Perseus Proteomics : Announcement of Patent Application on Therapeutic Agent for Aggressive NK-cell Leukemia with Tokai University

April 20, 2022

Perseus Proteomics Inc.

Securities Code: 4882 Growth TSE

To all stakeholders,

Announcement of Patent Application on Therapeutic Agent for Aggressive NK-cell Leukemia with Tokai University

Perseus Proteomics Inc. (HQ: Meguro-ku, Tokyo, President & CEO: Takuya Yokokawa, "the Company") is pleased to announce that the Company made a patent application in Japan on a therapeutic agent for aggressive NK-cell leukemia ("ANKL") with the research group led by Dr. Ai Kotani at Division of Hematological Malignancy, Institute of Medical Sciences, Tokai University

• 1. Outline of patent

  Name of invention: Therapeutic agent for aggressive NK cell leukemia Application No.: JPA2022-068757

  Application date: April 19, 2022 Summary:

  ANKL is a blood cancer categorized as malignant lymphoma, which originates in NK (natural killer) cells, one of immune cells. It is a fulminant type of refractory hematological malignancy, where symptoms will progress rapidly once developed. Cases are limited to Asia and part of South and Middle America. Also, it is an ultra-rare disease with approximately 20 to 30 new patients per year in Japan. Therefore, the causes of the disease are yet to be known and early establishment of the effective standard treatment has been awaited.

  As a result of the comprehensive analysis of genes related to proliferation of ANKL cells, the research group of Dr. Ai Kotani has found that transferrin receptors are deeply related to the existing period of tumors and that inhibiting the function of TfR leads to treatment mechanism. PPMX-T003, the antibody drug candidate under development by the Company, binds to TfR, which is highly expressed on the membrane of cancer cells, and inhibits iron intake into the cancer cells. Its inhibitory effect on cancer cell proliferation through this function has been confirmed.

  Dr. Kotani's research group and the Company conducted an administration experiment of PPMX-T003 on mouse models with tumor cells of ANKL patients transplanted. As a result, significantly high effect of inhibition of cancer cells proliferation and extension of survival time have been confirmed. This result has indicated the possibility of future development of new therapeutic method for ANKL, of which no effective therapeutic method exists currently. This patent application is related to the therapeutic agent for ANKL based on the research results stated above.

• 2. Future forecast

• There is no impact on the business results of the fiscal year 2022 ending March 31, 2023.

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The research and development of this therapeutic agent was adopted as Project Promoting Support for Drug Discovery Support Program for Orphan drug prior to the Designation by Japan Agency for Medical Research and Development (AMED) on March 22, 2022. The research group and the Company will proceed with the research for investigator-initiated clinical trials and practical application of the research findings.

Dr. Kotani at Tokai University website (Japanese only)

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