AMG 256 is a bi-specific, heteroimmunoglobulin molecule with an anti-PD-1 antibody domain and a single IL-21 mutein domain on the C-terminus. Nonclinical studies in cynomolgus monkeys revealed that AMG 256 administration led to the development of immunogenicity-mediated responses and indicated that the IL-21 mutein domain of AMG 256 could enhance the anti-drug antibody response directed toward the monoclonal antibody domain. Anti-AMG 256 IgE were also observed in cynomolgus monkeys. A first-in-human (FIH) study in patients with advanced solid tumors was designed with these risks in mind. AMG 256 elicited ADA in 28 of 33 subjects (84.8%). However, ADA responses were only robust and exposure-impacting at the 2 lowest doses. At mid to high doses, ADA responses remained low magnitude and all subjects maintained exposure, despite most subjects developing ADA. Limited drug-specific IgE were also observed during the FIH study. ADA responses were not associated with any type of adverse event. The AMG 256 program represents a unique case where nonclinical studies informed on the risk of immunogenicity in humans, due to the IL-21-driven nature of the response.

Abstract Background Disruption of the BBB is a harmful event after intracranial hemorrhage (ICH), and this disruption contributes to a series of secondary injuries. We hypothesized that FGF21 may have protective effects after intracranial hemorrhage (ICH) and investigated possible underlying molecular mechanisms. Methods Blood samples of ICH patients were collected to determine the relationship between the serum level of FGF21 and the $$\Delta$$ Δ GCS%. Wild-type mice, SIRT6flox/flox mice, endothelial-specific SIRT6-homozygous-knockout mice (eSIRT6−/− mice) and cultured human brain microvascular endothelial cells (HCMECs) were used to determine the protective effects of FGF21 on the BBB. Results We obtained original clinical evidence from patient data identifying a positive correlation between the serum level of FGF21 and $$\Delta$$ Δ GCS%. In mice, we found that FGF21 treatment is capable of alleviating BBB damage, mitigating brain edema, reducing lesion volume and improving neurofunction after ICH. In vitro, after oxyhemoglobin injury, we further explored the protective effects of FGF21 on endothelial cells (ECs), which are a significant component of the BBB. Mitochondria play crucial roles during various types of stress reactions. FGF21 significantly improved mitochondrial biology and function in ECs, as evidenced by alleviated mitochondrial morphology damage, reduced ROS accumulation, and restored ATP production. Moreover, we found that the crucial regulatory mitochondrial factor deacylase sirtuin 6 (SIRT6) played an irreplaceable role in the effects of FGF21. Using endothelial-specific SIRT6-knockout mice, we found that SIRT6 deficiency largely diminished these neuroprotective effects of FGF21. Then, we revealed that FGF21 might promote the expression of SIRT6 via the AMPK–Foxo3a pathway. Conclusions We provide the first evidence that FGF21 is capable of protecting the BBB after ICH by improving SIRT6-mediated mitochondrial homeostasis.

ABSTRACT Results of prior studies suggest that fibroblast growth factor 21 (FGF21) may be involved in bone turnover and in the actions of peroxisome proliferator-activated receptor (PPAR) α and γ in mice. We have conducted independent studies to examine the effects of FGF21 on bone homeostasis and the role of FGF21 in PPARα and γ actions. High-fat-diet-induced obesity (DIO) mice were administered vehicle or recombinant human FGF21 (rhFGF21) intraperitoneally at 0 (vehicle), 0.1, 1, and 3 mg/kg daily for 2 weeks. Additional groups of DIO mice received water or 10 mg/kg rosiglitazone daily. Mice treated with rhFGF21 or rosiglitazone showed expected metabolic improvements in glucose, insulin, and lipid levels. However, bone loss was not detected in rhFGF21-treated mice by dual-energy X-ray absorptiometry (DXA), micro-CT, and histomorphometric analyses. Mineral apposition rate, a key bone formation parameter, was unchanged by rhFGF21, while significantly decreased by rosiglitazone in DIO mice. Bone resorption markers, OPG/RANKL mRNA expression, and histological bone resorption indices were unchanged by rhFGF21 or rosiglitazone. Bone marrow fat was unchanged by rhFGF21, while increased by rosiglitazone. Furthermore, FGF21 knockout mice did not show high bone mass phenotype. Treatment with PPARα or PPARγ agonists caused similar metabolic effects in FGF21 knockout and wild-type mice. These results contrast with previous findings and suggest that FGF21 is not critical for bone homeostasis or actions of PPARα and PPARγ. © 2016 American Society for Bone and Mineral Research.

Objective:To understand the effect of puerarin combined with estradiol on bone tissue and serum calcium,phosphorus,and alkaline phosphatase in ovariectomized rats,and provide experimental basis for treating postmenopausal osteoporosis with traditional Chinese medicine combined with Western medicine.Methods:One hundred and twenty 5-month-old female rats were selected and divided into five experimental groups,24 rats in each group: sham-operation group,ovariectomized model group,puerarin group(the rats were treated with subcutaneous injection of puerarin,50 mg/kg,once a day),estradiol group(the rats were treated with subcutaneous injection of estradiol,200 μg/kg,twice a week),low-dose puerarin combined with estradiol group(combined therapy group)(the rats were treated with subcutaneous injection of estradiol,100 μg/kg,twice a week;subcutaneous injection of puerarin,25 mg/kg,once a day).At 4,8,12,and 20 weeks after start of the experiment,6 rats were randomly selected,femur smears were prepared to observe bone tissue;the blood samples were obtained to detect serum levels of calcium,phosphorus,and alkaline phosphatase;the data were analyzed statistically.Results:The pathological changes of osteoporosis were observed at 4,8,12,and 20 weeks in ovariectomized model group,the serum levels of calcium and phosphorus in ovariectomized model group were statistically significantly lower than those in sham-operation group(P﹤0.01);the serum levels of alkaline phosphatase at 4,8,12,and 20 weeks in ovariectomized model group were statistically significantly higher than those in sham-operation group(P﹤0.01).There was no statistically significant difference in bone tissue,serum levels of calcium,phosphorus,and alkaline phosphatase at 4,8,12,and 20 weeks between three treatment groups and sham-operation group(P﹥0.05).Bone tissue,serum levels of calcium,phosphorus,and alkaline phosphatase in combined therapy group basically returned to normal(P﹥0.05),compared with puerarin group and estradiol group,there was no statistically significant difference(P﹥0.05).Conclusion:The curative effect of low-dose estradiol combined with puerarin for treatment of osteoporosis in ovariectomized rats is similar to curative effects of relatively high-dose puerarin or estradiol.