For women of childbearing potential and men with partners of childbearing potential, agreement (by patient and/or partner) to use two effective forms of contraception from study entry through at least 6 months after the termination visit. For women of childbearing potential and men with partners of childbearing potential, agreement (by patient and/or partner) to use two effective forms of contraception from study entry through at least 6 months after the termination visit. For women of childbearing potential and men with partners of childbearing potential, agreement (by patient and/or partner) to use two effective forms of contraception from study entry through at least 6 months after the termination visit. For women of childbearing potential (defined as physiologically capable of becoming pregnant), agreement to use of highly effective contraception for at least 1 year following ACTR087 infusion. For men with partners of childbearing potential, agreement to use effective barrier contraception for at least 1 year following ACTR087 infusion Use of an effective means of contraception for women of childbearing potential and men with partners of childbearing potential For women of childbearing potential and men with partners of childbearing potential, agreement (by patient and/or partner) to use two effective forms of contraception from study entry through at least 6 months after the termination visit. Women with childbearing potential and partners must both use effective contraception during the study and for 3 months after the last dose Men and women of childbearing age and potential, who are not willing to use effective contraception Women of childbearing potential must use effective contraception Use of effective contraception by women of childbearing potental. Women of childbearing age must be on effective contraception For women of childbearing potential, agreement to use two effective forms of contraception For women of childbearing potential, agreement to use two effective forms of contraception For women of childbearing potential and men with partners of childbearing potential, agreement to use two effective forms of contraception For women of childbearing potential and men with partners of childbearing potential, agreement to use two effective forms of contraception Women who are pregnant or breastfeeding, or women of childbearing potential without using dual forms of effective contraception For women of childbearing potential and men with partners of childbearing potential, agreement (by patient and/or partner) to use two effective forms of contraception from study entry through at least 6 months after the termination visit. For women of childbearing potential, agreement to use two effective forms of contraception For women of childbearing potential and men with partners of childbearing potential, agreement to use two effective forms of contraception For women of childbearing potential, agreement to use two effective forms of contraception For women of childbearing potential and men with partners of childbearing potential, agreement to use two effective forms of contraception Women of childbearing potential should use effective contraception during and for two months after stopping fingolimod