Modulation of GABA-A Receptor Function for the Treatment of Anxiety Disorders

Modulation of GABA-A receptor function for the treatment of anxiety disorders

Rainer Rupprecht Department of Psychiatry and Psychotherapy University Regensburg Germany Biosynthesis of neurosteroids

Rupprecht et al. (1999) Trends in Neurosciences R. Rupprecht Pharmacology of GABAA receptors

Cl-

GABA GABA GABA agonists b a b + benzodiazepines BDZ g a barbiturates neurosteroids membrane alcohols

anesthetics

subunits: - Cl a1, a2, a3, a4, a5, a6; b1, b2, b3; g1, g2, g3; d; e; p R. Rupprecht Modulation of synaptic transmission by neurosteroids

Rupprecht et al. (2010) Nature Reviews Drug Discovery

R. Rupprecht Anxiolytic effects of neurosteroids

neurosteroids

3α, 5α-THP 3α, 5α-THDOC

R. Rupprecht Clinical symptoms of panic and requirements for new anxiolytic drugs

High anxiolytic efficacy

Rapid onset of action

Favourable side effect profile

Lack of tolerance development

Lack of abuse liability

R. Rupprecht Pharmacology of translocatorPharmacology protein of 18 kDa (TSPO)translocator ligands protein 18 kDa (TSPO) ligands

N O N O N N

XBD 173: a potential anxiolytic agent?

Rupprecht et al. (2010) Nature Reviews Drug Discovery R. Rupprecht Molecule structure of the translocator protein 18 kDa (TSPO)

Rupprecht et al. (2010) Nature Reviews Drug Discovery

R. Rupprecht XBD 173 enhances neurosteroidogenesis in rats

3000 3000

2500 2500

2000 2000

1500 1500

1000 1000

allopregnanolone (pg/g) allopregnanolone (pg/g) allopregnanolone 500 500

0 0 vehicle XBD173 vehicle diazepam (0.1 mg/kg) (0.1 mg/kg)

Rupprecht et al. (2009) Science R. Rupprecht XBD 173 enhances GABAergic neurotransmission in neocortical slices

120 XBD173 (5 µM)

100 200 80

XBD173 150 60 20 pA

100 amplitude (pA) amplitude 40 50 ms % change 50 20 0 control XBD173 XBD173 0 (1 µM) (5 µM) 0 3 6 9 12 32 35 38 41 44 time (min) amplitude charge

Rupprecht et al. (2009) Science R. Rupprecht Finasteride prevents the effects of XBD 173 on GABAergic neurotransmission

Finasteride: enzyme inhibitor preventing neurosteroidogenesis

time (min) finasteride XBD173 (5 µM) 80 (10 µM) 200

control

60 finasteride + XBD173 150

100

40 % change

50 amplitude (pA) amplitude 0 20 finasteride (10 µM) 5 pA + XBD173 (5 µM) 50 ms 0 amplitude charge 0 3 6 9 12 32 35 38 41 44

Rupprecht et al. (2009) Science R. Rupprecht XBD 173 does not induce tolerance effects in rats

80 80

70 70

60 60

50 50

40 40

30 30

20 20

Time spent in social contact (s) contact social in Timespent (s) contact social in Timespent 10 10

0 0 0 0.1 1 mg/kg controls XBD173 XBD173 diazepam (0.1 mg/kg) (0.1 mg/kg) (0.1 mg/kg) controls XBD173 + PK11195 (10 mg/kg) controls (9 x vehicle) acute (8 x vehicle + 1 x compound) subchronic (9 x compound) Rupprecht et al. (2009) Science R. Rupprecht Effects of XBD 173 in anxiety models

40 35

time (s) time 30 Effects of XBD 173 on 25 lactate induced panic 20 in rats 15

interaction 10

social

) vehicle vehicle XBD173 XBD173 XBD173 alprazolam

160 + saline + lactate (0.1 mg/kg) (1 mg/kg) (10 mg/kg) (1 mg/kg)

lines

140 + lactate + lactate + lactate + lactate

120 crossed

( 100

80 Effects of XBD 173

60 activity * in the open field test 40 in rats 20

0 locomotor vehicle + vehicle + XBD173 XBD173 XBD173 alprazolam saline lactate (0.1 mg/kg)+ (1 mg/kg)+ (10 mg/kg)+ (1 mg/kg)+ Rupprecht et al. (2009) lactate lactate lactate lactate Science R. Rupprecht Effects of XBD 173 on CCK-4 induced panic in rats

120 120

100 100

time time (s) 80

- 80

60 60

40 40

20 20 cumulated cumulated freezing

0 0 vehicle/CCK-4 alprazolam/ vehicle/solvent vehicle/CCK-4 XBD173/CCK-4 vehicle/solvent CCK-4

Rupprecht et al. (2009) Science R. Rupprecht Functional neuroanatomy of CCK-4 induced anxiety in volunteers

16 volunteers (25.6 ± 4.2 years) panic symptoms Panic Symptom Scale (PSS) (Bradwejn 1991) Panic criterion: 4 symptoms positive + moderate anxiety heart rate fMRI (1.5 T Avanto, Siemens)

Eser et al. (2009) Human Brain Mapping R. Rupprecht fMRI / CCK-4 study Study design and panic symptoms injection Advice to subjects: now CCK-4 Placebo 2 scans à 15 min: 1x CCK-4, 1x placebo possible

3 min 2 min 0 min 10 min

35 * 140

30 120

25 100 20 80 15 60

PSS Scan2 PSS 10 40 heart rate [bpm] rate heart 5 20 CCK-4 0 0 baseline CCK-4 -1 0 1 2 3 4 5 time Eser et al. (2009) Human Brain Mapping R. Rupprecht fMRI / CCK-4 study fMRI scans

after CCK-4 injection

random effects analysis; p<0.00001 during anti- cipatory anxiety

Eser et al. (2009) random effectsHuman analysis; Brain Mapping p<0.005 R. Rupprecht fMRI after CCK-4 injection: effect of placebo and alprazolam

Effect of alprazolam on functional connectivity Seed: vACC ROI

Leicht et al. (2013) Biological Psychiatry R. Rupprecht Neurosteroids during panic attacks in patients with panic disorder

progesterone 3α,5α-THP

6 4 placebo

5 lactate 3 4 CCK-4

3 2 THP THP (nmol/l)

2 - 1

3α,5α progesterone (nmol/l) progesterone 0 0 0 5 10 15 20 25 30 35 40 45 50 55 60 0 5 10 15 20 25 30 35 40 45 50 55 60

min. min.

4 3α,5β-THP 4 3β,5α-THP

3 3

2 2

THP THP (nmol/l)

β -

1 1

5α

3α,5 3β, 0 0 0 5 10 15 20 25 30 35 40 45 50 55 60 0 5 10 15 20 25 30 35 40 45 50 55 60

min. min.

Ströhle et al. (2003) Arch Gen Psychiatry R. Rupprecht Proof of concept study design for XBD 173

Screening physical examination (n = 121)

Exclusion Screening physical disease MINI (n = 21) (n = 100)

Exclusion day -1 Exclusion psychiatric disorder 1st CCK challenge other reasons (n = 7) (n = 85) (n = 8) maximum API score ≤ 14 > 14 points Exclusion Randomization low API score to treatment (n = 14) for 7 days (n = 71)

Alprazolam XBD173 placebo 10 mg/d (n=14) (n=14) 1 mg bid (n=14) 30 mg/d (n=14) 90 mg/d (n=15)

day 7 Exclusion 2nd CCK challenge physical disease (n = 70) (n = 1)

Exclusion API score API > 14 (baseline) final comparison (n = 7) (n=63)

Rupprecht et al. (2009) Science R. Rupprecht Proof of concept study readout for XBD 173

XBD173 XBD173 XBD173 alprazolam placebo (10 mg) (30 mg) (90 mg) (2 mg) baseline 0% 1200 -10% day 7 * -20% -30%

-40%

-50% * 800 -60%

AUC

Ratio delta AUC/baseline AUC AUC Ratiodelta AUC/baseline + (%) SEM -

API *

400

Rupprecht et al. (2009) placebo XBD173 XBD173 XBD173 alprazolam (10 mg) (30 mg) (90 mg) (2 mg) Science

Side effect profile of XBD 173 and alprazolam in healthy male volunteers

Adverse events (AE) by Body System XBD173 Alprazolam placebo 10 mg/day 30 mg/day 90 mg/day 2 mg/day (N=14) (N=14) (N=15) (N=14) (N=14) n (%) n (%) n (%) n (%) n (%)

Any Body System (TOTAL) 8 (57.1) 8 (57.1) 8 (53.3) 13 (92.9) 8 (57.1) Mild 2 (14.3) 3 (21.4) 2 (13.3) 3 (21.4) 5 (35.7) Moderate 6 (42.9) 4 28.6) 5 (33.3) 5 (35.7) 3 (21.4) Severe 0 (0.0) 1 (7.1) 1 (6.7) 5 (35.7) 0 (0.0)

Cardiac disorders 0 (0.0) 0 (0.0) 0 (0.0) 2 (14.3) 0 (0.0) Eye disorders 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 1 (7.1) Gastrointestinal disorders 4 (28.6) 5 (35.7) 4 (26.7) 5 (35.7) 4 (28.6) General disorders and administration 6 (42.9) 4 (28.6) 5 (33.3) 11 (78.6) 5 (35.7) site conditions Infections and infestations 0 (0.0) 1 (7.1) 0 (0.0) 0 (0.0) 1 (7.1) Increase in body temperature 0 (0.0) 0 (0.0) 1 (6.7) 0 (0.0) 0 (0.0) Musculoskeletal and connective tissue 1 (7.1) 0 (0.0) 2 (13.3) 1 (7.1) 1 (7.1) disorders Nervous system disorders 7 (50.0) 6 (42.9) 6 (40.0) 11 (78.6) 4 (28.6) Psychiatric disorders 1 (7.1) 0 (0.0) 1 (6.7) 8 (57.1) 0 (0.0) Renal and urinary disorders 1 (7.1) 1 (7.1) 1 (6.7) 0 (0.0) 0 (0.0) Respiratory, thoracic and mediastinal 1 (7.1) 0 (0.0) 2 (13.3) 0 (0.0) 0 (0.0) disorders Skin and subcutaneous tissue disorders 0 (0.0) 0 (0.0) 0 (0.0) 4 (28.6) 1 (7.1) Social circumstances 0 (0.0) 0 (0.0) 0 (0.0) 1 (7.1) 0 (0.0) Vascular disorders 0 (0.0) 0 (0.0) 1 (6.7) 0 (0.0) 0 (0.0) Total number of AEs 23 30 32 84 21

Rupprecht et al. (2009) Science

Withdrawal effects of XBD 173 and alprazolam in healthy male volunteers

Adverse events XBD173 Alprazolam placebo defined as withdrawal symptoms (WS)1 10 mg/day 30 mg/day 90 mg/day 2 mg/day (N=14) (N=14) (N=15) (N=14) (N=14) n (number of subjects) Abnormal dreams 0 0 0 4 0 Claustrophobia 0 0 0 1 0 Depressed mood 0 0 0 1 0 Dissociation 0 0 0 1 0 Fear 0 0 0 1 0 Hyperhidrosis 0 0 0 2 0 Insomnia 0 0 0 3 0 Nausea 0 0 0 1 0 Night sweats 0 0 0 1 0 Palpitations 0 0 0 2 0 Paranoia 0 0 0 1 0 Restlessness 1 0 1 4 0 Sleep disorder 0 0 1 5 0 Tension 0 0 0 1 0 Total number of WS 1 0 2 28 0 Total number of subjects (7%) (0%) (6.6%) (57%) (0%) with WS (%)

Rupprecht et al. (2009) Science

Outlook

R. Rupprecht TSPO ligand / XBD 173 binding in human brain tissue

Normal (~85%)

Non-binder (~15%)

Labeling with [3H]PBR28 (0.5 nM) Owen et al. (2010) Owen et al. (2011) Journal of Cerebral Blood Flow and Metabolism Synapse R. Rupprecht Prediction of TSPO ligand binding by rs6971 genotype within the TSPO gene

Ala147Thr polymorphism

Owen et al. (2012) Journal of Cerebral Blood Flow and Metabolism R. Rupprecht Effects of TSPO ligands

CNS

Astrocyte  TSPO Microglia Oligodendrocyte Astrocytes Neurons ? Oligodendrocytes ? Neuron

TSPO Neuroprotection ligands  Growth factors  Neurosteroids  Inflammation Microglia  Gliosis

PNS

Fibroblast  TSPO Macrophages Schwann cells Macrophage Neurons Neuron Fibroblasts ?

TSPO Neuroprotection Schwann cells ligands Regeneration  Growth factors  Neurosteroids  Inflammation Rupprecht et al. (2010) Nature Reviews Drug Discovery R. Rupprecht a b

Isoquinoline carboxamide Quinoline carboxamide Phenoxyphenyl acetamide PK 11195 VC198M DAA1106

Benzodiazepine Benzodiazepine Benzothiazepine Benzoxazepine Diazepam Ro5-4864 THIA-66 OXA-17f

Imidazopyridine acetamide Pyrazolopyrimidine acetamide Pyrazolopyrimidine acetamide Alpidem DPA-713 PYRA-3j R. Rupprecht e f

Arylindol acetamide Phenylindolylglyoxylamide Pyridazinoindole acetamide FGIN-1-27 IND-18 SSR180575 g h i

Phenylpurine acetamide Benzoxazine Alkaloid Emapunil (AC-5216/ XBD173) Etifoxine Vinpocetine

j k

Steroid Steroid Cholesterol Olesoxime/TRO19622 Porphyrin R. Rupprecht Protoporphyrin IX Putative therapeutic indications of TSPO ligands

Anxiety TSPO expression Depression? Neuroprotection

Neurodegeneration Stroke Anxiety Depression? Parkinson Microglia Alzheimer activation Glioma Pain Peripheral nerve lesions

R. Rupprecht Contributors

Departments of Psychiatry and Psychotherapy, University Regensburg and Ludwig-Maximilian University Munich T.C. Baghai, D. Eser, C. Mulert, C. Nothdurfter, C. Schüle, G. Leicht, A. Länger

Max-Planck-Institute of Psychiatry, Munich B. di Bendedetto, B. Eisensamer, T. Rein, G. Rammes, E. Wagner, S. Tanasic

Department of Genetics, Regensburg Imperial College, London B. Weber, T. Langmann D. Nutt, D. Owen

University Dundee, UK STAR*D/NIH University Rome J. J. Lambert A. J. Rush E. Romeo

Univ. San Francisco/ Chicago INSERM Paris/ Novartis, Basel S. Mellon, M, Rasenick M. Schumacher, D. Uzunov, K. Kucher

Supported by: EU, DFG, Max-Planck-Society, BMBF

R. Rupprecht Thank you for your attention !

R. Rupprecht