Title:  Method of treating sickle cell disease or thalassemia

United States Patent:  6,372,213

Assignee:  Eli Lilly and Company (Indianapolis, IN)

Filed:  November 22, 1999

The present invention provides a method of treatment of sickle cell disease (SCD) or thalassemia with protein C. The claimed invention provides a needed therapy for potentially serious and debilitating disorders while avoiding complications such as bleeding tendency, toxicity and general side effects of currently available anti-coagulant agents.

DETAILED DESCRIPTION OF THE INVENTION

For purposes of the present invention, as disclosed and claimed herein, the following terms are as defined below.

Protein C refers to a vitamin K dependent serine protease with anticoagulant, anti-inflammatory, and profibrinolytic properties which includes, but is not limited to, plasma derived and recombinant produced protein C. Protein C includes and is preferably human protein C although protein C may also include other species or derivatives having protein C proteolytic, amidolytic, esterolytic, and biological (anticoagulant, pro-fibrinolytic, and anti-inflammatory) activities. Examples of protein C derivatives are described by Gerlitz, et al., U.S. Pat. No. 5,453,373, and Foster, et al., U.S. Pat. No. 5,516,650, the entire teachings of which are hereby included by reference.

Zymogen--an enzymatically inactive precursor of a proteolytic enzyme. Protein C zymogen, as used herein, refers to secreted, inactive forms, whether one chain or two chains, of protein C.

Activated protein C or aPC refers to protein C zymogen which has been converted by limited proteolysis to its activated form. aPC includes and is preferably human protein C although aPC may also include other species or derivatives having protein C proteolytic, amidolytic, esterolytic, and biological (anticoagulant or pro-fibrinolytic) activities. Examples of protein C derivatives are noted above in the description of protein C.

HPC--human protein C zymogen.

r-hPC--recombinant human protein C zymogen.

r-aPC--recombinant human activated protein C produced by activating r-hPC in vitro or by direct secretion of the activated form of protein C from procaryotic cells, eukaryotic cells, and transgenic animals or plants, including, for example, secretion from human kidney 293 cells as a zymogen then purified and activated by techniques well known to the skilled artisan and demonstrated in Yan, U.S. Pat. No. 4,981,952, and Cottingham, W097/20043, the entire teachings of which are herein incorporated by reference.

Plasma derived activated protein C--activated protein C produced by activating plasma HPC as described in Eibl, U.S. Pat. No. 5,478,558, the entire teaching of which is herein incorporated by reference.

Continuous infusion--continuing substantially uninterrupted the introduction of a solution into a vein for a specified period of time.

Bolus injection--the injection of a drug in a defined quantity (called a bolus) over a period of time up to about 120 minutes.

Suitable for administration--a lyophilized formulation or solution that is appropriate to be given as a therapeutic agent.

Unit dosage form--refers to physically discrete units suitable as unitary dosages for human subjects, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect, in association with a suitable pharmaceutical excipient.

Pharmaceutically effective amount--represents an amount of a compound of the invention that is capable of inhibiting sepsis in humans. The particular dose of the compound administered according to this invention will, of course, be determined by the attending physician evaluating the particular circumstances surrounding the case.

The present invention provides for the treatment of sickle cell disease (SCD) or thalassemia with protein C. Protein C, with its anticoagulant, antiinflammatory, and profibrinolytic activities, is useful for the treatment of the hypercoagulable state or protein C deficiency that occurs in SCD or thalassemic patients.

The protein C administered according to this invention may be generated and/or isolated by any means known in the art or as described in U.S. Pat. Nos. 4,981,952, and 5,550,036, herein incorporated by reference. For example, protein C can be produced by secreting full-length, soluble protein C, or biologically active polypeptide variants of protein C from a cell which comprises (a) constructing a vector comprising DNA encoding protein C; (b) transfecting the cell with the vector; and (c) culturing the cell so transfected in culture medium under conditions such that full length soluble protein C or biologically active polypeptide variants of protein C, is secreted. Further, the cell is a eukaryotic cell, e.g. mammalian cell such as Syrian hamster AV12 cell, human embryonic 293 cell, or Baby Hamster Kidney cell.

The protein C used in the treatment of SCD or thalassemia can be formulated according to known methods to prepare pharmaceutically useful compositions. For example, a desired formulation would be one that is a stable lyophilized product of high purity comprising a bulking agent such as sucrose, a salt such as sodium chloride, a buffer such as sodium citrate and protein C or aPC.

The protein C will be administered parenterally to ensure its delivery into the bloodstream in an effective form by injecting the appropriate dose as continuous infusion for about 1 hour to about 240 hours.

Those skilled in the art can readily optimize pharmaceutically effective dosages and administration regimens for therapeutic compositions comprising protein C, as determined by good medical practice and the clinical condition of the individual patient. Generally, the amount of protein C administered will be from about 5.0 .mu.g/kg/hr to about 250 .mu.g/kg/hr. Preferably, the protein C used in the treatment of SCD is activated protein C (aPC). The amount of aPC administered will be from about 1.0 .mu.g/kg/hr to about 96 .mu.g/kg/hr. More preferably the amount of aPC administered will be about 1.0 .mu.g/kg/hr to about 50 .mu.g/kg/hr. While more preferably the amount of aPC administered will be about 1.0 .mu.g/kg/hr to about 35 .mu.g/kg/hr. Even more preferably the amount of aPC administered will be about 5.0 .mu.g/kg/hr to about 30 .mu.g/kg/hr. Yet even more preferably the amount of aPC administered will be about 15 .mu.g/kg/hr to 30 .mu.g/kg/hr. Still even more preferably the amount of aPC administered will be about 20 .mu.g/kg/hr to 30 .mu.g/kg/hr. The preferable amount of aPC administered will be about 24 .mu.g/kg/hr. The most preferable amount of aPC administered will be about 48 .mu.g/kg/hr. The appropriate dose of aPC administered will result in a reduction of the thrombotic complications associated with SCD.

The plasma ranges obtained from the amount of aPC administered will be about 2 ng/ml to about 300 ng/ml. The preferred plasma ranges are from about 2 ng/ml to 200 ng/ml. Most preferably, plasma ranges are from about 30 ng/ml to about 150 ng/ml and still more preferably about 100 ng/ml.

Alternatively, the aPC will be administered by injecting one third of the appropriate dose per hour as a bolus injection followed by the remaining two thirds of the hourly dose as continuous infusion for one hour followed by continuous infusion of the appropriate dose for twenty-three hours which results in the appropriate dose administered over 24 hours. In addition, the bolus injection will be administered via an intravenous bag drip pump or syringe pump at 2 times the normal rate for 15 minutes followed by 1.5 times the normal rate for 45 minutes. The normal rate i.e. that rate which has been determined to administer the appropriate dose level of the therapeutic agent per time period, is then continued for up to 240 hours.

The use of protein C in the treatment of SCD or thalassemia as presented in the present invention will provides a needed therapy for a potentially serious and debilitating disorder. The use of protein C is efficacious and avoids complications such as bleeding tendency, toxicity, and other general side effects of currently available anti-coagulant agents.

Claim 1 of 7 Claims

We claim:

1. A method of treating a patient suffering from sickle cell disease (SCD) or thalassemia which comprises, administering to said patient about 1 .mu.g/kg/hr to about 50 .mu.g/kg/hr of human activated protein C.

____________________________________________
If you want to learn more about this patent, please go directly to the U.S. Patent and Trademark Office Web site to access the full patent.