VEGF-A modified mRNA in diabetic wound healing and future treatment opportunities

Kenny Hansson, PhD, Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Gothenburg, Sweden

4th International mRNA Health Conference, Boston Nov 1, 2016

Diabetic foot ulcer (DFU) –an indication with high unmet medical need

• 10-15 percent of all diabetic patients will suffer from DFU during their lifetime

• The complications are severe with a risk of amputation in connection with a DFU being as high as 4.9% (US 2008)

• The 10 year mortality for diabetes + DFU is 49% compared to 35% for diabetes alone with similar severity - same rate as many cancers

• The estimated cost for treatment of DFU was between 9-13 BUSD in the US 2014

The role of VEGF-A in wound healing

VEGF-A

Angiogenesis

Granulationtissue

ReepithelializationInflammation

Keratinocytes Mast cellsMonocytes/

macrophages Fibroblasts

Vascularpermeability

The modified mRNA concept

• VEGF-A mRNA is taken up and transfects the cell• VEGF-A protein is produced • VEGF-A is secreted into the neighboring microenvironment

mimicking the paracrine role of the protein• VEGF-A is transiently locally expressed in tissue

Chien et al Cold Spring Harb Perspect Med. 2014

VEGF-A mRNA -induces efficient production of VEGF-A protein following intradermal injection in rabbit hind leg

# of probes with VEGF-Alevels >LLOQ

1 cm

1 cm

Microdialysis experimental design• 100 KDa probe (2/animal)• Intradermal positioning (probe), hind leg• 0.5 µL/min flow, push• Saline perfusate• Intradermal administration• 4x50 µg (4x50 µL) modRNA in citrate/saline• ~5 hr sampling• N=4

0 1 2 3 4 5 610

100

1000

LLOQ

MeanSEM

0/8 0/8

3/85/8 5/8

Time after VEGF-A mRNA injection (h)hV

EGF-

A in

elu

ate

(pg/

mL)

VEGF-A mRNA -Experimental outline and wound healing model in diabetic db/db mice

Day 0-Full-thickness wound punch-Injection of compound/vehicle -Imaging

Day 3-Injection-Imaging

Day 6-Imaging

Day 10-Imaging

Day 13-Imaging

Day 18-Imaging-Harvest of tissue

5 mm

-VEGF-A and VEGFR2 downstream signaling analysis-H&E and CD31 histology -VEGF-A protein analysis in tissue and plasma

5 mm

VEGF-A mRNA significantly increases wound healing rate and vascular density after two intradermal injections at day 0 and 3 in diabetic (db/db) mice

Improved closing of open wound area in mice treated with two intradermal injections of VEGF-A mRNA

Increased vascular density in mice treated with two intradermal injections

of VEGF-A mRNA

Data presented as mean + standard error. n=7-8

Data presented as mean + standard error. n=3

VEGF-A mRNA significantly increases wound oxygenation 6 days after intradermal injection

Day 3 Day 6 Day 3 Day 6

[F/P] 1.50Lower O2% Higher O2%

VEGF-A mRNADouble injection

Vehicle Double injection

Data: mean + SEM, n=3-4 * = p-value < 0.05 vs vehicle

Quantification of oxygen tensionWound oxygenation visualized byoxygen-sensitive nanoparticles

Day 3 Day 6100

120

140

160

180

200

220

240

Double inj vehicle Double inj VEGF-A mRNA

Mea

n gr

ey v

alue

*

Is VEGF-A enough to heal diabetic foot ulcers?

• FDA requires significant improvement in complete wound closure vs. standard of care/placebo for approval

• Telbermin (recombinant human VEGF-A) was evaluated in 2006-2008 by GenenTech in a phase 2 trial over 12 weeks but could failed

• Other single factor treatments (KGF, FGF2) have failed or been questioned for efficacy (Regranex (PDGF-BB))

We propose that a combination of factors influencing wound healing would be the next step to achieve complete wound closure

Conclusions

• Evidence of local VEGF-A production following intradermal injection of VEGF-A mRNA in rabbits

• Evidence to support effective wound healing following intradermal injection of VEGF-A mRNA in diabetic mice

– Improved wound healing rate

– Improved oxygenation

– New vessel formation

• Combination of factors influencing wound healing could be the way forward to address the DFU indication

Acknowledgement

• AstraZeneca R&D Gothenburg, Sweden

– Regina Fritsche-Danielson– Karin Jennbacken– Leif Carlsson– Susanne Pehrsson– Madeleine Antonsson– Monika Sundkvist– Alan Sabirsh

• University of Virginia, USA– Shayn Peirce-Cottler– Anthony Bruce– Scott Seaman

• Karolinska Institute, Sweden– Kenneth Chien– Jonathan Clarke

• Moderna, USA– Barry Ticho