A novel oral plasma kallikrein (PKal) inhibitor KV123833 blocks VEGF-mediated retinal vascular

hyperpermeability in a murine model of retinal edema (#3464)

Nivetha Murugesan, Allen C. Clermont, Louise J. Rushbrooke, Peter A. Robson, Robrecht Thoonen, Stephen J. Pethen, Sally L. Hampton & Edward P. Feener

ARVO Annual Meeting, May 1, 2018, Honolulu, Hawaii

Diabetic Macular Edema (DME)

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Severe NPDRCentral-

involved DME

Normal Retina

• Approximately 900,000 patients in the United States have active DME and are at serious risk of vision loss1

• DME is caused by breakdown of the blood-retinal barrier resulting in the leakage of fluid and circulating proteins into the neural retina2

_____Source: (1) Zhang X et al. JAMA. 2010;304(6):649-656; (2) Duh et al, JCI Insight 2017, July 20, 2(14)

• Post hoc analysis of Protocol I: Early and Long-term responses

Mean BCVA response among stratified ranibizumab treated eyes *

Mean Change:12 weeks Eyes

15.2 letters 37%(126 of 340)

6.9 letters 23%(79 of 340)

-0.3 letters 40%(135 of 340)

______Source: * Gonzalez VH et al. Am J Ophthalmol 2016;172:72–79.

40% of Eyes with DME have Minimal Visual Improvement in Response to Ranibizumab at 12 weeks

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0

1000

2000

3000

4000

0 10 20 30 40 50 60 70 80 90 100

VEG

F (P

G/M

L)

PLASMA PREKALLIKREIN (nM)

PREKAL VS VEGF

r=0.168, p = 0.499

DME Patients with high PPK and low VEGF

• Not all DME patients have increased VEGF1

• All patients show increased PKal1Mainly PKalincreased

VEGF & PKalincreased

Plasma Kallikrein and VEGF do not Correlate in DME Vitreous

______Source: (1) Kita T et al. Diabetes 2015;64:3588–3599.4

~50µg/ml in plasma

Inflammation & Edema

The Kallikrein Kinin System1

______Source: (1) Phipps JA & Feener EP Kidney International. 73(10):1114-9, 2008 May5

ContactActivationSystem

Factors implicated in triggering macular edema:

% Reduction in retinal vascular permeability/edema with:

Plasma Kallikrein Inhibitor

Plasma PreKallikreinGene Knockout

Diabetes/Hyperglycemia -83%1 -78%2

Inflammation (TNFα) -52%3

Hypertension -70%4

Hemorrhage (carbonicanhydrase) -81%5

VEGF -57%3 -47%3

Plasma Kallikrein Mediates Retinal Vascular Permeability and Edema Induced by Multiple Triggers

______Source: (1) Clermont et al, Diabetes 2011; (2) Kita et al, Diabetes 2015; (3) Clermont et al, IOVS 2016; (4) Phipps et al, Hypertension 2009; (5) Gao et al, Nature Medicine 2007

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VEGF

Saline VEGF

IVT Injection

Green – endothelial cells (CD31)Red – plasma prekallikrein (PPK)

VEGF increases Plasma Kallikrein levels in the Retina1

______Source: (1) Clermont et al. Invest OphthalmolVis Sci. 2016;57:2390–23997

Kallikrein Activation

• Knock-out of plasma prekallikreinreduced retinal edema triggered by intravitreal injection of VEGF

• Plasma kallikrein activity mediates, in part, the edematous effects of VEGF on the retina

Plasma Prekallikrein (Klkb1) knockout – in mice

p < 0.001

Plasma Prekallikrein contributes to VEGF-induced Retinal Edema in Mice1

______Source: (1) Clermont et al Invest OphthalmolVis Sci. 2016;57:2390–2399.8

KV123833: Pharmacological Profile

• MW: < 500 daltons

• Human Pkal Ki: 3nM

• > 500 fold selectivity vs. serine proteases

• Solubility: >500 µg/ml (aqueous and gastric fluid)

• Oral bioavailability: 36% (rats)

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Species PKal KV123833 IC50

Human 11.0nM ± 6.2

Mouse 14.8nM ± 5.7

Rat 17.5nM± 8.4

Dextran sulfate-stimulated kininogen (HK) cleavage in undiluted human plasma

Ex-Vivo Assay to Measure Plasma Kallikrein Activity in Whole Plasma

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% fu

ll-le

ngth

HK

FXII

Pkal

PPK

HK(fulllength)

CleavedHK

FXIIa

• KV123833 is protective against HK cleavage in undiluted human plasma

Retinal ExposurePlasma Exposure

Osmotic Pumps(s.c) VEH/KV123833

DAY1 DAY2

VEGF/PBSIVT

DAY3

Collect PlasmaPerfuse & Harvest Retina

Plasma and Retina exposure of KV123833 following systemic administration in mice using Alzet 1003D osmotic pumps

• VEGF increases retinal exposure of circulating KV123833

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KV123833 VEHICLE

137 ng/mL

Systemically administered PKal inhibitor KV123833 reduces VEGF-induced RVP in mice

Osmotic Pumps(s.c) VEH/KV123833

DAY1 DAY2

VEGF/PBSIVT

DAY4

RetinalEB assay

DAY3

EB infusion (2h)Retinal isolation

Retinal Vascular PermeabilityVEGF IVT (24hrs)

• KV123833: 1.92 mg/kg/day (2mg/ml in 10% PEG400/90% PBS (v/v))

• 1003D Alzet pumps inserted s.c. in mice

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- 85.3%

~ 137 ng/ml

Oral Pharmacokinetics of KV123833 in mice

• Oral gavage of 45 mg/kg KV123833 in mice maintains plasma exposure over 137 ng/ml for about 9 hours

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Mean Plasma Exposure of KV123833 (ng/mL)

Orally administered PKal inhibitor KV123833 is protective against VEGF-induced retinal leakage in mice

Retinal Vascular PermeabilityVEGF IVT (24hrs)

-GAVAGE 1 (VEH/833)

-IVT VEGF/PBS-GAVAGE 2(VEH/833)

DAY1 DAY2

-GAVAGE 3(VEH/833)-EVANS BLUE(EB) circulation-Retina & Plasma collection

DAY3

-RetinalEB assay

• Nominally 50mg/kg bid (in 10% DMSO/10% Cremophor/80% H2O)

- 86.1%

Conclusions

Intravitreal injection of VEGF increases retinal exposure of circulating KV123833 sugges-ting that retinal vascular hyper-permeability increases drug distribution to the retina

Previous work has implicated plasma kallikrein in mediating VEGF-independent DME.

Orally administered PKal inhibitor KV123833 is highly protective against VEGF-induced retinal edema in mice

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This current study suggests that oral PKal inhibitors may also provide an opportunity to reduce the edematous effects of VEGF in DME.

Diabetic Retinopathy

Diabetic Macular Edema

Retinaischemia

VEGF

Breakdown of the BRB, leaky microaneurysms, retinal hemorrhages

Plasma Kallikreinsystem

Anti-VEGFtherapies

Anti-PKalTherapiesIVT injectionKVD001

Oral PKalInhibitor

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• Approximately 123 patients who have discontinued treatment with anti-VEGF therapy and who still have significant edema and reduced visual acuity

• Sham-controlled, double-masked clinical trial will evaluate two doses

• Efficacy endpoints include best corrected visual acuity (BCVA), central subfield thickness (CST), and the diabetic retinopathy severity scale (DRSS)

• ClinicalTrials.gov Identifier: NCT03466099

Study of the Intravitreal Plasma Kallikrein Inhibitor, KVD001, in Subjects With Center-Involving Diabetic Macular Edema (ciDME)

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3-monthfollow up

3 months of treatment(4 injections)

2-month washout

Enroll-ment

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