The study will include adult patients of either sex with a histologically confirmed solid tumor who are ineligible for surgery and for whom all available pharmacological and radiotherapeutic options have been exhausted. The choice of drug administration route will depend on the extent of the tumor process. In patients with metastatic disease confirmed by imaging methods (CT/MRI/PET-CT as indicated, with assessment according to RECIST 1.1 criteria for solid tumors and RANO criteria for neuro-oncological tumors), EnteroMix will be administered intravenously. In patients with massive locally advanced disease without distant metastases, or with generalized disease showing an isolated progressive lesion confirmed by imaging methods (CT/MRI/PET-CT as indicated, with assessment according to RECIST 1.1 criteria for solid tumors and RANO criteria for neuro-oncological tumors), EnteroMix will be administered intra-arterially (into the afferent artery of the tumor).