Internet for Pharmaceutical and Biotech Communities
| Newsletter | Advertising |
 
 
 

  

Pharm/Biotech
Resources

Outsourcing Guide

Cont. Education

Software/Reports

Training Courses

Web Seminars

Jobs

Buyer's Guide

Home Page

Pharm Patents /
Licensing

Pharm News

Federal Register

Pharm Stocks

FDA Links

FDA Warning Letters

FDA Doc/cGMP

Pharm/Biotech Events

Consultants

Advertiser Info

Newsletter Subscription

Web Links

Suggestions

Site Map
 

 
   

 

  Pharmaceutical Patents  

 

Title:  EGFR inhibitors promote axon regeneration
United States Patent: 
7,449,442
Issued: 
November 11, 2008

Inventors:
 He; Zhigang (Boston, MA), Koprivica; Vuk (Boston, MA)
Assignee:  Children's Medical Center Corporation (Boston, MA)
Appl. No.: 
11/180,070
Filed: 
July 12, 2005


 

Executive MBA in Pharmaceutical Management, U. Colorado


Abstract

Compositions and methods for promoting neural regeneration in a patient determined to have a lesion in a mature CNS neuron are disclosed. The method comprises the step of contacting the neuron with an EGFR inhibitor sufficient to promote regeneration of the neuron.

Description of the Invention

FIELD OF THE INVENTION

The field of the invention is the use of epidermal growth factor receptor (EGFR) inhibitors for promoting neural regeneration of lesioned mature CNS neurons.

BACKGROUND OF THE INVENTION

Failure of successful axon regeneration in the CNS is attributed not only to the intrinsic regenerative incompetence of mature neurons, but also to the environment encountered by injured axons. The inhibitory activity is principally associated with components of CNS myelin and chondroitin sulfate proteoglycans (CSPGs) in the glial scar at the lesion site (1-4). Recent studies suggested that three myelin proteins, myelin-associated glycoprotein (MAG), Nogo-A and oligodendrocyte myelin glycoprotein (OMgp), collectively account for the majority of the inhibitory activity in CNS myelin (4-6). The inhibitory activity of MAG, OMgp and the extracellular domain of Nogo-A may be mediated by a common receptor complex that consists of the ligand-binding Nogo-66 receptor (NgR) and its signaling co-receptors p75/TROY and Lingo-1 (7-13). However, little is known about how signaling events occurring at the axonal membrane are translated into specific cytoskeletal rearrangements underlying inhibition of axon regrowth. For instance, it is known that MAG and perhaps other myelin inhibitors are able to induce an elevation of intracellular Ca.sup.2+ levels (14-16). But it is unclear how intracellular Ca.sup.2+ signaling may be involved in the inhibition of axon regeneration.

The involvement of EGFR activation in development and differentiation of CNS neurons has been studied extensively. Goldshmit et al. (J Biol Chem (2004) 279:16349-16355) report that overexpression of SOCS2 in CNS neurons promotes neurite outgrowth, and that this outgrowth is blocked by addition of EGFR inhibitors PP3 and AG490. Wu et al. (Mol Biol Cell (2004) 15:2093-2104) report that the chondroitin sulfate proteoglycan versican V1 induces NGF-independent neuronal differentiation and promotes neurite outgrowth in cultured PC12 cells by enhancing EGFR and integrin activities, and that addition of the EGFR inhibitor AG1478 significantly blocks differentiation. Wildering et al. (J Neurosci (2001) 21:9345-9354) report that EGF promotes axonal regeneration of neurons of the crushed right internal parietal (RIP) nerve in the pond snail Lymnaea stagnalis and that inhibition of EGF action by the specific EGFR inhibitor PD153035 counteracts the effect of EGF on axonal regeneration. Li et al. (J Neurosci (2003) 23:6956-6964) report that PC12 cell lines with reduced EGFR signaling have reduced neurite outgrowth in response to NGF and that AG1478, a specific EGFR tyrosine kinase inhibitor, is cytotoxic to these cells.

In light of these reports our finding that suppressing EGFR function promotes significant regeneration of a lesioned adult CNS neuron in the presence of myelin inhibitory molecules was quite unexpected.

SUMMARY OF THE INVENTION

The invention provides compositions and methods for promoting neural regeneration of a lesioned CNS neuron. In one embodiment, the invention provides a method of promoting neural regeneration in a patient determined to have a lesion in a mature CNS neuron, the method comprising the step of contacting the neuron with an EGFR inhibitor sufficient to promote regeneration of the neuron.

In particular embodiments, the lesion is an axon lesion.

In particular embodiments, the lesion results from a traumatic injury, CNS degeneration, an optic nerve injury, or glaucoma.

In particular embodiments, the lesion results from a traumatic injury, and the contacting step is effected within 96, 48, or 24 hours of formation of the lesion.

In a particular embodiment, the lesion results from an acute spinal cord injury, and the method optionally comprises contacting the neuron with methylprednisolone sufficient to reduce inflammation of the spinal cord.

In a particular embodiment, the EGFR inhibitor is a small molecule selected from the group consisting of erlotinib, gefitinib, GW2016, GW572016, PKI166, CL-1033, EKB-569, and GW2016.

In another embodiment, the EGFR inhibitor is a monoclonal antibody selected from the group consisting of cetuximab, panitumumab, TheraCIM, EMD 72000, and MDX447.

In particular embodiments the EGFR inhibitor is administered to the patient orally or by injection.

In another embodiment, the EGFR inhibitor is contained within an implantable device.

In a particular embodiment, the method further comprises the step of detecting a resultant neural regeneration, and optionally the neural regeneration is detected inferentially by neurological examination.

A further aspect of the invention is the use of an EGFR inhibitor for the manufacture of a medicament to promote neural regeneration in a patient determined to have a lesion in a mature CNS neuron.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

The invention provides methods and compositions for promoting neural regeneration of a lesioned CNS neuron. As used herein, the singular forms "a," "an," and "the," refer to both the singular as well as plural, unless the context clearly indicates otherwise. For example, the term "a CNS neuron" includes both single and multiple neurons and can be considered equivalent to the phrase "at least one CNS neuron." In preferred embodiments, the neuron is a mammalian neuron, and in particular embodiments is a human neuron.

The lesioned neuron is subject to growth inhibition by endogenous myelin growth repulsion factors and may be in situ, i.e. located within the brain, brainstem, spinal cord, or optic nerve of a patient or animal model, or in vitro co-cultured with oligodendrocyte myelin or with isolated myelin growth repulsion factors such as myelin-associated glycoprotein (MAG), Nogo-A, and oligodendrocyte myelin glycoprotein (OMgp). The lesion may present at any part of the neuron. In particular embodiments a neurite (i.e. axon and/or dendrite) is lesioned, and the EGFR inhibitor treatment promotes neurite outgrowth. In one aspect, the invention provides a method of promoting neural regeneration in a patient determined to have a lesion in a mature (i.e. terminally-differentiated, non-embryonic) CNS neuron, preferably a post-gestational, juvenile, pediatric or adult CNS neuron, the method comprising the step of contacting the neuron with an EGFR inhibitor sufficient to promote regeneration of the neuron. The patient is a mammal such as a companion animal (dog, cat, etc.), livestock, animal model for neurodegeneration or CNS injury (e.g. rat, mouse, primate, etc), etc. In particular embodiments the patient is human.

The lesion can result from traumatic injury, stroke, pressure build-up, chronic neurodegeneration, etc. In a particular embodiment, the lesion results from acute or traumatic injury such as caused by contusion, laceration, acute spinal cord injury, etc. In this embodiment, the contacting step is preferably initiated within 96 hours of formation of the lesion, and more preferably within 72, 48, 24, or 12 hours. The EGFR inhibitor can be administered to the injured neuron in combination with, or prior or subsequent to, other treatment regimes such as the use of anti-inflammatory agents. In a specific embodiment, the lesion results from acute spinal cord injury and the method additionally comprises contacting the neuron with methylprednisolone sufficient to reduce inflammation of the spinal cord. In another embodiment, the lesion results from neurodegeneration which, for example, can be caused by neurotoxicity or a neurological disease or disorder such as Huntington's disease, Parkinson's disease, Alzheimer's disease, multiple system atrophy (MSA), glaucoma, etc.

The EGFR inhibitor can be any inhibitor that specifically suppresses EGFR function, including antisense and RNAi oligonucleotide inhibitors, peptide nucleic acids, peptide antagonists, monoclonal antibodies (MAB), small molecule inhibitors (SMI), etc. In addition, various molecules known to interfere with EGFR signaling such as EGFR truncations, Gene 33 polypeptide (also called RALT and MIG6), and kekkon can be targeted, introduced or expressed in target cells. For example, a wide variety of technologies are available for protein transfection, including the use of cationic liposomes, calcium phosphate coprecipitation, electroporation, microinjection, viral vectors, and a large number of commercially-available, proprietary lipid, polyamine and amphoteric protein reagents, including "ProJect", "TransIT", "Profect-1", "Chariot" and ProteoJuice". In a particular embodiment, the EGFR inhibitor is a small molecule or monoclonal antibody that specifically suppresses the kinase function of EGFR. Table I (see Original Patent) lists several small molecule and antibody EGFR inhibitors that are FDA-approved or are in clinical trials.

The EGFR inhibitor can be contacted with the neuron using any suitable drug delivery method. For in vitro methods, the inhibitor is added to the culture medium, usually at nanomolar or micromolar concentrations (see Examples 1 and 3). For in situ applications, the EGFR inhibitor can be administered orally, by intravenous (i.v.) bolus, by i.v. infusion, intracranially, intraperitoneally, intraventricularly, by epidural, etc. Suitable protocols for administration of the EGFR inhibitor to a patient can be readily derived from the extensive animal studies and clinical trials that have been conducted on EGFR inhibitors for the treatment of cancer. In certain embodiments, the EGFR inhibitor is administered orally or intravenously. Several orally- and intravenously-administered EGFR inhibitors have shown to be well-tolerated and efficacious in glioma and other brain tumors, demonstrating that EGFR inhibitors delivered by these routes have a therapeutic effect on cells of the CNS. Small molecule EGFR inhibitors are typically administered orally at about 50-500 mg/day, and monoclonal antibodies are typically administered weekly by infusion at about 1-5 mg/kg body weight. In other embodiments, the EGFR inhibitor is contained within an implantable device specifically adapted for delivery to a CNS neuron. The devices include controlled release biodegradable matrices, fibers, pumps, stents, adsorbable gelatin (e.g. Gelfoam) or other devices loaded with premeasured, discrete and contained amounts of an EGFR inhibitor sufficient to promote neuronal regeneration (see Example 5). In a particular embodiment, the device provides continuous contact of the neuron with the EGFR inhibitor at nanomolar or micromolar concentrations.

The subject methods may further comprise the step of detecting a resultant neural regeneration. For in vitro applications, neural regeneration can be detected by any routinely used method such as a neurite outgrowth assay (see Example 1). For in situ applications, neural regeneration can be detected using imaging methodologies such as MRI. More commonly, neural regeneration will be detected inferentially by neurological examination showing improvement in the patient's neural function. The detecting step may occur at any time point after initiation of EGFR inhibitor treatment, e.g. at least one day, one week, one month, three months, six months, etc. after initiation of treatment. In certain embodiments, the detecting step will comprise an initial neurological examination and a subsequent neurological examination conducted at least one day, week, or month after the initial exam. Improved neurological function at the subsequent exam compared to the initial exam indicates resultant neural regeneration. The specific detection and/or examination methods used will usually be based on the prevailing standard of medical care for the particular type of neural lesion being evaluated (i.e. trauma, neurodegeneration, etc.).

The invention also provides EGFR inhibitor-eluting or EGFR inhibitor-impregnated CNS-implantable solid or semi-solid devices. Examples of CNS implantable devices include polymeric microspheres (e.g. see Benny et al., Clin Cancer Res. (2005) 11:768-76) or wafers (e.g. see Tan et al., J Pharm Sci. (2003) 4:773-89), biosynthetic implants used in tissue regeneration after spinal cord injury (reviewed by Novikova et al., Curr Opin Neurol. (2003) 6:711-5), biodegradable matrices (see e.g. Dumens et al., Neuroscience (2004) 125:591-604), biodegradable fibers (see e.g. U.S. Pat. No. 6,596,296), osmotic pumps, stents, adsorbable gelatins (see e.g. Doudet et al., Exp Neurol. (2004) 189:361-8), etc. Preferred devices are particularly tailored, adapted, designed or designated for CNS implantation. The implantable device may contain one or more additional agents used to promote or facilitate neural regeneration. For example, in one embodiment, an implantable device used for treatment of acute spinal cord injury contains an EGFR inhibitor and methylprednisolone or other anti-inflammatory agent. In another embodiment, the implantable device contains an EGFR inhibitor and a nerve growth factor or hormone that promotes neural cell survival, growth, and/or differentiation, such as brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF), nerve growth factor (NGF), etc.
 

Claim 1 of 16 Claims

1. A method of promoting axonal regeneration in vitro by contacting mature CNS neurons that are cerebellar granule cells (CGNs), dorsal root ganglion cells (DRGs) or retinal ganglion cells (RGCs) following lesion injury, with a small molecule epidermal growth factor receptor (EGFR) inhibitor sufficient to promote axonal regeneration.

____________________________________________
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.

 

 

     
[ Outsourcing Guide ] [ Cont. Education ] [ Software/Reports ] [ Training Courses ]
[ Web Seminars ] [ Jobs ] [ Consultants ] [ Buyer's Guide ] [ Advertiser Info ]

[ Home ] [ Pharm Patents / Licensing ] [ Pharm News ] [ Federal Register ]
[ Pharm Stocks ] [ FDA Links ] [ FDA Warning Letters ] [ FDA Doc/cGMP ]
[ Pharm/Biotech Events ] [ Newsletter Subscription ] [ Web Links ] [ Suggestions ]
[ Site Map ]