Provided is a treatment of cancer using a dual modulator of Insulin Receptor Substrate (IRS) and signal transducer and activator of transcription 3 (Stat3), as well with other agents. The combination can be used to treat a tumor that has developed resistance to an EGFR inhibitor, EGFR antibody, mTOR inhibitor, MEK inhibitor, mutated B-Raf inhibitor, chemotherapeutic agents, and certain combinations thereof, or to prevent acquired resistance of a tumor to any of said inhibitors or agents, or to prevent tumor recurrence following cease of treatment with any of said inhibitors or agents or a combination thereof. The subject matter further provides a treatment of cancer using combination therapy comprising a dual modulator of IRS and Stat3, in combination with an immunotherapy agent. The combination can be used to sensitize a tumor to immunotherapy.
