Preclinical studies of a factor X activator and a phase 1 trial for hemophilia patients with inhibitors.

BACKGROUND: Bleeding episodes in hemophiliacs with inhibitors are difficult to control. Staidson protein-0601 (STSP-0601), a specific factor (F)X activator purified from the venom of Daboia russelii siamensis, has been developed. OBJECTIVES: We aimed to investigate the efficacy and safety of STSP-0601 in preclinical and clinical studies. METHODS: In vitro and in vivo preclinical studies were performed. A phase 1, first-in-human, multicenter, and open-label trial was conducted. The clinical study was divided into parts A and B. Hemophiliacs with inhibitors were eligible for this study. Patients received a single intravenous injection of STSP-0601 (0.01 U/kg, 0.04 U/kg, 0.08 U/kg, 0.16 U/kg, 0.32 U/kg, or 0.48 U/kg) in part A or a maximum of 6 4-hourly injections (0.16 U/kg) in part B. The primary endpoint for each part was the number of adverse events (AEs) from baseline to 168 hours after administration. This study was registered at clinicaltrials.gov (NCT-04747964 and NCT-05027230). RESULTS: Preclinical studies showed that STSP-0601 could specifically activate FX in a dose-dependent manner. In the clinical study, 16 patients in part A and 7 patients in part B were enrolled. Eight (22.2%) AEs in part A and 18 (75.0%) AEs in part B were reported to be related to STSP-0601. Neither severe AEs nor dose-limiting toxicity events were reported. There were no thromboembolic event. The antidrug antibody of STSP-0601 was not detected. CONCLUSION: Preclinical and clinical studies showed that STSP-0601 had a good ability to activate FX and had a good safety profile. STSP-0601 could be used as a hemostatic treatment in hemophiliacs with inhibitors.

A randomized controlled dose-escalation study of SSS07, a humanized rabbit anti-human TNF alpha antibody, in healthy Chinese adults.

AIMS: SSS07 is a rabbit derived humanized anti-human TNF-α antibody. This study aimed to explore the pharmacokinetics, safety, and immunogenicity of SSS07 when administrated subcutaneously in healthy adults. METHODS: This was a double-blind, dose-escalation study of SSS07 in 71 adults. Dose cohorts were set to 5 mg, 15 mg, 30 mg, 50 mg, 75 mg, and 100 mg. In each dosage group, other than 100 mg, twelve healthy participants were randomly assigned to receive a single dose of SSS07 (n = 10) or placebo (n = 2). Blood samples were taken for pharmacokinetics and immunogenicity analysis. RESULTS: No deaths, serious adverse events or drug-related withdrawals occurred in this trial. No drug limited toxicity appeared. After subcutaneous injection, SSS07 was absorbed slowly with Tmax ranging from 60 to 264 h but eliminated quickly with a short half-life ranging from 21.69 to 78.4 h (1-3 days). From 5 mg to 100 mg, dose-exposure proportionality analysis found a 90% confidence interval (CI) of ß of Cmax (1.015-1.193), AUC0-t (1.096-1.263) and AUC0-∞ (0.999-1.174) partially within the range 0.926-1.074. The plasma concentration of TNF-α decreased significantly post-dose, but a few days later, levels of TNF-α elevated rapidly and exceeded its baseline value. All participants receiving SSS07 were found to be anti-drug antibody positive during the study. CONCLUSIONS: A single-dose injection of SSS07 was safe and well-tolerated in healthy adults. Doses of SSS07 from 5 mg to 100 mg could not be regarded as nonlinear, based on dose-exposure proportionality analysis. A high incidence of anti-drug antibodies indicated strong immunogenicity, which may influence the pharmacokinetics profile and interfere with the TNF-α inhibition capability of SSS07.