Company: PGEN
Filing Date: 2025-03-19
Form Type: 10-K
Source: 0001356090-25-000007
Chunk: 26

Company: PRECIGEN, INC.
Filing Date: 2025-03-19
Form: 10-K
Item: Item 1
Chunk 26
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 addition to broad expression on AML blasts, CD33 is expressed on LSCs underlying AML. LSCs are thought to be more resistant to chemotherapy treatment and to be capable of reinitiating the disease resulting in high relapse rates for AML. In healthy subjects, CD33 is primarily expressed on normal myeloid precursors, colony-forming cells, monocytes, and maturing granulocytes. Because CD33 is not expressed outside the hematopoietic system or on normal hematopoietic stem cells, it is an attractive target for treatment of AML.

AML is among the most common types of leukemia in adults with approximately 20,000 AML patients diagnosed in the United States annually. AML is a heterogeneous disease with 50-70 percent relapse rates and rapid progression. The prognosis for patients with AML is poor, with an average five-year survival rate of approximately 25 percent overall, and less than a 5 percent five‐year survival rate for patients older than 65. More than 10,000 cases of higher-risk MDS are diagnosed annually in the United States. Due to the aggressive nature of AML progression, rapid availability of treatment is of even greater importance in this patient population, and our non-viral UltraCAR-T manufacturing process would represent a significant potential advantage over current approaches that require long lead times for manufacturing.

In preclinical studies, PRGN-3006 demonstrated robust expansion in the presence of CD33 antigen, lack of autonomous expansion in the absence of CD33 and prolonged persistence in the absence of exogenous cytokines. PRGN-3006 exhibited target-specific killing of CD33+ tumor cells as well as a significant release of inflammatory cytokines such as IFNγ, upon co-culture with AML tumor cells. PRGN-3006 cells were specifically eliminated by kill switch activator treatment, displaying functionality of the kill switch, which is intended to improve the safety profile of PRGN-3006. In vivo, a single administration of PRGN-3006 UltraCAR-T cells only one day after gene transfer effectively eliminated the tumor burden and significantly improved overall survival of tumor bearing mice compared to CAR-T cells lacking mbIL15 expression (conventional CAR-T) in an aggressive xenograft model of AML. PRGN-3006 demonstrated engraftment and significantly higher expansion and persistence in mice compared to conventional CAR-T cells, which lack mbIL15 expression.

PRGN-3006 is in a Phase 1/1b clinical trial