Thrombin, Topical (Bovine)(GenTrac)

Thrombin-based formulations have been used for topical hemostasis in surgery for decades. However, the number of randomized clinical trials comparing bovine vs human thrombin is limited.

A randomized, double-blind, non-inferiority phase II study evaluated the hemostatic efficacy and safety of plasma-derived topical thrombin (human) Grifols (TTH-Grifols; Instituto Grifols SA) vs bovine THROMBIN JMI (BT-JMI; GenTrac Inc) (2:1 ratio) in vascular, hepatic, soft tissue, and spinal operations. The primary efficacy end point was the percentage of patients achieving hemostasis at target bleeding sites with mild to moderate bleeding (response) within 5 minutes (T₅) of treatment application. Non-inferiority was met if the lower limit of the 95% CI of the response ratio of TTH-Grifols relative to BT-JMI by T₅ exceeded 0.8. Secondary efficacy variables were the cumulative response by 3 and 4 minutes (T₃ and T₄), and the number of treatment failures. Safety parameters were assessed.

Randomized patients in TTH-Grifols and BT-JMI groups were n = 137 and n = 68, respectively. In modified intention-to-treat population, rates of hemostasis by T₅ were 78.3% (94 of 120) in TTH-Grifols and 80.3% (49 of 61) in BT-JMI (response ratio: 0.973; 95% CI 0.833 to 1.135). Rates of hemostasis in vascular, hepatic, soft tissue, and spinal operations ranged from 75.0% to 82.5% for TTH-Grifols and from 54.5% to 91.7% for BT-JMI. No significant differences in adverse events were observed between treatment groups. Antibodies to bovine factor V antigen were detected in 2 patients exposed to BT-JMI and in none exposed to TTH-Grifols.

The TTH-Grifols was safe and well tolerated as a local hemostatic agent and was non-inferior to BT-JMI. No antibodies to thrombin developed in TTH-Grifols-treated patients.

Topical hemostatic agents are used intra-operatively to prevent uncontrolled bleeding. Gelfoam(®) Powder contains a hemostatic agent prepared from purified pork skin gelatin, the efficacy of which is increased when combined with thrombin. However, the effect of increasing concentrations of thrombin on resultant hemostasis is not known. This study sought to evaluate the ability of various concentrations of thrombin in combination with Gelfoam Powder to control bleeding using a swine liver lesion model. Ten pigs underwent a midline laparotomy. Circular lesions were created in the left medial, right medial, and left lateral lobes; six lesions per lobe. Gelfoam Powder was hydrated with Thrombin-JMI(®) diluted to 250, 375, and 770 IU/mL. Each concentration was applied to two lesion sites per lobe. Bleeding scores were measured at 3, 6, 9, and 12 min using a 6-point system; comparison of bleeding scores was performed using ANOVA with the post hoc Tukey test. The bleeding scores with thrombin concentrations at 770 IU/mL were significantly lower than at 250 and 375 IU/mL at all four time points. The percentage of biopsies with a clinically acceptable bleeding score rose from 37.9, 46.6, and 71.2 % at 3 min to 55.2, 69.0, and 88.1 % at 12 min in the 250, 375, and 770 IU/mL thrombin groups, respectively. The study showed that the hemostatic response to thrombin was dose-related: using higher concentrations of thrombin with Gelfoam Powder yielded improved hemostasis, as determined by lower bleeding scores.