The present technology relates to medicine and includes the use of inhibitors which selectively interfere with the interaction between a fibroblast growth factor receptor and FRS2, and with the interaction with other components of the FRS2 complex. Use of the selective inhibitors described in the present technology leads to a proven increase in anti-tumor efficacy relative to other inhibitors and monoclonal antibodies, a decrease in the toxicity of treatment, and the possibility of achieving complete blockage using a low agent concentration and of conducting long-term treatment. The advantage of the technology includes the development of a novel class of medicinal agents for treating malignant neoplasms and other diseases.