Rakuten Medical's Anti-PD-L1 Antibody-IR700 Conjugate, RM-0256, Selected for AMED Funding

• AMED grant to support the clinical development of RM-0256 photoimmunotherapy for targeting malignant epithelial tumors
• Targeting PD-L1, pre-clinical observations indicate RM-0256 harnesses a triple mechanism of action, with potential applications across a broad range of solid tumors, including melanoma, ocular melanoma, urologic, and breast cancers ²

SAN DIEGO, June 4, 2025 /PRNewswire/ -- Rakuten Medical, Inc., a global biotechnology company developing and commercializing Alluminox™ platform-based photoimmunotherapy, today announced that its third drug candidate, RM-0256, has been selected for funding by the Japan Agency for Medical Research and Development (AMED) under its Support Program for Orphan Drug prior to the Designation.

RM-0256 is a novel antibody conjugate composed of IRDye®700DX (IR700)—a light-activatable dye for which Rakuten Medical holds exclusive global manufacturing and supply rights—and a proprietary anti-PD-L1 monoclonal antibody. The AMED funding will support the clinical development of RM-0256 photoimmunotherapy for unresectable, advanced, or recurrent malignant epithelial tumors.

In Japan, malignant epithelial tumors affect approximately 22,000 individuals annually¹. While systemic therapies, including chemotherapy and immune checkpoint inhibitors, are currently the mainstay of treatment for unresectable advanced or recurrent cases, patients who develop resistance to these treatments face limited treatment options, which underscores the urgent need for novel therapeutic approaches.

RM-0256 targets Programmed Cell Death Ligand 1 (PD-L1), a key immune checkpoint protein that allows tumors to evade immune detection by binding to PD-1 receptors on activated T cells. PD-L1 is widely expressed in various solid tumors—including melanoma, ocular melanoma, lung, urothelial, gastrointestinal, gynecological, breast, and head and neck cancers²—as well as on immunosuppressive cells within the tumor microenvironment.

Pre-clinical studies of PD-L1-targeted photoimmunotherapy have suggested three complementary mechanisms of action³:

1) Direct depletion (necrosis) of PD-L1-expressing tumor cells;
2) Activation of anti-tumor immunity through the elimination of PD-L1–expressing immunosuppressive cells;
3) Checkpoint blockade, by inhibiting PD-L1/PD-1 interaction, potentially enhancing systemic immune responses.

With the support of AMED funding, Rakuten Medical is accelerating the development of RM-0256 photoimmunotherapy as a novel, multimodal cancer therapy that may induce both local and systemic anti-tumor effects.

Disclaimer: Rakuten Medical's Alluminox™ platform-based photoimmunotherapy is investigational outside Japan.

1. Cancer Incidence of Japan 2020, Cancer and Disease Control Division, Ministry of Health, Labour and Welfare https://www.mhlw.go.jp/content/10900000/001231386.pdf
2. Kythreotou A, Siddique A, Mauri FA, et alPD-L1Journal of Clinical Pathology 2018;71:189-194. https://jcp.bmj.com/content/71/3/189
3. Thorne A. PD-L1 photoimmunotherapy kills immunosuppressive myeloid cells to activate local and systemic antitumor immunity. Abstract Number: 30050. The 83rd Annual Meeting of the Japanese Cancer Association. September 2024. https://rakuten-med.com/us/news/press-releases/2024/09/19/7864/

About Rakuten Medical, Inc. 

Rakuten Medical, Inc. is a global biotechnology company developing and commercializing Alluminox™ platform-based photoimmunotherapy, which, in pre-clinical studies, has been shown to induce rapid and selective cell killing. Rakuten Medical's photoimmunotherapy is currently investigational outside Japan. Rakuten Medical is committed to its mission to conquer cancer by developing its pioneering treatments as quickly as possible to as many patients as possible all over the world. The company has offices in 5 countries/regions, including the United States, where it is headquartered, Japan, Taiwan, Switzerland and India. For more information, visit www.rakuten-med.com.

About Alluminox™ platform  

The Alluminox™ platform is Rakuten Medical's investigational technology platform that combines pharmaceuticals, medical devices, medical technology, and other peripheral technologies. Rakuten Medical is developing Alluminox platform-based photoimmunotherapy, which involves two key steps: 1) drug administration and 2) targeted illumination using medical devices. The drug component consists of a cell-targeting moiety conjugated to a light-activatable dye, such as IRDye® 700DX (IR700), that selectively binds to the surface of targeted cells, such as tumor cells. The device component consists of a light source that locally illuminates the targeted cells with red light (690nm) to transiently activate the drug. Rakuten Medical's pre-clinical data have shown that this activation elicits rapid and selective necrosis of targeted cells through a biophysical process that compromises the membrane integrity of the targeted cells. Therapies developed on the Alluminox platform may also result in local and systemic innate and adaptive immune activation due to immunogenic cell death of the targeted tumor cells and/or the removal of targeted immunosuppressive cells within the tumor microenvironment. Photoimmunotherapy was originally developed by Dr. Hisataka Kobayashi and his team at the National Cancer Institute in the United States. Outside Japan, Rakuten Medical's Alluminox platform-based photoimmunotherapy is investigational.

About RM-0256

RM-0256 is an antibody conjugate comprised of a proprietary anti-PD-L1 monoclonal antibody (immune checkpoint inhibitor) and IRDye® 700DX, a light-activatable dye, that has been developed by Rakuten Medical to specifically target PD-L1-expressing cells. PD-L1 is an immune checkpoint protein that inhibits anti-tumor T cell responses by binding to PD-1 on activated T cells. It is widely expressed in many solid tumors, and is expressed on both tumor cells and immunosuppressive cells within the tumor microenvironment such as tumor-associated macrophages (TAMs) and myeloid- derived suppressor cells (MDSCs). Pre-clinical studies of PD-L1-targeted photoimmunotherapy have suggested activation of anti-tumor immune responses by destruction of target tumor cells and elimination of immunosuppressive cells. Inhibition of PD-L1/PD-1 binding has been also demonstrated, which may amplify the anti-tumor immune response.

Forward Looking Statements  

This press release contains forward looking statements that correspond to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These statements include various risks, uncertainties, and assumptions that may cause Rakuten Medical's business plans and results to differ from the anticipated results and expectations expressed in these statements. These "forward looking statements" contain information about the status and development of our products, including the Alluminox™ platform, as well as other regulatory and marketing authorization efforts, the potential benefits, efficacy, and safety of therapies created using the Alluminox platform, and the status of regulatory filings. The approval and commercial success of the product may not be achieved. Forward looking statements relate to the potential benefits, efficacy, and safety of our therapies, and the status of regulatory filings. Such statements may include words such as "expect," "believe," "hope," "estimate," "looks as though," "anticipate," "intend," "may," "suggest," "plan," "strategy," "will," and "do", and are based on our current beliefs. In addition, this press release uses terms such as "important," "notable," and "abnormal" to express opinions about clinical trial data. Ongoing clinical trial studies include various risks and uncertainties, in particular, problems that arise during the manufacturing stage of our therapies, the occurrence of adverse safety events, situations in failure to demonstrate therapeutic benefits, and other various risks and uncertainties, both reasonable and unreasonable. For this reason, actual results, including regulatory approvals and uncertainties in the commercialization process of our therapies, may differ from published information. Except to the extent required by applicable law, we undertake no obligation to publicly update this or any other forward-looking statement, whether because of new information, future developments or events, changes in assumptions, changes in the factors affecting forward-looking statements. If one or more forward-looking statement(s) is updated, no inference should be drawn that additional updates will be made to those or other forward-looking statements.

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