This mAb is currently being tested in a phase 1 trial (NCT02520791) but restricted to patients with a relapsed/refractory peripheral T-cell lymphoma follicular variant and angioimmunoblastic T-cell lymphoma expressing high ICOS levels with the objective to directly kill tumor cells rather than depleting Tregs and reactivating effector CD4+ T cells. Here, CD4 is linked to neoplasm.