Inclusion Criteria:

• Prior diagnosis of multiple myeloma as defined by IMWG criteria (Rajkumar et al, 2014).

• Measurable disease based on IMWG criteria as defined by at least 1 of the following:

  • Serum M-protein ≥0.5 g/dL.
  • Urinary M-protein excretion ≥200 mg/24 hours.
  • Serum immunoglobulin FLC ≥10 mg/dL (≥100 mg/L) AND abnormal serum immunoglobulin kappa to lambda FLC ratio (<0.26 or >1.65).

• Prior anti-multiple myeloma therapy including treatment with lenalidomide.

• ECOG performance status ≤2.

• Resolved acute effects of any prior therapy to baseline severity or CTCAE Grade ≤1.

• Not pregnant and willing to use contraception.

Exclusion Criteria:

• Smoldering multiple myeloma.
• Plasma cell leukemia.
• Amyloidosis.
• POEMS Syndrome.
• Stem cell transplant within 12 weeks prior to enrolment, or active graft versus host disease.
• Active HBV, HCV, SARS-CoV2, HIV, or any active, uncontrolled bacterial, fungal, or viral infection.
• Any other active malignancy within 3 years prior to enrolment, except for adequately treated basal cell or squamous cell skin cancer, or carcinoma in situ.
• Previous treatment with a BCMA-directed therapy.
• Live attenuated vaccine within 4 weeks of the first dose of study intervention.
• Administration with an investigational product (e.g. drug or vaccine) concurrent with study intervention or within 30 days preceding the first dose of study intervention used in this study.