osteoarthritis oa in vitro and animal models l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Osteoarthritis (OA): in vitro and animal models PowerPoint Presentation
Download Presentation
Osteoarthritis (OA): in vitro and animal models

Loading in 2 Seconds...

play fullscreen
1 / 40

Osteoarthritis (OA): in vitro and animal models - PowerPoint PPT Presentation


  • 777 Views
  • Uploaded on

Osteoarthritis (OA): in vitro and animal models. James Witter MD, PhD Division of Analgesic, Anti-inflammatory and Ophthalmic Drug Products (HFD-550) Center for Drug Evaluation (CDER) Food Advisory Committee Meeting June 7, 2004. OA: Are there links?. Human. Animal. Client

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Osteoarthritis (OA): in vitro and animal models' - houston


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
osteoarthritis oa in vitro and animal models

Osteoarthritis (OA): in vitro and animal models

James Witter MD, PhD

Division of Analgesic, Anti-inflammatory and Ophthalmic Drug Products (HFD-550)

Center for Drug Evaluation (CDER)

Food Advisory Committee Meeting

June 7, 2004

oa are there links
OA: Are there links?

Human

Animal

Client

(companion)

Experimental model

Histology

cell

enzyme

there are currently no fda approved therapies that alter joint structure in oa
There are currently no FDA approved therapies that alter joint structure in OA

Osteoarthritis Initiative

NIH/FDA/Industry/Academia

February 28-29, 2000

human oa some estimates
Human OA: Some Estimates
  • $76 billion, direct/indirect health care costs
    • 68 million lost work days (pain and loss of function)
  • clinical OA (MD diagnosis)
    • 12.1% of US or 21 million people
  • total joint replacements
    • 494,000/yr (hip-knee)
  • market size
    • symptoms- $4.0 billion
    • structure- $3.5 billion
human oa some questions
Human OA: Some Questions
  • is OA inevitable part of aging?
    • certain joints in most people normal in old age
  • what is the etiology of OA?
    • likely multiple, few examples…
      • genetic-developmental
      • overuse
        • acute and chronic trauma
      • underuse
        • atrophy
    • primary (idiopathic) vs. secondary
conceptual model of human oa
Conceptual Model of Human OA

Biochemical changes

Structural changes

Pain* and other signs and symptoms (OA)

Functional limitation*

Reduced quality of life*

Surgical replacement*

* important to the patient

surrogate approval subpart h 21 cfr 314 510
“Surrogate” ApprovalSubpart H21 CFR 314.510

FDA may grant marketing approval for a new drug product on the basis of adequate and well-controlled clinical trials establishing that the drug product has an effect on a surrogate endpoint that is reasonably likely, based on epidemiologic, therapeutic, pathophysiologic, or other evidence, to predict clinical benefit or on the basis of an effect on a clinical endpoint other than survival or irreversible mortality.

surrogate endpoint definition
Surrogate Endpoint: Definition
  • A surrogate endpoint of a clinical trial is a laboratory measurement or a physical sign used as a substitute for a clinically meaningful endpoint that measures directly how a patient feels, functions, or survives
  • Changes induced by a therapy on a surrogate endpoint are expected to reflect changes in a clinically meaningful endpoint
  • Only valid if the effect on the surrogate leads to a clinical benefit
surrogates vs biomarkers
Surrogates vs. Biomarkers
  • Surrogate endpoints are candidates for drug approval
  • Biomarkers do not have the same regulatory implication
  • Surrogates may be biomarkers, but not all biomarkers are surrogates.
slide11

Clinically Meaningful Outcome

Surrogate marker

Biomarker

delay in structural progression
Delay in Structural Progression
  • currently JSN (knee/hip) by X-ray accepted as surrogate
  • trial length: at least one year
  • include endpoints of pain, patient global, and patient reported outcome
  • can structure “stand alone”?
claim oa structure oa draft guidance 1999
Claim: OA StructureOA draft guidance-1999
  • “Normalize” the X-ray (stand alone)
  • Improve JSN over baseline (stand alone)
        • reflects new or regrown “physiologic” cartilage
  • Slow JSN by “clinically relevant amount”
        • may not need symptom evidence for approval
        • approval contingent on commitment to define the actual symptom benefit in phase 4 studies
  • Slow JSN by < “clinically relevant amount”
        • subpart H approach
        • JSN is surrogate
adult human cartilage
Adult Human Cartilage
  • chondrocytes in abundant extracellular matrix
    • 65-80% water
    • 20-35% dry weight is structural macromolecules
      • type II collagen ~50%
      • aggrecan ~ 25%
        • glycosaminoglycans (GAGs)
          • chondroitin sulfate (4 vs. 6)
          • keratan sulfate
      • other types of collagens (IX, XI)
      • other proteoglycans
      • hyaluronic acid
the oa joint as an organ
The OA Joint as an Organ
  • cartilage (hyaline, fibrocartilage)
      • aneural avascular alymphatic
  • menisci (medial, lateral)
  • tendons, ligaments,capsule
  • bone
  • synovial
    • membrane
    • fluid
  • muscles
slide17

Fixed Flexion

Extended

Knee Radiography Techniques

Semi-flexed Fluoroscopy

Semi-flexed MTP

Schuss

x ray standardization issues
X-ray: Standardization issues
  • conventional knee X-ray not reproducible
  • solution: (Buckland-Wright technique)
    • Semi-flexed AP view
    • Fluoro-assisted to allow to superimpose anterior and posterior margins of medial tibial plateau
      • To provide alignment of plateau and x-ray beam
    • Magnification-corrected JSW using xJSW software
  • problem: Not reproducible in clinic for
    • Entry criterion
    • Monitoring of disease
in vitro considerations
In Vitro: Considerations
  • maintain matrix equilibrium/environment
    • Chrondrocyte highly sensitive to feedback
      • anabolic
        • proteoglycans and GAGS
      • catabolic
        • matrix metalloproteinases (MMP)
      • biomarkers
    • cell-cell and cell-matrix interactions
    • loading stresses
      • nutrients and waste removal
    • temperature
      • core (37°C) vs. ankle joint (29°C)
mouse chondrocyte biochem j 2003 376 511 515
Mouse chondrocyteBiochem J. (2003) 376, 511-515
  • without glucose, glucosamine sole source of glycosaminoglycans (GAGs) for cell
  • with glucose
    • strong competitive inhibitor to utilization of glucosamine to produce GAGs
  • with glucosamine
    • do not stimulate production of GAGs
    • higher concentration produced less GAGs
  • what are likely levels of glucose, glucosamine at level of human cell?
animal model considerations
Animal model: Considerations
  • pain
    • primary clinical symptom
  • surgical intervention
    • not mimic human situation
  • species differences
    • 4 vs. 2 legs
    • biochemistry
  • underuse
    • muscle weakness (elderly women)
pain the symptom
Pain: The Symptom
  • studied directly (by patient) in humanOA
    • WOMAC for hip and knee
  • studied indirectly (veterinarians) in animalOA
    • chronic
      • lameness (function)
    • acute
      • vocalization
      • behavioral changes
      • decreased appetite
      • increases or decreases in activity
      • physiologic changes (pulse, blood glucose)
osteoarthritis treatment of signs and symptoms claim
Osteoarthritis: treatment of signs and symptoms claim
  • Primary efficacy endpoints:
    • Pain
    • Function
    • Patient global
  • Trial length:
    • 3 months
womac pain index
WOMAC pain index

1. Walking on flat surface

2. Going up or down stairs

3. At night while in bed

4. Sitting or lying

5. Standing upright

animal models of oa chemically induced intra articular
Animal Models of OA: chemically-induced (intra-articular)
  • iodoacetate
      • chicken
  • papain
      • guinea pig, mouse
  • chymopapain
      • dog
  • collagenase
      • mouse
  • TGF-ß
      • mouse
animal models of oa physically induced
Animal Models of OA:physically induced
  • anterior cruciate ligament transection
    • unilateral or bilateral
      • dog, rabbit
  • meniscectomy
      • rabbit, guinea pig
  • immobilization
      • rabbit, dog
  • patellar contusion
      • rabbit
animal models of oa spontaneous
Animal Models of OA:spontaneous
  • Age/obesity
      • Hartley guinea pig
  • Genetic
    • unidentified
      • mouse, primate
    • Transgenic mice
      • type IX or II collagen mutation
    • hip dysplasia
      • dog (purebred vs. mixed bred)
cruciate deficient dog lessons
Cruciate-Deficient Dog: Lessons
  • chondrocytes can repair damage
    • hypertrophic cartilage
      • increased GAGs
      • true in humans, rabbits and Rhesus macaques
  • neurogenic acceleration
    • dorsal route ganglionectomy
    • more rapid cartilage damage
      • not good model for primary (idiopathic) OA
        • homeostatic phase of hypertrophic repair differs
  • importance of periarticular muscle
    • immobilized joint has atrophic loss of GAGs
      • quadriceps weakness in elderly women
domain structure of matrix metalloproteinase mmp family
Domain Structure of Matrix Metalloproteinase (MMP) Family

Pre

Pro Catalytic Hemopexin-like

Fibronectin 1(V) Transmembrane

MMPPre Pro Cat Fn1(V) TmHpx

Matrilysin

Collagenase-1,-2,-3

Stromelysin-1,-2,-3

Macro elastase

MT MMP-1 to -4

Gelatinase A

Gelatinase B

evidence for mmps in pathophysiology of osteoarthritis
Evidence for MMPs in Pathophysiology of Osteoarthritis
  • hydrolyze relevant matrix substrates in vitro
  • upregulated by disease mediators (IL-1, TNF)
  • in situ hybridization and immunofluorescence at sites of tissue degeneration
  • signature cleavage fragments in vivo
    • Collagen neoepitopes
  • blockage by natural compounds and selective MMP inhibitors in vitro models
collagenases present in different species
Collagenases Present in Different Species

CollagenaseHumanRatMouseRabbitDog

1 Yes No No Yes Yes

2 Yes ? Yes Yes ?

3 Yes Yes Yes Yes Yes

protection of cartilage by therapy x in rabbit meniscectomy model
Protection of Cartilage by Therapy X in Rabbit Meniscectomy Model

Therapy X (mg/kg/d)

1

3

10

Parameter

Normal

Sham

Vehicle

2.1

Fibrillation

0.1

0.1

3.6

4.1

2.7

Fissures

0.1

0.1

3.5

4.5

2.1

0.7

Erosions

0.0

0.0

2.9

2.9

1.0

0.9

Global

0.3

0.5

13.1

15.9

8.8

5.5

p < 0.01

protection of cartilage by therapy x in dog cruciotomy model 8 months
Protection of Cartilage by Therapy X in Dog Cruciotomy Model (8 months)

Treatment Area Composite

Vehicle 32  10 1.7  0.6

Low Dose X 22  7.7 1.4  0.8

High Dose X 19  8.4 1.0  0.8

oa and structure modifiers
Hypothesis

Limit joint destruction

Results (clinical trials)

MMP inhibitors

No effect in RA or OA

Some stopped due to safety data in oncology trials

Stiffness/pain particularly in shoulders and hands

Bisphosphonates

Suggestion of efficacy in phase 2 trial, not confirmed in phase 3 trials (ACR-Orlando, 2003)

OA and Structure Modifiers
slide36

Timing of Approval and:

Structural Benefit

Clinical Benefit

RA

Drug approval

Time

OA

OA: structural modifier

slide37

OA: JSN progression

Rapid

JSN

Slow

No change

b

a

c

a

Time

virtual tjr endpoint in oa
“Virtual” TJR endpoint in OA
  • to facilitate and standardize development of disease-modifying agents
  • consists of the following key elements:
    • pain
    • function
    • radiographic endpoints
  • idea that agreed upon endpoint of joint failure reached (and surgery may occur)
slide39

Osteoarthritis: The “Joint Organ”

Total Joint Replacement

Clinical

Function

3 or 4

Pain

2

Surrogate

Tendon/Ligament

1

Synovium

Bone

Drug development

phase

Biomarkers

Cartilage

slide40

…validation of a molecular target in human disease can be obtained only

after positive results are obtained in Phase III clinical trials in humans.

Ken Brandt, Biorheology 39 (2002) 221-235

Human OA

In vitro

animal