• ≥18 years of age at the time of signing informed consent.

• Voluntarily signed informed consent form.

• Diagnosis of multiple myeloma and/or light-chain amyloidosis with relapsed or refractory disease, with measurable disease at screening visit

• Subject suffering from multiple myeloma must have been exposed to at least two prior lines of therapy including proteasome inhibitor, immunomodulatory (IMiDs) therapy or anti-CD38 antibody, or functionally high-risk patients (i.e. first relapse within 18 months of treatment initiation) may be included.

• Subject with amyloidosis must have been exposed to at least one prior line of therapy which includes proteasome inhibitor or anti-CD38 antibody, or subjects with insufficient response (i.e. not achieving a VGPR or CR after exposure to at least an anti-CD38 antibody and a proteasome inhibitor) may be included.

• Eastern Cooperative Oncology Group (ECOG) performance status 0 - 2.

• Women of child-bearing potential (WCBP), defined as a sexually mature woman who has not undergone a hysterectomy or tubal ligation or who has not been naturally postmenopausal for at least 24 consecutive months, must have a negative serum pregnancy test prior to treatment. All sexually active WCBP and all sexually active male subjects must agree to use effective methods of birth control throughout the study.

• Recovery to ≤ Grade 2 or baseline of any non-hematologic toxicities due to prior treatments, excluding alopecia and Grade 3 neuropathy.

• Ability and willingness to adhere to the study visit schedule and all protocol requirements.

• Subjects with relapsed multiple myeloma who have previously undergone allogenic stem cell transplantation must have no evidence of graft versus host disease after cessation of any immunosuppressive therapy for at least one month before recruitment to the study.