Study of Cell Therapies for the Treatment of Patients With Relapsed or Refractory Acute Myeloid Leukemia or High-risk Myelodysplastic Syndrome.

The study will have the following sequential phases: screening, enrollment, pretreatment with lymphodepletion (LD) chemotherapy, treatment with SPRX002 and ARCT cells, treatment extension with SPRX002, follow up, and long-term safety follow-up.

Following infusion of SPRX002 and a single infusion of ARC T (Day 0) and followed by regular administration of SPRX002 at the assigned dose level, both safety and efficacy data will be assessed. Dose limiting toxicities (DLTs) will be assessed through Day 28 and safety data will be collected throughout the study. Long-term safety data will be collected for up to 15 years per health authority guidelines. Efficacy will be assessed monthly for the first 6 months, then quarterly up to 2 years, or upon participants relapse.

ARC-T cells are a genetically modified autologous T-cell product. The T cell has been transduced using a third-generation lentiviral vector encoding a binding domain (referred to as AF101) chimeric antigen receptor (CAR), followed by CD8 spacer and transmembrane region that is fused to the intracellular signaling domains 4-1BB and CD3ζ. AF101 specifically binds to the "TAG" protein (referred to as Q26) of the soluble protein antigen-receptor x-linker (sparX; specifically, SPRX002).