AU2006200451A1 - Methods and kits for locally administering an active agent to an interstitial space of a host - Google Patents

Description

AUSTRALIA

Patents Act 1990 THE BOARD OF TRUSTEES OF THE LELAND STANFORD JUNIOR UNIVERSITY COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Methods and kits for locally administering an active agent to an interstitial space of a host The following statement is a full description of this invention including the best method of performing it known to us:- METHODS AND KITS FOR LOCALLY ADMINISTERING AN ACTIVE AGENT TO AN INTERSTITIAL SPACE OF A HOST CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of application serial no. 09/519,950; the disclosure of which is herein incorporated by reference.

INTRODUCTION

Field of the Invention The field of this invention is drug delivery, particularly localized drug delivery.

Background of the Invention One of the most complex and difficult problems that has plagued the medical profession and pharmaceutical industry for decades is the problem of achieving a therapeutic concentration of a drug locally at a target site within the body without producing unwanted systemic side effects. Parenteral or oral therapy of substances directed at treating disease in a particular internal organ or at a particular internal site must often be given in amounts dependent upon achieving critical systemic blood levels that can produce devastating side effects at other areas in the body. In yet other embodiments, the pharmacological agent being delivered may be expensive, making systemic administration costly. As such, systemic routes of administration are not always desirable or acceptable.

A number of protocols and delivery vehicles have been developed for use in local or regional administration of an active agent, where the agent is administered in such a way that it is confined to a particular area or location of the body, e.g. at or proximal to the target tissue. Such protocols include those in which the agent is delivered to the patient in a vehicle that acts as a depot for the agent, where a variety of synthetic and natural polymeric compositions have been used as depots in the local administration of active agents.

While a number of different protocols and vehicles have been developed for use in the local delivery of active agents, there continues to be a need for the development of new protocols of local agent delivery. Of particular interest would be the development of local delivery protocol which could provide for local delivery of an active agent into an interstitial space of a patient, preferably using a catheter based delivery system.

1 Relevant Literature U.S. Patents of interest include: 4,459,977; 4,689,041; 4,934,996; 5,011,468; 5,533,957; 5,597,377; 5,824,071; 5,885,238; 5,913,842; 5,922,687; and 6,159,196. Also of interest are: Mann et al., Proc. Nat'l Acad. Sci. USA (May 1999) 96:6411-6; von der Leyen et al., Hum. Gene Ther. (Sep. 1999) 10:2355-64; Baumbach et al., Catheter Cardiovasc.

Interv. May 1999) 47:102-106. See also Herity et al., Catheterization and Cardiovascular Interventions (2000) 51:358-363.

SUMMARY OF THE INVENTION Methods are provided for locally administering an agent to a host. Specifically, the subject methods provide for the local administration of an agent to an.interstitial space of a host. In the subject methods, an agent is retroinfused into a vessel of a host, typically a vein, under conditions sufficient for the agent to enter an interstitial space of the host proximal to the vessel location into which the agent is retroinfused. In practicing the subject methods, the agent is administered to the host in combination with the production of vascular stress, where the vascular tissue stress is sufficient to provide for transport of the agent from the intravascular space into the target interstitial space. In a preferred embodiment, the agent is retroinfused at a pressure sufficient to provide for mechanical stress on the vessel segments and branches within the target tissue region. Also provided are kits for use in practicing the subject methods. The subject invention finds use in the local administration of a variety of different agents for treatment of a variety of different disease or other conditions. One application of particular interest is the use of the subject methods for localized delivery of an agent to myocardial tissue via a coronary vein, in angiogenic applications.

BRIEF DESCRIPTION OF THE FIGURES Fig. 1 provides a graphical depiction of the results observed in the study described in Example 1A, infra.

Fig. 2 provides a representation oftransvenous pressure-assisted delivery according to the subject invention.

Fig. 3 provides a graphical representation of the results obtained in Example 4.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS Methods are provided for locally administering an agent to a host. Specifically, the subject methods provide for the local administration of an agent to an interstitial space of a host. In the subject methods, an agent is retroinfused into a vessel of a host, typically a vein, under conditions sufficient for the agent to enter an interstitial space of the host across the walls of the branches and segments upstream (from the standpoint of the usual flow) to the vessel location into which the agent is retroinfused. In many embodiments, the agent is administered to the host in combination with the production of vascular stress introduced at the site of administration, where the vascular tissue stress is sufficient to provide for augmented transport of the agent into the target interstitial space. In a preferred embodiment, the agent is retroinfused at a pressure sufficient to provide for mechanical stress on the vessel branches and segments within the target interstitial space. Also provided are systems and kits for use in practicing the subject methods. The subject invention finds use in the local administration of a variety of different agents for treatment of a variety of different disease or other conditions. In further describing the subject invention, the methods.of local active agent administration are described first in greater detail, followed by a review of representative applications in which the subject methods find use, as well as representative systems and kits that find use in practicing the subject methods.

Before the subject invention is described further, it is to be understood that the invention is not limited to the particular embodiments of the invention described below, asvariations of the particular embodiments may be made and still fall within the scope of the appended claims. It is also to be understood that the terminology employed is for the purpose of describing particular embodiments, and is not intended to be limiting. Instead, the scope of the present invention will be established by the appended claims.

It must be noted that as used in this specification and the appended claims, the singular forms and "the" include plural reference unless the context clearly dictates otherwise. Unless defined otherwise all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs.

METHODS

As summarized above, the subject invention provides methods of locally administering an active agent to a host. Specifically the subject invention provides methods for local administration of an active agent to an interstitial location of a host. By local administration is meant non-systemic, such that the active agent administered by the subject methods does not come into contact with more than a limited portion of the host. Generally, less than 50%, usually less than 25% and in many embodiments less than 10% by volume of the host will be contacted with an active agent that is delivered to the host by the methods of the subject invention. In many embodiments, the percent by volume of the host that comes into contact with the active agent following administration by the subject methods is much less than 10%. As such, the subject invention provides a method of regional delivery of an active agent to a host, where the regional delivery does not result in contact with more than a limited portion of the host's tissues with the active agent-i.e. the majority of the host is not contacted with an active agent when the agent is administered by the subject methods.

s1 In the subject methods, the active agent is retroinfused into a vessel or vascular location of the host in a manner such that the agent enters into an interstitial space of the host. By retroinfused is meant that a flowable formulation of the active agent is introduced into the circulatory or vascular system of the host in a retrograde manner, i.e. in a manner that is against the normal blood flow direction in the vascular or circulatory location (i.e.

vascular delivery site) in which the agent formulation is administered. Thus, the flowable agent formulation is administered via a retrograde infusion technique.

While the flowable agent formulation may, in principle, be administered to either an artery or vein, in many embodiments of the invention, the flowable formulation of the active agent is administered in a retrograde fashion into a venous location for delivery and thereby into a region drained, under normal flow conditions, by the venous branches. In these embodiments of the subject invention, a fluid delivery means is introduced into the circulatory system of the patient and advanced to the venous location downstream (under normal flow conditions) from the interstitial target site, i.e. the interstitial space into which agent delivery is desired. In other words, the distal end of the fluid delivery means through which fluid exits the delivery means is advanced to a vascular delivery site, e.g. venous delivery site, which site is next to, adjacent or near the target interstitial site.

While any convenient fluid delivery means capable of accessing the vascular deposition site may be employed, generally the fluid delivery means is a catheter delivery means that is introduced into the host's circulatory system at a site remote from the vascular deposition site. A variety of different catheter delivery means are known to those of skill in the art and have been used in retroinfusion procedures, where such means include those described in U.S. Patent Nos. 4,689,041; 5,533,957 and 5,913,842; the disclosure of which is herein incorporated by reference. In many embodiments, a standard femoral approach is employed, where this standard approach is well known to those of skill in the art.

In preferred embodiments, the catheter fluid delivery system that is employed includes at least the following elements: at least one distal port through which fluid leaves the catheter and enters the vascular delivery site; a proximal attachment means for attaching the proximal end of the catheter to a fluid reservoir of the agent and other external components, e.g. a balloon inflation means; and an occlusion means located next to the distal end of the catheter, where the occlusion means is capable of substantially occluding the vessel downstream (in the usual direction of flow) of the target interstitial site. In a preferred embodiment, the occlusion means is an inflatable balloon that can be inflated to substantially, if not completely, occlude the vessel at a proximal downstream (in the usual direction of flow) location from the vascular delivery site.

In certain preferred embodiments, the fluid delivery means also includes a pressure sensing device that is capable of detecting the pressure at the vascular delivery site and relaying this information to the health care practitioner performing the process, through a data processing and display means. Pressure sensing devices that aresuitable for use in the catheter systems are known in the art and include those described in U.S. Patent Nos.

4,689,041; 4,934,996 and 5,533,957; the disclosures of which are herein incorporated by reference.

As summarized above, the flowable formulation of the agent is introduced into the vascular delivery site, venous delivery site, in a manner such that the agent enters into the interstitial space of the host near to, adjacent to or next to, in the vicinity of, the vascular delivery site. By interstitial space is meant the region or tissue beyond the wall of the vascular site, beyond the intimal surface of the wall. In other words, the subject methods result in deposition of the agent in a space of the host that is on the non-blood side of the vessel into which the composition is administered. In yet another way of describing the subject method, the subject methods result in localizing the agent to a non-vascular space in a region near to the vascular site of delivery. As such, the subject methods provide for deposition of the active agent in tissue interstitium beyond the blood vessel wall and the cells

I

that make up the blood vessel wall, e.g. the intima and the endothelium of the blood vessel wall. Generally, the agent penetrates to a location that is at least beyond the outer cell layer of the vascular cell wall. As such, use of the subject methods results in introduction of the agent to a location that is next to, adjacent or near, but beneath the inner vessel wall along the length of the vessel branches and segments. See e.g. Fig. 1 for a representative myocardial interstitial space into which agent may be introduced using the subject methods.

As can be seen from Fig. 1, in entering the interstitial space, the agent travels beyond the vascular wall and cells associated therewith into the cells and tissues lying beyond the vascular wall. As such, an important feature of the subject methods is that they provide a means for readily administering an agent to interstitial locations and cells next to or associated therewith. Thus, for agents that act intracellularly or inside the cell, e.g. of nonvascular tissue or non-blood vessel tissue, the subject methods provide for deposition of the agent into the interstitial space next to the target cells, such that the agent may readily enter the target cells. Of certain embodiments of the particular interest, the interstitial space is interstitial space of the myocardial tissue, including epicardial and endocardial tissue.

In a more specific manner of describing the invention, the interstitial target space is an interstitial space located adjacent to venous branches, venules and capillary vessels, i.e., venous or arterial capillary vessels, and usually venous capillary vessels. As such, the interstitial target space is typically the interstitium associated with a venous capillary bed that is upstream (in the usual direction of flow) of the venous delivery site. Accordingly, by selecting the appropriate venous delivery site, the location of interstitial agent delivery can be precisely directed into the region of the tissue insterstitium that is served by the branching venous system that is upstream (in the direction of flow) from the venous delivery site.

A feature of the subject methods in many embodiments of the subject invention is that the agent is administered in combination with the application of stress to the vascular tissue associated with, i.e. at and near or next to, the vascular site of administration. More specifically, the subject methods are characterized by including the production of the stress to the vessel segments and branches upstream (in the usual direction of flow) from the vascular site of administration. More specifically, vascular wall stress occurs in the branch vessels and capillaries associated with the fluid delivery or administration site, the venous vessel walls upstream (in the usual direction of flow) of the venous deposition site.

The vascular wall stress that is produced in practicing the subject methods is sufficient to provide for the desired transport of the vascular administered agent to the target

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interstitial space. In other words, the amount of stress that is produced in the vasculature Sduring practice of the subject methods is sufficient to provide for transport of the desired Samount of agent from the vascular site of administration into the target interstitial space, O where it is then available for uptake by the target cells in those embodiments where the agent is to act intracellularly. The stress that is produced on the vessel walls as part of the subject Smethods may be produced before or during administration of the active agent. As such, the stress will be placed on the vessel walls prior to administration in certain embodiments. In Sother embodiments, the stress will be placed on the vessel walls during administration.

I\O The above described vascular wall stress may be produced in a number of different ways, where such ways include physical stress, chemical stress, combinations thereof, and C' the like. In some embodiments, the production of stress produces inflammation in the target intestitial area, where the inflammation is desired and provides for enhanced activity of the active agent upon reaching the target interstitial space. For example, in methods where the active agent is an angiogenic inducing agent, the subject methods may be performed in a manner that produces inflammation in the target interstitium, thereby enhancing the action of the angiogenic agent. As mentioned above, stress may be produced in the vessel wall using a single means or using a combination of means, e.g. a physical means and a chemical means.

Physical means of producing stress in the vasculature include pressure means, application of external energy, etc, where chemical means of producing stress in the vasculature include chemical inflammatory agents, etc. Representative physical and chemical means of producing stress in the vasculature that may be employed in the subject methods are nowdescribed in greater detail below.

In one preferred embodiment of the subject methods, the flowable formulation of the active agent is introduced into a vascular delivery space in a manner such that mechanical stress is introduced at the site of delivery and is conducted to the branching vessels upstream (in the usual direction of flow), where the mechanical stress is of sufficient magnitude to provide for passage of the active agent from the vascular space into the target interstitial space. In certain embodiments, the pressure is sufficient to result in distention of the vessel, whereby distention of the vessel is meant expansion of the vessel such that the vessel segments and branches upstream (in the usual direction of flow) are stretched. Where distention is employed in the subject methods, the volume of the effective vascular deposition site bounded by the vessel walls typically increases in many embodiments by a factor of at least about 100%. Distention of the vessel walls results in increased permeability of the vessel walls to the active agent, where the permeability increases by a factor of at least about 5 and usually by a factor of at least about In another preferred embodiment of the subject methods, the flowable formulation of the active agent is introduced into the vascular deposition space in a manner such that the mechanical stress is of sufficient magnitude to provide for actual disruption of the vessel wall. By disruption of the vessel wall is meant that the integrity of the wall is compromised such that actual passageways appear between the interior of the vessel and regions beyond the inner wall surface, i.e. between the vascular deposition site and the target interstitial space. These passageways may be sufficiently large to allow for the delivery of cells or particulate drug delivery means into the interstitium. In certain embodiments, the number of passageways that is created in the vessel is at least about 10, usually at least about 100 and more usually at least about 500, where in certain embodiments the number of passageways that are produced in the vessel walls is 1000, 2000, 3000 or more.

In those methods of the subject invention where the wall is subjected to mechanical stress to provide for the desired entry of the delivered active agent to the target interstitial space, a preferred means of providing the desired mechanical stress is to produce a high pressure environment in the target vascular branching system that is sufficient to provide the desired mechanical stress. The pressure of the high pressure environment that is produced in these embodiments may vary depending on the nature of the target tissue region and its vascular supply, whether it is a tissue site of small volume, large volume, the blood pressure at the vascular delivery site, the type of venous system, and the like. While exact, pressures vary depending on the nature of the tissue and the vascular pattern, in many embodiments the pressure of the vascular delivery site is elevated to a value of at least about mm Hg, usually at least about 60 mm Hg, where in certain embodiments the pressure may be elevated to a value that is at least about 1000 mm Hg or higher. However, the pressure that is employed is not so great as to cause unacceptable tissue damage, e.g., unacceptable internal bleeding, etc. As such, in most embodiments the pressure does not exceed about 500 mm Hg. A preferred pressure in many embodiments is or is about 100 mm Hg. As such, in many embodiments, the pressure that is employed ranges from about 60 to 140, usually from about 75 to 125 and more usually from about 90 to 110 mm Hg.

The elevated pressure in the vascular bed may be produced using any convenient protocol. Generally, the elevated pressure will result from a combination of blockage or occlusion of the vascular site at a location downstream (in the usual direction of flow) of the vascular delivery site and introduction of the fluid at elevated pressure into the vascular delivery site upstream (in the usual direction of flow). In these embodiments, power injectors may be employed to introduce the fluid at the desired elevated pressure. Alternatively, syringes or other fluid delivery means may be employed, where manual pressure is applied in such a manner as to achieve the desired pressure.

In yet other embodiments, retroinfusion of the agent to the target vascular site is accompanied by the application of energy to the vascular site under conditions sufficient to cause the desired stress in the vessel walls and thereby provide for migration of the active agent from the vascular site to the target interstitial location. In these embodiments, external energy is applied to the target vascular site to promote entry of the agent into the target interstitial space. .Any means of applying external energy to the vascular site may be employed. As such, jets or other such means on a catheter device which are capable of providing varying external forces to the target vascular deposition site may be employed. Of particular interest in many embodiments is the use of ultrasound. The ultrasound can be applied during part of, or the entire time of, agent administration. There are several devices for the application of ultrasound to cardiovascular tissue known to those of skill in the art.

For example, U.S. Patent No. 4,808,153, the disclosure of which is herein incorporated by reference, describes an ultrasound apparatus to be used in an artery without damaging the artery, and U.S. Patent 5,432,663, the disclosure of which is herein incorporated by reference, describes an apparatus for generating ultrasonic energy useful for removal of intravascular blockages. The ultrasound can be low frequency ultrasound. Another means that may be employed to apply external energy to target vascular site is to use a mechanical means of applying external energy. Mechanical means of interest include moving structures, e.g. rotating wires, which physically contact the target lesion and thereby apply physical external energy to the target lesion. Yet other means include localized application of heat, e.g. through a localized elevated temperature means.

One may also employ electroporation, where electrical energy is delivered such that the requisite stress is applied to the vessel walls and consequent transport of the agent to the interstitial target location is achieved. Catheter devices comprising electroporation means are known in the art and may be readily adapted for use in the subject methods. See e.g.

5,944,710, the disclosure of which is herein incorporated by reference.

It yet other embodiments, RF energy may be employed to provide the requisite vascular wall stress. A variety of catheter designs capable of directing RF energy to vascular wall are known and may be adapted for use in the subject methods. See e.g. 5,997,532; 5,954,719; 5,951,471; 5,944,716; 5,938,632; 5,938,599; 5,935,123; 5,931,835; 5,924,987; and the like.

Alternatively, or in addition to one or more of the above physical means, a variety of different chemical stress means may be employed to provide the requisite vascular tissue stress. Chemical means that may be employed include inflammatory agents, tissue disrupting agents, and the like, where such agents include small organic and inorganic compounds, e.g. acids, organic solvents, detergents and the like, as well as biological agents, e.g. enzymes (such as lipases, proteases, etc.) and the like.

A feature of the subject invention is that delivery of the fluid composition of the agent to a single vascular site can be used to administer agent to a relatively large region of interstitial space. For example, in those preferred embodiments in which the fluid agent composition is retroinfused into a venous site, the fluid agent composition can enter the entire upstream (in the usual direction of flow) region of the vein the branching network of venous capillaries, venules and veins that usually deliver blood to the venous site of delivery). More specifically, the agent can be targeted to the entire interstitial space surrounding the venous capillary bed upstream of the fluid deposition site. Thus, the agent may enter all of the venous branches of the vein upstream of the site of administration. As such, active agent will enter the interstitial spaces associated with not only the vein at the site of administration but also with the venous branches upstream of from the vascular site of deposition. In this way from a single catheter delivery site, deposition of the fluid into the interstitium is achieved via hundreds or even thousands of branches distributed throughout the target tissue region.

The interstitial tissue or region to which agent is administered during the subject method may be controlled or tailored in a number of different ways. For example, by proper selection of the vascular delivery site (that is, the location and order or generation of the branch vessel selected), one can limit the interstitial space to which agent is administered.

Furthermore, one or more upstream branches can be occluded, e.g. through use of a second balloon or embolization means, to further define or limit the interstitial space to which agent is administered. In addition, means can be employed to neutralize or remove agent that does not reach the target interstitium following administration, where such means include systemic neutralizing agents, flushing of the site of administration and upstream branched/tributaries following administration, and the like.

Depending on the agent being administered and/or application in which the subject methods are employed, disease condition being treated, the above described method of agent administration may be performed once or a number of times during a given time period. When the methods are performed a plurality of times during a given time period, the s dosing schedule can be hourly, daily, weekly, biweekly, monthly, half-yearly, yearly, etc., or some other interval schedule, depending on the particular application and the nature of the active agent being administered.

An important feature of the subject methods is that they are safe, despite the vessel wall stress that is produced in practicing the subject methods. The subject methods are deemed safe in that they do not produce a lasting adverse impact on the vessel tissue in the region of administration. In other words, any tissue trauma or stress produced during practice of the subject methods quickly heals, such that in a short period of time, 1 month, 2 months, 3 months or at most 6 months, substantially no tissue damage remains. In addition, there is substantially no impact on arterial blood flow in vessels upstream of the venous capillary vessel bed that is the site of tissue trauma or rupture during practice of the subject methods. Accordingly, the subject methods are safe.

The subject methods are suitable for use in delivery of agents to the interstitial spaces of a variety of different organs and tissues. Representative organs and tissues include: cardiac tissue, via coronary vein delivery, including but not limited to the coronary sinus, great cardiac vein and tributaries thereof, middle cardiac vein and tributaries thereof, small cardiac vein and tributaries thereof, etc.; peripheral tissue, via peripheral veins; central nervous tissue such as the brain, e.g. via the great cerebral vein or branches thereof, hepatic tissue, e.g. via the hepatic vein or a branch thereof, kidneys, e.g. via a renal vein; and the like. Of particular interest in certain embodiments is the use of the subject methods for the delivery of agents to myocardial tissue, e.g. the epicaridum, endocardium, etc., of the myocardium.

The subject methods have a drug delivery efficiency to the target interstitial location such that an effective amount of the active agent readily enters the target interstitial space from the initial vascular site of deposition. In the subject methods, the efficiency is generally such that at least about I by weight of the agent initially deposited in the vascular site reaches the target interstitial space, wherein in many embodiments the efficiency is at least about 10 and in certain embodiments is at least about 20 As compared to a control situation in which an analogous method is employed but vascular wall stress or damage is not provided, as is requisite in the subject methods, the efficiency of administration of the agent increases by at least about 10 fold, and in many embodiments by as much as 25 or even 50 fold.

The above described methods may be used to introduce a wide variety of active agents to a target interstitial space. The methods may be desirable for any drug or other biological agent in which there is potential toxicity for tissues outside of the region of interest or where the cost of the agent is sufficiently high that targeted delivery to the region of interest is preferred. Active agents of interest include both small molecule active agents, as well as macromolecular or large molecule active agents molecules having a molecular weight in excess of 5000 daltons, usually 10,000 daltons), including biological agents, where the administration of biological agents and derivatives thereof is of particular interest in many embodiments. Representative biological agents of interest include, but are not limited to, e.g. nucleic acids, such as oligonucleotides and polynucleotides, both ribo and deoxyribo, as well as mimetics thereof e.g. PNAs; polypeptides and proteins; polysaccharides; lipids; and mimetics thereof.

Of particular interest in many embodiments is the use of the subject methods to deliver therapeutic nucleic acids. The subject methods may be used to deliver a wide variety of therapeutic nucleic acids. Therapeutic nucleic acids of interest include genes that replace defective genes in the target host cell, such as those responsible for genetic defect based diseased conditions; genes which have therapeutic utility in the treatment of cancer; genes which stimulate angiogenesis (such as del-1); and the like. Specific therapeutic genes for.

use in the treatment of genetic defect based disease conditions include genes encoding the following products: factor VIII, factor IX, P-globin, low-density protein receptor, adenosine deaminase, purine nucleoside phosphorylase, sphingomyelinase, glucocerebrosidase, cystic fibrosis transmembrane regulator, a-antitrypsin, CD-18, ornithine transcarbamylase, arginosuccinate synthetase, phenylalanine hydroxylase, branched-chain ca-ketoacid dehydrogenase, fumarylacetoacetate hydrolase, glucose 6-phosphatase, a-L-fucosidase, 3glucuronidase, ct-L-iduronidase, galactose 1-phosphate uridyltransferase, FGF, VFGF, and the like, where the genes are preferably the genes encoding the human versions of the above proteins. Cancer therapeutic genes that may be delivered via the subject methods include: genes that enhance the antitumor activity of lymphocytes, genes whose expression product enhances the immunogenicity of tumor cells, tumor suppressor genes, toxin genes, suicide genes, multiple-drug resistance genes, antisense sequences, and the like. The subject methods can be used to not only introduce a therapeutic gene of interest, but also any expression regulatory elements, such as promoters, and the like, which may be desired so as to obtain the desired temporal and spatial expression of the therapeutic gene.

The subject methods may also be employed to deliver a variety of peptide and protein therapeutic agents. Representative peptide and protein therapeutic agents of interest include: potent cytokines, including various hematopoietic factors such as G-CSF, GM-CSF, M-CSF, MGDF, the interferons (alpha, beta, and gamma), interferon consensus, the interleukins erythropoietin (EPO), fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), VFGF, TNF, TNFbp, IL-Ira, stem cell factor, nerve 1o growth factor, GDNF, BDNF, NT3, platelet-derived growth factor, and tumor growth factor (alpha, beta), osteoprotegerin (OPG), and the like, where the proteins are typically the human proteins.

In yet other embodiments, the agent administered to the interstitial space via the subject methods is an imaging agent or dye. Imaging agents of particular interest include: non-ionic imaging agents, e.g. CONRAYT, OXILAN

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and the like.

In yet other embodiments, the agent that is administered to the interstitial space is not an active agent in its own right, but provides for the presence of an active agent in the target interstitial site. As such, a cell which provides for the presence of a desired compound in the interstitial target site, e.g. the presence of a desired protein which is expressed and secreted by the cell into the target interstitial space, may be administered via the subject methods. The method is also usable for the delivery of cells to replace lost or damaged cells in a region. of interest for delivery of heart muscle cells in an area of prior damage due to heart attack). Alternatively, an agent that recruits a subsequently systemically administered agent to the interstitial target site may be employed. For example, an agent exhibiting a specific epitope may be administered to the interstitial site. Subsequent to administration an antibody, potentially conjugated to an active agent, may be systemically administered upon which the antibody homes to and is recruited to the target interstitial site.

In yet other embodiments, the agent is an agent that is neutral upon administration, but subsequently activated to produce the active agent. Examples of such activatable agents include agents that re light activated, agent that have photolabile blocking groups that, upon exposure to light, are removed to produce an active agent, RF activated, ultrasound activated, heat activated, etc. With such methods, the subject methods further include a step of activating the initially neutral agent following delivery to the target interstitium. This step may conveniently be accomplished using technology incorporated into the system that is employed to practice the method, a light source such as a laser, and RF source, etc.

In the subject methods, the agent may be administered in any convenient fluid vehicle. In many embodiments, the agent is dissolved in a fluid delivery vehicle. The fluid delivery vehicle may be any convenient fluid which is suitable for vascular introduction, particularly intravenous administration. In these embodiments, the vehicle is generally an aqueous fluid, where the aqueous fluid may or may not include a number of additional optional components, e.g. electrolytes (such as Cl, K+,Na, Ca 2 etc.), nutrients amino acids), oncotic agents dextran), pH modulating agents lactate), etc. Generally, the aqueous fluid is made up of water for injection to which one of more optional agents such as the representative ones described above have been added.

Depending on the nature of the active agent, the active agent may be administered in combination with a vector or delivery means that provides a one or more desired functions, e.g. as a depot of the agent, to enhance delivery of the agent into a target cell, etc. Thus, in an alternative embodiment of the above described methods, the agent is administered in combination with a depot means, where the depot means and agent are administered under pressure sufficient to lodge the depot means/agent at the vascular site of administration or deposition such that agent enters the target interstitial space proximal (in the usual direction of flow) to the vascular site of administration. Any convenient depot means may be employed, so long as the depot is compatible with intravascular, e.g. intravenous, administration. Depot means of interest include particulate or viscous compositions that, when administered under pressure, lodge in the vascular space to which they are administered such that the active agent is capable of entering the target interstitial space.

Specific depot materials of interest include microcoils, e.g. platinum or stainless steel microcoils, polyvinyl alcohol sponges, bioglues cyanoacrylate glues), precipitative materials, and the like, where representative materials are disclosed in U.S. Patent No.

5,925,683, the disclosure of which is herein incorporated by reference.

Where the active agent is a nucleic acid e.g. DNA or RNA encoding a therapeutic produce, antisense, etc., a variety of different nucleic acid vectors may be employed.

Alternatively, an agent that modulates the distribution of the vector in the multicellular organism may be employed. For example, lipid based, e.g. liposome, vehicles may be employed. Patents disclosing such methods include: U.S. Patent Nos. 5,877,302; 5,840,710; 5,830,430; and 5,827,703, the disclosures of which are herein incorporated by reference.

Alternatively, polylysine based peptides may be employed as carriers, and the like. (Broo!:s, et al. 1998, J. Neurosci. Methods V. 80 p: 137-47; Muramatsu, Nakamura, and H.M. Park 1998, Int. J. Mol. Med. V. 1 p: 55-62). In yet other embodiments, the system components may be incorporated onto viral vectors, such as adenovirus derived vectors, sindbis virus derived vectors, retroviral derived vectors, etc. hybrid vectors, and the like. The above vectors and delivery vehicles are merely representative. Any vector/delivery vehicle combination may be employed, so long as it provides for desired delivery of the active agent from the interstitial site of deposition.

As discussed above, the above described methods of the subject invention result in to the localized administration of an active agent into a target interstitial space of a host, where the agent is administered via the vascular system of the host. In other words, the subject methods provide a means for delivering an agent to a target interstitial space from a vascular site of administration, where the target interstitial space is not within a vessel e.g. is not within a vein.

The subject methods may be used in the delivery of active agents to a variety of hosts. Generally such hosts are "mammals" or "mammalian," where these terms are used broadly to describe organisms which are within the class mammalia, including the orders carnivore dogs and cats), rodentia mice, guinea pigs, and rats), lagomorpha (e.g.

rabbits) and primates humans, chimpanzees, and monkeys). In many embodiments, the hosts will be humans.

The subject methods find use in a number of different applications. Of particular interest is the use of the subject methods to locally administer one or more active agents to a host, where administration of the active agent(s) is desired to treat a disease or other condition of the host. Representative disease conditions in which the subject invention finds use include: cardiovascular disease conditions, treatment of cellular proliferative diseases, gene therapy applications, central nervous system disorders, renal disease conditions, peripheral vascular disease conditions, and the like.

The subject methods are particularly suited for use in the delivery of one or more active agents safely and efficiently to cardiac interstitial space, particularly myocardial interstitial space. Figure 2 provides a representation of the how the subject methods achieve introduction of agent into the myocardial interstitium. In many embodiments, the target myocardial interstitium is a region of the left ventricular myocardium, the interventricular septum, anterior and posterior left ventricular walls, left ventricular apex, etc. In targeting this particular interstitial site, the coronary sinus or major tributaries thereof, the great cardiac vein, middle cardiac vein, small cardiac vein, may be employed as the fluid composition delivery site using a femoral vein approach. A more complete description of a representative protocol for accessing the coronary sinus and tributaries thereof to practice the subject methods is provided in the experimental section, infra. Using the guidelines provided above in terms of pressure etc., the agent may be administered to the above myocardial interstitial target regions safely and efficiently, without adverse impact on upstream arterial flow, left anterior descending artery anterior flow, etc., and no long term tissue damage, as described above. A variety of different agents may be administered to myocardial interstitium using the subject methods, where agents of interest include those listed supra.

One specific type of representative agent that can be administered to myocardial interstitium with the subject methods is angiogenic agents, e.g. where the subject methods may be employed to target such agents to the interstitial space of myocardial tissue, including the epicardium, endocardium etc. In this embodiment of the subject methods, a fluid composition of the angiogenic agent is retroinfused into a coronary vessel, typically a coronary vein, in conjunction with the application of stress to the coronary venous vessel walls, e.g. by administering the fluid agent at high pressure, e.g. in excess of 50 mm Hg and generally around 100 mm Hg, as described above. Angiogenic factors of interest include those described in U.S. Patent Nos.: 5,972,903; 5,941,868; 5,866,561; 5,798,386; 5,756,453; 5,470,831; 5,356,874; 5,332,804; 5,318,957; 5,238,925; 5,171,845; 5,137,734; 4,921,838; 4,916,073; 4,900,673; 4,897,464; 4,895,838; 4,888,324; 4,879,312; 4,727,137; 4,721,672; 4,710,490; 4,699,788; 4,698,301; 4,529,590; 4,503,038; 4,273,871 and the like, the disclosures of which are herein incorporated by reference. In certain preferred embodiments, the angiogenic factor is administered in a manner that produces inflammation at the site of administration, as described above.

Another specific representative application in which the subject methods find use in the treatment of hepatic cellular proliferative diseases, e.g. liver cancer. In such applications, an antineoplastic agent is retroinfused into the hepatic vein in conjunction with application of stress to the walls of hepatic vein. In many embodiments, the antineoplastic agent is retroinfused into the hepatic vein under pressure such that there is structural disruption of the venous walls and transport of the active agent to the hepatic interstitial space and cells located therein. Representative antineoplastic agents which may be employed in this representative method include those described above.

Analogous procedures can be employed to administer agents to a variety of other interstitial target regions of various tissues and organs, where a common feature of each of these embodiments is the use of the subject methods to introduce the agent into the target interstitial location.

SYSTEMS

Also provided are systems for use in practicing the subject methods. The subject systems at least include a fluid delivery means for accessing the target delivery site, where the fluid delivery means is typically a catheter delivery means, as described above. The proximal end of the fluid delivery means is in fluid communication with a source of the fluid composition to be administered, where the fluid composition is as described above. The source of fluid composition is-generally present in a fluid reservoir, container. Also present in many embodiments is a means for introducing the fluid from the reservoir into the fluid delivering means under pressure, a pressurized fluid delivery means.

KITS

Also provided by the subject invention are kits for use in practicing the subject methods. The kits of the subject invention include at least one of: a catheter delivery means, as described above, (where a representative catheter delivery means is described in the experimental section, infra) and (ii) the active agent, where in certain embodiments the kits will include a catheter (or analogous intravenous fluid delivery means) and an active agent. The active agent may be present as a fluid composition or as a storage stable dried composition that is reconstituted prior to administration, a lyophilized preparation, etc.

In addition, the kit may include a fluid delivery vehicle, such as water for injection or intravenous fluid, which may be modified to include one or more additional optional components such as those described above, e.g. electrolytes, nutrients, oncotic agents, etc.

In addition to at least one of the fluid delivery means and the active agent(s), the subject kits also include instructions for administering the active agent according to the subject invention. Specifically, the subject kits also include instructions for using the components of the kit in methods of retroinfusing an agent in a manner that results in localized delivery of the agent to an interstitial space. The instructions for practicing the above described methods or variations thereof are generally recorded on a suitable recording medium. For example, the instructions may be printed on a substrate, such as paper or plastic, etc. As such, the instructions may be present in the kits as a package insert, in the labeling of the container of the kit or components thereof associated with the packaging or subpackaging) etc. In other embodiments, the instructions are present as an electronic storage data file present on a suitable computer readable storage medium, e.g. CD-ROM, diskette, etc.

The following examples are offered by way of illustration and not by way of limitation.

EXPERIMENTAL

Example 1.

A.

Background: Therapeutic angiogenesis is a promising option for patients with refractory angina unsuitable for revascularization, but current delivery methods either require openchest surgery or provide only short-lived, transient exposure to growth factors. This study assessed the feasibility of percutaneous coronary venous cannulation and selective regional injection as a novel approach to local myocardial drug delivery.

Methods and Results: In 13 anesthetized pigs the coronary sinus was cannulated percutaneously and a balloon-tipped catheter was advanced to the anterior interventricular vein (AIV) or middle cardiac vein (MCV). During balloon occlusion, selective venous injection of radiographic contrast (diatrizoate) caused localized myocardial staining.

Injection was performed with hyperbaric pressure in 8/13 cases In the total group, videodensitometric analysis showed that diatrizoate persisted for at least 30 minutes, with clearance over approximately the first 4 minutes (figure Venous injection ofEvans Blue dye showed that localized, regional infiltration was reproducibly accomplished in targeted myocardial regions: the left ventricular apex, anterior interventricular septum and anterior wall via the AIV and the inferoposterior wall via the MCV.

Conclusions: The percutaneous coronary venous route is a favorable delivery approach for therapeutic angiogenic substances, being reproducibly accessible and facilitating selective regional myocardial delivery and persistence of delivered substances.

B. Intracardiac Venous System as a Novel Conduit for Local Drug Delivery Background: Effective strategies for administering angiogenic factors involve either multiple myocardial injections or intracoronary delivery into highly diseased conduits. Alternatively, access to cardiac venous system through the coronary sinus provides an extensive network of vessels for regional delivery of angiogenic agents to the distal myocardium.

Methods: Five swine underwent simultaneous right and left heart cardiac catheterization. A 7F balloon tip catheter over a guidewire was used to cannulate the anterior interventricular vein (AIV). 15 tm fluorescent microspheres were used to determine the territory of myocardium that drains into the AIV, and would be potentially available for drug delivery.

A different color set of microspheres was used to label the left anterior descending artery territory (through subselective engagement of LAD). All injections were performed over constant time and pressure. Simultaneous ventricular end diastolic pressure (LVEDP), coronary wedge pressure, and distal venous wedge pressure were measured during the balloon inflation. The hearts were harvested and a circumferential sample was divided into eight segments; each segment was divided further into the epicardial and endocardial layers.

These samples were processed for microspheres sedimentation, and subjected to scanning fluorometery to determine the amount of different color microspheres in each region.

Results: There was no significant increase in the LVEDP, and only transient elevation of VWP during the injections (range of 5 to 30 mm Hg). The concentration of microspheres in the LAD territory was similar in both LAD and AIV injections (93% 3.5 vs. 81% respectively). 68% of the microspheres delivered through the AIV localized to the epicardial layer of myocardium vs. 53% delivered through the LAD (endocardial localization after AIV and LAD injections were 32% and 47%, respectively).

Conclusion: These data demonstrate the feasibility of using the cardiac venous system for regional myocardial reagent delivery.

Example 2 The following provides a more detailed write up of the above experiments, and provides additional experimental data.

A. Materials And Methods The protocol was approved by the Stanford University Administrative Panel on Laboratory Animal Care. Female Yorkshire swine (8 -12 weeks old, 31-81 kg) were premedicated and anesthetized by approved techniques. Following sterile skin preparation and cutdown, 8 Fr sheaths were placed in the right femoral artery and vein and in the left femoral vein.

1. Percutaneous Coronary Venous Access An 8 Fr Amplatz left 0.75, Amplatz right modified, or Hockey stick coronary guiding catheter (Cordis, Miami FL) was advanced to the right atrium, slowly withdrawn, and rotated posteromedially to engage the coronary sinus ostium. An exchange length extra support guidewire (0.035", Terumo Corporation, Tokyo, Japan) was advanced via the great cardiac vein (GCV) to the anterior interventricular vein (AIV), which parallels the left anterior descending artery (LAD) in the anterior interventricular sulcus. Alternatively, the guidewire was directed into the middle cardiac vein (MCV), which runs in the posterior interventricular sulcus to access the posterolateral wall of the left ventricle. The guiding catheter was replaced over-the-wire by a 7 Fr balloon-tipped Swan-Ganz catheter, which was then advanced to the AIV or MCV and the guidewire was withdrawn.

2. Effect of AIV Occlusion on LAD Flow In six pigs, an 8 Fr Hockey stick arterial guiding catheter was advanced via the femoral arterial sheath to the ascending aorta and positioned in the left coronary ostium. A Doppler coronary guidewire (0.0140 FloWire, Endosonics, Rancho Cordova CA) was advanced through the guiding catheter to the mid part of the LAD or circumflex (Cx) artery and connected to a dedicated display and velocity calculation system (FloMap, En-dosonics).

The wire tip position was gradually adjusted until a satisfactory visual and auditory spectral signal was obtained. Velocity measurements were recorded at baseline and during pharmacological hyperemia (intra-coronary adenosine 24-mg bolus), a cineangiographic recording of the artery was made within 10 sec of adenosine injection and the end-diastolic arterial diameter was measured at the tip of the Doppler wire, using quantitative coronary angiography (Philips). Baseline and hyperemic flow velocity measurements were made in the LAD and Cx (which served as a control) before and during a 5-min balloon occlusion of the AIV.

3. Myocardial Clearance of Radiographic Contrast Following selective cannulation of the AIV or MCV, the Swan-Ganz catheter balloon was inflated to the point of complete venous occlusion and a single injection of 10 ml of undiluted ionic radiographic contrast (diatrizoate, Hypaque) was made over 5 sec through the distal catheter port with sufficient manual pressure to cause myocardial contrast staining observed by fluoroscopy. Angiographic recordings were made in a straight anteroposterior projection before injection (the background control), at the time of injection, at 1-min intervals to 6 min postinjection, at 2-min intervals between 6 and 20 min postinjection, and at 5-min intervals between 20 and 30 min postinjection. Balloon occlusion of the vein was maintained throughout this 30-min period. Images were acquired using a manually selected constant radiographic technique of 65-75 kVP and 420-520 mA and recorded at frames/sec on cineangiographic film. A copper plate (3-mm thickness) attached to the under side of the image intensifier served as a quality control, by which it was ensured that all of the sequential angiograms were recorded at identical brightness settings. End-diastolic images from each time point were digitized using commercial desktop computer software (F/64 Pro, Coreco) for subsequent intensity analysis (Adobe Photoshop, Adobe Systems). A constant region of interest in the area of myocardial staining was chosen and the median brightness signal intensity measured in that region for each time point. Measurements were standardized on a percentage scale where the preinjection signal intensity (the background control) was assigned 0% and the immediate postinjection signal intensity was assignedl00%.

4. Regionality of Myocardial Infiltration At the end of each experiment, a selective venous injection of 0.5% Evans Blue, 6 ml mixed with 4 ml of diatrizoate, was performed during balloon occlusion of the AIV or MCV.

Euthanasia was performed by administration of potassium chloride within 5 min (10 mg/kg IV) and the heart was explanted for direct visual localization of the region of staining.

Statistical Analysis Data are presented as mean 6 standard deviation or standard error as appropriate.

Within-group comparisons used the paired t-test (SigmaStat, Jandel) and P 0.05 was considered statistically significant.

B. Results In all cases, localized myocardial staining followed injection of diatrizoate or Evans Blue dye into the AIV (n 12) and MCV (n Injection of the AIV, distal to a balloon occlusion, caused selective regional staining of the anterior LV wall, apex, and anterior interventricular septum and MCV injection selectively stained the inferior LV wall, posterior septum, and the posterior walls of the left and right ventricles.

Complete balloon occlusion of the AIV had no impact on LAD flow parameters (Table 1).

Table 1. Effect of Anterior Interventricular Vein (AIV) Occlusion on Coronary Arterial Flow Parameters in Six Anesthetized Pigs, Before and During Adenosine- Induced Hyperemia 2 4 -pg Intracoronary Injection)*.

Before AIV Occlusion During AIV Occlusion Baseline Hyperemic Hyperemic Baseline Hyperemic Hyperemic APV APV arterial APV APV arterial diammeter diammeter (mm) M (mm) T LAU 12.33(3.01) 24.33(5.68) 2.95 (0.42) 14.67(3.78) 24.33(5.72.) 291(.030) Cx 16.83 (4.58) 28.00 2.75(0.57) 16.17(5.71) 28.00(4.24) a 2.84(0.62) Mean APV=average peak velocity of blood in cm/sec 'P<0.05 compared with baseline value by paired t-test.

Specifically, the average peak velocity (APV) of blood in the LAD was unaffected by AIV occlusion, both before and in the setting of adenosine-induced hyperemia and the hyperemic diameter of the LAD was unchanged by AIV occlusion. Calculated hyperemic LAD flow (the product of APV and cross-sectional area) was 106 (SD 51) ml/min before and 99 (SD 33) ml/min during AIV occlusion (P hyperemic flow in the control Cx was 105 (SD 49) ml/min before and 111 (SD 51) ml/min during AIV occlusion (P =NS).

Videodensitometric analysis (n 7) showed that myocardial clearance of contrast followed two phases: a relatively rapid elimination phase followed by a plateau phase associated with persistence of about 20% of the initial signal intensity until at least 30 min postinjection (Fig. The time taken for 50% of the maximum density signal to clear was approximately 4 min. During the 30-min period of venous occlusion, no adverse hemodynamic or electrocardiographic changes occurred.

C. Discussion This above results demonstrate that coronary veins draining most regions of the left ventricular myocardium can be selectively cannulated, that complete balloon occlusion of these veins for up to 30 min does not impede regional or global arterial perfusion, and that the persistence of substances delivered by this technique is theoretically sufficient to exert a biological effect.

The subject modes of delivery obviate the anesthetic risks ofthoracotomy, avoid the risks of repeated arterial instrumentation associated with intracoronary delivery, and permit selective regional myocardial treatment in the setting of total coronary arterial occlusion (a near ubiquitous finding in this group of patients).

The observation that complete balloon occlusion of the. AIV, the principal venous conduit on the anterior surface of the heart, makes little difference to LAD flow is consistent with previous descriptions of alternative venous channels through the heart. Thus, when blood is prevented from draining through the AIV, it can be diverted through apical venovenous anastomoses to the middle cardiac vein or via the Thebesian system directly into the atrial and ventricular cavities. Therefore, brief periods of venous occlusion used to maximize local myocardial delivery by this technique are unlikely to cause myocardial ischemia, arrhythmias, chest pain, or systolic dysfunction. Consistent with this conclusion, in our study no arrhythmias or hemodynamic disturbances were observed during balloon occlusion of, or injection into, the coronary venous system.

A principle feature of the present technique is a single injection to penetrate mechanically the venocapillary vasculature, thus infiltrating the myocardial interstitium and creating a reservoir of potentially biologically active material, which exerts a local effect over the time that it is retained therein. Unlike other systems, where the pressure of infusion is set to prevent inadvertent capillary injury, the current technique is designed to incorporate controlled venocapillary damage as an integral component. In its current form, it relies on the exquisite control of the human hand, reinforced by fluoroscopic visual feedback, to achieve tissue penetration without jeopardizing the integrity of epicardial veins. However, appropriate ranges of injection pressures are readily identified, and with such one can obtain the automation of the venous injection. This relatively simple procedure is designed to last a few minutes (rather than the several hours associated with other methods), to be suitable for ambulatory patients, and to be applicable to repeated treatments if necessary.

In summary, the above work demonstrates that the coronary sinus and its major.

tributaries can be reliably and reproducibly accessed using currently available percutaneous catheter technology and a standard femoral approach. Selective regional myocardial infiltration can be achieved with no impact on arterial blood flow and substances that are delivered disperse slowly. Avoiding the need for anesthesia and thora-cotomy and at the same time achieving local and selective delivery suggests that this technique may be a favorable route for therapeutic angiogenesis, gene therapy, or other local drug delivery applications for the heart.

Example 3. Studies Of Parameters That Best Predict Angiographically Visible Penetration During Cardiac Venous Injection A. Introduction While cardiac venous injection is a feasible and promising technique for local S delivery to the heart (Herity NA, et al. Catheter Cardiovasc Interv 2000; 51: 358-63), safe and effective injection parameters must be determined so that the injection technique is standardized for more widespread application.

B. Methods In 8 anesthetized pigs, repeated cardiac venous injections ofdiatrizoate (radiographic contrast, 10cc) were performed while varying external pressure of delivery (mmHg), flow rate through the delivery catheter (mlmin) or pressure within the cardiac vein during injection. Presence or lack of penetration was determined angiographically.

C. Results In all, 67 injections were performed. External delivery pressure (measured outside the delivery catheter) was a poor predictor of visible penetration with near-complete overlap between penetrating and non-penetrating injections. Similarly flow rate through the catheter poorly predicted penetration. By contrast mean injection pressure within the AIV was a more accurate predictor: in no case did visible penetration occur below a mean delivery pressure of 50 mmHg and in very few cases did penetration fail to occur above 100 mmHg.

Mean internal delivery pressures of up to 200 mmHg were well tolerated without venous perforation.

D. Conclusions For the development of this delivery system, a system for measuring internal venous pressure during injection is the most likely method to ensure myocardial penetration in every case. A target mean internal pressure of 100 mmHg is a safe and effective threshold in this model. Clinical studies will determine the appropriate delivery threshold in patients although it is likely to be similar.

Example 4. Regional Myocardial Treatment by Selective Delivery through the Cardiac Venous System An optimal approach for regional myocardial treatment has not been fully established. In order to achieve therapeutic efficacy through local delivery, a delivery approach that can safely provide a critical concentration of reagent(s) is required. The cardiac venous system represents a potential conduit for the delivery of various reagents to the myocardium. In this study, regional access into the myocardium (LAD territory) was demonstrated by retroinfusion of fluorescent microspheres (15 pm) via the anterior intraventricular vein (AIV). Histological sections confirmed the penetration of these microspheres within both endocardial and epicardial layers of myocardium. Venous retrograde infusion of 1 2 I-labeled albumin through AIV resulted in retention of 4.14 1.2% t of the total albumin injected into non-ischemic animals. In a model of chronic myocardial ischemia 1 2 SI-bFGF delivered through the AIV resulted in increased efficiency of delivery to 12.3 5.5% of the dose. After four hours, 81.0 11.0% of the total myocardial N radioactive uptake was confined within the ischemic tissue of the LAD territory and was present within both the epicardial and endocardial layers of the myocardium. There was no hemodynamic compromise during the delivery process, and prolonged selective occlusion of AIV did not increase the coronary sinus lactic acid levels. The above results are graphically represented in Fig. 3. These data support the feasibility and efficacy of delivery through selective cannulation of cardiac veins for the regional treatment of the distal ischemic myocardium.

Example 5. Ongoing safety study of transvenous delivery of agent Recently, a series of 4 porcine experiments were conducted with transvenous delivery of agent. Systemic and local pressure monitoring optimized the entire procedure. At 4 week-follow up study, animals were sacrificed and harvested hearts were examined by independent cardiovascular pathologist. Results, provided in Table 2 below, showed normal pathological appearance of the myocardium. These results demonstrate saftey of pressurized transvenous delivery of agent.

In \o Table 2 Animal Weight Hemodynamics Procedural Gross Path Histology Comments Comment Comments 867 45kg 75/48-129/94 normal RV free wall contraction banding 908 38.2kg 90/57-107/73 Difficult AIV normal RV free wall with interstitial scar access, difficult but within normal limits. No lat wall echo organizing ischemia, no evidence of prior ischemia. Normal tissue.

909 33.8 kg 81/52-82/52 Very simple and normal Normal. No intimal changes in easy vein including intramyocardial segments.

910 40.1 kg none recorded Also easy normal Normal.

Acute vs. Chronic Protocol.

Single lumen pulmonary artery catheter to AIV Inflate balloon for 5 minutes, injection, deflate balloon after 5 minutes cc saline at 100 mm Hg mean injection pressure as measured by pressure wire Echo at baseline, 30 minutes, and 4 hour (acute) or 28 day (chronic) CK, CKMB, and cTnT at baseline and 30 minutes (chronic) or 4 hours (acute) It is evident from the above discussion that the subject invention provides an important new means for locally administering an active agent to a host. Specifically, the subject invention provides a method for locally administering an active agent to an interstitial target site proximal to a vessel. The subject methods are suitable for use in the delivery of a wide variety of different agents, and are particularly suited for use in the delivery of biological agents, such as polypeptides and nucleic acids. One advantage of the subject methods is that they provide a new and convenient methodology for delivering active to agents, including biological agents, to the myocardium. Other advantages of the subject methods include the ability to deliver agent to a large region of interstitial space from a single administration point. Additional advantages include the ability of the host to tolerate the mode of administration such that damage caused by the route of administration, if any, is outweighed by the benefits provided by the subject method of administration and the ability to produce inflammation at the site of administration, when desired. As such, the subject invention represents a significant contribution to the art.

All publications and patent applications cited in this specification are herein incorporated by reference as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention.

Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is readily apparent to those of ordinary skill in the art in light of the teachings of this invention that certain changes and modifications may be made thereto without departing from the spirit or scope of the appended claims.

Claims (23)

1. A method of locally administrating an active agent to a host, said method comprising: retroinfusing said agent into a vascular vessel of said host under conditions sufficient for said agent to enter an interstitial space of said host; whereby said agent is locally administered to said host.

2. The method according to Claim 1, wherein said vessel is a vein.

3. The method according to Claim 1, wherein said retroinfusing comprises providing stress to said vascular vessel at a site at least proximal to said interstitial space.

4. The method according to Claim 3, wherein said retroinfusing comprises administering said agent at a pressure sufficient to produce at least a mechanical stress on said vessel.

The method according to Claim 1, wherein said method further comprises using depot means.

6. The method according to Claim 1, wherein said method further comprises administration of energy to said vessel.

7. The method according to Claim 1, wherein said interstitial space is myocardial interstitial space.

8. A method of locally administering an active agent to a host, said method comprising: retroinfusing said agent into a'vein of said host under conditions sufficient for said agent to enter an interstitial space of said host; whereby said agent is locally administered to said host.

9. The method according to Claim 8, wherein said retroinfusing comprises administering said agent at a pressure sufficient to produce at least a mechanical stress on said vein.

10. The method according to Claim 9, wherein said pressure is sufficient to at least distend said vein.

11. The method according to Claim 9, wherein said pressure is sufficient to disrupt said vein.

12. The method according to Claim 8, wherein said agent is a biological agent selected from the group consisting of peptides, proteins, nucleic acids, lipids, polysaccharides, and mimetics thereof.

13. The method according to Claim 8, wherein said method further comprises producing inflamation in said vascular vessel.

14. The method according to Claim 8, wherein said interstitial space is myocardial interstitial space.

A method of locally administering an active agent to a host, said method comprising: retroinfusing said agent into a vein of said host with a catheter and at a pressure sufficient to produce at least a mechanical stress on said vein such that said agent enters an interstitial space of said host proximal to said vein; whereby said agent is locally administered to said host.

16. The method according to Claim 15, wherein said pressure is sufficient to at least distend said vein.

17. The method according to Claim 16, wherein said pressure is sufficient to disrupt said vein.

18. The method according to Claim 16, wherein said agent is a biological agent selected from the group consisting of peptides, proteins, nucleic acids, lipids, polysaccharides, and mimetics thereof.

19. The method according to Claim 16, wherein said method further comprises producing inflamation in said vascular vessel.

A kit for use in the local administration of an agent to a host, said kit comprising: at least one of: a catheter, and (ii) said agent; and instructions for locally administering an agent to a host according to the method of Claim 1.

21. The kit according to Claim 20, wherein said kit comprises both said catheter and said agent.

22. The kit according to Claim 20, wherein said kit further comprises a depot.

23. The kit according to Claim 20, wherein said agent is a biological agent selected from the group consisting ofpeptides, proteins, nucleic acids, lipids, polysaccharides, and mimetics thereof Dated this second day of February 2006 The Board of Trustees of the Leland Stanford Junior University Patent Attorneys for the Applicant: F B RICE CO