A Study of Gemcitabine and Demcizumab (OMP-21M18) With or Without Abraxane® as 1st-line Treatment in Subjects With Locally Advanced or Metastatic Pancreatic Cancer

The purpose of this study is to test the safety and determine the optimal dose of a new experimental drug, demcizumab (OMP-21M18), when given in combination with gemcitabine with or without (+/-) Abraxane®. Historically, single agent gemcitabine has been the standard treatment for pancreatic cancer. However, recent data suggests that gemcitabine plus Abraxane® may be superior to gemcitabine alone, thus this combination is emerging as the new standard therapy for pancreatic cancer. However, Abraxane® has not been approved for the treatment of pancreatic cancer at this time. Demcizumab is a humanized monoclonal antibody and was developed to target cancer stem cells. This study is sponsored by OncoMed Pharmaceuticals, which is referred to as OncoMed or the Sponsor in this consent form. The study is designed to test the safety of demcizumab at different dose levels when given with gemcitabine +/- Abraxane® and the effects, both good and bad, that it has on participants. Demcizumab may block the growth of cancer stem cells, the remaining tumor cells, and it may also prevent the growth of new blood vessels that tumors need to grow and spread. Although demcizumab has been administered with gemcitabine to cancer patients, it has not been given in combination with gemcitabine and Abraxane®; thus, it is not known if it will provide any benefit to participants and may cause harmful side effects.

Current cancer therapies often produce an initial reduction in tumour size but may not have long term benefits. One possible explanation for this is the presence cancer cell known as a cancer stem cells. Cancer stem cells represent a small part of the tumour but are believed to be responsible for much of the growth and spread of the cancer. They may also be more resistant to traditional therapy, such as chemotherapy and radiation therapy. The purpose of this study is to test the safety and determine the optimal dose of a new experimental drug, demcizumab, when given in combination with gemcitabine, a drug that is a standard treatment for advanced pancreatic cancer that has not been treated previously with chemotherapy. Demcizumab is a humanized monoclonal antibody (a protein made in the laboratory) and was developed to target cancer stem cells. The way the body handles demcizumab will also be investigated. Up to 50 subjects will be enrolled at up to 8 centers in Australia, New Zealand, and Spain. Up to 28 days (4 weeks) prior to treatment you will undergo testing to determine your eligibility to take part in this study, and then if you are enrolled in the study you will receive intravenous (in the vein) infusions of the demcizumab administered once every 2 weeks, and gemcitabine and Abraxane® administered weekly for 3 weeks, out of every 4 weeks. After 9 weeks, you will undergo assessments to determine the status of your disease. If there is no evidence of progression of your disease or if your tumor is smaller, you will continue to receive one additional infusion of demcizumab, and you will continue to receive infusions of gemcitabine and Abraxane® once weekly for 3 consecutive weeks out of every 4 weeks until it has been shown that your cancer has progressed. You will undergo assessments every 8 weeks thereafter to determine the status of your disease. If there is no evidence of progression of your disease or if your tumor is smaller, you will continue to receive one additional infusion of demcizumab, and you will continue to receive infusions of gemcitabine and Abraxane® once weekly for 3 consecutive weeks out of every 4 weeks until it has been shown that your cancer has progressed. You will undergo assessments every 8 weeks thereafter to determine the status of your disease. In addition to routine testing of blood and urine (for complete blood counts with differential and platelets, coagulation studies to determine how quickly your blood is clotting , serum chemistries, B-type natriuretic peptide [BNP] and Troponin I which indicates how well your heart if working, and urinalysis), special tests will be performed during the study at specific time points. In addition, you will have and ECG and Doppler echocardiogram performed during screening, then every 28 days on study and at treatment termination. Your Doppler echocardiograms may be sent to a Cardiologist at another hospital who may perform a central read on some of the Doppler echocardiograms in this study. Finally, you will have a head CT or MRI at baseline and CT scans and/or other radiographs performed every 56 days to assess the status of your tumor. The study includes an optional part which will investigate how variations in people's genetic makeup affect their response to medications. This involves the collection of one blood sample just before participants receive their first dose of study treatment. DNA will be extracted from the blood sample for testing.

• Pancreatic Cancer

• DRUG: Demcizumab
• DRUG: Abraxane®
• DRUG: Gemcitabine

• M18-002