Pharmacokinetic properties of an escherichia-coli-produced recombinant plasminogen activator (BM 06.022) in rabbits

Fischer, Stephan; Kohnert, Ulrich; Rudolph, Rainer; Sponer, G.; Stern, Anne; Strein, K.

doi:10.1016/0049-3848(91)90188-3

Cited by 17 publications

(12 citation statements)

References 10 publications

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“…6A). This data are consistent with findings that rPA is more susceptible to inhibition by PAI-1 than tPA (Martin et al, 1991;Lijnen et al, 1994). However, free tPA and rPA caused comparable lysis of fibrin clots (Fig.…”

Section: Blood Clearance and Activity Of Rbc-coupled Fibrinolytics 1109supporting

confidence: 82%

“…To begin to address this issue, we compared the pharmacokinetics of RBC-bound tPA (molecular mass 60 kDa) versus its truncated variant Retavase (molecular mass 40 kDa), which has a lower affinity for fibrin and is more susceptible to plasma inhibitors but enjoys a longer half-life in the circulation than does tPA (Martin et al, 1991;Kohnert et al, 1992;Rijken et al, 1994).…”

Section: Discussionmentioning

confidence: 99%

“…For example, Retavase (rPA, a mutant tPA derivative lacking the finger, extracellular growth factor, and kringle-1 domains) is more susceptible to inhibitors and has lower affinity for fibrin than wild-type tPA. However, due to its lack of domains recognized by hepatic and other tissue receptors, rPA circulates for a longer time than tPA, which may offset these limitations (Martin et al, 1991;Bu et al, 1992;Kohnert et al, 1992;Rijken et al, 1994;Noble and McTavish, 1996;Topol et al, 2000). In this study, we examined effects of coupling to RBCs on the functional profiles of tPA versus rPA and found that it causes profound and, in some cases, unanticipated favorable alterations in the pharmacokinetics and enzymatic regulation of PAs of direct relevance to drug development.…”

mentioning

confidence: 99%

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Blood Clearance and Activity of Erythrocyte-Coupled Fibrinolytics

Ganguly

Krasik²,

Medinilla³

et al. 2004

J Pharmacol Exp Ther

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Conjugating tissue-type plasminogen activator (tPA) to red blood cells (RBCs) endows it with features useful for thromboprophylaxis. However, the optimal intensity and duration of thromboprophylaxis vary among clinical settings. To assess how the intrinsic properties of a plasminogen activator (PA) affect functions of the corresponding RBC/PA conjugate, we coupled equal amounts of tPA or Retavase (rPA; a variant with an extended circulation time, lower fibrin affinity, and greater susceptibility to PA inhibitors). Conjugation to RBC markedly prolonged the circulation of each PA in rats and mice, without detrimental effects on carrier RBC. The initial blood clearance of RBC/tPA was faster than RBC/rPA, yet it exerted greater fibrinolytic activity, in part due to greater resistance of tPA and RBC/tPA to plasma inhibitors versus rPA and RBC/rPA observed in vitro. Soluble and RBC-coupled tPA and rPA exerted the same amidolytic activity, yet RBC/tPA lysed fibrin clots more effectively than RBC/rPA, notwithstanding comparable fibrinolytic activity of their soluble counterparts. Conjugation to RBC suppressed rPA's ability to be activated by fibrin, whereas the fibrin activation of RBC-coupled tPA was not hindered. Therefore, the functional profile of RBC/PA is influenced by: pharmacokinetic features provided by carrier RBC (e.g., prolonged circulation), intrinsic PA features (e.g., clearance rate, resistance to inhibitors), and changes imposed by conjugation to RBC (e.g., loss of cofactor stimulation). These factors, different from those guiding the design of soluble PA for lysis of existing clots, can be exploited in the rational design of RBC/PA tailored for specific prophylactic indications.

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Section: Blood Clearance and Activity Of Rbc-coupled Fibrinolytics 1109supporting

confidence: 82%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Blood Clearance and Activity of Erythrocyte-Coupled Fibrinolytics

Ganguly

Krasik²,

Medinilla³

et al. 2004

J Pharmacol Exp Ther

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“…Previous studies showed that the complement regulatory proteins including decay accelerating factor fused with the Ter-119 scFv enhanced the resistance of RBCs to complement-mediated lysis in vitro (Spitzer et al, 2004) and in vivo (Spitzer et al, 2005). In this study, we fused scFv Ter-119 to a truncated form of mouse tPA containing kringle 2 and the protease domain (truncation of auxiliary tPA domains reduces its clearance and side effects) (Martin et al, 1991;Kohnert et al, 1992). Additional mutations homologous to those in Tenectaplase (K296A, H297A, R298A, and R299A) were introduced in the protease domain to confer higher resistance to the plasma inhibitor, PAI-1 (Davydov and Cheng, 2001;Tanswell et al, 2002).…”

mentioning

confidence: 99%

Targeting of a Mutant Plasminogen Activator to Circulating Red Blood Cells for Prophylactic Fibrinolysis

Зайцев

Spitzer

Murciano

et al. 2009

J Pharmacol Exp Ther

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Chemical coupling to carrier red blood cells (RBCs) converts tissue type plasminogen activator (tPA) from a problematic therapeutic into a safe agent for thromboprophylaxis. The goal of this study was to develop a more clinically relevant recombinant biotherapeutic by fusing a mutant tPA with a single-chain antibody fragment (scFv) with specificity for glycophorin A (GPA) on mouse RBCs. The fusion construct (anti-GPA scFv/PA) bound specifically to mouse but not human RBCs and activated plasminogen; this led to rapid and stable attachment of up to 30,000 copies of anti-GPA scFv/PA per mouse RBC that were thereby endowed with high fibrinolytic activity. Binding of anti-GPA scFv/PA neither caused RBC aggregation, hemolysis, uptake in capillary-rich lungs or in the reticuloendothelial system nor otherwise altered the circulation of RBCs. Over 40% of labeled anti-GPA scFv/PA injected in mice bound to RBC, which markedly prolonged its intravascular circulation and fibrinolytic activity compared with its nontargeted PA counterpart, anti-GPA scFv/PA, but not its nontargeted PA analog, prevented thrombotic occlusion in FeCl 3 models of vascular injury. These results provide proof-of-principle for the development of a recombinant PA variant that binds to circulating RBC and provides thromboprophylaxis by use of a clinically relevant approach.

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“…Likewise, the loss of in vivo biological activity of aglycosylated GM-CSF also results from rapid clearance [10]. The nonglycosylated form of tPA, on the other hand, loses a carbohydratedependent hepatic recognition site, and its in vivo half-life is doubled from 3 to 6 min [11]. Clinical trials of aglycosylated tPA, however, has shown its disadvantages in terms of safety and efficacy over its natural counterpart.…”

Section: Therapeuticsmentioning

confidence: 98%

Natural and biotech-derived therapeutic proteins: What is the future?

Liu

2000

Electrophoresis

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Pharmacokinetic properties of an escherichia-coli-produced recombinant plasminogen activator (BM 06.022) in rabbits

Cited by 17 publications

References 10 publications

Blood Clearance and Activity of Erythrocyte-Coupled Fibrinolytics

Blood Clearance and Activity of Erythrocyte-Coupled Fibrinolytics

Targeting of a Mutant Plasminogen Activator to Circulating Red Blood Cells for Prophylactic Fibrinolysis

Natural and biotech-derived therapeutic proteins: What is the future?

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