The tumoricidal complex alpha1-oleate targets bladder cancer cells, triggering rapid, apoptosis-like tumor cell death. Clinical effects of alpha1-oleate were recently observed in patients with non-muscle invasive bladder cancer (NMIBC), using a randomized, placebo-controlled study protocol. Here, patients with NMIBC were treated by intravesical instillation of increasing concentrations of alpha1-oleate (1.7 mM, 8.5 mM, or 17 mM) and the treatment response was defined relative to a placebo group. Strong, dose-dependent anti-tumor effects were detected in alpha1-oleate treated patients for a combination of molecular and clinical indicators; a complete or partial response was detected in 82% of tumors treated with 8.5 mM compared to 45% of tumors treated with 1.7 mM of alpha1-oleate. Uptake of alpha1-oleate by the tumor triggered rapid shedding of tumor cells into the urine and cell death by an apoptosis-like mechanism. RNA sequencing of tissue biopsies confirmed the activation of apoptotic cell death and strong inhibition of cancer gene networks, including bladder cancer related genes. Drug-related side effects were not recorded, except for local irritation at the site of instillation. These dose-dependent anti-tumor effects of alpha1-oleate are promising and support the potential of alpha1-oleate treatment in patients with NMIBC.