We consider the type IIB Green-Schwarz superstring theory on AdS 2 × S 2 × T 6 supported by homogeneous Ramond-Ramond 5-form flux and its type IIA T-duals. One motivation is to understand the solution of this theory based on integrability. This background is a limit of a 1/4 supersymmetric supergravity solution describing four intersecting D3-branes and represents a consistent embedding of AdS 2 × S 2 into critical superstring theory. Its AdS 2 × S 2 part with corresponding fermions can be described by a classically integrable P SU (1, 1|2)/SO(1, 1) × U (1) supercoset sigma-model. We point out that since the RR 5-form field has non-zero components along the 6-torus directions one cannot, in general, factorize the 10d superstring theory into the supercoset part plus 6 bosons and 6 additional massless fermions. Still, we demonstrate that the full superstring model (i) is classically integrable, at least to quadratic order in fermions, and (ii) admits a consistent classical truncation to the supercoset part. Following the analogy with other integrable backgrounds and starting with the finite-gap equations of the P SU (1, 1|2)/SO(1, 1) × U (1) supercoset we propose a set of asymptotic Bethe ansatz equations for a subset of the quantum string states.