A Safety Study of SEA-BCMA in Patients With Multiple Myeloma

A Phase 1 Study of SEA-BCMA in Patients With Relapsed or Refractory Multiple Myeloma

This trial will study SEA-BCMA to find out whether it is an effective treatment for multiple myeloma (MM) and what side effects (unwanted effects) may occur.

The study will have several parts. In Parts A and B, participants get SEA-BCMA by itself. This part of the study will find out how much SEA-BCMA should be given for treatment and how often. It will also find out how safe the treatment is and how well it works.

In Part C of the study, participants will get SEA-BCMA and dexamethasone. In Part D, participants will get SEA-BCMA, dexamethasone, and pomalidomide. Dexamethasone and pomalidomide are both drugs that can be used to treat multiple myeloma. These parts of the study will find out whether these drugs are safe when used together.

Inclusion Criteria:

• Histologically confirmed diagnosis of MM
• Must have MM that is relapsed or refractory
• Has received a proteasome inhibitor, an immunomodulatory drug, and an anti-CD38 antibody
• Measurable disease, as defined by at least one of the following: (1) serum M protein 0.5 g/dL or higher, (2) urine M protein 200 mg/24 hour or higher, and (3) serum immunoglobulin free light chain (FLC) 10 mg/dL or higher and abnormal serum immunoglobulin kappa lambda FLC ratio.
• Eastern Cooperative Oncology Group (ECOG) status score of 0 or 1
• Life expectancy of greater than 3 months in the opinion of the investigator
• Adequate hematologic, renal, and hepatic function

Exclusion Criteria:

• Parts A and D: Prior treatment with a BCMA-directed therapy

• History of another malignancy within 3 years

• Active cerebral or meningeal disease related to the underlying malignancy

• Uncontrolled Grade 3 or higher infection

• Prior antitumor therapy that is not completed at least 4 weeks prior to first dose of study drug, or at least 2 weeks if progressing. Prior CAR-T-cell therapy must be completed 8 weeks before first dose of study drug.

• Combination therapy only:

  1. Known intolerance to corticosteroids
  2. Uncontrolled psychoses