Rakuten Medical Investigational Anti-cancer Therapy Candidate Seen to Activate Immune System Response and Synergize with PD1 Checkpoint Blockade in Animal Models

NATIONAL HARBOR, Md., Nov. 9, 2019 /PRNewswire/ -- Rakuten Medical, Inc. (RMI) a clinical-stage, global biotechnology company developing precision-targeted cancer therapies based on Rakuten Medical's Illuminox™, its proprietary, anti-cancer treatment platform, introduced new preclinical data suggesting CD25 photoimmunotherapy (PIT) treatment, combined with an anti-PD1 therapy, may stimulate the immune system, and lead to a synergistic, anti-cancer activity in targeted tumors.

"These exciting data suggests that anti-CD25 photoimmunotherapy may alter the immune tumor environment and unlock the potential of combination immunotherapies for patients living with certain types of cancers for which there are few treatment options," said Miguel Garcia-Guzman, Ph.D., Vice Chairman and Chief Scientific Officer at Rakuten Medical. "We are committed to harnessing the full potential of the immune system through modulation of the cancer tumor environment, and these results support our clinical development program based on our anti-cancer treatment platform, Rakuten Medical's Illuminox."

The preclinical data were showcased during a poster presentation during the Society for Immunotherapy of Cancer (SITC) 34^th annual meeting:

"Intratumoral depletion of regulatory T-cells using CD25 targeted photoimmunotherapy elicits anti-cancer immune activity and synergizes with PD1 checkpoint blockade in immunocompetent mouse models." (Abstract P774), presented by Jerry J. Fong, Cancer Biology and Pharmacology, Rakuten Medical.

The poster discusses intratumoral depletion of regulatory T-cells (T_regs), a significant source of immune suppression, with an anti-CD25-IR700 conjugate therapy using PIT. Anti-cancer activity and subsequent immune responses following anti-CD25-IR700 PIT treatment, administered alone or in combination with anti-PD1 treatment, were evaluated in immunocompetent mouse models. Key highlights from the studies include:

• Rapid and significant reduction of intratumoral T_regs, eliciting significant anti-cancer activity
• An increase of non-exhausted T-cells following a single treatment, suggesting systemic activation and intratumoral recruitment of new CD8 T-cells from the periphery
• Significant enhancement of anti-cancer activity in vivo, as demonstrated by percentage of mice achieving complete responses (CRs) with combination treatment in comparison to animals receiving one treatment alone
• Durable increase of intratumoral CD8 T-cell/T_reg ratio
• Enhanced systemic adaptive immune responses and induced abscopal anti-cancer effects in a CD8 T-cell dependent manner
• Tumor-specific immune memory response as demonstrated by systemic tumor-antigen-specific cytotoxic lymphocytes expansion and prevention of new tumor growth in CR mice
• Combination treatment enhanced systemic adaptive immune responses and induced abscopal anti-cancer effects in a CD8 T-cell dependent manner

About Rakuten Medical
Rakuten Medical, Inc. (RMI) is a privately funded, clinical-stage biotechnology company with offices in the U.S., Japan, Taiwan, Germany and the Netherlands. Rakuten Medical aims to become a leader in precision-targeted medicines through Rakuten Medical's Illuminox™, its proprietary, anti-cancer treatment platform. The Company's lead product, ASP-1929, the first investigational product based on RMI's Illuminox, has achieved Fast Track designation from both the FDA and the Japanese Ministry of Health, Labour, and Welfare. ASP-1929 is currently the subject of a global, Phase 3 clinical trial for recurrent head and neck squamous cell carcinoma. Additional Phase 2 studies for ASP-1929 are also underway to evaluate the safety in patients with other cancer types. For more information, visit www.rakuten-med.com.

About Rakuten Medical's Illuminox™
Rakuten Medical's Illuminox™ is a proprietary, anti-cancer treatment platform that is comprised of drug, device and other related technologies. Transient excitation of a drug, including antibodies conjugated to light-excitable dyes, with non-thermal light is believed to result in anti-cancer activity and in rapid and selective cell killing and tumor necrosis with minimal effects on surrounding normal tissue. It may also lead to the systemic induction of innate and adaptive immunity. RMI's Illuminox is based upon the photoimmunotherapy treatment platform developed at the National Institutes of Health (NIH) and licensed exclusively to Rakuten Medical for commercialization. None of the therapies based on RMI's Illuminox have been approved by any regulatory authority. The RMI Illuminox platform is not a drug nor device on its own and is not the brand name of a drug nor device.

Forward Looking Statement
This press release contains forward-looking statements made pursuant to the safe harbor provisions of the (United States) Private Securities Litigation Reform Act of 1995 that involve risks, uncertainties, and assumptions that could cause Rakuten Medical's actual results and experience to differ materially from anticipated results and expectations expressed in these forward-looking statements. These forward-looking statements include information concerning its proprietary anti-cancer platform known as Rakuten Medical's Illuminox™ and the commercialization of services related to Rakuten Medical products such as the investigational product ASP-1929 and other initiatives toward regulatory approval for products to be sold and marketed. These products may not successfully be granted regulatory approval to be sold and marketed, or may not be commercially successful. Forward-looking statements suggest potential profitability, efficacy and safety, and the status of the application for approval. Rakuten Medical has in some cases identified forward-looking statements by using words such as "anticipates," "believes," "hopes," "estimates," "looks," "expects," "intends," "potential," "may," "suggest," "plans," "strategizes,"  "likely", "will", and similar expressions. Such forward-looking statements are based upon Rakuten Medical's current beliefs. Moreover, this press release states an opinion related to clinical research data, hence the use of expressions such as "important," "notable" and "abnormal." Ongoing clinical studies involve risks and uncertainties that could cause actual results to differ materially from those reflected in such statements, including uncertainty of success in regulatory approval or commercialization of ASP-1929 which may be impacted by, among other things, problems with the manufacturing process for ASP-1929, the occurrence of adverse safety events, failure to demonstrate therapeutic benefit, and the other risks and uncertainties, both reasonable and unreasonable. Rakuten Medical undertakes no obligation to release publicly the results of any revisions to any such forward-looking statements that may be made to reflect new information obtained, events or circumstances after the date of this press release or to reflect the occurrence of unanticipated events, except as required by applicable law or regulation. In the event of one or more revisions to Rakuten Medical's forward-looking statement, it should not be inferred that such revisions or other forward-looking statements will be further revised.

SOURCE Rakuten Medical, Inc.