Study of ACTR087 in Combination With SEA-BCMA in Subjects With Relapsed or Refractory Multiple Myeloma

Inclusion Criteria:

Signed written informed consent obtained prior to study procedures
Histologically- or cytologically-confirmed relapsed or refractory multiple myeloma (MM) with measurable disease
Must have received at least 3 prior lines of therapy to include treatment with a proteasome inhibitor (eg, bortezomib, carfilzomib, or ixazomib) and an immunomodulatory agent (eg, lenalidomide, pomalidomide) unless double-refractory to both; and a hematopoietic stem cell transplant (HSCT), for those subjects considered HSCT-eligible.
Quantitative serum IgG levels for subjects with IgG MM must not exceed the institutional upper limit of normal (ULN)
ECOG 0 or 1
Life expectancy of at least 6 months
Absolute neutrophil (ANC) count greater than 1000/ µL
Platelet count greater than 50,000/µL
Estimated GFR >30mL/min/1.73m2

Exclusion Criteria:

Known active central nervous system (CNS) involvement by MM
Systemic rheumatic or autoimmune diseases or acute or chronic infections
Uncontrolled thromboembolic events or recent severe hemorrhage
Subjects who are currently using more than 5mg/day of prednisone (or an equivalent glucocorticoid exceeding physiologic replacement levels)

Prior treatment as follows:

T cell-directed antibody therapy (eg. Alemtuzumab, anti-thymocyte globulin) within 6 months of enrollment
Any prior myeloma-directed therapy including cytotoxic chemotherapy, biologic therapy, or radiotherapy within 2 weeks of enrollment
Any mAb or other protein therapeutic containing Fc-domains within 4 weeks of enrollment
Experimental agents within 3 half-lives prior to enrollment, unless progression is documented on therapy
Prior BCMA-directed investigational agents at any time
Prior cell or gene therapy, excluding transfers of genetically unmodified autologous cells (eg. Hematopoietic stem cell transplantation), at any time; or prior allogeneic HSCT at any time
Pregnant or breastfeeding