Curing chronic wounds with fibrin.

Recently, we finished a study in which we have found that applying fibrin onto
wounds in diabetic rats improves wound healing, as well as wound perfusion. It
is highly expected that fibrin will also have a positive effect on the healing
of chronic foot ulcers in diabetic patients. In this project we will apply a
fibrin gel onto chronic wounds in diabetic patients to improve wound healing.
The application of fibrin is highly feasible in a clinical setting and fibrin
is tolerated by patients. This is known because in high concentrations, fibrin
is already used in the clinic as tissue glue (Tisseel).

In the EU only, chronic wound care costs approximately 20 billion euros. These
chronic wounds, caused by among others few and bad blood vessels, will lead to
amputation of the lower extremities in 24% of all patients. After amputation
the mortality is 50-60% within the first 2 years. This mortality is even higher
than the mortality of many forms of cancer. Chronic wounds also cause
additional problems, such as pain, social isolation and loss of income.

We will apply fibrin to chronic wounds to fasten wound healing. Fibrin is one
of the major components in coagulation. After wound infliction it stops the
bleeding and, importantly, attracts new blood vessels to the wound site, thus
improving angiogenesis. We were able to show this in our own in vitro
endothelial (blood vessel) cell ingrowth model. This is essential for proper
wound healing.

Additional to our in vitro data we have recently finished our study in which we
have shown the positive effect of fibrin on wound healing and vessel formation
in normal and diabetic rats. The wounds will get a boost, so the healing
process will not be hampered in the first phase of healing, as in diabetic
wounds. This is exactly what happens in patients with chronic wounds. Their
blood vessels in wounds and lower extremities cause low nutrients and oxygen
supply, causing delayed wound healing, eventually leading to chronic wounds.
When we analyze the graphical representation of the wound size at the patient's
first return to the outpatient clinic, following fibrin application, we observe
that the majority of patients present themselveswith a decreased wound size.
However, this decline in wound size reverts at subsequent outpatient clinic
visits which isn't unexpected since fibrin will be rapidly resolved by the
body. Therefore, we request authorisation for more frequent fibrin
applications, within the trial period, whenever the medical person in charge
considers this beneficial for his/her patient.

For this study, we will work with doctors from different departments within the
Erasmus MC (Surgery and Dermatology), the Alrijne (Rijnland) hospital, the
Ikazia Hospital, the Franciscus Gasthuis Hospital, the Groene Hart hospital,
the Reinier de Graaf hospital, the Maasstad Hospital, the IJsselland hospital,
the HMC Westeinde hospital and the Frankelandgroep nursing homes. These doctors
deal with chronic wounds and their consequences on a daily basis.

After showing positive results in this study, clinical implementation will be
fast and efficient, as fibrin is known in the clinic.

Summarized: the positive results of our in vitro and in vivo studies show that
it is time for a proof-of-principle study in chronic wounds of patients.

To cure chronic wounds with fibrin treatment.

Fibrinogen: In this project we will use commercial fibrinogen (Tisseel) that is
currently used in the clinic as Fibrin Sealant (91 mg/mL) on wound edges. The
fibrinogen will be diluted to an optimal concentration (2 mg/ml). Thrombin
(also from Tisseel) will be used to form a fibrin matrix.

Patients: 33 patients with poor-healing wounds will be included in this study.
The most important inclusion criteria are:
- Non-healing, non-infected wound on either the foot or leg (Texas
classification 1 or 2) that is non-respondent to treatment for at least 6 weeks.
- Older than 18 years old.
- BMI <40 kg/m2.
- HbA1c <10%.
- Willing to participate in our study.

This group will receive a fibrin treatment on top of standard wound care. The
treatment will be executed by Dr M.J.E. van Rijn (diabetic foot clinic,
Surgery Department) and Dr. C. van Montfrans (Dermatology Department) of the
Erasmus MC; by Drs W. Brekelmans of the Alrijne hospital wound center; by Dr G.
Cazander of the Ikazia hospital Wound Expert Center; dr. E.M.L. Corten of the
Franciscus Gasthuis hospital Wound Expert Center; dr E.J. Waasdorp of the
Groene Hart hospital Wound Expert Center; dr O. Schouten of the Reinier de
Graaf Wound Expert Center; nurse specialist mrs E.C. Punt of the Maasstad
hospital Wound Expert Center, dr. S.E. Buijk of the IJsselland hospital Wond
Expert Center; dr. K.E.A. van der Bogt (HMC Westeinde hospital) and by drs
H.I.M. Ploeg (Frankelandgroep). Wounds of patients in the fibrin group will be
filled with fibrin (2 mg/ml). Patients will be invited for evaluation of the
wound fortnightly until the wound is healed or over a period of 12 weeks.

During the first trial visit, a fibrin matrix will be created in the wound of
all trial patients. At subsequent outpatient clinic visits during the trial
period, the patient may receive a fibrin matrix at all instances where the
medical person in charge considers this beneficial for his/her patient.

Not applicable (see p27, paragraph 11.4 and p29, paragraph 13.2 of the research
protocol).