PEGylated Recombinant Human Growth Hormone Jintrolong® Exhibits Good Long-Term Safety in Cynomolgus Monkeys and Human Pediatric Growth Hormone Deficiency Patients.

Jintrolong® is a long-acting PEGylated recombinant human growth hormone (PEG-rhGH) developed for weekly injection in patients with pediatric growth hormone deficiency (PGHD). Although PEG modification of therapeutic proteins is generally considered safe, concerns persist about the potential for adverse vacuolation in tissues with long-term exposure to PEG-included therapies, particularly in children. We assessed the safety of Jintrolong® in cynomolgus monkeys with an examination of vacuolation in the brain choroid plexus (CP) and reported long-term clinical safety data obtained from children with PGHD. The toxicity of Jintrolong® was assessed following the 52-week administration with doses at 0.3, 1, or 3 mg/kg/week. The levels of vacuolation of CP in animals were dose-dependent and at least partially reversible after a 104- or 157-week recovery period. Vacuolation in the CP epithelium did not lead to obvious subcellular structural or cell functional abnormalities. Compared with the clinical dose of 0.2 mg/kg/week Jintrolong® in PGHD patients, exposure in monkeys under NOAEL 3 mg/kg/week exhibited safety margins greater than 120.5, the predicted minimum dose to induce vacuolation in monkeys is equivalent to 1.29 mg/kg/week in humans, which is 6.45-fold higher than the clinical dose. The safety data acquired in clinical trials for Jintrolong® were also analyzed, which included phase III (360 patients), phase IV (3,000 patients) of 26-week treatment, and a follow-up study with treatment lasting for 3 years. There was no statistically significant difference in the incidence of adverse reactions between the Jintrolong® group and the daily rhGH control group (no PEG), and no new adverse effects (AE) were observed in the Jintrolong® group at the clinical therapeutic dose of 0.2 mg/kg/week.

A simple and cost-effective assay for measuring anti-drug antibody in human patients treated with Adalimumab.

It has been reported that 90% of the anti-drug antibody (ADA) to Adalimumab in human patients bound to the TNF-binding area, resulted in the annual loss of responses to Adalimumab up to 24%. It is of urgency to develop a cost-effective and easy-to-use ADA diagnostic kit for diagnosis of potential drug-resistance in patients treated with Adalimumab in clinic hospitals to avoid the tremendous economic and human costs to patients and health-care providers. In this study, we reported the generations of mouse monoclonal and monkey polyclonal antibodies against Adalimumab as assay standards and positive quality controls respectively. A Bridging ELISA assay was successfully developed with a limit of detection (LOD) between 22-80ng/ml. The preliminary validation of assay was carried out first with 50 normal human sera, further validated by screening the ADA in 192 serum samples from monkeys treated with or without Adalimumab. Our data showed that the Bridging ELISA kit is very sensitive, highly specific and ready for study in human clinic trials.

A toxicity study of multiple-administration human umbilical cord mesenchymal stem cells in cynomolgus monkeys.

Therapies based on stem cells have shown very attractive potential in many clinical studies. However, the data about the safety of stem cells application remains insufficient. The present study was designed to evaluate the overall toxicology of human umbilical cord mesenchymal stem cells (hUC-MSCs) in cynomolgus monkeys with repeated administrations. hUC-MSCs were administered by intravenous injection once every 2 weeks for 6 weeks. The dose levels employed in this study were 2×10(6), 1×10(7) cells/kg body weight. Toxicity was evaluated by clinical observations (body weight, body temperature, and ophthalmology exams), pathology (blood cell counts, clinical biochemistry, urinalysis, and bone marrow smears), immunologic consequences (lymphoproliferation assay, the secretion of interferon-γ and interleukin-4, the percentage of CD3, CD4, CD8 T cells, and the ratio of CD4 and CD8 T cells) and anatomic pathology. Pharmacodynamics in blood and distribution of hUC-MSCs in the tissues of cynomolgus monkeys were measured by real-time polymerase chain reaction. All animals survived until scheduled euthanasia. No stem cells transplantation-related toxicity was found in this study. hUC-MSCs could be found in the blood of cynomolgus monkeys beyond 8 h. The findings of this 6-week toxicity study showed that the transplantation of hUC-MSCs did not affect the general health of cynomolgus monkeys.

[Promotion of Thrombopoiesis by rhIL-11 in Normal and Myelosuppressed Mice]

Hematological effects of rhIL-11 on normal and myelosuppressed male BALB/c mice were observed. Mice were subcutaneously injected with rhIL-11 for 7 consecutive days, at the dose of 200 or 400 micro g/kg per day, peripheral blood platelet counts were moderately elevated on 5 days after administration and returned to base level within 4 days after discontinuation of injection. In myelosuppressed mice, treatment with rhIL-11 significantly ameliorated the degree of thrombocytopenia, the recovery of thrombocytopenia was also significantly accelerated at the dose range of 100 - 400 micro g/kg per day, and blood platelet counts reached pre-irradiated level after 13 - 15 days of treatment. The magnitudes of platelet count elevation were similar among groups of 100, 200 and 400 micro g/kg per day, although recovery appeared earlier in group of 400 micro g/kg per day. Significant increases in CFU-Meg were observed both in normal and myelosuppressed mice. Our results suggest that rhIL-11 promotes the increase of peripheral blood platelets both in normal and myelosuppressed mice, and can be used as a potential therapeutic agent for thrombocytopenia induced by chemotherapy.

[Therapeutic Effects of rhIL-11 on Carboplatin-Induced Thrombocytopenia in Monkeys]

A model of myelosuppression with thrombocytopenia was produced in monkey by i.v. administration of carboplatin to the evaluate effects of rhIL-11 treatment in monkeys. Following myelosuppression, rhIL-11 was subcutaneously injected for 19 consecutive days at the dose of 50 or 100 micro g/kg. In myelosuppressed monkeys treated with rhIL-11, peripheral blood platelet started to drop at the day 8 after the administration of carboplatin, and reaching the nadir between the day 12 - 14, the decrease in blood platelet was less severe compared with untreated monkeys; peripheral blood platelet began to recovery on day 11 - 13 (D14 - D16) after rhIL-11 treatment, and reached or surpassed the baseline value before carboplatin administration after 13 - 15 days rhIL-11 treatment. Blood platelet counts remained high level after discontinuation of rhIL-11 administration and returned to baseline after 4 days. The results demonstrated that rhIL-11 has a significant thrombopoietic activity, it can reduce the severity of thrombocytopenia as well as shorten the duration of thrombocytopenia caused by myeloablastive agents, and is likely to become an effective agent against thrombocytopenia induced by chemotherapy.

[Study of recombinant stem cell factor].

Stem cell factor is an important hematopoietic growth factor. In this study, the human stem cell factor was produced by recombinant E. coli, and the structure and biological activity of the recombinant stem cell factor(rhSCF) was studied. It was indicated that the rhSCF was a uncovalent dimer in phosphate buffer,and had the correct mass spectra, mass peptides spectra, composition of amino acid, N-terminal sequernce, C-terminal sequence and intrachain disulfide linkages, rhSCF alone or synergy with rhG-CSF could mobilze hematopoietic progenitors to blood in monkey.