We are pleased to announce that the Phase II clinical trial for angiosarcoma※1 conducted in collaboration with CICS Co., Ltd. (Koto-ku, Tokyo) using BNCT※2 (Boron Neutron Capture Therapy) has achieved the primary endpoint. Details of the trial results will be presented at the “European Society for Medical Oncology (ESMO) Congress 2025” to be held in Berlin, Germany, from October 17 to 21, 2025.
This trial was conducted as a single-arm trial※3 at the National Cancer Center Hospital, with the primary objective of evaluating the response rate※4 of BNCT using CICS’s neutron irradiation device (CICS-1) and our boron-based drug (SPM-011) in patients with unresectable cutaneous angiosarcoma.
The target patients are those with locally advanced or locally recurrent angiosarcoma for whom chemoradiotherapy or radiotherapy is difficult. Currently, for angiosarcoma with no response to chemoradiotherapy or radiotherapy, there are no established treatment options for local control, and new treatment methods with high local control rates are required. In this context, our boron-based drug Borofalan (10B) (SPM-011), currently under development as a boron-based drug for BNCT, has been designated as an orphan drug※5 by the Ministry of Health, Labour and Welfare in December 2023 for the treatment of unresectable cutaneous angiosarcoma.
In this trial, the response rate was the primary endpoint that met the pre-specified criteria, suggesting that BNCT using SPM-011 may serve as a new treatment option for unresectable cutaneous angiosarcoma.
We plan to submit an approval application based on the results of this trial. We will continue to advance development to provide BNCT as a treatment option for patients.
【Announcement Overview】
・Presentation format: Poster (planned)
・Presentation number: 1672P
・Presenter: Dr. Tairo Kashihara (Department of Radiation Oncology, National Cancer Center Hospital)
※1 Angiosarcoma
Angiosarcoma is cancer that develops endothelial cells of blood vessels. It can occur anywhere in the body but mostly occurs in the skin.
※2 BNCT (Boron Neutron Capture Therapy)
Boron Neutron Capture Therapy is one sort of radiation therapy where a reaction between a boron containing drug and thermal neutrons occurs. As new cancer treatment, the damage caused to the body is small and the effectiveness is expected to be high.
※3 Single-arm trial
A single-arm trial is a clinical trial in which all participants are treated with the same treatment without dividing them into multiple groups for comparison.
※4 Response rate
The response rate is a measure used to evaluate the effectiveness of a treatment, representing
the proportion of cases in a clinical trial that achieved partial response (tumor reduction of 30% or more from baseline) or complete response (complete disappearance of the tumor, with no detectable tumor on examination).
※5 Orphan drug
An orphan drug is a rare disease drug designated by the Minster of Health, Labour and Welfare and is given priority review. The number of target patients in Japan must be less than 50,000, a serious disease as target and no existing alternative suitable treatment or drug are also conditions. Furthermore, the drug’s effectiveness or safety must be expected significantly higher than existing drugs and a high medical need is required. There must be a theoretical justification for using the drug for the target disease and the development plan must be accepted as appropriate.
An orphan drug is given preferential review for approval review process and research and development subsidies from the government.