HuMab-5B1 is a Fully Human Antibody With Remarkable Preclinical Specificity and Antitumor Activity Against Pancreatic Cancer

SAN DIEGO, CA, USA I March 21, 2016 I MabVax Therapeutics Holdings, Inc. (MBVX), a clinical-stage oncology drug development company, announced initiation of a phase I clinical trial of HuMab-5B1 for patients with locally advanced or metastatic adenocarcinoma of the pancreas (PDAC) or other CA19-9 positive malignancies. The CA19-9 target is expressed on more than 90% of pancreatic cancers and is a validated biomarker for the disease. The Company filed an Investigational New Drug (IND) application for this product on November 30, 2015 and received U.S. Food and Drug Administration (FDA) authorization to proceed with the study on December 24, 2015.

The study is a phase I, open-label, multi-center, dose-escalation clinical trial. The primary objectives are to determine the safety, maximum tolerated dose (MTD), and the pharmacokinetics (PK) of HuMab-5B1. The phase I trial will also evaluate the tumor response rate based on RECIST 1.1 and the duration of response of HuMab-5B1 as a single agent or in combination with a standard of care chemotherapy regimen. The study will enroll up to approximately 60 patients at multiple centers in the United States.

On January 28, 2016 MabVax received authorization from FDA to proceed with a second phase I clinical trial with [Zr-89]-HuMab-5B1 as a new generation PET imaging agent in patients with pancreatic cancer. [Zr-89]-HuMab-5B1 combines a well-established PET imaging radiolabel [Zr-89] with the targeting specificity of the HuMab-5B1 antibody. Preclinical xenograft animal models demonstrated high image resolution of tumors, making [Zr-89]-HuMab-5B1 attractive as a potential diagnostic agent for use with the HuMab-5B1 therapeutic product. Some of the data was previously published in the Journal of Nuclear Medicine, Bioconjugate Chemistry, and the Proceedings of the National Academy of Sciences.

David Hansen, President and CEO, said, “Data generated in the early portions of these two Phase I trials could demonstrate important initial safety, PK and targeting specificity data of the antibody and signal the potential utility of the HuMab-5B1 antibody in the diagnosis and treatment of patients with this devastating disease. We anticipate reporting interim-study data from both trials in mid-year 2016. Additionally, we are excited about the potential applicability of our dual-product development approach in other cancers with HuMab-5B1, as well as with follow-on antibodies under development at MabVax.”

About HuMab-5B1:

MabVax’s HuMab-5B1 antibody is fully human and was discovered from the immune response of cancer patients vaccinated with an antigen-specific vaccine during a Phase I trial at Memorial Sloan Kettering Cancer Center. In preclinical research, the 5B1 antibody has demonstrated high specificity and affinity, and has shown potent cancer cell killing capacity and efficacy in animal models of pancreatic, colon and small cell lung cancers. The antigen the antibody targets is expressed on more than 90% of pancreatic cancers making the antibody potentially broadly applicable to most patients suffering from this type of cancer.

About MabVax:

MabVax Therapeutics Holdings, Inc. is a clinical-stage biotechnology company focused on the development of vaccine and antibody-based products and vaccines to address unmet medical needs in the treatment of cancer. MabVax has discovered a pipeline of human monoclonal antibody products based on the protective immune responses generated by patients who have been immunized against targeted cancers with the Company’s proprietary vaccines. MabVax also has the exclusive license to the therapeutic vaccines from Memorial Sloan Kettering Cancer Center. MabVax has two cancer vaccines targeting recurrent sarcoma and ovarian cancer in proof-of-concept Phase II multicenter clinical trials. Additional information is available at www.mabvax.com.

SOURCE:MabVax Therapeutics