Safety and Efficacy Study of OPC-415 in Patients With Relapsed and/or Refractory Multiple Myeloma

Inclusion Criteria:

• Patients aged between 20 and 80 (75 for the phase 1 part) years, both inclusive, atthe time of consent

• Patients with a definitive diagnosis of active multiple myeloma

• Patients who have had 2 or more prior regimens (including all proteasome inhibitors,immunomodulators, and anti-CD38 antibody)

• Patients with relapsed and/or refractory Multiple Myeloma

• Patients who are positive for MMG49 antigen

• Patients with an Eastern Cooperative Oncology Group (ECOG) performance status (PS)score of 0 or 1. Those with an ECOG-PS score of 2 due solely to MM bone lesions canbe enrolled

• Patients who are expected to survive for at least 3 months

Exclusion Criteria:

• Patients who are scheduled to receive high-dose chemotherapy in combination withautologous stem cell transplantation as the next treatment.

• Patients who have other active double/multiple cancers

• Patients on continuous and systemic (oral or intravenous) medication withcorticosteroids or other immunosuppressive agents

• Patients with graft-versus-host disease that requires treatment.

• Patients who underwent a highly invasive and extensive surgical procedure within 2weeks.

• Patients who previously underwent allogeneic stem cell transplantation or organtransplantation.

• Patients who underwent autologous stem cell transplantation within 90 days.

• Patients with systemic amyloidosis (except localized amyloidosis without organderangement) or plasma cell leukemia.

• Patients with prior or current central nerve involvement in MM.

• Patients whose best ever response to MM treatment is PD.

• Patients who previously received gene therapy or cell therapy (except hematopoieticstem cell transplantation).

• Pregnant women, nursing mothers, or women with a positive pregnancy test.