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Biothera Pharmaceuticals to Present Immune Pharmacodynamic Data (IPD) Showing Immune Activation in Phase 2 Melanoma and Triple Negative Breast Cancer StudyTwo Late-Breaking Poster Presentations at the Society for Immunotherapy of Cancer (SITC) Annual Meeting Imprime PGG-induced IPD Changes Associated with Stable Disease, Progression-Free Survival and Overall Survival EAGAN, Minn., Nov. 08, 2019 (GLOBE NEWSWIRE) -- Biothera Pharmaceuticals, Inc. announced today immune pharmacodynamic data from its Phase 2 clinical study evaluating the therapeutic combination of Imprime PGG and KEYTRUDA® (pembrolizumab), Merck’s anti-PD-1 therapy, in chemo-refractory metastatic triple negative breast cancer (mTNBC) patients and metastatic melanoma patients who have failed immune checkpoint inhibitor (CPI) therapy. The data are being presented in two late-breaking posters at the Society for Immunotherapy of Cancer’s annual meeting on November 8 and 9 in National Harbor, MD. Analyses of peripheral blood samples taken over the course of the IMPRIME 1 study show that Imprime PGG, a dectin receptor agonist, induced anti-tumor immune responses culminating in a substantial increase in activated killer T cells. “These data provide key evidence that Imprime PGG, in combination with pembrolizumab, successfully activates T cells, particularly in patients who realize the greatest clinical benefit,” said Jeremy Graff, Ph.D., President and Chief Scientific Officer of Biothera Pharmaceuticals. IMPRIME 1 Study Results Translational analysis of blood samples from 41 patients found Imprime PGG successfully elicited serum and cellular immune pharmacodynamic changes (e.g., Anti-beta glucan antibody levels, circulating immune complexes, complement activation, cytokine/chemokine and gene expresion changes) in patients who showed the greatest clinical benefit. Similar results were observed in the melanoma arm of the study, which tested the combination of Imprime PGG and KEYTRUDA in heavily CPI pre-treated melanoma patients (20 patients; 13/20 had ³2 prior CPI regimens and 17/20 had progressed on pembrolizumab). The disease control rate was 50% (1 CR and 9 SD as best response), 12-month OS rate was 45%. “In this difficult to treat population, we see clear evidence that Imprime PGG re-awakened the immune system and triggered robust anti-cancer immune responses critical to effective CPI therapy,” said Dr. Graff. “In both melanoma and TNBC patients there is a compelling link between the mechanistic data and clinical benefit of combining Imprime PGG with CPI therapy. This proof of concept study gives us the confidence to advance the clinical development of Imprime PGG.” Late-Breaking Poster Presentations at SITC
IMPRIME 1 Study Design The primary endpoint was ORR by RECIST v1.1 and safety, and secondary endpoints included OS and DCR. Pre- and on-therapy tumor biopsies were collected to assess immune activation at the tumor site. The tissue samples showed that Imprime PGG induced heavy infiltration of tumor tissues by activated innate immune cells (M1 state, PD-L1+) and activated CD8 and CD4 T cells. On-treatment peripheral blood samples showed Imprime PGG-specific innate immune cell mobilization and activation, as well as enhanced T cell activation. About Biothera Pharmaceuticals, Inc. Contact:
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