STAT degraders and uses thereof

A method of degrading STAT3 protein in a patient or biological sample comprising administering to said patient, or contacting said biological sample with a compound of formula I:

• or a pharmaceutically acceptable salt thereof, wherein:
• LBM is a cereblon E3 ubiquitin ligase binding moiety;
• L is a covalent bond or a bivalent, saturated or unsaturated, straight or branched C1-50 hydrocarbon chain, wherein 0-6 methylene units of L are independently replaced by —Cy-, —O—, —N(R)—, —Si(R)2—, —Si(OH)(R)—, —Si(OH)2—, —P(O)(OR)—, —P(O)(R)—, —P(O)(NR2)—, —S—, —OC(O)—, —C(O)O—, —C(O)—, —S(O)—, —S(O)2—, —N(R)S(O)2—, —S(O)2N(R)—, —N(R)C(O)—, —C(O)N(R)—, —OC(O)N(R)—, —N(R)C(O)O—,
• wherein
• each-Cy- is independently an optionally substituted bivalent ring selected from phenylenyl, 8-10 membered bicyclic arylenyl, 4-7 membered saturated or partially unsaturated carbocyclylenyl, 4-11 membered saturated or partially unsaturated spiro carbocyclylenyl, an 8-10 membered bicyclic saturated or partially unsaturated carbocyclylenyl, 4-7 membered saturated or partially unsaturated heterocyclylenyl having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur, 4-11 membered saturated or partially unsaturated spiro heterocyclylenyl having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur, 8-10 membered bicyclic saturated or partially unsaturated heterocyclylenyl having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur, 5-6 membered heteroarylenyl having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur, and 8-10 membered bicyclic heteroarylenyl having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur, and
• each R is independently hydrogen, or an optionally substituted group selected from C1-6 aliphatic, phenyl, 4-7 membered saturated or partially unsaturated heterocyclic having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur, and 5-6 membered heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur, or:
• two R groups on the same nitrogen are optionally taken together with their intervening atoms to form a 4-7 membered saturated, partially unsaturated, or heteroaryl ring having 0-3 heteroatoms, in addition to the nitrogen, independently selected from nitrogen, oxygen, and sulfur;
• r is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10;
• and
• STAT is a STAT3 protein binding moiety selected from