Transcript Modulation of the Immune System: Treatment Options

Modulation of the Immune System:
Treatment Options and new Developments
PD Dr. Chris Rundfeldt
DrugConsult.Net
Magdeburg and Dresden, Germany
Diseases and conditions with (pathological)
involvement of the immune system
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Inflammatory conditions, associated with trauma,
infection or tissue destruction
Chronic perpetuating inflammations: COPD, arthritis
Allergic diseases: type I-IV
Atopic diseases: atopic dermatitis, atopic rhinitis,
asthma
Autoimmune related diseases: rheumatoid arthritis,
inflammatory bowl disease, colitis ulcerosa, morbus
Crohn, psoriasis, multiple sclerosis, coeliac disease,
Rasmussen's encephalitis, myasthenia gravis, ……
Organ / tissue transplantation and rejection reactions
Localized effects of the ubiquitous organ
“Immune system”
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The immune system is involved in numerous
physiological and pathological processes
Each organ can be a disease target (CNS, skin,
gut, muscle, soft tissue…..)
Often targeted tissues are limited and reasons for
localized effects are not known
Potential reasons for localization are hidden in the
complex nature of such multifactor diseases
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 A drug with immune modulator activity can
be useful for diverse diseases
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For example glucocorticoids are used for many conditions
Intervention options: well established drugs
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Anti-inflammatory drugs
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Immune modulators
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Inhibitors of cyclooxygenases (Ibuprofen...)
Inhibitors of lipoxygenases (Zileuton…)
Leukotriene receptor antagonists ( Montelukast…)
Glucocorticoids
Selective cytokine blockers (Biologics)
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TNFa inhibitor antibody / fusion protein (Infliximab,
Ethernacept…)
IL-1 receptor antagonist (Ankarinra)
Anti-T-cell fusion protein (Alefacept)
…….
Intervention options: Immunosuppressives
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Antimetabolites
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Calcineurin inhibitors (IL2 synthesis inhibitors)
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Cyclosporin
Tacrolimus, Pimecrolimus
mTOR, kinase inhibitor, activation of T-cells inhibited
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Purine synthesis inhibitors (Azathioprine …)
Purine analog mimics adenosine, DNA synth. Inhibit. (Cladribine)
Pyrimidine synthesis inhibitors (Leflunomide …)
Antifolate (Methotrexate)
Sirolimus (=Rapamycin)
TNFa-synthesis inhibitor (Thalidomide, Lenalidomide)
(Thalidomide: teratogenic effect phocomelia, now used for Erythema nodosum leprosum, cancer, etc.
Limitations of pharmacological intervention
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Immune suppressive agents can facilitate potentially
life threatening infections
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Invasive aspergillosis
Tuberculosis
General infections
Unexpected adverse events include disturbance of
learning and memory (Rapamycin)
Inhibition of rapidly dividing tissues
Glucocorticoids lack a good separation of
pharmacologically active and toxic doses
Limitations of pharmacological intervention:
Biologics
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Biologics are thought to be selective but can induce:
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Flu-like symptoms, nausea, fatigue, loss of appetite
Redness, rash, and/or pain at injection site
Allergic reaction to mouse protein with monoclonal antibodies
Increased risk of Hodgkin’s and non-Hodgkin’s lymphoma and
other types of cancer in children and teens taking TNF inhibitors
Lupus-like syndrome
Possible reactivation of latent tuberculosis infections with TNF
inhibitors
Progressive Multifocal Leukoencephalopathy (PML), see
Natalizumab case (Tysabri)
Induction of antibodies against therapeutics results in
loss of effect
New treatment options?
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Novel treatment options should be:
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Selective for pathological conditions (reduce overactivation of the immune system component)
Have a good separation of effects and adverse
reactions
Be easy to handle, at best oral treatment
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While no such drugs are readily available, a few
interesting candidates can be discussed
Examples for new treatment options
 Inhibitors
 Stabilized
of Phosphodiesterase 4
cAMP analogues
 Dimethylfumarate
 Raft-modulators
Phosphodiesterase 4 inhibitors
Inhibitors of Phosphodiesterase 4 (PDE4)
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Prototype: Rolipram
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Initial development as antidepressant
Early investigation in multiple sclerosis indicate
pharmacological effect, but GI related side effects
Numerous development projects worldwide for
diverse diseases
Currently only roflumilast marketed in EU for
treatment of COPD
Other potential indications for roflumilast: Asthma,
atopic dermatitis, psoriasis
Roflumilast (PDE4i)
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Initial studies in patients with asthma
Roflumilast (PDE4i)
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Significant effects in patients with COPD
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But effect size lower than known for Theophyllin!
Roflumilast (PDE4i)
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Significant effects: reduction of exacerbations
Novel PDE4i: how to test preclinically
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In vitro tests:
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Cytokine release in PBMCs or whole blood
Induction with LPS or anti-CD3/CD28 or similar
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Ex vivo tests: Cytokine release from whole blood
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In vivo tests: Ovalbumin induced eosinophilia in
sensitized BN rats (asthma model)
LPS-induced neutrophilia in Lewis rats and in ferrets
(COPD model)
Emesis in ferrets and domestic pigs
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Example development strategy for PDE4i
Quality Lead
Metabolic stability in
plasma and liver prepar.,
species comparison,
metabolite profile
Stable in plasma,
no or low turnover
in liver preps.
Expl. kinetics in rat and dog
(i.v. vs p.o.)
Dog: t 1/2 > 2 h
BV > 30%
Inhibition of cytokine
release - PBMC‘s ; Maph
(IL2, 4, 5, 13, IFN)
(IL1, 6, 8, 12, 15, 17, MCP1)
IC50 < 100 nM
LTB4
(neutrophils)
LTC
(eosinophils)
IC50 < 100 nM
CYP3A4 Induction
Effect on- LPS-induced
neutrophilia in rats and ferrets
- late phase eosinophilia
in rats
- bronchial hyperreactivity
in mice
Equal or better
than Roflumilast
Side effect profile in
- ferrets (emesis and CNS)
- pigs (cardiovascular)
- mice, rats (CNS)
TI > 10
no induction
Preselection preclinical candidate
Example development strategy for PDE4i
Genotoxicity
- Ames test
- chromosome
aberration test
- micronucleus test
No effect
Receptor screening
initiated
initiated
Selectivity > 100
Preclinical Candidate
PK / ME
Identification of
- major metabolites
- metabolic pathways
- involved enzymes
Safety
Efficacy
Tolerability
- Irwin test (rat)
- acute toxicity (rat,
mice, dog)
Respiratory models
- allergic rhinitis (rat)
- LPS-induced neutrophilia
( ferrets and pigs)
- allergen-induced bronchoconstriction (guinea pigs)
acceptable
14C Pharmacokinetic
and metabolic
profiling
Full 4-week tox package
Clinical Program
Non-respiratory
inflammation models
- skin (mice)
- other models (CRO)
CNS diseases
Indication
extension
Example data: Ovalbumin induced eosinophilia
Novel compound
Example data: LPS induced neutrophilia
Novel compound
Example data: Safety profile in experimenta
animals
Rationale: clinical dose of roflumilast is limited by CNS side effects,
not by emesis
Test
Novel
Roflumilast
LPS neutrophilia >50%
0.01
mg/kg
0.01 mg/kg
Highest dose tested
without emesis
3 mg/kg
0.1 mg/kg
Highest dose tested
without CNS effects
0.3 mg/kg 0.01 mg/kg
not free of CNS effects
TI in relation to emesis p.o. ~300
~10
TI in relation to
CNS effects p.o.
< 1, no separation
~30
Compounds were administered to ferrets with gastric tube as a solution
or suspension
Translation of preclinical data in phase I
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Phase I is dedicated to determination of safety
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Options to get insight in efficacy in phase I
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LPS induced TNFa release from whole blood
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i.v. LPS induced hyperthermia and flu-like reaction in volunteers
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Intratracheal LPS administration followed by lung lobe lavage
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Local non-allergic or allergic skin irritation in sensitive patients,
with skin prick test or with Balsam of Peru
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Allergen induced late phase bronchoconstriction in volunteerpatients with mild stable asthma
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Methacholine induced bronchoconstriction
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Local non-allergic or allergic skin irritation in sensitive patients,
with skin prick test or with Balsam of Peru
PDE4 inhibition, other options
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Increased cAMP levels: cAMP substitution instead
of PDE4 inhibition
Stable cAMP analogues can be active but activate
also protein kinases
Clinically known stable analogue: Dibuturyl-cAMP
(bucladesine)
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Bucladesine is a safe drug, no emesis
Was developed as cardiotonic for i.v. administration
Was developed as skin healing cream
Failed for different reasons: Cardiotonic function
difficult to test, skin cream has strong odor (butyric
acid is released)
Clinical data showing a homogenous clinical
effect of cAMP level modulation
Goyarts et al.,
Skin Pharmacol Appl
Skin Physiol 2000:13,
86-92
Increase in thickness (mm)
DB-cAMP, water free
ointment
0.15
0.10
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0.05
0.00
vehicle
0.5%
1.5%
Increase in thickness (mm)
Dibuturyl-cAMP is active in arachidonic acid
induced ear swelling in mice
0.15
Ketoprofen, commercial
cream
0.10
0.05
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0.00
vehicle
ketoprofen
DB-cAMP
Drugs were administered onto the outer surface of the mouse ear 3 h before arachidonic acid
challenge. Measurement of ear thickness. 60 min later the ear thickness was measured.
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2-deoxy-cAMP may be an interesting candidate for a topical antiinflammatory ointment, but safety of this compound is not tested
No patent protection possible
Fumaric acid esters: old drugs with
novel mode of action
Dimethyl fumarate: A novel old drug for oral
treatment of immune diseases
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Dimethyl fumarate (DMF) is marketed in Germany as main
component of a first line oral drug for treatment of moderate
to severe psoriasis (Fumaderm®)
Fumaric acid esters are an effective therapy in patient with
moderate to severe psoriasis, even in those who have
previously been intolerant of systemic therapy
The mode of action of DMF is not fully understood
Problem: tolerability, GI irritation and flush, skin irritation
Problem: Papilloma / carcinoma in forestomach rats
Biogen Idec has developed a novel micro-tablet formulation
(immediate release) and tested positive for psoriasis and
MS. Now in phase III for MS
Forward Pharma has solved the challenge of developing a
modified release formulation. Now in phase II for Psoriasis
Fumaric acid ester (FAE) and Dimethylfumarate:
Pharmacology
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FAEs cause an increase of the intracellular calcium concentration
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FAEs inhibit the expression of the ICAM-1 T-cell receptor ligands
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The treatment of psoriatic patients with Fumaderm® results in a reduced
infiltration of the skin with granulocytes and T helper cells, followed by a
reduction of the acanthosis and hyperkeratosis
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Monomethyl fumarate increases the IL-4 and IL-5 production of activated
T cells, in a dose-dependent manner
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Dimethyl fumarate inhibits cytokine-induced E-selectin, VCAM-1 expression
in human endothelial cells
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Dimethyl fumarate inhibits cytokine-induced nuclear translocation of NF-kB.
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Dimethyl fumarate induces apoptosis in human monocyte-derived dendritic
cells.
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Monomethyl fumarate suppresses the FMLP-stimulated respiratory burst in
granulocytes
Fumaric acid ester (FAE) and Dimethylfumarate:
Pharmacology (2)
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In in vitro tests DMF is more potent than MMF
In plasma samples, only MMF can be found (rapid
demethylation)
In urine, DMF-conjugates with glutathione were
found
Proposed MOA: Intracellular uptake in leukocytes
Rapid conjugation with glutathione
Dimethyl fumarate induces immune suppression
via glutathione depletion and subsequent
induction of heme oxigenase
DMF pathways
Lumen
-Gut wall-
ERY
Tablet
DMF
Blood streem
ERY
no
metabol.
ERY
ERY
1 DMF Plasma Esterases MMF
2
WBC:
DMF
DMF-GSH
Active
Transp.
ERY
DMF-GSH
WBC:
MMF
MMF-GSH
Active
Transp.
Plasma Esterases MMF-GSH
Mercapturic acid derivatives,
excreted in urine
Glutathione depletion is immune suppressive
Top:
PBMCs were stimulated with
LPS/IFNg (1 mg/ml, 10 ng/ml)
or PHA (100 mg/ml) in the
presence of DMF
Bottom:
Mixed lymphocyte reaction to
quantify dose response and
reversibility
Substitution of reduced GSH
abolishes the inhibition of
inflammatory cytokine
secretion and alloreactive
lymphocyte proliferation by
DMF and DEF
FAEs are active in moderate to severe psoriasis
Mrowietz et al.
Br. J. Dermatol. 1998
138: 456-460
Effect of DMF in MS patients (Biogen)
Tabel from:
Lee et al., The International MS Journal
2008; 15: 12–18
Figure from:
Kappos et al., Lancet 2008; 372: 1463–72
Raft modulation as novel lipid
chemistry target
Raft modulation: Innovation ahead?
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Lipid Rafts are specific clusters of lipids and proteins
regulating a wide range of biological and pathological
processes
Lipid Rafts concentrate proteins to increase process
efficacy
Rafts coordinate disease events at specific sites and times
Signal transduction, virus entry & budding, bacterial entry,
receptor recycling, protein maturation are dependent on
Lipid Rafts
Each process occurs in a Raft of unique composition
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Rafts are novel pharmaceutical targets
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Example: IgE receptor RAFT as drug target
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IgE-receptor clustering drives RAFT formation
Protein-driven (specificity) reaction is combined
with novel lipid chemistry target
Receptor clustering
and RAFT coalescence
IgE
FceRI
multivalent
allergen
RAFT
lipids
kinase
unrelated
RAFT receptor
Signal cascade, release
of immune modulators
Miltefosine is a clinically effective RAFT
modulator
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Skin-prick test on human volunteers; IgE-dependent
allergic response
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Pretreatment with miltefosine (Miltex) or saline
Skin-prick with allergen & positive control (histamine)
Weller et al. 2008 Miltefosine inhibits human mast cell activation in-vitro and in-vivo. J Invest Dermatol
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Clinical effect back-translated in preclinical
model: TDI induced ear swelling in mice
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Conclusion
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Immune modulator drugs represent a diverse
family of drugs
Despite the large number of marketed drugs,
there is need for better drugs
Even among old drugs there are interesting new
approaches to immune modulation
Recent data indicate the reduction in glutathione
concentration can induce immune modulation
Raft modulation is a 2nd novel approach to
immune modulation
Thank you for your attention
I am ready to take your questions