EMERGING THERAPIES FOR DIABETIC FOOT ULCERS Approved and commercially available

1
EMERGING THERAPIES FOR DIABETIC FOOT
ULCERSApproved and commercially available
Alejandra Vivas, MD Post Doctoral Research
AssociateWound Healing Research
ClinicDermatology and Cutaneous
SurgeryUniversity of Miami Miller School of
Medicine
2
The epidemic of the 21st century

• 25.8 million people in the US has diabetes. 1
• It is estimated that gt 400 million individuals
  will be affected by diabetes by 2025 worldwide.2
• Up to 25 of diabetics develop a diabetic foot
  ulcer (DFU) during their lifetime.3

1Data from the 2011 National Diabetes Fact
Sheet 2 Boulton AJ, VileikyteL,
Ragnarson-Tennvall G, Apelqvist
J.Lancet.2005366(9498)171924 3 Singh N,
Armstrong DG, Lipsky BA. JAMA 2005293(2)217-28
3
The epidemic of the 21st century

• 20 of diabetes-related hospital admissions4 and
  85 of amputations in diabetics are due to
  complications of a diabetic foot.5
• Recent prevalence data of 2011 states that one
  lower extremity is lost every 20 seconds globally
  due to diabetes. 6

4 Mondy S. Savannah Health Perspectives.20062(6)
24-25 5 Reiber GE, Vilekyte L, Boyko EJ, del
Aguila M, Smith DG, Lavery LA, Boulton AJ.
Diabetes Care. 1999 22157-62 6 International
Working Group on the Diabetic Foot
4
Treatment of DFUsStandard of care

5
Levels quality of evidence
6
Advanced therapies for DFUs

• Randomized controlled trials (RCTs) have
  demonstrated that advanced biological therapies
  in combination with standard care including
  offloading and debridement lead to improved
  healing of DFUs compared with standard care
  alone7

7 Margolis DJ, Kantor J, Santanna J, Strom BL,
Berlin JA. Diabetes Care.200124(3)483-88
7
Gold standards

• Bioengineered Skin Substitutes
• Allogeneic Bi-Layered Cultured Skin Equivalent
• Dermal Skin Substitute
• Growth Factors
• Becaplermin

8
Bioengineered Skin Substitutes
9
Allogeneic Bi-Layered Cultured Skin Equivalent

• Apligraf Organogenesis Inc., Canton, MA
• FDA approved for VLUs (1998) and DFUs (2000)
• Bovine collagen type I
• Human neonatal cultures living fibroblasts and
  keratinocytes
• Fibroblasts produce the same matrix proteins,
  cytokines and growth factors as to those produced
  by normal skin during the healing process
• Epidermal keratinocytes are allowed to stratify

10
Allogeneic Bi-Layered Cultured Skin Equivalent

• RCT 18

• RCT 29

• Weekly application (up to 5)
• vs. SOC
• - Higher incidence of complete wound healing (56
  vs. 38)
• (P 0.0042)
• - Higher healing rate (P 0.0042)
• - Shorter time to complete closure (P 0.0026)

• Maximum of 3 applications vs. SOC
  

12 weeks
- Higher incidence of complete wound closure (p
0.049) - Shorter time to complete wound healing
(p 0.059)
8 Veves A, Falanga V, Armstrong DG, Sabolinski
ML. Diabetes Care. 200124(2)290-5 9 Edmonds M.
Int J Low Extre Wounds. 20098(1)11-8
11
Allogeneic Bi-Layered Cultured Skin Equivalent
Proposed mechanism of action

• Expression of growth factors and cytokines
• Basement membrane restoration
• Reversion of arrested cell cycle of stalled
  cells

Ongoing research is using microarray technology
to identify and characterize the molecular
mechanism of action of Apligraf in promoting
healing of venous leg ulcers
12
Dermal Skin Substitute

• Dermagraft Advanced Biohealing, La Jolla, CA
• FDA approved for the treatment of DFUs in 2001
• Human fibroblast-derived dermal substitute in a
  bioabsorbable polyglactin mesh scaffold

13
Dermal Skin Substitute

• Human fibroblasts produce dermal collagen, matrix
  proteins, growth factors and cytokines which help
  rebuild the damaged tissue
• Indicated for full-thickness DFUs that have been
  present for longer than six weeks not involving
  tendon, muscle, joint capsule or bone.

14
Dermal Skin Substitute
RCT10 n314 245 with ulcers of gt6 weeks
duration Treatment Control (up to 8
weekly applications) (SOC)

• 30 healed ulcers
• Median wound closure 91

• 18 healed ulcers
• Median wound closure 78

(P 0.023)
(P 0.044)

• Faster time to complete wound closure (P 0.04)
  
• 1.7 times more likely to have complete wound
  closure at any given time than the control group
• Ulcer-related adverse events significantly lower
  in the Dermagraft- treated group (P 0.007)

10Marston WA, Hanft J, Norwood P, Polak R,
Dermagraft Diabetic Foot Ulcer Study Group
.Diabetes Care.200326(6)1701-5
15
Dermal Skin Substitute

• RTC11
• Assessment at weak 12
• Complete wound healing 71.4 (Control 14.3)
• p 0.003
• Treatment patients achieved wound closure
  significantly faster (p 0.004) and showed a
  statistically significant higher percent of wound
  closure than control patients (p 0.002)

101Hanft JR, Surprenant MS. J Foot and ankle
surgery. 2002 41(5)291-9.
16
Growth Factors
17
Becaplermin

• Regranex, Healthpoint Biotherapeutics, Fort
  Worth, TX
• Recombinant platelet-derived growth factor (PDGF)
• Incorporation of the gene for the B-chain of
  human PDGF into the yeast Saccharomyces cerevisiae

- Chemotaxis - Cell proliferation (fibroblasts,
smooth muscle and endothelium) - Angiogenesis -
Fibronectin and hyaluronic acid

Endogenous PDGF
18
Becaplermin

• The only FDA- and European Medicines
  Agency-approved growth factor for full-thickness
  DFUs that have adequate arterial perfusion.
• RCTs have provided evidence for the efficacy of
  becaplermin in increasing healing rates and
  incidence of complete healing and decreasing time
  to complete closure of DFUs. 12
• Cost analyses have repeatedly shown a favorable
  cost-effectiveness ratio13,14

12Smiell JM, Wieman TJ, Steed DL, Perry BH,
Sampson AR, Schwab BH.Wound Repair Regen.
19997(5)335-4 13Sibbald RG, Torrance G, Hux M,
Attard C, Milkovich N. Ostomy Wound Manage.
200349(11)76-84 14Persson U, Willis M, Odegaard
K, Apelqvist J. Value Health. 20003 Suppl 139-46
19
Becaplermin

• Stimulates tumor
• Infiltrating fibroblasts
• found in human
• melanoma cells 15
• Its overexpressed
• in all stages of human
• astrocytoma growth16

PDGF
15Herlyn M, Satyamoorthy K. Lippincott Williams
Wilkins 20012010-11 16Louis DN, Cavenee WK.
Lippincott Williams Wilkins, 200192
20
Becaplermin
Retrospective study showed increased mortality
from malignancy in becaplermin-exposed patients
Follow up data from two RCTs showed the
frequency of new cancer was 2.7 in the
becaplermin group, compared with 1 in the
control group (p lt 0.005)17

• 5-fold the risk of remote malignancies

17Quam L, Ellis LBM, Venus P, Clouse J, Taylor
CG, Leatherman S. Med Care.199331498-507
21
Becaplermin

• A follow-up study looked at 1,622 becaplermin
  users matched to a cohort of 2809 non-users for 5
  years.
• 2.9 of the becaplermin users had confirmed
  diagnosis of distant malignancy compared to 3 of
  the non-users cohort

No elevated cancer mortality risk overall No
statistically significant increase in the
subgroup with more than 3 dispensings
Ziyadeh N, Fife D, Walker AM, Wilkinson GS,
Seeger JD. Adv Skin Wound Care. 201124(1)31-9
22
Becaplermin and cancer risk in veterans

• No increased in risk of cancer incidence or death
  with becaplermin use
• Hazard ratios close to 1.0 with narrow CI
• - NM skin cancers 1.02 (0.64-1.61)
• - All other cancers 1.06 (0.83-1.36)
• - Cancer deaths 0.94 (0.76-1.18)
• No risk increase with high dose (3 tubes) - does
  not confirm signal from previous study

23
Summary of PDGG clinical trials
24
Becaplermin
In patients with diagnosed malignancy
25
Platelet rich plasma
26
Platelet Rich Plasma (PRP)

• Portion of the plasma fraction of autologous
  blood having a platelet concentration above
  baseline

PRP
Gel - Gelatin-like product that results from
adding thrombin and calcium to PRP - Fibrin
polymerizes producing a glue-like gel
Releasate - Liquid product prepared by platelet
activation using thrombin or by
platelet destruction using freeze-thawing
27
Platelet Rich Plasma (PRP)
Platelet derived angiogenic factor
Platelet-derived growth factor
Transforming growth factor-ß
Insulin like growth factor
Vascular endothelial cell growth factor
Cytokines
28
PRP Other uses

• Repairs artificial bone defects
• Induces bone mineralization
• Increases osteogeneration
• when applied with
• deproteinated bovine bone

• Adjuvant treatment for macular holes and corneal
  epithelial defects

Borzini P, Mazzucco L. Curr Opin Hematol.
200512(6)473-9
29
Platelet Rich Plasma

• Suppresses cytokine release limiting the
  inflammatory phase
• Interacts with macrophages to improve tissue
  regeneration
• Increase migration and proliferation of
  endothelial and mesenchymal cells
• Accelerates epithelialization
• Promotes new capillary growth

Expression of multiple growth factors is
increased in granulation tissue of refractory
diabetic dermal ulcers after the treatment of PRP
30
Platelet Rich Plasma

• Centrifugation of autologous whole blood
  separates whole blood into three layers

• PRP becomes a gelatinous solution
• Platelets trapped in the gel are activated and
  release bioactive molecules slowly over 710 days
• Clinically valuable PRP contains at least one
  million platelets per microliter

31
Platelet Rich Plasma

• There is scientific evidence that PRP favors
• the healing process and has favorable outcomes
  on the treatment of DFUs
• RCT18, n72 DFUs
• Ulcers treated with PRP gel healed significantly
  more (81.3 vs 42.1) than their control gel
  matching group (P 0.036)
• RCT19 application of PRP led to a statistically
  significant shorter mean healing time compared to
  platelet poor plasma.

18 Driver VR, Hanft J, Fylling CP, Beriou JM.
Ostomy Wound Manage. 200652(6)68-70, 72, 74
passim 19Saad Setta H, Elshahat A, Elsherbiny K,
Massoud K, Safe I. Int Wound J. 20118(3)307-12
32
Platelet Rich Plasma

• Large, observational case series
• Clinical response rate 96.5 of all wounds
  within 2.2 weeks and 2.8 treatments, suggesting
  that this treatment can possibly reverse the
  non-healing state of chronic diabetic foot ulcers
• de Leon JM, Driver VR, Fylling CP et al. Adv
  Skin Wound Care. 201124(8)357-68
• Cost-effectiveness analysis
• The use of PRP gel led to improved quality of
  life and lower cost of care over a 5-year period
  compared to other treatment modalities for
  nonhealing DFUs
• Dougherty EJ.Adv Skin Wound Care. 2008
  Dec21(12)568-75

33
Platelet Rich Plasma

• RPP gel is typically applied 1 or 2 times per
  week
• Adjuvant therapy in diabetic foot surgeries

Accelerate postoperative wound healing
Hemostatic
34
Advanced biological therapy

• Wounds treated with engineered skin as the first
  advanced biological therapy were 31 more likely
  to heal than wounds first treated with topical
  recombinant growth factor (P lt 0.001), and 40
  more likely to heal than those first treated with
  platelet releasate (P 0 .01)

Kirsner RS, et al. Arch Dermatol.2010146(8)857-6
2
35
Acellular matrices
36
Acellular matrix wound dressings

• Integra (Integra LifeSciences, Plainsboro, NJ )
• Initially developed for the treatment of burn
  injuries
• More recently approved for VLUs, degloving
  injuries and scar contractures

37
Matrix wound dressings
Single layer dermal replacement layer

• Angiogenesis
• Cellular migration
• Collagen remodeling

Bovine tendon collagen and glycosaminoglycan biod
egradable matrix
Bilayer temporary epidermal substitute
Control of fluid loss Bacterial barrier
Silicone
38
Matrix wound dressingsEvidence

• Case reports of the use of dermal matrix to cover
  exposed tendons and bones in diabetic feet have
  been reported with good healing and preservation
  of stump length
• Algaratnam S et al. Int J Extrem Wounds. 2012,
  Jun 3
• Retrospective review (n105 DFUs) Successful limb
  salvage in patients with low risk of amputations
  after treatment. In patients with higher risk of
  amputations limb salvage was 46
• Iorio ML et al. Plast Reconstr Surg.
  2011127(1)260-7

39
Matrix wound dressings Evidence

• Surgical debridement of an acute diabetic foot
  infection with remaining exposed tendon/bone
  was followed by coverage with a bi-layer matrix
  wound dressing
• After 21 days, a skin graft was performed
• 86.7 of patients had complete wound closure
• Amputation level was significantly more distal
• (P lt 0.003) with respect to that potentially
  required

Clerici G, Caminiti M, Curci V, Quarantiello A,
Faglia E. Int Wound J.20107(3)176-83
40
Hyaluronan-based biomaterial 
41
Hyaluronan-based biomaterial 

• HYAFF-11 (VLA Healthcare, Berkshire, UK)
• Benzyl ester of hyaluronic acid
• Biodegradable and bioabsorbable
• Sponges, fibers, threads and microfibers
• Biological scaffold for many cellular transplants
  
• Human vascular endothelial cells
• Autologous chondrocytes
• Mesenchimal stem cells
• Fibroblasts
• Keratynocytes

42
Hyaluronan-based biomaterialIndications

• Tri- dimensional HYAFF (HYALOMATRIX Anika
  therapeutics, Bedford, MA, USA)
• - Second-degree burns
• -Pressure ulcers
• - VLUs
• - DFUs
• - Arterial ulcers
• -Tunneled/undetermined wounds
• - Surgical and trauma wounds

43
Hyaluronan-based biomaterial

• Hyaluronic acid based dressings have been
  recently used to grow
• - cultured expanded autologous fibroblasts
• (Hyalograft 3D autograft, Anika therapeutics)
• - cultured expanded autologous keratinocytes
• (Laserskin autograft, Anika therapeutics)

44
Cellular hyaluronan-based biomaterialEvidence

• RCT
• n 82 DFUs
• Compared treatment with Hyalograft-3D autograft
  followed by Laserskin autograft against standard
  care
• The study demonstrated the efficacy of the
  treatment with statistically significant
  differences compared with standard care

Caravaggi C, De Giglio R, Pritelli C. Diabetes
Care. 200326(10)2853-9
45
Hyperbaric Oxygen
46
Hyperbaric Oxygen (HBO)

• Short-term, high-dose 100 oxygen delivered
  systemically through respiratory airways into the
  blood

47
Hyperbaric Oxygen Weak evidence base?

• Weak evidence on the positive effect of HBO on
  wound healing of DFUs and prevention of lower
  extremity amputations
• Technology assessment report (Ontario Health
  Technology Advisory Committee 2005)
• Quality of the evidence assessing the efficacy
  of HBO as an adjunct to standard therapy
  non-healing DFUs is low, and the results are
  inconsistent

48
Hyperbaric OxygenNew data

• 3 double blinded RCTs support the use of
  adjunctive HBO treatment for a subset of
  patients with DFUs

Unpublished data Efficacy of HBO in the
prevention of major amputations in diabetic
patients. N118 Should provide sufficient power22
At higher TcPO2 , HBOT can improve healing of
DFUs Recommendation HBOT on DFUs when basal
TcPO2 (dorsum of the foot) gt 25 mmHg20
HBO significantly improves Health related Quality
of Life21
20 Löndahl M, Katzman P, Hammarlund C, et al.
Diabetologia. 201154(1)65-8 21 Löndahl M,
Landin-Olsson M, Katzman P. 201128(2)186-90 22
O'Reilly D, Linden R, Fedorko L, Trials.
20111269
49
Hyperbaric OxygenNew data

• Recent study on the effect of HBOT on endothelial
  cell gene expression
• - Downregulation of 19 genes involved in
  adhesion, inflammation and oxidative stress
• - Upregulation of angiogenin (promotes
  angiogenesis and nitric oxide production)

Elevated oxygen transiently regulates
inflammatory gene expression in endothelial
cells, which may enhance chronic wound healing
Kendall AC, Whatmore JL, Harries LW . Exp Cell
Res. 2012318(3)207-16
50
Hyperbaric OxygenNew data

• In animals accelerated blood vessel formation
  and mobilization of vasculogenic stem/progenitor
  cells (SPCs) from bone marrow to diabetic
  wounds23,24
• In humans significant elevation (plt0.004) of
  circulating SPCs and mobilization to diabetic
  wounds through nitric oxide synthase25
• Blood measurements of N-terminal propeptides of
  type I and III collagens showed significant
  increase in type I and III collagen synthesis26

23 Thom SR, Bhopale VM, Velazquez OC et al. Am J
Physiol Heart Circ Physiol. 2006290(4)H1378-86 2
4 Goldstein LJ, Gallagher KA, Bauer SM, et
al.Stem Cells. 200624(10)2309-18 25 Thom SR,
Milovanova TN, Yang M. Wound Repair Regen.
201119(2)149-61 26 Gurdol F, Cimsit M,
Oner-Iyidogan Y. Physiol Res. 201059(3)423-9
51
Light-based therapy
52
Light-based therapy

• Low-energy light treatment (LEL) or low-power
  laser therapy (LPLT)
• Common devices
• -Low energy narrow band lasers (10mW/cm2)
• -Light Emitting Diodes (LEDs)

53
Light-based therapy

• Low-energy stimulation of tissues increases
  cellular activity
• Excitation and relaxation of cellular
  photosensitizers produces low flux of reactive
  oxygen species (ROS)

• transcription factors
• gene expression
• muscle contraction
• cell activation and growth
• modulation of the inflammatory response
• fibroblast proliferation
• Angiogenesis
• collagen deposition,
• re-epithelialization

Activation
54
LEL
Cultured fibroblasts

• TGF- ß

GMCSF
PDGF
55
Light-based therapy

• In vitro studies with fibroblasts and
  keratinocytes indicate that accelerated mitosis
  occurs at low energy doses of a Helium-Neon laser
  or a 780 nm diode laser Grossman N, Schneid N,
  Reuveni H. Lasers Surg Med 1998 22212-8
• Green light (570 nm) was recently found to
  enhance fibroblast growth
• Vinck EM, Cagnie BJ, Cornelissen MJ.
  Photomed Laser Surg 2005 23 (2)67-71
• Human studies with laser light have demonstrated
  greater amounts of epithelialization for wound
  closure and stimulation of skin graft healing
• Whelan HT, Smits RL Jr, et al. J Clin
  Laser Med Surg. 2001 Dec19(6)305-14

56
Light-based therapy

• Non-diabetic and diabetic mouse wounds model
• 532-, 633-, 810-, 980-, and 10,600-nm lasers
  (visible to far infrared) and polychromatic LED
  clusters (510872 nm, visible to infrared
• The effects on the diabetic wounds at the
  optimal incident doses were outstanding
• The 633-nm laser rendered the best results
  significantly improving wound healing by 40.3

Al-Watban FA. Photomed Laser Surg.
200927(1)127-35
57
Light-based therapyBroadband light device

• 400-800 nm
• Recently patented
• Irradiates large areas of skin and is more likely
  to be absorbed by cellular photosensitizers
• Irradiation of DFUs and VLUs resulted in 70
  healing in 40 days
• Bactericidal effect mediated by ROS formation
• Includes wavelengths in the blue region, which
  were found to improve microcirculatory blood flow
  (greater cellular ROS and NO)

58
Light-based therapyBroadband light device

• Small-scale double-blind controlled study using
  broadband light therapy for DFUs (80) and VLUs
  (20)
• Treatment group demonstrated a high wound closure
  rate, 90 compared to 33 of the placebo group
• Higher wound area reduction, 89 versus 54 of
  the placebo group

Landau Z, Migdal M, Lipovsky A, Lubart R.
Photomed Laser Surg.201129(6)399-404
59
Summary

• Human-derived cellular bio-engineered skin
  substitutes and recombinant platelet-derived
  growth factor are the most effective therapies
  for DFUs when conventional treatments fail
• Human recombinant platelet-derived growth factor
  should be used vigilantly when benefit outweighs
  the potential harm
• PRP seems to be an effective and safe therapy for
  the treatment of DFUs

60
Summary

• Acellular matrices appear to be successful in
  management of non-healing DFUs and in limb
  salvage and preservation of maximal foot length
  in patients with low risk of amputations.
• HBO has a positive effect on healing of DFUs when
  basal TcPO2 gt25 mmHg, improves health related
  quality of life and appears to elevates
  circulating and mobilizing stem cells to the
  wound.
• Light therapy is a new promising therapy for
  promoting wound healing of DFUs based on its
  stimulatory effects

61
THANK YOU