Biothera Pharmaceuticals Presents Data Broadening Imprime PGG Mechanism of Action

Reduces expression of IDO, a potent suppressor of an anti-cancer T cell response

Supplementation with IVIG boosts biomarker levels, restoring Imprime-driven pharmacodynamic responses

EAGAN, MN November 13, 2017 Biothera Pharmaceuticals, Inc. announced today the presentation of clinical and preclinical research supporting the mechanism of action for the Company’s cancer immunotherapy Imprime PGG, which is currently being evaluated in combination with immune checkpoint inhibitor therapy in multiple Phase 2 clinical trials.  The data were presented at the Society for Immunotherapy of Cancer (SITC) annual meeting taking place at the Gaylord National Hotel & Convention Center in National Harbor, MD.

New Biothera preclinical research demonstrates that Imprime PGG, a pathogen associated molecular pattern (PAMP), reduces Indoleamine 2,3-dioxygenase (IDO) expression.  IDO expression is one of many mechanisms that may dampen T cell based anti-cancer immunity.  Recent clinical studies combining IDO inhibitors with immune checkpoint inhibitors have shown clinical promise.  Biothera’s data complement previous research indicating that Imprime PGG can reprogram the immunosuppressive microenvironment that tumors establish to evade detection and destruction by infiltrating T cells.

“Imprime PGG activates a host of innate immune responses that culminate in anti-tumor T cell responses,” said Jeremy Graff, Ph.D., Chief Scientific Officer and Senior Vice President, Research, at Biothera Pharmaceuticals.  “These new data suggest that Imprime PGG also regulates or dampens IDO expression in the tumor bed, which may allow for a sustained T cell attack.”

The Company’s late-breaking poster #P521 is entitled, “Imprime PGG, a novel phase 2 immunotherapeutic, enhances the anti-tumor activity of checkpoint inhibitors (CPI) and suppresses CPI-induced Indoleamine 2,3-dioxygenase (IDO) expression.” First author: Xiaohong Qui.

Biothera Pharmaceuticals also presented at SITC a clinical case demonstrating that supplementation with intravenous immunoglobulin (IVIG) can increase levels of anti-beta glucan antibody (ABA), a mechanism-based biomarker for Imprime PGG.  Boosting ABA levels restored pharmacodynamics responses to Imprime PGG.

The poster presentation, #974, is entitled, “Increasing the levels of anti-beta glucan antibodies by administration of intravenous immunoglobulin (IVIG) induces immunopharmacodynamic (IPD) responses of a novel immunotherapeutic Imprime PGG.”  First author: Nadine Ottoson.

About Biothera Pharmaceuticals, Inc.
Biothera Pharmaceuticals is a privately held clinical stage immuno-oncology company developing Imprime PGG, a Phase 2 cancer immunotherapy that has been shown in preclinical studies to enhance the efficacy of anti-cancer immune responses in combination with immune checkpoint inhibitor, tumor-targeting and anti-angiogenic antibodies.  Biothera Pharmaceuticals has clinical research agreements with Merck to evaluate Imprime PGG and KEYTRUDA® (pembrolizumab), Merck’s anti-PD-1 antibody, in Phase 2 studies in advanced melanoma, metastatic triple negative breast cancer, and head and neck squamous cell cancer.  This therapeutic combination is also being evaluated in a Big Ten Cancer Research Consortium Phase 1b/2 trial for patients with non-small cell lung cancer.

David Walsh
Biothera Pharmaceuticals, Inc.



David Walsh

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