Clinical Trial for Evaluation of Vermillion's Blood Test to Predict the Probability of Peripheral Artery Disease

Peripheral artery disease (PAD) affects 8 to 12 million individuals in the United States and
is also prevalent in Europe and Asia. A regional pilot study of community screening for PAD
demonstrated that patient awareness of a PAD diagnosis was low, and was associated with
atherosclerosis risk factors, antiplatelet therapy, and claudication treatment intensity.
PAD has not emerged as a focus of public health efforts to improve quality of life, nor to
decrease the associated cardiovascular ischemic risk. Smoking, diabetes, and age are the
strongest risk factors for PAD. Smokers have a 2 to 6-fold increased likelihood of having
PAD, and the risk of PAD increases in a dose-dependent manner with the duration and amount
of smoking. Diabetes confers a 2 to 4-fold increased risk of having PAD. The prevalence of
PAD increases as a function of age. Criqui et al showed that the prevalence of PAD in
individuals under 60 years of age was about 2.5%, whereas the prevalence increased to over
20% in individuals over 75 years of age.

A study in smokers and diabetics 50 years of age or older, and in all those 70 years of age
or older, identified in an outpatient, primary care clinic setting has shown that the
prevalence is 29%. About half of the cases found were newly-identified PAD patients.
Further, while 83% of those with a prior diagnosis of PAD were aware of their condition,
only 49% of the primary-care physicians were aware that their patients had a diagnosis of
PAD. Another study examined internal medicine physicians' approaches to PAD and found that
only 37% reported taking histories for claudication, and only 26% evaluated the foot for
ulcers.

PAD is as prevalent in women as in men. When symptomatic, PAD causes limb discomfort,
tiredness, heaviness, cramping, or pain brought on by exertion and relieved by rest (i.e.,
intermittent claudication) and reduces functional capacity and quality of life. Classic
claudication is only noted by 10-30% of patients and atypical leg discomfort occurs in
20-40%. Up to 50% of patients are asymptomatic. PAD1 is an in vitro diagnostic that provides
a PAD1 score derived from multiple biomarkers in human plasma, serum, or whole blood, which
predicts a low or high probability of the presence of PAD in patients at risk for PAD. A
positive PAD1 score(above the cutoff), indicating a higher risk for PAD than expected in the
general population, would then guide the physician to more aggressively determine the
presence of PAD.

The preliminary studies have shown an association of four proposed biomarkers with ABI, and
have demonstrated the construction of a PAD risk algorithm. This study is powered to test
each of the four biomarkers and their interactions and develop the PAD1 risk score in the
intended use population.

Inclusion Criteria:

Subject is one or more of the following:

- ≥50 years old and subject-reported current or former history (<10 years) of smoking
for a minimum of 10 pack years.

- ≥50 years old and history of type 2 diabetes (meeting American Diabetes Association
criteria) as documented in the medical record, or use of diabetes medications or
diabetes-specific diet.

- ≥70 years old. 2. Subject provides written informed consent to participate in this
study. 3. Subject agrees to de-identified biorepository storage of own processed
blood sample for future testing.

Exclusion Criteria:

1. Significant hepatic or renal insufficiency, including either of the following:

- Renal insufficiency or renal failure within the past 6 months, or creatinine
>2.5 mg/dL within the past 6 months (if results available), or currently on
dialysis.

- Severe liver disease or any chronic hepatitis within the past 6 months, or AST
and ALT >3xULN (upper limit of normal), or bilirubin >2xULN within the past 6
months (if results available).

2. Active viral or bacterial infection or subject is currently taking an antibiotic or
antiviral agent.

3. Active inflammatory condition requiring treatment with systemic steroids or immune
modulating therapy within the past 6 months.

4. Active malignancy that requires active anti-neoplastic therapy (stable basal cell
skin cancer is allowed; cancer being treated solely with hormonal therapy is
allowed).