IgG Fc Fusion Protein Research Articles

742-P: Phase 1 Study of Safety, Tolerability, PK, and PD of Once-Weekly Basal Insulin Fc (BIF) in Japanese Patients with T2DM

BIF (LY3209590) is a novel, once weekly, long-acting IgG Fc-fusion protein that is being assessed for the treatment of diabetes mellitus. This phase 1, multiple-site, randomized, single-dose, dose-escalation study of BIF included 3 cohorts. Cohorts 1 and 2 each included 12 Japanese insulin-naïve patients with T2DM who were randomized double-blind to receive a single SC dose (dose 1 in cohort 1; dose 2 in cohort 2) of BIF (N=8) or placebo (N=4). Cohort 3 included 7 Japanese patients with T2DM previously treated with basal insulin, with or without a stable dose of up to 2 prespecified types of oral anti-hyperglycemic medications, who received a single SC dose of open-label BIF at dose 3. The primary objective was to investigate safety and tolerability. Secondary objectives included characterization of the PK and PD. ClinicalTrials.gov identifier: NCT03603704. Four patients (12.9%; 1 patient in each treatment group) reported a treatment-emergent adverse event; all were mild and none were related to study drug. Six patients (19.4%) reported hypoglycemic events (most events were with dose 3 and none were severe); each event was self-treatable and resulted in a prompt recovery. PK analyses showed BIF exposure after administration of each dose increased with dose, and tmax was observed by approximately day 4 at all 3 doses. The geometric mean t1/2 estimates ranged from 11 to 16 days across doses. All 3 doses decreased fasting glucose from baseline to day 15. Fasting glucose decreased from day 2 until approximately day 7 or 8 at all doses followed by a trend of fasting glucose returning to baseline. Compared with placebo, BIF at doses 1 and 2 significantly decreased (p<0.1) fasting glucose levels from baseline at most time points between days 3 and 15. In Japanese patients with T2DM, single SC doses of BIF were well tolerated, and the PK and PD of BIF allows weekly dosing. Disclosure K. Ohwaki: Employee; Self; Eli Lilly Japan K. K., Stock/Shareholder; Self; Eli Lilly and Company. K. Furihata: None. R. Nasu: Employee; Self; Eli Lilly Japan K. K. T. Oura: Employee; Self; Eli Lilly Japan K. K., Stock/Shareholder; Self; Eli Lilly and Company. M. Imori: Employee; Self; Eli Lilly Japan K. K. Funding Eli Lilly and Company

重组人Ⅱ型肿瘤坏死因子受体-抗体融合蛋白联合糖皮质激素治疗急性泛发性发疹性脓疱病一例

重组人Ⅱ型肿瘤坏死因子受体-抗体融合蛋白联合糖皮质激素治疗急性泛发性发疹性脓疱病一例

Basal Insulin Fc (BIF), A Novel Insulin Suited For Once Weekly Dosing For The Treatment of Patients With Diabetes Mellitus

Abstract An optimally designed once-weekly basal insulin with reduced day-to-day pharmacokinetic (PK)/pharmacodynamic (PD) fluctuations compared to daily basal insulins should have a low peak-to-trough ratio at steady state. An insulin with this flat profile could improve glycemic efficacy while reducing hypoglycemia. Basal insulin Fc (BIF; LY3209590) is an insulin IgG Fc-fusion protein developed for once weekly dosing. The results of the first in-human studies of BIF assessing the safety, tolerability, PK, and PD following single and once-weekly doses of BIF are presented below. The single ascending dose (SAD) study assessed 6 dose levels of BIF, administered to healthy subjects or patients with type 2 diabetes mellitus (T2DM). In the multiple ascending dose (MAD) study, patients with T2DM previously treated with basal insulin received a one-time loading dose at Week 1 followed by a once-weekly maintenance dose for 5 additional weeks. Four fixed-dose maintenance dose levels were evaluated. The loading dose was implemented to rapidly achieve steady-state BIF concentration at each dose level. Patients with T2DM in the control group received insulin glargine at the same dose as their previous daily insulin dose. Key objectives were safety and tolerability, PK endpoints with a focus on half-life and peak-to-trough ratio at steady state, and finally PD measures. The SAD study included 57 patients with T2DM and 16 healthy subjects. The mean age of patients with T2DM was 58.4 years and the mean BMI was 29.5±3.2 kg/m2. The mean age of healthy subjects was 35.8±9.3 years and the mean BMI was 26.1±3.1 kg/m2. In the SAD study, BIF demonstrated linear PK with dose-proportional concentration profiles in healthy subjects and patients with T2DM. The maximum BIF concentration was reached on Day 4. BIF had a mean half-life of approximately 17 days in patients with T2DM. Following a single dose of BIF, a decrease in FBG was observed on Day 1 and was sustained until at least 5 days post-dose. In the MAD study in 33 subjects with T2DM aged between 40 and 69 years, BIF demonstrated a nearly peak-less PK profile over a one-week dosing interval with a peak-to-trough ratio of ~1.1 at steady state. This flat profile is in contrast to insulin glargine. Following once-daily dosing, insulin glargine has a daily peak-to-trough ratio of ~2. Over the 6-week duration, the 7-point glucose profiles remained constant over time and were similar to insulin glargine profiles. BIF was well tolerated and had a safety profile similar to insulin glargine-treated subjects. In particular, hypoglycemia rates were also similar to insulin glargine and there was no occurrence of hypoglycemic events with cognitive dysfunction. These data support continued development of BIF as a once-weekly insulin treatment of diabetes mellitus.

Once Weekly Basal Insulin Fc (BIF) is Safe and Efficacious in Patients with Type 2 Diabetes Mellitus (T2DM) Previously Treated With Basal Insulin

Basal insulin Fc (BIF; LY3209590) is a novel, once-weekly, long-acting IgG Fc-fusion protein that is being assessed for the treatment of diabetes mellitus. The presented study evaluated the safety and efficacy of BIF compared to insulin degludec over 32 weeks in patients with T2DM previously treated with oral antidiabetic drugs and a basal insulin. The study design included 2 different dosing algorithms for BIF (BIF-A1 and BIF-A2) with two different fasting glucose (FG) targets of ≤140 mg/dL (BIF-A1) and ≤120 mg/dL (BIF-A2). Insulin degludec was titrated to a FG target of ≤100mg/dL using a modified Riddle treat-to-target algorithm. Study participants (N=399) were randomized in a 1:1:1 ratio to 1 of 3 parallel treatment groups. The average age of participants was 60.2 years, baseline HbA1c was 8.1% and duration of diabetes 14.7 years. There were no statistically significant differences in demographics or baseline characteristics across the 3 treatment groups. Both BIF groups achieved non-inferiority (non-inferiority margin = 0.4%) for the primary endpoint of HbA1c change from baseline to Week 32 with a mean±SE reduction for BIF-A1, BIF-A2 and insulin degludec of 0.6±0.1%, 0.6±0.1% and 0.7±0.1%, respectively. In line with the different fasting serum glucose (FSG) targets, insulin degludec achieved greater FSG lowering from baseline as compared to the BIF arms. Similarly, both BIF dosing groups showed significantly fewer hypoglycemic events compared to insulin degludec (all documented events as well as nocturnal events) when assessing events ≤70 mg/dL (3.9 mmol/L). Hypoglycemic events <54 mg/dL (3.0 mmol/L - all documented events as well as nocturnal events) were not significantly different between the three dosing groups. Two severe hypoglycemic events were reported in BIF-A2. The reported treatment-emergent adverse events and serious adverse events were balanced across the 3 treatment groups. Both BIF groups had a statistically significantly smaller increase in body weight compared to insulin degludec from baseline to Week 32. In summary, BIF, when administered weekly according to either dosing algorithm, was noninferior to insulin degludec for glycemic control as measured by change in HbA1c after 32 weeks with a lower rate of documented and nocturnal hypoglycemia ≤70 mg/dL and less weight gain. Additionally, no safety signals were detected. While higher FG targets were chosen in this first Phase 2 study with BIF, the safety and tolerability results allow assessment of lower target glucose ranges in future trials. The results from this study support continued development of BIF as a once-weekly insulin treatment of diabetes mellitus.

Characterization of a TNFR2-Selective Agonistic TNF-α Mutant and Its Derivatives as an Optimal Regulatory T Cell Expander.

Regulatory T cells (Tregs) are a subpopulation of lymphocytes that play a role in suppressing and regulating immune responses. Recently, it was suggested that controlling the functions and activities of Tregs might be applicable to the treatment of human diseases such as autoimmune diseases, organ transplant rejection, and graft-versus-host disease. TNF receptor type 2 (TNFR2) is a target molecule that modulates Treg functions. In this study, we investigated the role of TNFR2 signaling in the differentiation and activation of mouse Tregs. We previously reported the generation of a TNFR2-selective agonist TNF mutant, termed R2agoTNF, by using our unique cytokine modification method based on phage display. R2agoTNF activates cell signaling via mouse TNFR2. In this study, we evaluated the efficacy of R2agoTNF for the proliferation and activation of Tregs in mice. R2agoTNF expanded and activated mouse CD4+CD25+ Tregs ex vivo. The structural optimization of R2agoTNF by internal cross-linking or IgG-Fc fusion selectively and effectively enhanced Treg expansion in vivo. Furthermore, the IgG-Fc fusion protein suppressed skin-contact hypersensitivity reactions in mice. TNFR2 agonists are expected to be new Treg expanders.

Research in Brief

RSLV-132, a biological drug consisting of an RNase–IgG1 Fc fusion protein, improved severe fatigue in patients with primary Sjögren's syndrome in a phase 2 randomised trial. James Posada and colleagues randomly assigned 30 patients (3:1) to receive 10 mg/kg intravenous RSLV-132 (n=22) or placebo (n=8) for 12 weeks. Patients in the RSLV-132 group achieved clinically meaningful improvements on the EULAR Sjögren's syndrome patient reported index (ESSPRI), FACIT fatigue, profile of fatigue, and the digit symbol substitution test, which correlated with increases in interferon-inducible gene expression (the primary outcome) via an unclear mechanism.

Treatment of intestinal graft-versus-host disease with unrelated donor fecal microbiota transplantation capsules

Introduction:Fecal microbiota transplantation (FMT), administering fecal suspensions via a nasoduodenal tube, has achieved a promising effect in the treatment of intestinal graft-versus-host disease (GvHD) in some pilot studies. In this study, oral FMT capsules from unrelated donor were used for the first time in the treatment of intestinal GvHD. Patient concerns: A 31-year-old male who was diagnosed as “myelodysplastic syndromes with excess blasts II” (intermediate risk 2 of international prognostic scoring system) received human leukocyte antigen -matched sibling donor allogeneic hematopoietic stem cell transplantation. The patient developed diarrhea, vomiting, and bloody stool on 28 days after transplantation.Diagnosis:Intestinal acute GvHD was diagnosed clinically with histological confirmation by colonoscopy and pathological biopsy.Interventions:This patient was treated with first cycle of oral FMT capsules after failure to initial treatment of methylprednisolone (2 mg/kg/d) combined with recombinant human tumor necrosis factor–α receptorII: IgG Fc fusion protein (25 mg, biw). The symptoms of intestinal GvHD were relieved but recurred 11 days later. Second cycle of oral FMT capsules was carried out.Outcomes:After 2 cycles of fecal bacteria transplantation, intestinal GvHD was gradually controlled and did not recur again during the 2-month follow-up. The diversity and structure of the intestinal flora after FMT was closer to that of healthy donors than that before.Conclusion:Our case showed oral FMT capsules could be used as a treatment option for corticosteroid refractory intestinal GvHD. Further studies are warranted to assess the clinical efficacy and safety of oral FMT capsules in the treatment of intestinal GvHD.Rationale:Fecal microbiota transplantation (FMT), administering fecal suspensions via a nasoduodenal tube, has achieved a promising effect in the treatment of intestinal graft-versus-host disease (GvHD) in some pilot studies. In this study, oral FMT capsules from unrelated donor were used for the first time in the treatment of intestinal GvHD.Patient concerns:A 31-year-old male who was diagnosed as “myelodysplastic syndromes with excess blasts II” (intermediate risk 2 of international prognostic scoring system) received human leukocyte antigen -matched sibling donor allogeneic hematopoietic stem cell transplantation. The patient developed diarrhea, vomiting, and bloody stool on 28 days after transplantation.Diagnoses:Intestinal acute GvHD was diagnosed clinically with histological confirmation by colonoscopy and pathological biopsy.Interventions:This patient was treated with first cycle of oral FMT capsules after failure to initial treatment of methylprednisolone (2 mg/kg/d) combined with recombinant human tumor necrosis factor–a receptorII: IgG Fc fusion protein (25 mg, biw). The symptoms of intestinal GvHD were relieved but recurred 11 days later. Second cycle of oral FMT capsules was carried out.Outcomes:After 2 cycles of fecal bacteria transplantation, intestinal GvHD was gradually controlled and did not recur again during the 2-month follow-up. The diversity and structure of the intestinal flora after FMT was closer to that of healthy donors than that before.Conclusion: Our case showed oral FMT capsules could be used as a treatment option for corticosteroid refractory intestinal GvHD. Further studies are warranted to assess the clinical efficacy and safety of oral FMT capsules in the treatment of intestinal GvHD.Lessons:There is still a possibility of recurrence after the treatment of GvHD with capsule fecal microbiota transplantation. How to optimize the dosage and treatment course of fecal microbiota capsule administration needs further exploration.

Clinical study of anti-human T cell porcine immunoglobulin with recombinant human tumor necrosis factor-α receptor II: IgG Fc in the treatment of 35 cases of grade III/IV acute graft-versus-host disease after allo-HSCT

目的评估抗人T细胞猪免疫球蛋白（P-ATG）联合重组人Ⅱ型肿瘤坏死因子受体-抗体融合蛋白（益赛普）治疗Ⅲ/Ⅳ度急性移植物抗宿主病（aGVHD）的疗效及安全性。方法对接受P-ATG（5 mg·kg−1·d−1×3～5 d，序贯5 mg/kg隔日1次～每周2次）联合益赛普（25 mg每周2次，儿童剂量减半）方案治疗的35例异基因造血干细胞移植（allo-HSCT）后合并Ⅲ/Ⅳ度aGVHD患者进行回顾性分析。结果①35例Ⅲ/Ⅳ度aGVHD患者中，男21例，女14例，中位年龄10（3～54）岁。急性髓系白血病（AML）19例，急性淋巴细胞白血病（ALL）13例，重型再生障碍性贫血（SAA）、骨髓增生异常综合征（MDS）、混合表型急性白血病（MPAL）各1例。②治疗28 d疗效评估：完全缓解（CR）12例（34.3％），部分缓解（PR）18例（51.4％），总有效率为85.7％（30/35），Ⅲ度aGVHD组总有效率高于Ⅳ度aGVHD组［100％（19/19）对68.8％（11/16），P＝0.004］。③治疗56 d疗效评估：CR 22例（62.9％），PR 5例（14.3％），总有效率为77.2％（27/35），Ⅲ度aGVHD组总有效率高于Ⅳ度aGVHD组［89.5％（17/19）对62.5％（10/16），P＝0.009］。④不良反应：35例患者输注P-ATG过程中均为发生发热、寒战、皮疹等不良反应，亦无明显肝肾功能损害发生。巨细胞病毒、EB病毒再激活率分别为77.1％（27/35）、22.9％（8/35），细菌感染发生率为48.6％（17/35）。⑤中位随访时间为13（1～55）个月，移植后1、2年的总生存率分别为（68.1±8.0）％、（64.3±8.4）％，Ⅲ度aGVHD组移植后1年总生存率高于Ⅳ度aGVHD组［（84.2±8.4）％对（47.6±13.1）％，χ2＝3.38，P＝0.05］。结论P-ATG联合重组人Ⅱ型肿瘤坏死因子受体-抗体融合蛋白治疗allo-HSCT后Ⅲ/Ⅳ度aGVHD有较好的疗效和安全性。

Signal Peptide Optimization to Prevent N-terminal Truncation of Glucagon Like Peptide-1/IgG-Fc Fusion Protein

Dulaglutide (glucagon like peptide-1/IgG-Fc fusion protein, GLP-1-Fc) is a long lasting GLP-1 agonist, which consists of two arms of GLP-1 moieties fused to IgG Fc fragment. Dulaglutide is a safe and effective medication for type 2 diabetes. In an attempt to develop a biosimilar version of dulaglutide, we found that up to 75% of GLP-1-Fc displayed N-terminal truncations in one or both GLP-1 arms. We proposed that the N-terminal heterogeneity was caused by mis-cleavage of signal peptide and solved this problem through signal peptide optimization. Murine immunoglobulin kappa light chain signal peptide (KASP) significantly improves GLP-1-Fc N-terminal integrity and homogeneity. 92.8–95.7% of GLP-1-Fc molecules directed by KASP contain intact N-terminus. The productivity of GLP-1-Fc could reach 2.2 g/L in shaking flask fed batch culture. KASP is an optimal signal peptide for GLP-1-Fc expression in Chinese hamster ovary (CHO) cells.

重组人Ⅱ型肿瘤坏死因子受体-抗体融合蛋白联合糖皮质激素治疗一例中毒性表皮坏死松解症

重组人Ⅱ型肿瘤坏死因子受体-抗体融合蛋白联合糖皮质激素治疗一例中毒性表皮坏死松解症

重组人Ⅱ型肿瘤坏死因子受体-抗体融合蛋白治疗中毒性表皮坏死松解症的临床疗效观察

重组人Ⅱ型肿瘤坏死因子受体-抗体融合蛋白治疗中毒性表皮坏死松解症的临床疗效观察

QL0902, a proposed etanercept biosimilar: pharmacokinetic and immunogenicity profile to its reference product in healthy Chinese male subjects

ABSTRACT Objectives: To study the pharmacokinetics, safety and immunogenicity of Recombinant Human Tumor Necrosis Factor-α Receptor II: IgG Fc Fusion Protein for Injection (QL0902) and evaluate the pharmacokinetic similarity between QL0902 and reference Etanercept in healthy male subjects. Methods: A randomized, double-blinded, single-dose, two-period, two-sequence and crossover study was conducted in healthy males. Sixty-eight subjects were randomized at 1:1 ratio to receive a single 50-mg subcutaneous injection of QL0902 or reference Etanercept. The statistical analysis was conducted by SAS Enterprise Guide statistical software. Results: The main pharmacokinetic parameters of QL0902 were as follows: AUC0-∞ was 461861.60 ± 126861.42 (h*ng/mL), AUC0-t was 453304.68 ± 124424.94 (h*ng/mL), Cmax was (2634.03 ± 833.82)ng/mL; The main pharmacokinetic parameters of reference Etanercept were as follows: AUC0-∞ was 537977.72 ± 153295.70 (h*ng/mL), AUC0-t was 528817.19 ± 150910.05 (h*ng/mL), Cmax was (2874.21 ± 822.31) ng/mL. Conclusions: After a single subcutaneous injection of QL0902 and reference Etanercept, the 90% confidence intervals of the ratios of AUC0-∞, AUC0-t, Cmax of healthy subjects were respectively 82.76% to 89.15%, 82.66% to 89.00%, 87.30% to 93.95%, which were between 80.00% and 125.00%. It indicts that their pharmacokinetic characteristics were similar. No serious adverse events occurred and the immunogenicity of QL0902 was lower. Trial Registration: The trial is registered at www.chictr.org.cn (ChiCTR1900023 437).

Etanercept biosimilar (recombinant human tumor necrosis factor-α receptor II: IgG Fc fusion protein) and methotrexate combination therapy in Chinese patients with moderate-to-severe plaque psoriasis: a multicentre, randomized, double-blind, placebo-controlled trial.

Etanercept biosimilar recombinant human tumour necrosis factor-α receptor II: IgG Fc fusion protein (rhTNFR-Fc, trade name Yisaipu) has shown good efficacy in the treatment of moderate-to-severe plaque psoriasis. To compare the efficacy and safety of rhTNFR-Fc plus methotrexate (MTX) and rhTNFR-Fc plus placebo in Chinese patients with moderate-to-severe plaque psoriasis. In this multicentre, randomized, placebo-controlled trial, patients with moderate-to-severe plaque psoriasis were enrolled and randomly assigned in a 1:1 ratio to receive rhTNFR-Fc plus MTX or rhTNFR-Fc plus placebo. The primary endpoint was the proportion of patients achieving Psoriasis Area and Severity Index improvement of at least 75% (PASI 75) from baseline at week 24. Adverse events (AEs) were recorded to evaluate safety. Efficacy analysis was performed using the intent-to-treat principle. A total of 466 patients were enrolled and randomly received rhTNFR-Fc plus MTX (combination group, n = 233) or rhTNFR-Fc plus placebo (monotherapy group, n = 233). PASI 75 at week 24 was significantly higher in the combination group than in the monotherapy group (81.86% vs. 65.50%, p < 0.001). Similar results were observed in other PASI improvement scores at week 12 [PASI 75, 62.39% vs. 44.54% (p < 0.001); PASI 50, 87.17% vs. 75.55% (p = 0.001); and PASI 90, 34.07% vs. 18.78% (p < 0.001)] and week 24 [PASI 50, 92.48% vs. 85.59% (p = 0.019); and PASI 90, 64.16% vs. 42.36% (p < 0.001)]. Significantly more patients had a static Physicians' Global Assessment of clear or almost clear in the combination group than in the monotherapy group at week 12 (26.46% vs. 12.50%, p < 0.001) and week 24 (62.38% vs. 40.83%, p < 0.001). The most common AEs in the two groups were upper respiratory tract infection and abnormal liver function. The combination therapy of rhTNFR-Fc plus MTX was an effective therapy for moderate-to-severe plaque psoriasis with an acceptable safety and tolerability profile, indicating that it was feasible and well tolerated for patients.

Clinical effect of recombinant human tumor necrosis factor-α receptor II: IgG Fc fusion protein combined with sodium hyaluronate intra-articular injection in the treatment of rheumatoid arthritis

Objective To investigate the clinical efficacy of recombinant human tumor necrosis factor-α receptor II: IgG Fc fusion protein combined with sodium hyaluronate in the treatment of rheumatoid arthritis (RA). Methods Forty adult RA patients (12 males, 28 females) aged from 36 to 79 were selected in Department of Rheumatology of the Second People′s hospital of Datong from February 2016 to February 2018.The patients were randomly divided into the observation group and the control group according to the digital table, with 20 cases in each group.The observation group was treated by intra-articular injection of recombinant human tumor necrosis factor-α receptor II: IgG Fc fusion protein and sodium hyaluronate, and the control group was only treated with recombinant human tumor necrosis factor-α receptor II: IgG Fc fusion protein.The joint swelling, joint pain, joint mobility, morning stiffness, X-ray grade and total effective rate of the two groups were statistically analyzed before and after treatment. Results Before treatment, there were no statistically significant differences in joint swelling, joint pain, joint mobility, morning stiffness, clinical score and X-ray grade between the two groups (all P>0.05). After treatment, the symptoms and signs of the two groups were obviously improved.The joint pain, joint pressure pain, joint activity, morning stiffness and clinical score in the observation group were (1.2±1.2)points, (0.8±0.7)points, (0.5±0.4)points, (0.7±0.7)points and (4.5±2.6)points, respetively, which were significantly better than those in the control group [(2.2±1.4)points, (1.5±0.9)points, (1.5±0.9)points, (1.5±0.6)points and (8.6±4.6)points, U=125, 111, 68, 89 and 97, all P<0.05]. The total effective rate of the observation group was 100% (20/20), while that of the control group was 75% (15/20), there was statistically significant difference between the two groups (χ2=14.10, P<0.01). Conclusion The injection of recombinant human tumor necrosis factor-α receptor II: IgG Fc fusion protein combined with sodium hyaluronate in the treatment of RA can effectively improve the clinical symptoms of RA patients, and it is more effective than single use.It is worthy of popularizing in clinic. Key words: Arthritis, rheumatoid; Tumor necrosis factor receptor-associated peptides and proteins; Hyaluronic acid; Injections, intra-articular; Randomized controlled trial

In vivo characterization of RC28-E, a fusion protein targeting VEGF and bFGF: Pharmacokinetics and ocular distribution in primates

Administration of RC28-E, a VEGF/bFGF dual decoy receptor (IgG1 Fc-fusion protein), have shown relative therapeutic value in ocular in vivo models, including laser-induced choroidal neovascularization (CNV) in monkeys and streptozotocin (STZ)-induced diabetic retinopathy (DR) in rats. In the present study, we have elucidated the pharmacokinetics profiles of RC28-E at the systemic, vitreous and aqueous humor after administration in a primate model (Macaca fascicularis). Moreover, here we tease out the ocular tissue distribution of RC28-E after intravitreal administration, and we also determine the systemic bioavailability after both intravitreal and intravenous administration. Our results show that RC28-E is rapidly and well-distributed into ocular tissues after intravitreal administration. Drug exposure in choroid and retina was approximately one-quarter and one-twelfth of that in vitreous humor, while its half-life in vitreous and aqueous humor were well-sustained (3.3 and 3.0 days). Remarkably, RC28-E could cross the blood-ocular barrier, and the systemic bioavailability of RC28-E was ~25%. No drug accumulation after multiple administration was noticed, but low titers of antibody produce against RC28-E were detected. Overall, RC28-E exhibited high clinical value due to adequate pharmacokinetic profiling, safety and efficacy.

Heterogeneity of antigen specificity between HLA-A*02:01 and other frequent Chinese HLA-A2 subtypes detected by a modified autologous lymphocyte-monocyte coculture

HLA-A2 is the most common serological HLA type among all ethnic groups. Through advances in DNA typing, more than 800 subtypes of HLA-A2 have been identified, and the existence of heterogeneity of antigen specificity among the HLA-A2 subtypes has been suggested by retrospective analyses of allogeneic transplantation patients and by studies of antigen amino acid structure. However, prior to this study, the antigenicity of a given subtype or the mismatch extent between two given subtypes could not be studied in vitro. Here, we used a modified autologous lymphocyte-monocyte coculture method to reveal heterogeneity of antigen specificity among HLA-A2 subtypes. The coculture was set up with HLA-A2 (non-A*02:01) lymphocytes and monocytes, and the monocytes were coated with an HLA-A*02:01/IgG1-Fc fusion protein (dimer) by high-affinity binding of the IgG1-Fc to FcgRI. Lymphocyte proliferation following coculture indicated that HLA-A*02:01 showed antigenicity against the HLA-A2 (non-A*02:01) subtype. Among the most frequent HLA-A2 subtypes in the Chinese population (HLA-A*02:01, -A*02:03, -A*02:06 and -A*02:07), we identified significant -A*02:01 antigenicity for T cells from -A*02:03 or -A*02:06 but not -A*02:07 individuals. Our findings were consistent with retrospective studies of allograft patients with a limited number of involved subtypes, indicating that this modified coculture method provides a practical and reliable means to study the antigenicity of HLA allele subtypes in vitro.

Skint8, a Novel B7 Family–Related Molecule, Negatively Regulates T Cell Responses

Immune responses are tightly controlled by T cell costimulatory and coinhibitory molecules. In this study, we identify Skint8 as a new member of the T cell coinhibitory group, whose extracellular domains share significant homology with existing B7 family members. Skint8 mRNA is expressed in resting and activated B cells, monocytes, and CD4 T cells. The Skint8 putative receptor is expressed on activated CD4 and CD8 T cells, B cells, monocytes and dendritic cells. Recombinant Skint8-IgG Fc fusion protein inhibits T cell proliferation, activation, and cytokine production in vitro. In vivo administration of Skint8-IgG Fc reduces T cell activation and alleviates experimental autoimmune encephalomyelitis in mice. The findings broaden our understanding of the regulation of immune responses and may have implications for treating immune-related diseases.

A genetically engineered Fc-binding amphiphilic polypeptide for congregating antibodies in vivo

We report herein an affinity-based hydrogel used in creating subcutaneous depots of antibodies in vivo. The biomaterials design centered on pG_EAK, a polypeptide we designed and expressed in E. coli. The sequence consists of a truncated protein G (pG) genetically fused with repeats of the amphiphilic sequence AEAEAKAK (“EAK”). Capture of IgG was demonstrated in vitro in gels prepared from admixing pG_EAK and EAK (“pG_EAK/EAK gel”). The binding affinities and kinetics of pG for IgG were recapitulated in the pG_EAK polypeptide. Injecting IgG antibodies formulated with pG_EAK/EAK gel into subcutaneous space resulted in retention of the antibodies at the site for at least six days, whereas only signal at background levels was detected in grafts injected with IgG formulated in saline or diffusion-driven gel. The local retention of IgG in pG_EAK/EAK gel was correlated with limited distribution of the antibody in liver, spleen and lymph nodes, in contrast to those injected with antibodies formulated in saline or non-Fc binding EAK gel. In addition, antibodies formulated with pG_EAK/EAK gel and injected in mouse footpads were found to retain at the site for 19 days. As a demonstration of potential bioengineering applications, thymic epithelial cells (TECs), the primary population of thymic stromal cells that are critical for the development of T-lymphocytes, were mixed with pG_EAK/EAK gel formulated with TEC-specific anti-EpCAM antibodies and injected subcutaneously into athymic nude mice. The injected TECs congregated into functional thymic units in vivo, supporting the development of both CD4+ and CD8+ T cells as well as Foxp3+ regulatory T cells in the mice. In conclusion, pG_EAK/EAK gel can be used to retain IgG locally in vivo, and can be tailored as scaffolds for controlling deposition of molecular and/or cellular therapeutics. Statement of significanceThe unique concept of the work centers on the genetic fusion of an Fc-binding domain and a self-assembling domain into a single polypeptide. To our knowledge, such bi-functional peptide has not been reported in the literature. The impact of the work lies in the ability to display IgG antibodies and Fc-fusion proteins of any specificity. The data shown demonstrate the platform can be used to localize IgG in vivo, and can be tailored for controlling deposition of primary thymic epithelial cells (TECs). The results support a biomaterials-based strategy by which TECs can be delivered as functional units to support T-lymphocyte development in vivo. The platform described in the study may serve as an important tool for immune engineering.

Protein Engineering on Human Recombinant Follistatin: Enhancing Pharmacokinetic Characteristics for Therapeutic Application.

Follistatin (FS) is an important regulatory protein, a natural antagonist for transforming growth factor-β family members activin and myostatin. The diverse biologic roles of the activin and myostatin signaling pathways make FS a promising therapeutic target for treating human diseases exhibiting inflammation, fibrosis, and muscle disorders, such as Duchenne muscular dystrophy. However, rapid heparin-mediated hepatic clearance of FS limits its therapeutic potential. We targeted the heparin-binding loop of FS for site-directed mutagenesis to improve clearance parameters. By generating a series of FS variants with one, two, or three negative amino acid substitutions, we demonstrated a direct and proportional relationship between the degree of heparin-binding affinity in vitro and the exposure in vivo. The triple mutation K(76,81,82)E abolished heparin-binding affinity, resulting in ∼20-fold improved in vivo exposure. This triple mutant retains full functional activity and an antibody-like pharmacokinetic profile, and shows a superior developability profile in physical stability and cell productivity compared with FS variants, which substitute the entire heparin-binding loop with alternative sequences. Our surgical approach to mutagenesis should also reduce the immunogenicity risk. To further lower this risk, we introduced a novel glycosylation site into the heparin-binding loop. This hyperglycosylated variant showed a 10-fold improved exposure and decreased clearance in mice compared with an IgG1 Fc fusion protein containing the native FS sequence. Collectively, our data highlight the importance of improving pharmacokinetic properties by manipulating heparin-binding affinity and glycosylation content and provide a valuable guideline to design desirable therapeutic FS molecules.

Pharmacology study of a chimeric decoy receptor trap fusion protein on retina neovascularization by dual blockage of VEGF and FGF-2

BackgroundClinical anti-vascular epithelial growth factor (VEGF) therapy trials faced a major challenge due to upregulated expression of other pro-angiogenic factors, such as fibroblast growth factor-2 (FGF-2). RC28, a novel recombinant dual decoy receptor IgG1 Fc-fusion protein, can block VEGFA and FGF-2 simultaneously. It is designed for the treatment of neovascular age-related macular degeneration and other pathological ocular neovascularization. The present study investigated the prevention efficacy of RC28 on choroidal neovascularization (CNV) in a monkey model and compared to the other mono VEGF antagonists; biodistribution and pharmacokinetics performance were also investigated. MethodsELISA and endothelial cell proliferation, migration, and tubule formation assay evaluated the bioactivity of RC28 in vitro, and an initial comparison was made among the mono target antagonists, Bevacizumab (Avastin), Ranibizumab (Lucentis), Aflibercept (EYLEA), Conbercept (KH902), and Ranibizumab (Lucentis). Laser-induced CNV in monkeys, and both VEGF and FGF-2 serum levels were detected in animals before and after the CNV model were induced. RC28 prevention efficacy was compared to other VEGF antagonists on CNV with respect to the incidence of CNV and several ophthalmic examinations. Ocular and systemic levels of RC28 were analyzed by 89Zr-labeled RC28 after single intravitreal administration for the biodistribution and pharmacokinetic profiles. ResultsRC28 is a unique fusion protein with high affinity to both VEGF and FGF-2, and beneficial to in vitro and in vivo bioactivity. The in vivo pharmacological studies demonstrated that the incidence of CNV formation was largely reduced in RC28 treatment groups with a low dosage as compared to other VEGF antagonist control groups. Furthermore, traces of RC28 were detected as dispersing from eyeballs to the liver after 20 days, and a prolonged half-time pharmacokinetic profile was exhibited.