Single- and repeated-dose toxicity studies on the novel HIV maturation inhibitor QF-036 in Sprague-Dawley rats.

QF-036 is a novel human immunodeficiency virus (HIV) maturation inhibitor that is a lupine triterpenoid derivative. The objective of this study was to evaluate the safety of QF-036. A single oral toxicity and a 4-week repeated oral toxicity were investigated in Sprague-Dawley (SD) rats. The single oral toxicity study of QF-036 in SD rats showed that no mortality or visible pathological changes were noted at doses of 100, 300, and 1000 mg/kg. QF-036 exhibited a non-linear toxicokinetic profile over the dose range of 100-1000 mg/kg in the single dose study, and a saturation trend appeared at doses of 100 and 300 mg/kg. In the 4-week oral toxicity and toxicokinetic study, SD rats were given 0, 50, 100, and 200 mg/kg QF-036 once daily for 4 weeks, followed by a 4-week recovery period. No mortality or significant effects on food consumption, body weight, or behavior were observed. In addition, there were no test article-related changes in hematology, clinical biochemistry and histopathology. The no observed adverse effect level (NOAEL) was 200 mg/kg. The toxicokinetic study demonstrated a dose-dependent increase in the systemic exposure to QF-036 after 4 weeks of oral administration. There were no marked sex differences or drug accumulation observed for repeated doses of QF-036.

Preclinical pharmacokinetics of a recombinant humanized rabbit anti-VEGF monoclonal antibody in rabbits and monkeys.

TMAB001 is a humanized rabbit monoclonal antibody (mAb) designed to bind and neutralize human vascular endothelial growth factor (VEGF)-165. The purpose of the study was to investigate the pharmacokinetics (PK) and ocular tissue distribution after a single intravitreal (IVT) dose in rabbits and monkeys. Rabbits (2.5 mg/eye; n = 40) and monkeys (2.5 mg/eye; n = 12) received TMAB001 as a bilateral IVT dose. TMAB001 concentrations were measured in ocular tissues in all rabbits and monkeys by enzyme-linked immunosorbent assay (ELISA). TMAB001 and VEGF concentrations were measured in serum of monkeys by ELISA. Following a single bilateral IVT injection of TMAB001 2.5 mg/eye, the highest concentration was in vitreous humor, followed by retina and choroid, and the lowest concentration was in lens. In rabbits, TMAB001 was still detectable in ocular tissues at day 21 after single IVT dose, with the highest level in the vitreous humor and then retina, with longest t1/2 in aqueous humor and shortest t1/2 in choroid. In monkeys, tmax in serum was 43 h and t1/2 was approximately 5.5 days. Cmax in serum was much lower than that in vitreous, nearly 1/200. After IVT injection of TMAB001, total VEGF concentrations in serum and ocular tissues increased over time. VEGF concentration in retina and choroid increased over time, up to 336 h after administration. This study demonstrated that TMAB001 could reach the drug target sites-retina and choroid after a single bilateral IVT administration in rabbits and monkeys, with a long t1/2 in vitreous humor. TMAB001 also showed strong capability to neutralize VEGF. The study further confirmed that full-length antibodies can also efficiently diffuse and distribute in ocular tissues.

Recombinant humanized anti-vascular endothelial growth factor monoclonal antibody efficiently suppresses laser-induced choroidal neovascularization in rhesus monkeys.

Neovascular age-related macular degeneration, characterized by abnormal choroidal neovascularization (CNV), is a major cause of blindness worldwide. Anti-vascular endothelial growth factor (VEGF) antibodies have demonstrated significant efficacy in improving visual acuity. TMAB001 is a new recombinant humanized rabbit anti-VEGF monoclonal antibody. It presents high activities in vitro studies. In the binding affinity assay, TMAB001 exhibited a high binding capability to VEGF with an affinity constant of 10-11M. In the receptor antagonist activity assay, IC50 of TMAB001 was 0.15µg/ml. In a cell-based assay, TMAB001 inhibited VEGF165-induced HUVEC cells proliferation in a dose-dependent manner. Furthermore, in the rhesus monkey model of laser-induced CNV, results showed the growth and leakage of experimental CNV were significantly decreased with a single bilateral intravitreal injection of TMAB001, and the grade 4 lesions were complete absence in TMAB001 groups. The efficacy of TMAB001 was maintained for at least 28days. In a mice model of oxygen-induced retinopathy, the retina fluorescence leakage was reduced and the vascular morphology in retina was normalized by TMAB001 intraperitoneal administration. In conclusion, those results indicate that TMAB001 might be a potential drug candidate for wet AMD.

Effects of GW002, a novel recombinant human glucagon-like peptide-1 (GLP-1) analog fusion protein, on CHO recombinant cells and BKS-db mice.

AIMS: GLP-1-based strategies have many advantages in treatment of type 2 diabetes mellitus (T2DM), but native GLP-1 has a short half-life in the circulation, which limits its clinical application. The purpose of this study was to evaluate the effects of GW002, a novel recombinant GLP-1 analog fusion protein produced by linking the human GLP-1 analog C-terminus to the N-terminus of human serum albumin via a linker, in vitro and in BKS-db mice. METHODS: To determine whether GW002 can activate the GLP-1 receptor in cells, the level of luciferase expression was evaluated in vitro. In vivo, body weight, food intake, non-fasting and fasting blood glucose, oral glucose tolerance test, blood glucose and insulin levels, liver histology, liver function parameters and antibody levels in BKS-db mice were investigated to evaluate the effects of GW002. Albiglutide was chosen as a positive comparator. RESULTS: Cyclic adenosine monophosphate levels were increased in a dose-dependent manner in cells. In vivo studies demonstrated that GW002 lowers non-fasting and fasting blood glucose levels and improves glucose tolerance and insulin secretion in BKS-db mice. The degree of hepatic steatosis and hepatic biochemical indexes was also decreased. In this study, the mice body weight was not reduced significantly. CONCLUSIONS: The above results showed that the efficacy of GW002 in BKS-db mice displayed a significant hypoglycemic effect, which indicated that GW002 might be a potential candidate for the treatment of T2DM.