Substituted condensed thiophenes as modulators of sting

A compound of formula (I), wherein R1 is selected from (i) H, (ii) C3-6cycloalkyl, (iii) C3-7heterocyclyl optionally substituted with a group selected from: methyl and ester, and (iv) linear or branched C1-4alkyl optionally substituted with a group selected from: alkoxy, amino, amido, acylamido, acyloxy, alkyl carboxyl ester, alkyl carbamoyl, alkyl carbamoyl ester, phenyl, phosphonate ester, C3-7heterocyclyl optionally substituted with a group selected from methyl and oxo, and a naturally occurring amino acid, optionally N-substituted with a group selected from methyl, acetyl and boc; A1 is CRA or N; A2 is CRB or N; A3 is CRC or N; A4 is CRD or N; where no more than two of A1, A2, A3, and A4 may be N; one or two of RA, RB, RC, and RD, (if present) are selected from H, F, Cl, Br, Me, CF3, cyclopropyl, cyano, OMe, OEt, CH2OH, CH2OMe and CH2NMe2; the remainder of RA, RB, RC, and RD, (if present) are H; Y is O, NH or CH2; RY is selected from: (RYA) and (RYB).