NEW YORK – The combination of anti-PD-1 immunotherapy pembrolizumab (Merck's Keytruda) with Imprime PGG, a dectin receptor agonist being developed by Biothera Pharmaceuticals, nearly doubled the median overall survival rate for metastatic triple-negative breast cancer (mTNBC) patients in a Phase II clinical trial of the combination compared to pembrolizumab monotherapy.