OncoSTING is developing OS-101, a breakthrough recombinant Bacillus Calmette-Guérin (rBCG) immunotherapy that overexpresses a potent Stimulator of IFN Genes (STING) agonist. STING agonists potentiate anti-tumor responses through the innate immune STING-IRF3-NF-κB pathway. In Phase I of this Fast Track project, OncoSTING will create a next-generation, antibiotic resistance-free version of 0S-101, a breakthrough rBCG using a novel, patent-pending method. In Phase II, OS-151 will be compared to ADU-S100 (Aduro's small molecule STING agonist which is in current clinical trials) and wild type BCG in relevant models of bladder cancer. Finally, tumor repetitive dosing studies and rechallenge studies will be carried out in mouse syngeneic models. Once approved, OS-151 will first be used to treat patients with BCG-unresponsive non-muscle invasive bladder cancer (NMIBC), with potential to expand to other cancer indications.