Cancer treatment often fails due to acquired resistance. Evidence suggests that adaptive protocols may outperform standard protocols in delaying resistance. However, current adaptive strategies primarily focus on preventing resistant mutant takeover, while overlooking adaptive mechanisms of resistance — feedback and bypass pathways that reestablish the tumor’s pathological set-points. Instead of searching for drug combinations that exhaust the redundant pathways, we ask a different question: assuming we are limited to treatments the physiology can adapt to, is there still a way to eliminate the tumor by precisely timing treatment? We formulated this challenge using dynamical systems theory, and utilized optimal control to reveal dosing strategies capable of eliminating the tumor despite adaptation. We found that treatments failing in a constant regime can become effective when timed appropriately. The resulting strategies are surprising — examples include induction of resonance in tissues or applying a preliminary drug with the opposite of the intended effect. Finally, we show how to use our strategies to simultaneously overcome both mutational and adaptive resistance. Our work establishes a conceptual framework as well as practical strategies for overcoming the main modes of resistance, relevant across a wide range of cancers and therapeutic modalities.