Company: HURA
Filing Date: 2025-02-07
Form Type: S-4
Source: 0001193125-25-022803
Chunk: 418

Company: TuHURA Biosciences, Inc./NV
Filing Date: 2025-02-07
Form: S-4
Chunk 418
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 an innate immune response to generate tumor specific activated T cells.

Oncolytic Virus Vaccines. Oncolytic virus vaccines are designed to preferentially induce viral replication-dependent oncolysis (viral induced killing) in tumors in an effort to stimulate antitumor immune responses. Intratumoral injection is thought to trigger both local and systemic immunological responses leading to cell lysis, the release of tumor-associated antigens, and subsequent activation of innate and adaptive immune systems to induce tumor antigen-specific effector T-cell antitumor immunity.

Tumor-associated antigen vaccines. Another approach is to utilize Tumor-Associated Antigens (“TAAs”), some of which may also be similar to self-antigens, although preferentially overexpressed on tumor cells. However, these TAAs may also be displayed by normal healthy cells or cancer testis antigens that are only expressed by tumor cells and adult reproductive tissues. T and B cells with high affinity toward these TAAs also target self-antigens leading to the removal of these T and B cells from the immune repertoire by central and peripheral tolerance. Thus, a potent vaccine must break tolerance for them to work. To date, this approach has had limited success.

Individual Neoantigen Therapy. Tumor-Specific Antigens (“TSAs”) differ from tumor-associated antigens since they are not shared with similar self-antigens. They are typically de novo epitopes expressed by cancer-causing viruses (or oncoviruses) or private neoantigens encoded by somatic mutations. TSAs are truly tumor specific with no central tolerance. Deciding which TSAs to select and how to configure such multivalent vaccines is itself a daunting challenge. It may be insufficient to rely entirely on sequencing the expressed tumor genome looking for point mutations, translocation fusions, or CT antigens. Not only might this vary from patient to patient or even from cell to cell within a single patient’s tumor, expression at the messenger RNA or protein

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**level does not assure that predicted antigenic peptides will be generated and expressed as peptide-MHCI complexes, especially in the face of the allelic complexity in the MHC. Several groups are actively approaching this problem by using a combination of informatics and mass spectroscopy of peptides eluted from MHCI molecules. Early clinical trials used as neo-adjuvant therapy in combination with checkpoint inhibitors among patients with potentially surgically curable disease at risk for relapse has yielded encouraging results, although how best