THE 30STARTUPS OF KANSAI

Periotherapia Co., Ltd. is an Osaka-based, clinical-stage biotechnology company developing innovative antibody medicines for breast cancer and other solid tumors. Our lead program, PT0101, targets a disease-associated form of periostin in the tumor microenvironment—the tissue surrounding cancer cells that can protect them from treatment. By improving this environment, PT0101 is designed to help existing anticancer treatments work more effectively and overcome treatment resistance. We are currently advancing clinical development in breast cancer and advanced solid tumors in Japan, while preparing for further global development, including in the United States.

Drug resistance is estimated to contribute to up to 90% of cancer-related deaths, leaving many patients with few effective treatment options. One major cause is the tumor microenvironment, which can protect cancer cells and promote resistance to multiple therapies. PT0101 is designed to block a key protective signal in this environment and make tumors more responsive to treatment. Rather than replacing existing medicines, our approach aims to strengthen the effects of chemotherapy, antibody-drug conjugates, and other anticancer treatments for patients with difficult-to-treat solid tumors.

Most cancer medicines attack cancer cells directly. Periotherapia takes a different approach by targeting pathological periostin, a disease-associated protein found in the tumor stroma. Our lead antibody, PT0101, is designed to distinguish this pathological form from normal periostin and improve the tumor microenvironment without broadly disrupting healthy tissue. This highly selective, microenvironment-focused approach originated from research at The University of Osaka. It offers a new way to address treatment resistance and may be combined with multiple existing cancer therapies across different solid tumors.

We first aim to demonstrate the clinical proof of concept of PT0101 in breast cancer. Based on this evidence, we plan to expand its use to other solid tumors and combine it with a wide range of anticancer treatments. Our near-term priorities are to advance clinical development in Japan and the United States and identify patients most likely to benefit through biomarker research. By building partnerships with pharmaceutical companies and investors, we aim to deliver a new treatment option from Osaka to patients worldwide whose cancers no longer respond adequately to current therapies.