MabVax Therapeutics Antibody Program Results Featured in Three Presentations at 2018 American Association for Cancer Research (AACR) Annual Meeting

On April 18, 2018 MabVax Therapeutics Holdings, Inc. (NASDAQ: MBVX), a clinical-stage oncology drug development company, reported that three poster presentations on the Company’s antibody development programs were made at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting being held April 14-18, 2018 in Chicago, Illinois at McCormick Place (Press release, MabVax, APR 18, 2018, View Source [SID1234525497]).

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MabVax Therapeutics Logo (PRNewsfoto/MabVax Therapeutics Holdings, I)

Paul Maffuid, Ph.D., Executive Vice President of Research and Development of MabVax, stated, "We successfully shared the significant progress we have made through these clinical and preclinical studies that continue to establish our growing body of data supporting the development of MVT-1075 for the treatment of pancreatic cancer and other CA19-9 cancers, MVT-2163 as a immunoPET imaging agent, and our most advanced research program focused on the Tn and sTn cancer antigen targets."

MabVax Poster Presentation Details

Jonah Rainey, Ph.D., Executive Director, Antibody Research at MabVax presented a poster on Sunday April 15th entitled: "A fully human antibody binds Tn and sTn carbohydrate antigens specifically on serine residues, without need for polypeptide interaction."

Dr. Rainey’s presentation included results from the Company’s successful human antibody discovery and engineering efforts that resulted in creating a panel of anti-Tn antibodies with specificity and affinity for the Tn and sTn epitopes. This observation was confirmed by a binding array analysis performed by a well-known independent academic based consortium. These antibodies bind preferentially to a particular presentation of the Tn epitope that exhibits a pharmaceutically useful pattern that is expressed on ovarian and breast cancers, including triple-negative breast cancer.

Paul Maffuid, Ph.D., Executive Vice President, Research & Development MabVax Therapeutics presented a poster on Tuesday April 17th entitled: "Phase 1 dose escalation study of 177Lu-HuMab-5B1 (MVT-1075) in combination with MVT-5873 as radioimmunotherapy (RIT) in subjects with relapsed / refractory pancreatic cancer or other CA19-9+ malignancies."

Dr. Maffuid’s presentation summarized results from the first cohort of three patients treated in the Phase 1 clinical trial of the Company’s MVT-1075 radiopharmaceutical product in late stage pancreatic cancer. These results at the initial dose support a high uptake of the on-target lesions with a prolonged time of residence and accumulation on target lesions. The predominant treatment-related toxicities in the first cohort included expected and manageable (Grade 1-3) changes in hematologic and liver function parameters.

Though the current data set is small, clinical biodistribution studies with the immunoPET imaging agent MVT-2163 in a prior Phase 1 study were used to successfully predict the absorbed organ doses of MVT-1075 and in particular red marrow which is the dose limiting organ. In addition, the studies completed to date were sufficient to establish a fractionated dosing schedule of MVT-1075 combined with image-based dosimetry as a feasible RIT Phase 1 dosing strategy, permitting within cycle patient specific dose adjustments to achieve a selected target red marrow exposure. A fourth patient has been treated in a second cohort at a planned escalated dose.

Jonah Rainey, Ph.D., Executive Director, Antibody Research at MabVax was a co-presenting author of a second poster on Tuesday April 17th entitled: "PEGylated Hyaluronidase Increases Tumor Uptake of 89Zr-DFO-HuMab-5B1 (MVT-2163) in a CA19-9 Positive Hyaluronan-Accumulating Pancreatic Cancer Model"

This poster was the result of a preclinical collaboration with Halozyme Therapeutics, Inc. combining the use of MabVax’s immunoPET imaging agent MVT-2163 with Halozyme’s PEGylated Hyaluronidase, PEGPH20 to determine if the enzymatic degradation of HA could improve the uptake of MVT-2163 on tumor lesions as measured by in vivo PET imaging and ex vivo gamma counting, in a CA19-9-positive, HA-rich human pancreatic tumor xenograft model. PEGPH20 increased both the tumor uptake and the tumor-to-liver ratios of MVT-2163 as well as decreased liver uptake in a CA19-9 positive xenograft mouse model of HA-accumulating pancreatic cancer. The increased tumor uptake and the decreased liver uptake support further investigation into the potential diagnostic utility for the combination of PEGPH20 and MVT-2163.

To access the three full abstracts, please click here.

About MVT-1075

MVT-1075 is a radioimmunotherapy product that combines established efficacy of radiation therapy with tumor specific targeting. MVT-1075 has the potential to deliver a more potent HuMab-5B1-based product, by using small doses of a radioisotope coupled to the Company’s MVT-5873 antibody to target pancreatic cancer cells and kill them.

About the HuMab-Tn Antibody Targeting Tn and sTn

HuMab-Tn is a fully human antibody discovered by MabVax from a patient vaccinated with a pool of cancer glycans, including Tn. The antibody has been affinity-matured and demonstrates highly selective Tn/sTn glycan binding. Further, the antibody recognizes a wide array of cancers, particularly ovarian and breast including approximately 90% of triple negative breast cancers tested.

About MVT-2163

MVT-2163 is an immunoPET imaging agent product that combines the established PET imaging capabilities of 89Zr with HuMab-5B1 tumor specific targeting. It has the potential to aid in identifying the best surgical treatment options for patients with pancreatic cancer and as a potential companion diagnostic with treatment options.