Pharmacokinetics, Pharmacodynamics, Safety, and Tolerability of Stapokibart in Healthy Volunteers and Adult Subjects with Atopic Dermatitis.

INTRODUCTION: Stapokibart, a novel humanized anti-interleukin (IL)-4 receptor alpha monoclonal antibody, inhibits the signaling of IL-4 and IL-13, which are key drivers of type 2 inflammation in atopic dermatitis (AD). This study aimed to assess the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of stapokibart in a randomized, double-blind, placebo-controlled single ascending dose (SAD) study and a multiple ascending dose (MAD) study. METHODS: The SAD study enrolled 33 healthy male adults aged 18-65 years at a single center. The MAD study enrolled 39 patients with moderate-to-severe AD aged 18-70 years at seven centers. Enrolled subjects were randomized to subcutaneous (SC) doses of stapokibart (75-600 mg) or placebo. Serum thymus and activation-regulated chemokine (TARC) and total immunoglobulin E (IgE) were measured as PD biomarkers for stapokibart. RESULTS: Similar PK characteristics were observed in healthy volunteers and subjects with AD after the initial administration. Stapokibart exhibited non-linear pharmacokinetics in both types of subjects. Following single doses, the mean maximum serum concentration (Cmax) ranged from 5.3 to 63.0 µg/mL, median Tmax ranged from 3.0 to 7.0 days, mean terminal half-life (t1/2z) ranged from 2.39 to 7.43 days, and mean apparent volume (Vz/F) ranged from 3.64 to 6.73 L in healthy subjects. The mean AUC accumulation ratio was 2.29 in subjects with AD after three doses of stapokibart 300 mg administered every 2 weeks. The median serum total IgE and TARC levels on day 43 decreased from baseline by 14.9-25.2% and 48.6-77.0%, respectively, among subjects with AD receiving three doses of stapokibart. No subjects developed grade ≥ 3 adverse events (AEs) or serious AEs or discontinued the study because of AEs. The incidence of AEs was similar between stapokibart and placebo groups. CONCLUSION: Stapokibart showed favorable pharmacokinetics, pharmacodynamics, safety, and tolerability in the SAD and MAD studies. Based on these results, phase II and phase III trials of stapokibart have been performed in subjects with moderate-to-severe AD. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT06161090 (29 November, 2023), NCT04893941 (15 May, 2021).

Preclinical Pharmacokinetics and Pharmacology Study of RC98: A Programmed Cell Death Ligand 1 Monoclonal Antibody in Cynomolgus Monkeys.

INTRODUCTION: RC98 is the monoclonal antibody against Programmed Cell Death Ligand 1 (PD-L1). Relevant reports have confirmed that the influence of PD-L1 expressed by tumor cells on antitumor CD8+ T cell responses is well characterized, but the impact of PD-L1 expressed by immune cells has not been well defined. OBJECTIVE: This study aimed to design a Pharmacokinetics/Pharmacology (PK/PD) study of RC98 in normal cynomolgus monkeys to research the effect on the immune system. METHODS: RC98 and vehicle were administered to cynomolgus monkeys at 15 mg/kg via intravenous infusion once a week for 4 weeks to evaluate the relationship between PK and PD. The pharmacodynamic activity was measured by the PD-L1 receptor occupancy (RO) in CD3+ T cells, A T-cell-dependent antibody response (TDAR), and the concentration of soluble PD-L1. RESULTS: The pharmacokinetic result showed that the exposure from the last administration was lower than that of the first administration, probably due to immunogenicity production. There was a strong correlation between systemic exposure and RO in CD3+ T cells but decreased RO levels after the last dose, which indirectly reflected the activation of T cells. The keyhole limpet hemocyanin (KLH)-induced TDAR in the RC98 group was higher than in the vehicle group. The concentration of soluble PD-L1 had increased feedback with RC98, and the concentration of soluble PD-L1 was maintained at a higher level after multiple doses than before dosing. CONCLUSION: These data indicate that the immune system was clearly activated. In addition, the non-clinical data could provide a basis for its efficacy evaluation in clinical trials.

Bioactivity and Pharmacodynamics of X002, a Follicle-stimulating Hormone-IgG4 Fc Fusion Protein.

Current follicle-stimulating hormone (FSH) drugs meet safety criteria but have suboptimal efficacy, poor patient compliance, and high cost. Alternative FSH-like drugs would help to meet the high market demand. Here, we evaluated X002, an FSH-Fc fusion protein, for bioactivity and half-life in vitro and in vivo. In all cases, the effects of X002 were compared with those of a commercially available short-acting FSH recombinant hormone. First, female Kunming mice (age, 21 to 24 d) were stimulated with pregnant mare serum gonadotropin (PMSG) for 46 h, after which naked oocytes were harvested, treated with X002 or the comparison agent at 37 °C for 4 h, and then evaluated for germinal vesicle breakdown. Second, cumulus-oocyte complexes (COC) were collected from PMSG-stimulated mice and cocultured with X002 or the comparison agent for 14 h; the COC diameters were then measured, and the expression of genes involved in COC expansion were evaluated using quantitative RT-PCR analysis. Third, to assess the pharmacokinetics of X002, female Sprague-Dawley rats (age, 6 to 8 wk) were injected subcutaneously with X002 or the comparison agent; serum samples then were collected at various times and assessed via ELISA. Fourth, to evaluate X002 pharmacodynamics, 26-d-old female Sprague-Dawley rats were treated with X002 or the comparison agent; 84 h later, the rats were stimulated with human chorionic gonadotropin (hCG). At 12 h after hCG injection, euthanasia was performed. Ovaries were removed and weighed, and serum levels of estradiol and progesterone were measured. Finally, to assess superovulation, the oocytes in the fallopian tubes were counted at 108 h after in vivo treatment of rats with X002 or the comparison agent. The data show that X002, a long-acting agent, promoted germinal vesicle breakdown and COC expansion in vitro and in vivo ovarian weight gain and superovulation to a degree similar to the short-acting comparison agent.

Recombinant Human HPS Protects Mice and Nonhuman Primates from Acute Liver Injury.

Acute liver injury shares a common feature of hepatocytes death, immune system disorders, and cellular stress. Hepassocin (HPS) is a hepatokine that has ability to promote hepatocytes proliferation and to protect rats from D-galactose (D-Gal)- or carbon tetrachloride (CCl4)-induced liver injury by stimulating hepatocytes proliferation and preventing the high mortality rate, hepatocyte death, and hepatic inflammation. In this paper, we generated a pharmaceutical-grade recombinant human HPS using mammalian cells expression system and evaluated the effects of HPS administration on the pathogenesis of acute liver injury in monkey and mice. In the model mice of D-galactosamine (D-GalN) plus lipopolysaccharide (LPS)-induced liver injury, HPS treatment significantly reduced hepatocyte death and inflammation response, and consequently attenuated the development of acute liver failure. In the model monkey of D-GalN-induced liver injury, HPS administration promoted hepatocytes proliferation, prevented hepatocyte apoptosis and oxidation stress, and resulted in amelioration of liver injury. Furthermore, the primary pharmacokinetic study showed natural HPS possesses favorable pharmacokinetics; the acute toxicity study indicated no significant changes in behavioral, clinical, or histopathological parameters of HPS-treated mice, implying the clinical potential of HPS. Our results suggest that exogenous HPS has protective effects on acute liver injury in both mice and monkeys. HPS or HPS analogues and mimetics may provide novel drugs for the treatment of acute liver injury.

Development and Validation of a Simoa Assay for Determination of Recombinant Batroxobin in Human Serum.

Recombinant batroxobin (S3101) is a thrombin-like serine protease that binds to fibrinogen or is taken up by the reticuloendothelial system. A literature survey showed no adequate method that could determine sufficient concentrations to evaluate pharmacokinetic parameters for phase I clinical studies. Therefore, a sensitive method is urgently needed to support the clinical pharmacokinetic evaluation of S3101. In this study, a sensitive bioanalytical method was developed and validated, using a Quanterix single molecular array (Simoa) assay. Moreover, to thoroughly assess the platform, enzyme-linked immunosorbent assay and electrochemiluminescence assay were also developed, and their performance was compared with that of this novel technology platform. The assay was validated in compliance with the current guidelines. Measurements with the Simoa assay were precise and accurate, presenting a valid assay range from 6.55 to 4000 pg/mL. The intra- and inter-run accuracy and precision were within -19.3% to 15.3% and 5.5% to 17.0%, respectively. S3101 was stable in human serum for 280 days at -20°C and -70°C, for 2 h prior to pre-treatment and 24 h post pre-treatment at room temperature (22°C-28°C), respectively, and after five and two freeze-thaw cycles at -70°C and -20°C, respectively. The Simoa assay also demonstrated sufficient dilution linearity, assay sensitivity, and parallelism for quantifying S3101 in human serum. The Simoa assay is a sensitive and adequate method for evaluating the pharmacokinetic parameters of S3101 in human serum.

Development and validation of a triplex assay to study an antibody cocktail against Ebola virus in cynomolgus serum.

Background: To support the rapid development of an antibody cocktail against Ebola virus and avoid unnecessary exposure to infectious environments, an automatic and fast turnover triplex assay was developed using Simoa® (Quanterix Corporation, MA, USA). Materials & methods: A robust triplex assay was developed and validated for simultaneous quantification of the antibody cocktail against Ebola virus in cynomolgus serum. Results: The assay had a quantitation range of 78.1-5000 ng/ml. The intra- and interassay precisions (%CV) were within 11.4 and 13.9%, and the accuracies (%RE) were within -10.8 to 6.8%, respectively. Cross-reactivity was evaluated, and the results met the acceptance criteria. Conclusion: The assay was successfully applied to a pharmacokinetics study following a single-dose intravenous administration of 10 mg/kg the antibody cocktail against Ebola virus to cynomolgus monkeys.

Simple and Rapid LC-MS/MS Methods for Quantifying Catabolites of Antibody-Drug Conjugates with SMCC Linker.

The stability and exposure of toxin-related catabolites in system circulation contributes to the evaluation of the stability, targeted delivery and off-target toxicity for antibody-drug conjugates (ADC) at different stages during drug development. In this study, simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods for determination catabolites of Mertansine (DM1), MCC-DM1 and Lys-MCC-DM1 in cynomolgus serum have been developed. The serum samples are processed by protein precipitation. The LC-MS/MS methods are applied on a Phenomenex C8 column (50 × 2.0 mm, 5 µm) with gradient elution with water-formic acid 0.1% (A) and acetonitrile-formic acid 0.1% (B) at a flow rate of 0.5 mL/min. The analytical run time is only 4.0 min and the calibration ranges of the standard curve are 0.500-200 ng/mL for DM1, 1.00-500 ng/mL for MCC-DM1 and 2.00-1000 ng/mL for Lys-MCC-DM1. Intra- and inter-day precision of low, middle and high quality controls was <15%, and accuracy was 99.2-110.9%. The methods were successfully applied to evaluate three catabolites of novel ADCs with N-succinimidyl-4-(N-maleimidomethyl)-cyclohexane-1-carboxylate linker in vitro and in vivo studies.

Simultaneous quantitative determination of liraglutide and insulin degludec in rat plasma by liquid chromatography-tandem mass spectrometry method and its application.

A simple, fast and high-throughput LC-tandem mass spectrometry method was developed and validated to simultaneously measure liraglutide and insulin degludec in rat plasma. After protein precipitation, plasma samples were subjected to gradient elution using an InertSustain Bio C18 column with 1000/20/1 water/acetonitrile/formic acid (v/v/v) and 1000/1 acetonitrile/formic acid (v/v) as the mobile phase. The method was validated from 1.00 to 500 ng/mL of liraglutide and insulin degludec. Further, the extraction recovery from the plasma was 41.8%-49.2% for liraglutide and 56.5%-69.7% for insulin degludec. Intra- and inter-day precision of liraglutide was 3.5%-9.4% and 8.4%-9.8%, respectively, whereas its accuracy was between -12.6% and -1.3%. Intra- and inter-day precision of insulin degludec was 5.2%-13.6% and 11.8%-19.1%, respectively, showing an accuracy between -3.0% and 9.9%. As a result, the method was successfully applied to a pharmacokinetics study of liraglutide and insulin degludec following a single-dose subcutaneous administration to rats.

Method development and validation of LC-MS/MS-based assay for the simultaneous quantitation of trastuzumab and pertuzumab in cynomolgus monkey serum and its application in pharmacokinetic study.

We present a simple and robust LC-MS/MS assay for the simultaneous quantitation of an antibody cocktail of trastuzumab and pertuzumab in monkey serum. The LC-MS/MS method saved costs, decreased the analysis time, and reduced quantitative times relative to the traditional ligand-binding assays. The serum samples were digested with trypsin at 50°C for 60 min after methanol precipitation, ammonium bicarbonate denaturation, dithiothreitol reduction, and iodoacetamide alkylation. The tryptic peptides were chromatographically separated using a C18 column (2.1 × 50 mm, 2.6 µm) with mobile phases of 0.1% formic acid in water and acetonitrile. The other monoclonal antibody, infliximab, was used as internal standards to minimize the variability during sample processing and detection. A unique peptide for each monoclonal antibody was simultaneously quantified using LC-MS/MS in the multiple reaction monitoring mode. Calibration curves were linear from 2.0 to 400 µg/mL. The intra- and inter-assay precision (%CV) was within 8.9 and 7.4% (except 10.4 and 15.1% for lower limit of quantitation), respectively, and the accuracy (%Dev) was within ±13.1%. The other validation parameters were evaluated, and all results met the acceptance criteria of the international guiding principles. Finally, the method was successfully applied to a pharmacokinetics study after a single-dose intravenous drip administration to cynomolgus monkeys.

Safety, Efficacy, and Biomarker Analysis of Toripalimab in Previously Treated Advanced Melanoma: Results of the POLARIS-01 Multicenter Phase II Trial.

PURPOSE: In contrast to the predominant chronic UV exposure-induced cutaneous melanoma in Caucasians, acral and mucosal comprise the majority of melanomas in Asia and respond less effectively to established treatments. The clinical application of PD-1 blockade is yet to be explored in metastatic melanoma in China. PATIENTS AND METHODS: This phase II study was to evaluate safety and efficacy of toripalimab in advanced Chinese patients with melanoma who had failed in systemic treatments. Toripalimab was given at 3 mg/kg i.v. once every 2 weeks until disease progression or unacceptable toxicity. The primary objective was safety and objective response rate. RESULTS: 128 Patients with melanoma were enrolled, including 50 acral and 22 mucosal. As of August 15, 2019, 23 months after the last enrollment, 116 (90.6%) experienced treatment-related adverse events. ≥Grade 3 TRAEs occurred in 25 (19.5%) patients. Among 127 patients assessed, 1 complete response, 21 partial response, and 51 stable disease were observed for objective response rate of 17.3% and disease control rate of 57.5%. Median duration of response was not reached. Median progression-free survival was 3.6 months [95% confidence interval (CI) 2.7-5.3] and median overall survival was 22.2 months (95% CI, 15.3-NE). Patients with positive PD-L1 staining in tumor biopsies had significant better ORR (38.5% vs. 11.9%, P = 0.0065), PFS (7.7 months vs. 2.7 months, P = 0.013), and OS (not reached vs. 14.4 months, P = 0.0005) than PD-L1-negative patients. CONCLUSIONS: This is the largest prospective anti-PD-1 clinical study in advanced melanoma with predominantly acral and mucosal subtypes. Toripalimab demonstrated a manageable safety profile and durable clinical response in Chinese patients with metastatic melanoma refractory to standard therapy.See related commentary by Shoushtari et al., p. 4171.

Safety and clinical efficacy of toripalimab, a PD-1 mAb, in patients with advanced or recurrent malignancies in a phase I study.

PURPOSE: This is a first-in-human phase I study investigating the safety and efficacy of toripalimab, a humanized monoclonal antibody against the programmed cell death-1 (PD-1) receptor, in Chinese patients with advanced or recurrent malignant tumor refractory to standard treatment. PATIENTS AND METHODS: During dose escalation, patients received a single-dose intravenous infusion of toripalimab for 56 days followed by multidose infusions every two weeks. The planned dosing groups were 1, 3 and 10 mg/kg. During dose expansion, patients received toripalimab every two weeks. Clinical response was evaluated by investigators every 6 weeks. RESULTS: Thirty-three patients were enrolled, including 12 patients with alveolar soft part sarcoma (ASPS), seven with non-small-cell lung cancer and 11 with lymphoma. Patients were heavily pretreated with a median of 3 prior lines of systemic treatments. Toripalimab was well tolerated without dose-limiting toxicity. All patients experienced treatment-related adverse events. Grade 3 and above treatment-related adverse events occurred in six (18.2%) patients. Among 22 solid tumors, the objective response rate (ORR) was 22.7% per RECIST v1.1. The ORR was 90.9% in 11 lymphoma patients per IWG 2007. The median duration of response was 21.5 months. The median progression-free survival was 5.7 months for solid tumors and 8.3 months for lymphomas. The median OS was not reached for all patients and the lymphoma subgroups. The median OS was 34.7 months for patients with ASPS. CONCLUSION: Toripalimab was well tolerated up to 10 mg/kg Q2W without dose-limiting toxicity and showed promising and durable antitumour activities in patients with ASPS and lymphoma, who were heavily pretreated. CLINICAL TRIAL INFORMATION: ClinicalTrials.gov Identifier: NCT02836834.

Preclinical safety profile of disitamab vedotin：a novel anti-HER2 antibody conjugated with MMAE.

The HER2 pathway plays a pivotal role in cell proliferation and differentiation, while the receptor overexpression caused by amplification of HER2 gene is associated with the growth of several tumors. Previously published clinical trials have demonstrated that antibody-conjugated drugs (ADCs) remarkably improved clinical effects compared with antibodies alone for the same target. In order to provide more effective drugs, we developed Disitamab vedotin based on ADC. The antibody part was a humanized monoclonal antibody targeting HER2, the small molecule toxin was monomethyl auristatin E (MMAE), a synthetic antineoplastic agent. A protease cleavable linker covalently attached MMAE to the antibody. In this study, we characterized the toxicity profile of Disitamab vedotin through single- and repeat-dose toxicity studies in monkeys. The toxicities of small molecules and naked antibody (Disitamab) were also assessed in these studies. Monkeys were well tolerated with Disitamab vedotin at doses of 6 mg/kg, while equivalent MMAEs resulted in severe myelosuppression. This finding proves that ADCs improve the therapeutic effect. In addition, the safety profiles of Disitamab vedotin and MMAE were similar and consistent with the activation mechanism of MMAE. Toxicology finding included bone marrow/hematology toxicity and lymphoid organ toxicity, while no significant toxicity was observed in animals treated with naked antibody. These side effects were found to be consistent with data acquired from clinical phase I/II patients treated with Disitamab vedotin.

Receptor occupancy measurement of anti-PD-1 antibody drugs in support of clinical trials.

Aim: The reliable measurement of receptor occupancy (RO) provides informative data for efficacy and safety evaluation. This study aimed to assess factors affecting RO measurement of anti-PD-1 antibodies in clinical studies. Materials & methods: RO performance was assessed using different T-cell activation markers measured by flow cytometry. The validated methodology was then used in support of a clinical study. Results: The optimized active cell population was comprised of CD45RO+ or CD45RA- T cells. The bioanalytical method was validated for inter- and intra-assay precision (coefficient of variation ≤30%) and sample storage stability for 3 days. Consistent RO saturation was observed in Phase Ia clinical trial, although receptor regulation appeared to be different. The formation of anti-drug antibodies had markedly influenced pharmacokinetics and RO. Conclusion: RO measurement in combination with pharmacokinetics and anti-drug antibodies data could allow the integrated evaluation and better understanding of efficacy and safety.

Safety and clinical activity with an anti-PD-1 antibody JS001 in advanced melanoma or urologic cancer patients.

BACKGROUND: JS001, a humanized IgG4 monoclonal antibody against the programmed death-1 (PD-1) receptor, blocks the interaction of PD-1 with its ligands and promotes T cell activation in preclinical studies. This phase I study is designed to evaluate the safety, tolerability, and clinical activity of JS001 in advanced melanoma or urologic cancer patients who are refractory to standard systemic therapy. PATIENTS AND METHODS: In the dose escalation cohorts, subjects initially received a single-dose, intravenous infusion of JS001, and were followed for 28 days followed by multi-dose infusions every 2 weeks. In the dose expansion cohorts, subjects received multi-dose infusions every 2 weeks. Clinical response was evaluated after each 8-week treatment cycle according to RECIST v1.1 criteria. RESULTS: Thirty-six subjects diagnosed with advanced melanoma (n = 22), urothelial cancer (UC) (n = 8), or renal cell cancer (RCC) (n = 6) were enrolled. Melanoma subjects included 14 acral and 4 mucosal subtypes. JS001 was well tolerated, and no dose-limiting toxicity was observed. By the safety data cutoff date, 100% of subjects had treatment-related adverse events (TRAE) with most adverse events being grade 1 or 2, and ≥ grade 3 TRAEs occurred in 36%. Among all 36 subjects, 1 confirmed complete response (acral melanoma), 7 confirmed partial responses (2 acral melanoma, 1 mucosal melanoma, 2 UC, and 2 RCC), and 10 stable disease were observed, for an objective response rate of 22.2% (95% CI, 10.1 to 39.2), and a disease control rate of 50.0% (95% CI, 32.9 to 67.1). Clinical responses were correlated with PD-L1 expression on tumor cells, the presence of tumor infiltrating lymphocytes (TIL), baseline tumor volume, ECOG performance status, serum LDH levels, high percentage of activated CD8+ T cells and CD3- CD16+ CD54+ NK cells in the peripheral blood as well as tumor mutational burden (TMB). CONCLUSION: JS001 was well tolerated and demonstrated promising anti-tumor activity in UC and RCC as well as in previously underexplored acral and mucosal melanoma subtypes. Subjects with an immune-active profile in the tumor microenvironment or in peripheral blood responded favorably to JS001 treatment. The completion of the current phase I study has led to the initiation of the first prospective anti-PD-1 registration trial in Asia focusing on acral and mucosal melanoma subtypes, representative of the regional disease epidemiology. TRIAL REGISTRATION: Clinical Trial ID: NCT02836795 , registered July 19, 2016, retrospectively registered.

A Phase I Study Comparing the Pharmacokinetics, Safety, and Immunogenicity of Proposed Biosimilar GB242 and Reference Infliximab in Healthy Subjects.

OBJECTIVE: The objective of this study was to compare the pharmacokinetics (PKs), safety, and immunogenicity of GB242 as a potential biosimilar infliximab with those of reference infliximab in healthy Chinese subjects. METHODS: We conducted a randomized, single-center, double-blind, parallel-controlled phase I study in which 48 healthy subjects were divided equally into a GB242 group and reference infliximab group. Both the test and reference drug were administered as a single intravenous dose of 3 mg/kg. Blood samples were collected as per a designated schedule to evaluate PKs and immunogenicity. Safety was assessed throughout the study. PK similarity was concluded if the 90% confidence intervals (CIs) for the geometric mean ratios of the GB242 to reference infliximab for maximum concentration (Cmax), area under the concentration-time curve (AUC) from time zero to the last quantifiable concentration (AUCt), and AUC from time zero to infinity (AUC∞) were within the predefined bioequivalence range of 80-125%. RESULTS: The mean serum concentration-time curves were similar between GB242 and reference infliximab. The 90% CIs for the geometric mean ratios of the GB242 to reference infliximab for Cmax, AUCt, and AUC∞ were completely within 80-125% for the PK similarity comparison. The proportion of subjects with treatment-emergent adverse events was similar between the GB242 group and the reference infliximab group. Antidrug antibody profiles were comparable between the two treatments groups. CONCLUSIONS: This study demonstrated high PK similarity between GB242 and its marketed reference infliximab in healthy subjects. Both treatments showed comparable safety and immunogenicity. REGISTRATION NUMBER: ChiCTR-IPR-15007098.

Pharmacokinetics and immunogenicity of T0001, a newly developed anti-TNFα fusion protein, in healthy volunteers.

PURPOSE: T0001 was the first mutant of recombinant fusion protein of human tumor necrosis factor receptor and Fc fragment (rhTNFR:Fc) based on etanercept on a global scale. This study was carried out to investigate the pharmacokinetics (PK) and immunogenicity of T0001 in healthy Chinese volunteers. METHODS: This study was randomized, with a single ascending dose, and the first-in-human clinical trial of T0001. Healthy Chinese volunteers (n = 56; male: female = 1:1) were randomly assigned to receive a single subcutaneous (sc) injection of 10, 20, 35, 50, 65 or 75 mg of T0001. Blood samples were collected at designated time points after sc injection to assess immunogenicity and pharmacokinetics of T0001. RESULTS: During the study, no serious adverse events were observed. T0001 was slowly absorbed with a median Tmax of 84 h and slowly eliminated with a T1/2Z of 42.1-58.2 h. In the dose-exposure proportionality analysis, the estimated points for AUC0-∞ and Cmax were 0.87 with a 90% CI of 0.76-0.98 and 0.86 with a 90% CI of 0.74-0.97 respectively. The plasma concentration of free (unbound T0001) plasma TNFα and total (bound and unbound T0001) TNFα both increased significantly after the injection of T0001. Ten out of 56 volunteers (17.9%) tested positive for anti-drug antibodies (ADAs) at a low level. CONCLUSIONS: T0001 was safe and well-tolerated at doses up to 75 mg. Cmax and AUC0-∞ had an increasing tendency with dose levels, but we could not conclude that T0001 has linear PK properties in this study.

Preclinical evaluation of the efficacy, pharmacokinetics and immunogenicity of JS-001, a programmed cell death protein-1 (PD-1) monoclonal antibody.

JS-001 is the first monoclonal antibody (mAb) against programmed cell death protein-1 (PD-1) approved by the China Food and Drug Administration (CFDA) into the clinical trails. To date, however, no pre-clinical pharmacological and pharmacokinetic (PK) data are available. In this study, we investigated the efficacy of JS-001 and conducted a preclinical PK study, including the monitoring of anti-drug antibodies (ADAs). We found that JS-001 specifically bound to PD-1 antigen with an EC50 of 21 nmol/L, and competently blocked the binding of PD-1 antigen to PD-L1 and PD-L2 with IC50 of 3.0 and 3.1 nmol/L, respectively. Furthermore, JS-001 displayed distinct species cross-reactivity: it could bind to the PD-1 antigen on the peripheral blood mononuclear cells (PBMCs) of humans and cynomolgus monkeys, but not to those of mice and woodchucks; the Kd values for the interaction between JS-001 and PD-1 antigens on CD8+ T cells of human and cynomolgus monkey were 2.1 nmol/L and 1.2 nmol/L, respectively. In vitro, treatment with JS-001 (0.01-10 µg/mL) dose-dependently stimulated human T cell proliferation, as well as IFN-γ and TNF-α secretion. In HBsAg-vaccinated cynomolgus monkeys, the expression of PD-1+/CD4+ and PD-1+/CD8+ was significantly elevated, intramuscular injection of JS-001 (1 and 10 mg/kg) resulted in dramatic decreases in PD-1+/CD4+ and PD-1+/CD8+ expression in a dose-dependent manner, which was supported by PD-1 receptor occupancy (RO) results. In the PK study, 18 cynomolgus monkeys treated with single, ascending doses of 1, 10, and 75 mg/kg, and another 6 cynomolgus monkeys received 10 mg/kg successive administration. The plasma clearance of JS-001 followed a linear PK profile with single administration in the 1 and 10 mg/kg groups and a non-linear PK profile in the 75 mg/kg group. In the successive 10 mg/kg administration group, no drug accumulation was observed. But the AUC from the last exposure was lower than that of the first administration, which was probably due to the production of ADAs, as demonstrated in immunogenicity study. These non-clinical data are encouraging and provide a basis for the efficacy and safety of JS-001 in clinical trials.

HER2-targeted antibody drug conjugates for ovarian cancer therapy.

HER2 targeted delivery of ovarian cancer therapy has been beneficial for some patients, although, its efficacy is yet to be confirmed in large populations. We generated a novel anti-HER2 humanized antibody (Hertuzumab) and conjugated it to a microtubule-disrupting drug monomethyl auristatin E conjugate (MMAE) with a lysosomal protease-cleavable valine-citrulline linker. The average drug to antibody ratio (DAR) of Hertuzumab-vc-MMAE was varied by conjugating Hertuzumab antibodies with increasing linker-drugs (LDs) from D0-D8. The resulting conjugates were tested for kinetic affinity for soluble HER2-ECD, cytotoxicity, and in vivo pharmacokinetics. The kinetic binding constant values (KD) were obtained by the bio-layer interference (BLI) method. The half time (t1/2) and clearance (Cl) results of the pharmacokinetic profile in rats were DAR-dependent. Hertuzumab-vc-MMAE with DAR4 was selected for further evaluation. Both Hertuzumab and Hertuzumab conjugates could bind to HER2 antigen, and exhibited significant cytotoxicity on HER2 positive tumor cells after internalization by receptor-mediated endocytosis. Hence, Hertuzumab-vc-MMAE conjugates were significantly selective both in vitro and in vivo as compared to other ovarian cancer clinical therapies that are currently used. Cell signal transduction and cell cycle were also affected, as shown by down regulation of PI3K/AKT pathway and arrested mitosis in the G2/M phase. The pharmacokinetics and pharmacodynamics (PK-PD) of the conjugates in nude mouse xenograft model demonstrated a correlation between efficacy and drug concentration. These results show that Hertuzumab-vc-MMAE is a potential therapeutic agent for HER2 positive ovarian cancer.

Construction, expression, purification, and characterization of a dual-targeting PD-1/VEGF-A fusion protein (P-V).

Targeting programmed death-1 (PD-1) is regarded as a novel and promising means for the treatment of many types of solid tumor. In the tumor microenvironment (TME), VEGF expression is dramatically up-regulated, and compounds that neutralize VEGF or block the interaction of VEGF with its receptors exhibit potent antitumor activity, and blocking PD-1 might promote T cell infiltration into TME and significantly enhance local immune activation. Thus, we fused domain II and domain III of kinase-insert domain receptor (KDR), the receptor of VEGF-A, to the Fc side of an anti-PD-1 monoclonal antibody with a (Gly4Ser)3 linker to generate a dual targeting fusion protein. The recombinant plasmid was successfully constructed and the fusion protein was expressed in 293E cells. Protein purification was performed in a single step by using protein A affinity chromatography. The molecular weight of the fusion protein was approximately 220kDa, and the yield was approximately 2.97g/L. Specific binding of recombinant protein to PD-1 and VEGF was detected by enzyme-linked immunosorbent assay (ELISA) analysis. Half maximal effective concentration (EC50) values were 0.561nM for PD-1 and 0.682nM for VEGF-A; accordingly, half maximal inhibitory concentration (IC50) values were 0.914nM and 0.583nM, respectively. Proliferation inhibition assays indicated that the fusion protein could inhibit the growth of human umbilical vein endothelial cells effectively. Taken together, the results indicate that this novel fusion protein can simultaneously target PD-1 and VEGF and may be beneficial for combining anti-angiogenesis with immunotherapeutic approaches for the treatment of patients with cancer.