Pharmacokinetics, pharmacodynamics and safety of recombinant canine FVIIa in a study dosing one haemophilia A and one haemostatically normal dog

[Prophylactic treatment with low- and intermediate-dose factor VIII in children with severe hemophilia A: comprehensive evaluation of joint outcomes and correlation analysis]

OBJECTIVE

To study the effect of low- and intermediate-dose factor VIII (FVIII) for prophylactic treatment of severe hemophilia A in children by comprehensively evaluating the outcomes of the joints.

METHODS

Forty-seven children with severe hemophilia A (FVIII activity ≤2%) were enrolled in this study. Eighteen of the children received prophylactic treatment with low-dose FVIII (10 U/kg, 2-3 times a week), 20 received prophylactic treatment with intermediate-dose FVIII (15-30 U/kg, 3 times a week), and 9 received on-demand treatment with FVIII infusion when bleeding occurred according to the Chinese Expert Consensus on the Diagnosis and Treatment of Hemophilia. The children were followed up for 180 days to observe the changes in the indexes of clinical bleeding phenotype, joint structure, joint function, and joint mobility, and the correlation of these indexes were analyzed.

RESULTS

Compared with on-demand treatment, prophylactic treatment with low- and intermediate-dose FVIII significantly improved the clinical hemorrhage phenotype (P<0.01), and the improvement was significantly more conspicuous with intermediate-dose prophylactic treatment (P<0.05). Comprehensive evaluation of the joint structure and function changes showed that compared with on-demand treatment, prophylactic treatment with low- and intermediate-dose FVIII resulted in significant improvements in the total score of Hemophilia Joint Health Score (HJHS), Functional Independence Score in Hemophilia (FISH), the single most severe target joint ultrasound and HJHS score of the target joint (P<0.05) and prophylactic treatment with intermediate-dose FVIII appeared to produce better outcomes of the joint than low-dose FVIII. No correlation was found between annual target joint bleeding rate (ATJBR) and ultrasound score, between ATJBR and HJHS change, or between annual joint bleeding rate (AJBR) and the total score of FISH (P>0.05).

CONCLUSION

Compared with on-demand treatment, prophylactic treatment with low- and intermediate-dose FVIII can significantly improve the bleeding phenotype and delay the progression of joint injury, but the clinical hemorrhagic phenotype is not sufficient to monitor the disease progression.

Single-dose safety and pharmacokinetic evaluation of fluorocoxib A: pilot study of novel cyclooxygenase-2-targeted optical imaging agent in a canine model

We evaluated preclinical single-dose safety, pharmacokinetic properties, and specific uptake of the new optical imaging agent fluorocoxib A in dogs. Fluorocoxib A, N-[(5-carboxy-X-rhodaminyl)but-4-yl]-2-[1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl]acetamide, selectively binds and inhibits the cyclooxygenase-2 (COX-2) enzyme, which is overexpressed in many cancers. Safety pilot studies were performed in research dogs following intravenous (i.v.) administration of 0.1 and 1  mg/kg fluorocoxib A. Blood and urine samples collected three days after administration of each dose of fluorocoxib A revealed no evidence of toxicity, and no clinically relevant adverse events were noted on physical examination of exposed dogs over that time period. Pharmacokinetic parameters were assessed in additional research dogs from plasma collected at several time points after i.v. administration of fluorocoxib A using high-performance liquid chromatography analysis. The pharmacokinetic studies using 1  mg/kg showed a peak of fluorocoxib A (92±28  ng/ml) in plasma collected at 0.5 h. Tumor specific uptake of fluorocoxib A was demonstrated using a dog diagnosed with colorectal cancer expressing COX-2. Our data support the safe single-dose administration and in vivo efficacy of fluorocoxib A, suggesting a high potential for successful translation to clinical use as an imaging agent for improved tumor detection in humans.