©2007 Myriad Genetic Laboratories, Inc.

Learning Objectives At the conclusion of this presentation participants should understand the following: Use of pharmacogenetics in understanding patient susceptibility to 5-FU toxicity Toxicity risks associated with variations in the genes DPYD and TYMS –DPYD = DPD (Dihydropyrimidine Dehydrogenase) –TYMS = TS (Thymidylate Synthase) Use of genetic test results in medical management

©2007 Myriad Genetic Laboratories, Inc. Cancer Genetic Testing Hereditary Cancer testing –What is the likelihood that my patient will develop a future cancer? –Example: Hereditary Breast and Ovarian Cancer Syndrome Tumor Characteristic testing –Are there characteristics about this tumor that would dictate treatment options? –Example: HER2/neu testing Pharmacogenetic testing –Does my patient have something innate that will cause him/her to respond differently to treatment?

©2007 Myriad Genetic Laboratories, Inc. Pharmacogenetics The study of genetic variation that determines an individual’s response to drugs Pharmacogenetic testing can be beneficial in oncology because it can help determine –How a patient will respond to chemotherapy Example: cytochrome P450 2D6 (CYP2D6) genotype and ability to metabolize tamoxifen –The likelihood that a patient will experience severe side effects Example: TheraGuide ® 5-FU

5-Fluorouracil metabolism 85% 15% Nature Reviews Cancer. 2003; 3:

©2007 Myriad Genetic Laboratories, Inc. DPD Deficiency Mechanism of Action Variations in DPYD can lead to DPD insufficiency This results in an inability to inactivate 5-FU leading to increased levels of active drug in the system that can result in greater toxicity

©2007 Myriad Genetic Laboratories, Inc. TS Deficiency Mechanism of Action Variations in TYMS can lead to altered TS expression Lower levels of the TS enzyme can lead to − Increased levels of active 5-FU − Toxicity

©2007 Myriad Genetic Laboratories, Inc. Is toxicity a significant clinical problem? 5-FU (diarrhea) Meta Analysis Group in Cancer study % (5-FU bolus) Cassidy 2002 Before dose modification 13% (Mayo Clinic regimen) Goldberg % (FOLFOX4) Schmoll % (Mayo and Rosewell Park) Schwab % (5-FU monotherapy) JCO : Ann Oncol Apr;13(4): JCO. 2006:24(25): JCO : JCO. 2008;26(13): Prevalence Rate: Grade 3-4 diarrhea

©2007 Myriad Genetic Laboratories, Inc. Is toxicity a significant clinical problem? Cassidy study: several patients discontinued treatment due to related side effects -6.7% of 5-FU patients –Of patients who continued treatment following dose modification (reduced by 25-50%), several continued to have side effects 45/138 Hand Foot Syndrome 21/89 Diarrhea 6/30 Stomatitis Ann Oncol Apr;13(4):

FDA WARNING FDA 2003 warning had been issued stating 5-FU is contraindicated in patients with a known DPD deficiency FDA package warnings –

©2007 Myriad Genetic Laboratories, Inc. Who benefits from TheraGuide ® 5-FU? 5-FU therapy candidates About 1 in 14 (7%) patients treated with 5-FU have Grade 3-4 toxicity associated with a DPYD or TYMS gene variation Mol Cancer Ther (11): J Clin Oncol. 2008;26(13):

©2007 Myriad Genetic Laboratories, Inc. What are the risks? DPYD gene variations are associated with a 7-fold (or up to a 60%) risk of severe toxicity. Mol Cancer Ther (11): Pharmacogenomics J (1): JCO. 2008;26(13): Study Patients (unselected) Overall Grade 3-4 toxicity DPYD and Grade 3-4 toxicity DPYD and toxicity relative risk Moreln = 4879%60%7-fold Schwabn = 68316%50%3-fold

©2007 Myriad Genetic Laboratories, Inc. What are the risks? TYMS gene variations are associated with a 1.4 to 2.5-fold (or 22-52%) increased risk of severe toxicity Pharmacogenomics J (1): Clin Cancer Res Sep 1;10(17): Clin Cancer Res Jul 1;12(13): J Clin Oncol. 2008;26(13): Study Patients (unselected) Overall Grade 3-4 toxicity TYMS and Grade 3-4 toxicity TYMS Grade 3-4 toxicity relative risk Meta analysis n = 20022%52%2.5 fold Schwabn = 68316%22%1.4 fold

©2007 Myriad Genetic Laboratories, Inc. The only clinical test that performs: –Full sequencing of the DPYD gene and –Analysis of the TYMS gene promoter region What is included in TheraGuide ® 5-FU analysis?

©2007 Myriad Genetic Laboratories, Inc. TheraGuide ® 5-FU includes full sequencing of DPYD DPYD (DPD deficiency) –Three common variations account for the majority of known 5-FU toxicity to date IVS14+1 G>A, D949V, and I560S –More than 40 different variations in DPYD have been identified as causing DPD deficiency –Full sequencing is the “gold standard” for identifying mutations Mol Cancer Ther (11):

©2007 Myriad Genetic Laboratories, Inc. TheraGuide ® 5-FU includes analysis of TYMS TYMS variations –2R/2R –2R/3R –3R/3R –4R variations have also been described The 2R/2R variation confers a fold increased risk for adverse events

©2007 Myriad Genetic Laboratories, Inc. How are TheraGuide ® 5-FU results reported? As many as 1 in 4 individuals have a variation that increases the risk for 5-FU related toxicity –DPYD – 5% –TYMS – 15-20% TheraGuide ® 5-FU is used to determine a patient’s likelihood of 5-FU toxicity –High Risk 7-fold (or up to 60%) risk for Grade 3 or Grade 4 toxicity –Moderate Risk 1.4 to 2.5-fold (or 23-53%) risk for Grade 3 or Grade 4 toxicity –Low Risk Common causes of 5FU toxicity is ruled out –Indeterminate Mol Cancer Ther (11): Pharmacogenomics J (1):

©2007 Myriad Genetic Laboratories, Inc. Identifies patient risk for 5-FU toxicity Allows for personalized treatment options for cancer therapy –More informed discussion regarding toxicity risk –Enhanced patient monitoring –Dose reduction considerations –Alternate chemotherapies Mol Cancer Ther (11): Pharmacogenomics J (1): Cancer Invest Mar;24(2): Semin Oncol Apr;34(2 Suppl 1):S Ann Oncol Dec;16(12): J. Clin. Onc : Drugs (2): How are TheraGuide ® 5-FU results used?

©2007 Myriad Genetic Laboratories, Inc. In Summary TheraGuide ® 5-FU can help predict a patient’s risk of toxicity to 5-FU Patient management can be personalized based on results Avoiding adverse events can help physicians save time, money, and improve patient quality of life

©2007 Myriad Genetic Laboratories, Inc. Supplemental Slides

©2007 Myriad Genetic Laboratories, Inc. National Cancer Institute Common Toxicity Criteria Adverse Event Short Name12345 Diarrhea Increase of <4 stools per day over baseline; mild increase in ostomy output compared to baseline Increase of 4 – 6 stools per day over baseline; IV fluids indicated <24hrs; moderate increase in ostomy output compared to baseline; not interfering with ADL Increase of ≥7 stools per day over baseline; incontinence; IV fluids ≥24 hrs; hospitalization; severe increase in ostomy output compared to baseline; interfering with ADL Life-threatening consequences (e.g., hemodynamic collapse) Death Dehydration Increased oral fluids indicated; dry mucous membranes; diminished skin turgor IV fluids indicated <24 hrs IV fluids indicated ≥24 hrs Life-threatening consequences (e.g., hemodynamic collapse) Death Mucositis/stomatitis (clinical exam) – Select: – Anus – Esophagus – Large bowel – Larynx – Oral cavity – Pharynx – Rectum – Small bowel – Stomach – Trachea Mucositis (clinical exam) – Select Erythema of the mucosa Patchy ulcerations or pseudomembranes Confluent ulcerations or pseudomembrane s; bleeding with minor trauma Tissue necrosis; significant spontaneous bleeding; life- threatening consequences Death

©2007 Myriad Genetic Laboratories, Inc. National Cancer Institute Common Toxicity Criteria Adverse Event Short Name12345 Nausea Loss of appetite without alteration in eating habits Oral intake decreased without significant weight loss, dehydration or malnutrition; IV fluids indicated <24 hrs Inadequate oral caloric or fluid intake; IV fluids, tube feedings, or TPN indicated ≥24 hrs Life-threatening consequences Death Vomiting 1 episode in 24 hrs 2 – 5 episodes in 24 hrs; IV fluids indicated <24 hrs ≥6 episodes in 24 hrs; IV fluids, or TPN indicated ≥24 hrs Life-threatening consequences Death Rash: hand-foot skin reaction Hand-foot Minimal skin changes or dermatitis (e.g.,erythema) without pain Skin changes (e.g., peeling, blisters, bleeding, edema) or pain, not interfering with function Ulcerative dermatitis or skin changes with pain interfering with function interfering with function —— Febrile neutropenia (fever of unknown origin without clinically or microbiologically documented infection) (ANC <1.0 x 109/L, fever ≥38.5°C) Febrile neutropenia ——Present Life-threatening consequences (e.g., septic shock, hypotension, acidosis, necrosis) Death

©2007 Myriad Genetic Laboratories, Inc. Metastatic Breast Cancer Patient Low Risk Result 68 yo female Presented with recurrent breast cancer and lymphangitic lung disease after 3 years of being disease free TheraGuide ® 5-FU was ordered due to the previous –life threatening toxicity –effectiveness of 5-FU in treating her cancer Patient was found to have a low risk result –Proceeded with a 5-FU regimen –Currently on treatment with marked improvement and has no 5-FU related toxicities