Biothera Pharmaceuticals and Merck Expand Research Collaboration to Include Phase 2 Clinical Trial in Head and Neck Cancer

Biothera Pharmaceuticals, Inc. today announced an expansion of its research collaboration with Merck (known as MSD outside the United States and Canada) to include a Phase 2 clinical study investigating Biothera’s Imprime PGG in combination with KEYTRUDA^® (pembrolizumab), Merck’s anti-PD-1 therapy, in second- and third-line patients with head and neck squamous cell cancer (HNSCC).
A previously announced agreement between Biothera and Merck covers Phase 2 clinical testing of this therapeutic combination in melanoma and triple negative breast cancer.  In addition, the Big Ten Cancer Research Consortium is conducting a Phase 1b/2 study in second line non-small cell lung cancer (NSCLC) with KEYTRUDA and Imprime PGG, under separate agreements with Merck and Biothera.
The goal of the new Phase 2 study will be to determine the potential of Imprime PGG, a Pathogen Associated Molecular Patterning molecule or PAMP, to increase patient responses to KEYTRUDA, a humanized monoclonal antibody that works by increasing the ability of the body’s immune system to help detect and fight tumor cells. Imprime PGG acts as an immunological “ignition switch” to activate the innate immune system, which then instructs cytotoxic T cells to recognize and kill cancer cells.  In preclinical studies, Imprime PGG has been shown to enhance the efficacy of immune checkpoint inhibitor antibodies.The multicenter, open-label Phase 2 study will enroll 87 patients with advanced HNSCC into two cohorts with distinct patient populations.  One cohort (n=38) will include patients with progressive disease following prior treatment with an immune checkpoint inhibitor.  A second cohort (n=49) will include patients with stable disease, who have failed to demonstrate an objective response after at least three months of KEYTRUDA monotherapy. The primary study endpoints are safety and overall response rate.  Secondary endpoints include progression-free survival and overall survival.  Investigation of tumor biopsies post-Imprime treatment will be conducted to assess changes to tumor histology and immune activity in the tumor microenvironment.  A patient selection biomarker for Imprime PGG will be used to screen prospective study subjects for inclusion into this trial. Preclinical and clinical data have demonstrated that biomarker positive subjects (those with natural anti-beta glucan antibody > 20ug/ml) are more likely to respond to Imprime PGG.“This study aims to demonstrate that Imprime PGG can ignite immune responses critical to expanding the benefits of KEYTRUDA to more head and neck cancer patients,” said Barry Labinger, President and Chief Executive Officer of Biothera Pharmaceuticals.  “This study should provide clinical proof of concept, as well as critical pharmacodynamic and biomarker data, and insight into Imprime PGG’s ability to activate innate immune cells and reduce immunosuppression in the tumor microenvironment.”
About Biothera Pharmaceuticals, Inc.
Biothera Pharmaceuticals is a privately held biotechnology company developing Imprime PGG, a mid-clinical stage cancer immunotherapy that enhances the efficacy of tumor targeting, anti-angiogenic, and immune checkpoint inhibitor antibodies.  The Company has clinical research agreements with Merck to evaluate Imprime PGG and Merck’s KEYTRUDA^® (pembrolizumab) in Phase 2 studies advanced melanoma, metastatic triple negative breast cancer and head and neck squamous cell cancer. This therapeutic combination is the focus of a Big Ten Cancer Research Consortium Phase 1b/2 trial in patients with non-small cell lung cancer. Imprime PGG has been well-tolerated and has established proof of concept in trials with more than 400 subjects.KEYTRUDA^® is a registered trademark of Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.Contact:
David Walsh
SVP Communications
Biothera Pharmaceuticals, Inc.
651-256-4606
dwalsh@biothera.com