WO2000015227A1

WO2000015227A1 - Use of 3,4-dihydro-6, 7-dimethoxy-alpha-phenyl- n,n-bis [(2,3,4-trimethoxyphenyl) ethyl]-1-i soquinolineacetamide in the manufacture of a medicament for the reduction of motor dysfunction

Info

Publication number: WO2000015227A1
Application number: PCT/EP1999/006706
Authority: WO
Inventors: Helmut Ensinger; Walter Loesel; Dietrich Arndts; Andreas Leusch; Tracy Kahl Mcintosh; Kathryn Eileen Saatman; Ramesh Raghupathi
Original assignee: Boehringer Ingelheim Pharma Kg
Priority date: 1998-09-14
Filing date: 1999-09-10
Publication date: 2000-03-23
Also published as: GB2341318A; GB9903524D0

Abstract

The present invention relates to a new use of 3,4-dihydro-6, 7-dimethoxy-alpha-phenyl- N,N-bis [(2,3,4-trimethoxyphenyl) ethyl]-1- isoquinolineacetamide or its pharmaceutically acceptable salts for the preparation of a medicament for reducing motor dysfunction of a mammal who has experienced traumatic brain injury.

Description

USE OF 3.4-DIHYDR0-6, 7-DIMETHOXY-ALPHA-PHENYL- N.N-BIS [(2,3,4-TRIMETHOXYPHENYL) ETHYL]-1-I SOQUINOLINEACETAMIDE IN THE MANUFACTURE OF A MEDICAMENT FOR THE REDUCTION OF MOTOR DYSFUNCTION

The present invention relates to a new use of 3,4-dιhydro-6,7-dιmethoxy-alpha- phenyl-N,N-bιs[2, 3, 4-tπmethoxyphenyl)θthyl]-1 -isoquinolineacetamide (LOE 908) or its pharmaceutically acceptable salts foi the reduction of motor dysfunction in a patient who has experienced traumatic brain injury

LOE 908 is a broad spectrum channel blocker LOE 908 and its preparation is known from WO 92/1 1 010 Therein the compound is described as a cerebroprotective agent being suitable for the treatment of epilepsy and Alzheimer's disease and particularly for treating patients who have suffered a stroke or are at risk of suffering a stroke, as well as being suitable for treating chronic inflammatory processes and for inhibiting blood clotting It is also shown therein that the effect of the compound is not based on an improvement in the blood flow through the tissues

Stroke describes the neuronal cell damage which happens to the surrounding brain tissue (so- called penumbra) of a thrombotic brain artery occlusion

Traumatic brain injury includes lesions/damage to the neuronal tissue after mechanical impact such as from bike, or motor bike accident, a strong shock or concussion to the head of a person at any age from childhood to senescence occurring e g during car accidents, sudden drops etc

Some of the toxic sequelae after stroke and traumatic brain injury might be m common such as the activation of the excitotoxic glutamatergic pathway, but there are additional lesions occurring especially after a (mechanical) traumatic brain injury such as vascular disruption, mtraparenchymal hemorrhage, extravasation of potentially harmful blood borne products, breakdown of the blood brain barrier, neuronal tissue shearing and membrane disruption

Thus it cannot be expected that a compound being active in stroke treatment will also show efficacy in the treatment of traumatic brain injury In fact, it has been shown that several specific classes of compounds (such as competitive NMDA glutamate antagonists), which are extraordinarily protective in experimental models of stroke, have absolutely no benefit whatsoever in experimental models of brain trauma

There still is the need to provide a medicament for reducing the dysfunction caused by traumatic brain injury, especially physical brain injury in consequence of accidents

It has now been found that, surprisingly, LOE 908 fulfils this need This is shown by the following test results

1 Fluid percussion model

2 Assessment of neurologic motor function damage caused by fluid percussion Fluid percussion model

Male rats (350-400 g) are initially anesthetized intravenously with sodium pentobarbital (Nembutal, 50 mg/kg) During surgical preparation and throughout the experimental procedure, all wounds are infused with a topical anesthetic (2 0% hdocame hydrochlonde) Drugs are administered through a cannula placed m the femoral vein The femoral artery is cannulated to monitor heart rate, mean arterial blood pressure and pulse pressure, as well as to sample arterial blood gases

With the animal in a stereotaxic frame, the scalp and temporal muscle are reflected Next, a hollow tube (the Luer-Lok syringe through which the saline impulse is injected) is rigidly fixed with dental acrylic to the animal's skull over a 2 0 mm cramotomy centered over the left parietal cortex, midway between lambda and bregma A piezoelectric pressure transducer affixed to the injury device will measure the pressure transient, which is recorded on a storage oscilloscope The duration and peak pressure in atmospheres (atm) will be noted for each injury

The fluid percussion (FP) model of head injury will be employed using the anesthetized rat This model was initially developed by Lmdgren and Rmder in the rabbit (LINDGREN, S and RTNDER, L (1969) ACTA Physiol Scand 76, 340-351, "Production and distribution of lntracramal and mtraspmal pressure changes at sudden extradural fluid volume input in rabbits") and utilizes hydrauhcally-induced pressure changes to produce quantifiable, mechanical deformation of the brain The FP device for induction of brain injury was modified to accommodate a rat (Mclntosh et al , 1989) The modified FP devices are manufacture at Medical College of Virginia with modifications for the rat

This FP device consists of a Plexiglas cylindrical reservoir bounded at one end by a Plexiglas, cork-covered plunger mounted on 0-rιngs The opposite end of the reservoir is fitted with a second hollow Plexiglas cylinder, which is in turn attached to a cylindrical transducer for measuring the pressure generated at the time of injury The entire device is attached to the Luer-Lok syringe, which is rigidly fixed with dental acrylic to the opening in the animal's skull The dura is left intact at this opening The Luer-Lok syringe is tightly connected to the transducer housing and the entire system is filled with 0 9% sodium chloride solution at 37°C The pendulum is then allowed to fall from a predetermined height, striking the plunger and forcing a rapid pulse of saline through the cramotomy and into the closed cranial cavity The injury is recorded on a storage oscilloscope which is triggered photoelectπcally by descent of the pendulum This device produces a pulse of increased lntracramal pressure of fairly constant duration 21-23 msec), and the pressure transient is associated with distortion and deformation of bram tissue The height of the pulse is variable and can be regulated by raising or lowering the pendulum Since the duration of the pulse is constant, the amplitude of the increased lntracramal pressure (measured in atm) is used as a measure of the magnitude of the brain injury

The above model yields a predictable degree of brain injury and simulates many aspects of head injury in humans

In the present study, a moderate severtiy of brain injury was produced, corresponding to 2,5-2,7 atm Experimental Protocol

Prior to injury, animals have an indwelling catheter implanted into the femoral vein All animals are injured at a moderate severity (2 5 - 2,7 atm) At 15 mm after FP bram injury, animals are randomly assigned to treatment with two doses of LOE 908 or control vehicle (equal volume) An infusion of a loading dose is performed over a 12- minute period followed by an infusion of a maintenance dose for 24 hours After drug treatment, animals are randomly assigned to the study groups described below

Assessment of neurologic motor function damage caused by fluid percussion Neurological scoring of motor function is performed at 48 h in animals treated with LOE 908 or a control vehicle The composite neurological scoring paradigm includes (1) contralateral forehmb flexion upon suspension by the tail, (2) decreased resistance to lateral pulsion toward the right as compared with pulsion toward the left, (3) the ability to stand on an inclined angle-board (inclined plane) with the maximal angle at which the animal can stand vertically and/or horizontally for 2 sec recorded, (4) hmdlimb flexion when the forehmb s remain on a hard surface and the hindhmbs are lifted up and back by the tail All animals are graded as follows for each task Grade 4 = normal, Grade 3 = mild deficit, Grade 2 = moderate deficit, Grade 1 = moderate/severe, Grade 0 = extremely severe deficit A composite neurological score is developed This composite scoring paradigm is extremely sensitive in depicting the correlation between neurological outcome and severity of injury

Details of the test results

Adult male Sprague-Dawley rats were anesthetized (60 mg/kg pentobarbital, l p ), and subjected to surgery and lateral fluid percussion bram injury (2 5-2 7 atm, n=38) or surgery without bram injury (n=15) At 15 mm postinjury, animals received intravenous (femoral vein) LOE 908 MS at either a low dose (bolus of 2 mg/kg followed by a 24 hr infusion of 80 mg/kg, n=12) or a high dose (4 mg/kg bolus followed by a 24 hr infusion of 160 mg/kg, n=13), or vehicle (n=13) Uninjured animals received the high dose of the compound (n=8) or vehicle (n=7) Both doses of LOE 908 significantly improved motor function at 48 hrs in brain-injured animals compared to vehicle-treated, brain-injured animals

Dosing paradigm

Route of administration Intravenous (femoral)

Vehicle 5% Xylitol in sterile water

Rates 15 min following injury, 12 mm infusion at 10 ml/hr/kg followed by 24 hours infusion at 1 ml/hr/kg

Dose Low 2 mg/kg followed by 80 mg/kg

High 4 mg/kg followed by 160 mg/kg

Outcome measures at 48 hours post-injury

Composite neuroscore evaluation (includes forehmb and hmdlimb flexion, lateral pulsion, and inclined plane tests, total score=28) Experimental groups

Statistical analyses

Vehicle-treated, injured animals were compared to vehicle-treated, sham animals to test for significant dysfunction following brain injury. Injured, LOE 908-treated groups were then compared to the vehicle-treated, injured group to test for treatment effects. Neuroscores are nonparametric data (presented as median scores) and are compared using Mann-Whitney U-tests.

Results

Injury

Brain-injured animals were randomly assigned to one of three treatment groups. The vehicle, low dose LOE 908, and high dose LOE 908 groups received equivalent levels of injury (2.8+0.3, 2.7+0.3 and 2.7+0,3 atm, respectively; mean+s.d.) and displayed equivalent mean post-injury apnea (27, 27, and 29 sec, respectively) and weight loss.

Composite neuroscore

Brain injury resulted in significant motor dysfunction in vehicle-treated rats (compared to vehicle-treated sham, ^*=p<0.001 for composite neuroscore, p<0.05 for each individual test in the composite). Administration of high dose LOE 908 did not affect the motor function of sham animals. Compared to vehicle treatment, both the low and the high dose of LOE 908 resulted in significantly improved motor function (composite neuroscore, +=p<0.02) at 48 hours following injury. Analyses of individual tests within the composite revealed that high dose LOE 908 administration resulted in significant improvement in both left and right lateral pulsion tests (p<0.05), and low dose LOE 908 administration led to improvement in left lateral pulsion (p<0.05).

Composite Neuroscore

Sham Veh Sham Drug bij. V«h Inj. Low Inj. High

(1) injured, low dose-treated rats

(2) injured, high dose-treated rats

The above graph shows the assessment of neurological motor function 48 hours after brain injury or sham treatment Animals were evaluated for motor function using four separate tests which were combined to yield a composite neuroscore with a maximum score of 28 points Sham treated animals resolved either vehicle (Veh) or LOE 908 (Drug), while brain-mjured animals (Inj ) received either vehicle (Veh), low-dose LOE 908 (Low) or high-dose LOE 908 (High) Vehicle-treated brain injured animals showed a significant deficit when comparted to Sham vehicle-treated animals (*p<0 001) Treatment with either low or high dose LOE 908 significantly attenuated motor dysfunction when compared to vehicle treatment (+p<0 02)

Claims

1. Use of LOE 908 (as herein defined) or a pharmaceutically acceptable salt thereof for the preparation of a medicament for reducing motor dysfunction of a mammal who has experienced traumatic brain injury.

2. Use as claimed in claim 1, wherein said medicament is accompanied by instructions to administer a first dose of said medicament to the mammal shortly after it has received the traumatic brain injury.

3. Use as claimed in claim 2, wherein said instructions indicate administration of subsequent doses of said medicament over a period of at least 2 to 3 days.

4. Use as claimed in claim 1, wherein said medicament contains instructions to administer said medicament at a dosage sufficient to provide a plasma level of LOE 908 in the mammal of between 0.5 ╬╝g/ml and 2 ╬╝g/ml.

5. Use as claimed in claim 4, wherein said plasma level is maintained for at least 1 to 2 or up to 7 days.