Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form
Reexamination Certificate
1997-02-19
2001-01-30
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
C424S009300, C424S009363, C424S009323, C424S009520, C540S450000, C540S451000, C540S452000
Reexamination Certificate
active
06180113
ABSTRACT:
The invention relates to the objects characterized in the claims, i.e., pharmaceutical agents that contain monomeric, perfluoroalkyl-substituted metal complexes and complex salts in tumor therapy and interventional radiology.
The use of foreign materials—brought by injection into the blood circulation to induce an embolism there—was proposed as early as at the beginning of this century [Dawbarn, Journal of the American Medical Association 43:792, (1904)].
This idea was taken up seriously again only about 30 years ago (Young, British Medicinal Journal 283, 1144, 1981). Embolization was used for diagnostic and therapeutic purposes, especially for the treatment of tumors. Embolization of the vascular trunk, which supplies a tumor area with blood, is a technique that is used to bring about either a permanent vascular block and in so doing to promote tumor necrosis or a temporary embolization to increase the therapeutic effect of a simultaneously co-administered chemotherapy agent. The last-mentioned technique is referred to as chemoembolization. The advantage of such a treatment is its local limit. A condition is the presence of a sufficiently large vessel (i.e., a vessel that makes possible a catheterization) that supplies the tumor with blood.
In humans, tumors in the liver are especially accessible for embolization therapy. Liver tumors are supplied with blood via the hepatic artery 80-100%. The normal liver parenchyma, however, is supplied mainly (about 75%) by the portal vein. Consequently, a selective treatment of primary and metastatic liver cancer can be achieved by embolization of the hepatic arteries.
Hepatocellular carcinoma (HCC) is an event that occurs rather rarely in Europe and the USA, but it is regarded in Asia (Japan, South Korea) and Africa as the most common malignant tumor disease, which in a large number of cases accompanies cirrhosis of the liver, caused by Hepatitis B and C [Therapie Konzepte Onkologie [Therapy Concept Oncology, see Seber, J. Sch{umlaut over (u)}tte (Editors) Springer, 536-545, (1995)]. Despite extensive efforts, to date no major improvement in the very poor prognosis has been achieved in the case of this disease. Both untreated and after systemic treatment with cytostatic agents (mainly 5-fluorouracil, mitomycin C, cisplatin, doxorubicin), the average survival time is 1-9 months after a diagnosis is established [K. Okuda et al. Natural History of HCC and Prognosis in Relation to Treatment. Study of 850 Patients. Cancer 56, 918-928, (1985)]. Solely by the surgical removal of the tumor, which is possible only in about 20% of the patients, however, can a considerable prolongation of life be achieved, but only in a very few cases can an actual cure be achieved.
A worthy goal of new therapy principles is mainly an improvement in the quality of life for the patients, since a complete cure is very difficult to achieve owing to the basic primary disease Hepatitis B according to present understanding. The surgical removal of the tumor represents high stress just as does systemic chemotherapy.
In recent years, chemoembolization has emerged as the method of choice. It is defined as the simultaneous administration of a cytostatic agent mixed with an embolization agent for the purpose of forming a local, temporary embolus, from which the pharmaceutical substance is released slowly and basically over a long period of time (optimum 5-8 days). Because of the limitation of blood flow, it results in an increased pharmaceutical substance exposure of the tumor tissue [P. H. Madoule et al. Chemoembolization: Principles and Perspectives, J. Microencapsulation 1, 21-25, (1984)]. The locally developing ischemia supports the control of the tumor.
In the methods of chemoembolization that are used most often in Japan and South Korea, an emulsion consisting of Lipiodol® (ethyl ester of iodinated poppyseed oil) and aqueous cytostatic agent solutions are used as a peripheral embolizate and as a depot. Since, there are no corresponding ready-to-use preparations on the market, the emulsions are produced in clinics on the spot using “home-made” remedies. This causes the quality of the preparations to vary greatly from clinic to clinic, and no precise and reproducible data on the most parameters such as particle size, retention time in the tumor and extractability exist. The emulsion is introduced via a percutaneous catheter selectively/superselectively in the tumor-carrying branch of the hepatic artery. Generally, the arterial supply is then stopped in addition by Gelfoam® particles, to prevent too quick flushing of the lipiodol emulsion. Lipiodol® accumulates to a certain extent in HCC (T. Konno et al. Selective Targeting of Anticancer Drug and Simultaneous Image Enhancement in Solid Tumors by Arterial Administered Lipid Contrast Medium. Cancer 54, 2367-2374, 1984) and is found only in a small part in healthy liver parenchyma. A problem in this process is that a nonquantifiable portion passes through the capillary bed and then accumulates in the lung or spleen. The embolism is present over a lengthy period (1-4 weeks) and, in addition to the lengthy retention time of the cytostatic-agent in the tumor, serves to place an ischemic stress on the tumor. Owing to deficient biodegradability, Lipiodol® is virtually not excreted and remains in the necrotized tumor tissue, which can thus be resorbed only inadequately. Generally, this treatment is regularly repeated at an interval of several weeks. With this method, survival rates are somewhat below those of surgical removal of the tumor, but significantly above those of chemotherapy alone (T. Kanematsu, A 5-Year Experience of Lipiodolization: Selective Regional Chemotherapy for 200 Patients with HCC, Hepatology, 10, 98-102, 1989. D. Vetter et al. Transcatheter Oily Chemoembolization in the Management of Advahced HCC in Cirrhosis; Results of a Western Comparative Study in 60 Patients, Hepatology, 13, 427-433, 1991).
Despite the problems described, the Lipiodol® process in comparison with other embolization techniques with more or less biodegradable particle suspensions (see Table 1) has gained more acceptance than the as yet most common therapy concept in Asia.
TABLE 1
Chemoembolization Agents
Lipiodol
Gelfoam
Spherex
Manufacturer
Byk Gulden
Upjohn
Kabi Pharmacia
Guerbet
Composition
iodinated
gelatin powder
degradable
poppyseed oil
(sponge) that
starch
can absorb
microspheres,
amilomer
25-45 &mgr;m
Use
RKM for direct
HCC chemoem-
adjuvant in
lymphography.
bolization,
i.a. liver
(No approval
often used
tumor therapy
for
also with
with
embolization)
lipiodol
cytostatic
trauma
agents
Ethibloc
Contour Emboli
Angiostat
Manufacturer
Ethicon
Rehaforum,
Regional
Interventional
Therapeutic
Ther. Corp.
Inc., CA
USA
Composition
zein, poppy-
nondegradable
collagen
seed oil,
polyvinyl
fibers (5 × 75
amidotrizoate,
alcohol, foam
&mgr;m)
emulsion
Ivalon 45-1180
&mgr;m
Use
vascular
presurgical
embolization
embolization
embolization
of tumors and
in tumors of
of
abnormal
the kidney,
hypervascular
vascular
pancreas,
tumors and AVM
sections
hemangioma
Additional bibliographic references in the Table:
Concerning Spherex: T. Taguchi, Chemo-Occlusion for the Treatment of Liver Cancer. A New Technique Using Degradable Starch Microspheres, Clin. Pharmacokinet. 26, 275-291, 1994.
Concerning Avitene, Angiostat, Gelfoam: D. Struk et al. Stability Studies on Chemoembolization Mixtures. Dialysis Studies of Doxorubicin and Lipiodol with Avitene, Gelfoam and Angiostat. Invest. Radiol. 28, 1024-1027, 1993.
The perfluoroalkyl-containing metal complexes according to the invention show physicochemical properties that are unusual in aqueous solution. They are thixotropic to a surprisingly high extent, so that these compounds are very suitable as embolizates. These solutions have gel-like consistency in the resting position, but they can flow under the effect of shearing forces (can be conveyed by pumps and by long catheters).
The high viscosity of the compounds that are suitable for use according to the invention r
Frenzel Thomas
Niedballa Ulrich
Platzek Johannes
Rad{umlaut over (u)}chel Bernd
Schlecker Wolfgang
Channavajjala Lakshmi
Millen White Zelano & Branigan P.C.
Page Thurman K.
Schering AG
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