NK engager molecules and methods of use thereof
Inventors
Miller, Jeffrey S. • Felices, Martin • Vallera, Daniel A. • Lenvik, Todd R.
Assignees
University of Minnesota System
Publication Number
US-12319737-B2
Publication Date
2025-06-03
Expiration Date
2039-10-17
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Abstract
Provided are compositions for activating NK cells to stimulate an immune response for treating cancer and other disorders. In one embodiment, the invention provides a compound comprising an NK engaging domain that binds to CD 16; an NK activating domain operably linked to the NK engaging domain; and a targeting domain that selectively binds to a target cell and is operably linked to the NK activating domain and the NK engaging domain, wherein the targeting domain binds to CLEC12A.
Core Innovation
The invention provides compositions and compounds designed to activate natural killer (NK) cells to elicit targeted immune responses for the treatment of cancer and other disorders. The compounds, in one embodiment, comprise three operably linked domains: an NK engaging domain that selectively binds to NK cell receptors such as CD16; an NK activating domain, such as IL-15 or a functional fragment thereof; and a targeting domain that selectively binds to a specific antigen on a target cell, with an emphasis on CLEC12A.
The background identifies a significant limitation in current NK cell therapy, namely the lack of antigen specificity and complications arising from the induction of regulatory T cells (Tregs) by agents like IL-2, which can suppress NK cell activity. Another challenge is the targeting of CD33, which is not specific to cancer cells and is also present on normal hematopoietic cells and some lymphoid cells, leading to off-target toxicity and failure to address chemotherapy-resistant leukemic stem cells (LSCs) that lack CD33.
To solve these problems, the disclosed tri-specific killer engager (TriKE) molecule incorporates a CD16-binding NK engager, an IL-15 NK activating domain, and a CLEC12A-targeting domain. CLEC12A is highly expressed on AML cells and leukemic stem cells, including many that do not express CD33, while having limited expression on normal hematopoietic stem cells. The TriKE structure is designed to bring NK cells into proximity with CLEC12A-positive cancer cells, provide a self-sustaining activation signal via IL-15, and promote selective tumor cell killing while minimizing off-target effects.
Claims Coverage
The independent claims reveal five main inventive features covering specific sequences, compound structure, compositions, and methods of use.
Isolated amino acid sequence comprising SEQ ID NO:1
An isolated amino acid sequence identified as SEQ ID NO:1 is defined, which embodies a tri-specific killer engager (TriKE) molecule designed to activate NK cells by combining an NK engaging domain, an NK activating domain, and a targeting domain that binds CLEC12A.
Isolated DNA sequence encoding SEQ ID NO:1
An isolated DNA sequence is claimed that encodes the amino acid sequence of SEQ ID NO:1, enabling the expression of the TriKE molecule by genetic means.
Isolated amino acid sequence comprising SEQ ID NO:2
An isolated amino acid sequence comprising SEQ ID NO:2, which represents a variant of the TriKE molecule possessing a His tag and spacer, is disclosed.
Isolated DNA sequence encoding SEQ ID NO:2
An isolated DNA sequence encoding the amino acid sequence of SEQ ID NO:2, supporting recombinant production of the His-tagged TriKE molecule, is claimed.
Compound comprising NK engaging, NK activating, and targeting domains (SEQ ID NO:1 or SEQ ID NO:2)
A compound is defined that includes: - an NK engaging domain; - an NK activating domain operably linked to the NK engaging domain; - a targeting domain that selectively binds to a target cell and is operably linked to the other domains; - wherein the compound has an amino acid sequence comprising SEQ ID NO:1 or SEQ ID NO:2.
Composition comprising the TriKE compound and pharmaceutically acceptable carrier
A pharmaceutical composition is claimed that contains the TriKE compound (as previously defined) in combination with a pharmaceutically acceptable carrier.
Method of inducing NK-mediated killing of CLEC12A-expressing target cell
A method is claimed where the TriKE compound is administered to a subject in an amount effective to induce NK-mediated killing of a target cell that expresses CLEC12A.
Method for stimulating expansion of NK cells in vivo
A method is disclosed comprising administration of the TriKE compound in an amount effective to cause expansion of NK cells in a subject.
Method of treating cancer comprising CLEC12A-expressing cells
A method is presented involving administration of the TriKE compound effective for treating cancer in a subject, where the cancer cells express CLEC12A.
In summary, the claims cover the specific TriKE sequences, DNA constructs encoding them, the multi-domain TriKE compounds themselves, their pharmaceutical compositions, and their use in stimulating NK cells and treating CLEC12A-expressing cancers.
Stated Advantages
The invention enables specific activation, priming, and expansion of NK cells, enhancing NK-cell-mediated cytotoxicity against cancer cells expressing CLEC12A.
Targeting CLEC12A addresses the problem of off-target toxicity associated with prior targets like CD33, since CLEC12A is highly expressed on AML cells and leukemic stem cells but not on normal hematopoietic stem cells.
The TriKE architecture provides NK cell antigen specificity, expansion, and persistence, while reducing the negative regulatory effects associated with Treg activation by agents such as IL-2.
Use of a human or humanized nanobody as the NK engaging domain may increase drug yield, stability, and NK cell ADCC efficacy.
Documented Applications
Treatment of cancer in subjects, including prostate, lung, colon, rectum, urinary bladder, melanoma, kidney, renal, oral cavity, pharynx, pancreas, uterine, thyroid, skin, head and neck, cervical, ovarian, and hematopoietic cancers where cells express CLEC12A.
Induction of NK-mediated killing of CLEC12A-expressing target cells, including AML and myelodysplastic syndromes (MDS).
Stimulation of in vivo NK cell expansion by administration of the TriKE compound.
Treatment methods may involve administration prior to, simultaneously with, or following chemotherapy, surgical resection, or radiation therapy.
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