS-3583, a FLT3 agonist Fc fusion protein, from single-ascending-dose phase I study in healthy participants.

Conventional dendritic cells subtype 1 (cDC1) play a vital role in the priming and expansion of tumor-specific CD8+ T cells and their recruitment to tumor microenvironment. However, cDC1s are often underrepresented in the microenvironment. Systemic administration of Fms-like tyrosine kinase 3 ligand, a hematopoietic growth factor that binds to FLT3 on myeloid and lymphoid progenitor cells, leads to cDC1 expansion in the periphery and recruitment into the microenvironment. FLT3 pathway stimulation using GS-3583, a novel FLT3 agonistic Fc fusion protein, has the potential to promote T-cell mediated antitumor activity. This was a first-in-human, placebo-controlled study of GS-3583 in healthy participants to evaluate the safety, pharmacokinetics (PK), and pharmacodynamic (PD) of escalating single doses (75-2000 µg) of GS-3583. Each dose cohort enrolled 8-12 healthy participants who received GS-3583 or placebo as single IV infusion at 3:1 ratio. As part of the PD evaluation, the changes in the number of cDC1 cells were investigated. GS-3583 was well-tolerated in healthy participants up to the highest evaluated dose (2000 µg). There have been no serious or grade III or higher adverse events. PK analysis suggested a dose-dependent increase in GS-3583 exposure with target-mediated disposition characteristics at low doses. PD analysis shows that administration of GS-3583 resulted in transient, dose-dependent increases in cDC1 cells that returned to baseline within 3 weeks of drug administration. The pharmacokinetics and pharmacodynamics of GS-3583 following single dosing were characterized in this study which enabled subsequent phase Ib assessments in patients with advanced solid tumors.