Healthy Normal Reference Dataset (US patent #6960439)

Foundational to all Source MDx's biomarker and diagnostic development programs is the generation of and reference to a healthy normals dataset for each of the over 1,800 gene assays available as Precision Profiles™. A key requirement for the application of gene expression technology in a clinical setting is the ability to distinguish between natural variations in gene expression among healthy subjects and changes associated with disease. Source MDx has been granted a patent regarding the establishment of a normal range of expression for a subject population as a "reference range" for molecular diagnostics (patent #6,960,439 issued November 1, 2005). Several key Source MDx discoveries are included in this issued patent. First, the dynamic range of expression of many genes is limited among healthy subjects; second, expression levels for most genes analyzed are approximately log-normally distributed; and third, tight regulation and homeostatic control of gene expression responses are fundamental characteristics of the immune system as reflected in the narrow range of expression levels observed among healthy subjects and the return to set points for key targets in inflammatory/immune pathways following stimulation and/or treatment. This brings gene expression measurements closer to traditional vital signs used in medicine, for which normal ranges are essential. This also establishes the foundation of a molecular "treat-to-normal" strategy for the diagnosis, prognosis, monitoring and treatment of disease in a variety of clinical settings with further, broad-based utility across the entire drug development continuum.

Source MDx routinely includes the generation of a healthy normals dataset in Precision Profile™ assays providing critical standards for interpretation of the diagnosis and management of disease. The Source MDx Normal Reference Dataset can target age, gender and ethnic diversity to mirror the general United States population or it can be further refined to meet specific medical criteria (i.e. blood chemistries) and stratification criteria (i.e. females, over 45 and menopausal) for more refined comparisons to disease specific populations. Overall, Source MDx’s previous as well as ongoing programs in the collection of normal subject samples encompasses over 2,200 normal subjects, ranging from qualified blood bank donors to medically defined subjects as described in more detail below.

Blood Bank Donor Normals

Source MDx has been engaged in the collection of PAXgene™ Blood RNA tubes at the Bonfils Blood Bank Center in Denver, Colorado since 2000. This population of "all-comers" meets Bonfils Blood Bank donation criteria and are considered normal and healthy as defined by feeling well and able to perform normal activities. Donors with chronic conditions such as diabetes or high blood pressure are considered "healthy" provided they are being treated and the condition is under control. Early collection efforts involving 300 minimally characterized (age and gender) blood bank donor subjects established foundational concepts and intellectual property in target specific normal ranges and use thereof.

In 2007/2008 Source MDx collected over 300 single time point, blood bank donor subject samples stratified across age, gender, race and ethnicity with further characterization of BMI, smoking status/history as well as pre-existing conditions and concomitant medications. This effort included not only the collection of PAXgene™ Blood RNA Tubes for whole blood gene expression but in addition, the collection of Veridex Cell Save™ tubes for circulating tumor cell (CTC) and circulating endothelial cell (CEC) enumeration. This served to establish CEC ranges and to confirm the expected absence of CTCs in this normal blood bank donor population. EDTA tubes were also collected for future interest in the characterization of CEC gene expression in this normal population. Currently, continued collection of an additional 300+ blood bank donor subjects is ongoing with a focus on the collection of the first 100 PAXgene™ Blood RNA Tubes from normal subjects over 45 years.

Overall, blood bank donor collections have provided and continue to provide access to a broadly defined population that contributes to our vested interest in understanding and defining normals at the molecular level. This also provides the opportunity to define relevant "Normal" sub-populations such as: current smokers, those who have quit smoking (within defined time periods) and those who have never smoked. These "Normal" sub-populations are of interest as stand-alone populations as well as relevant comparator populations in a variety of clinical settings requiring general stratification beyond simply age and gender-matching.

Medically Defined Normals

In addition to blood bank donor normals, Source MDx continues with ongoing efforts in the regional collection of PAXgene™ Blood RNA Tubes from medically defined normal populations. This collection targets specific age groups (20 – 80+ yrs) in increments of 10 years (for 20 - 40 year olds) and 5 years (for 40 – 80 year olds) with equal gender representation across all age groups. Furthermore, in this population of medically defined normals individual subjects are characterized by their:

• Demographics
• Medical/surgical history
• Smoking history
• Vital signs, including height, weight and BMI
• Physical examination
• Family cancer history
• Concomitant meds
• Complete blood counts
• Complete metabolic panel, including CRP, CA-125 (females) and PSA (males)
• Menstrual history, menopausal status, birth control history, HRT use (females only)

To date, Source MDx has collected over 600 single time-point samples from regional centers in Indiana, South Carolina and Florida. An ongoing collection of medically defined normals provides access to very specifically defined normal populations and sub-populations that are able to support clinical studies across multiple disease areas. As an example, the medically defined normals collection yields a sub-population of males, over the age of 50, with and without benign prostate hyperplasia (BPH). This sub-population of normals is very relevant as a comparative reference population in prostate cancer studies. Similarly, females with defined CA-125 levels are relevant as a comparative subpopulation in ovarian cancer studies.

Study-Specific Normals

Source MDx continues to opportunistically collect study-specific normal populations ranging from undiagnosed "all-comers" to more medically defined normals. In-house studies in cancer and inflammation-related diseases as well as client-specific studies across a broad range of interests have involved independent efforts in study-specific collection of over several hundred normal subject samples across Russia, Asia, Europe and the U.S. Such efforts continue to enhance our understanding of normal ranges across ethnic and geographically distinct populations.