Peptidream Announces First Administration in a Specific Clinical Study of Cancer Radiopharmaceutical Candidate 64Cu-PD-29875 Targeting Claudin18.2 in Gastric Cancer Patients

Peptidream Inc. (President and CEO: Patrick Reid, Headquarters: Kawasaki City, Kanagawa Prefecture, hereinafter referred to as "the Company") is pleased to announce that the first subject has been administered a dose in a specific clinical study (hereinafter referred to as "the Specific Clinical Study") of its cancer radiopharmaceutical candidate, 64Cu-PD-29875, which targets Claudin18.2 (hereinafter referred to as "CLDN18.2").

Objective of the Clinical Study

The Specific Clinical Study is a first-in-human trial (*1) of 64Cu-PD-29875, designed to evaluate its safety, pharmacokinetics, and tumor uptake using PET/CT imaging in patients with gastric cancer or gastroesophageal junction cancer. In addition to its potential as a diagnostic agent, the study also aims to obtain initial insights into its potential for development into a therapeutic radiopharmaceutical through a radiotheranostic (*2) approach. The results are expected to contribute to accelerating future clinical development.

*1: First-in-Human Trial

A "first-in-human trial" refers to a study where a drug is administered to humans for the first time.

*2: Theranostics

Theranostics refers to a medical approach that integrates diagnosis and treatment based on the same drug, such as peptides, by utilizing different isotopes for diagnostic and therapeutic purposes. Theranostics enables simultaneous diagnosis and treatment of cancer, offering potential benefits such as effective patient selection for those likely to respond to treatment and continuous monitoring of treatment efficacy.

What is Claudin18.2 (CLDN18.2)?

CLDN18.2 belongs to the Claudin family of proteins. While primarily expressed in gastric epithelial cells in normal tissues, it has been reported to be highly expressed in various cancers, including gastric cancer, esophageal cancer, pancreatic cancer, and lung adenocarcinoma. This makes it a promising molecular target for both diagnosis and treatment.

PD-29875 is a cyclic peptide created using the Company's proprietary Peptide Discovery Platform System (PDPS®) technology. It is a development candidate that the Company has optimized based on the results of in vivo imaging (*3) and efficacy studies conducted by its subsidiary, PDR Pharma.

*3: In Vivo Imaging

In vivo imaging involves administering a compound labeled with a radionuclide or other methods to observe its behavior within the body. For example, in vivo imaging techniques can provide visual information on how a drug distributes, metabolizes, and is excreted after administration.

President's Comment

Patrick Reid, President and CEO of Peptidream Inc., stated:

"The initiation of the first administration for PD-29875 marks a significant advancement towards realizing our vision of establishing a robust foundation for radiotheranostics. PD-29875, our second proprietary radiopharmaceutical program, is a cyclic peptide targeting CLDN18.2, a protein of interest in oncology, and was generated from our powerful peptide drug discovery engine. As part of our integrated radiotheranostic strategy, we are advancing development from both diagnostic (64Cu-labeled) and therapeutic (225Ac-labeled) perspectives, aiming to accelerate our mission of delivering next-generation radiopharmaceuticals to cancer patients."

The development of PD-29875 was selected for the "Research Project for the Practical Application of Innovative Cancer Therapies" by the Japan Agency for Medical Research and Development (AMED) in 2024, and is being promoted with research grants.

About Gastric Cancer and Gastroesophageal Junction Cancer

Gastric cancer was the fifth most common cancer worldwide and the fourth leading cause of cancer death in 2020, accounting for approximately 7% of all cancer diagnoses globally. It is also known for its poor prognosis, with a 5-year survival rate of 32%. In 2020, approximately 1.1 million people worldwide were diagnosed with gastric cancer, and 770,000 died. The number of patients is projected to increase to 1.8 million by 2040. Gastroesophageal junction cancer, which arises at the junction of the esophagus and stomach, has been increasing in recent years. Like gastric cancer, CLDN18.2 expression is observed in this type of cancer.