Conclusion of an Agreement with the National Cancer Center, Sumitomo Heavy Industries, Ltd. and CICS, Inc. for Clinical Trial of BNCT

Stella Pharma announces that it has signed an agreement with the National Cancer Center (NCC) (Tokyo), Sumitomo Heavy Industries, Ltd. (SHI, Tokyo), and CICS Inc. (Tokyo) regarding a Phase I/II basket study of CICS-1^*1 and SPM-011 as Boron Neutron Capture Therapy (BNCT) for patients with recurrent thoracic solid malignant tumors^*2 that are refractory to standard treatment and unresectable.

The purpose of the study is to evaluate the safety and efficacy of BNCT using CICS’s neutron irradiation system (CICS-1) and our boron agent (SPM-011) in patients with recurrent, unresectable, solid thoracic malignant tumors for which standard radiation therapy or chemotherapy is difficult to administer, and in which the lungs, heart, liver, spinal cord, and esophagus are common risk organs in the BNCT treatment plan based on therapeutic position CT.

Furthermore, the study will perform [¹⁸F] FBPA-PET^*3 on all patients prior to BNCT to evaluate the safety of [¹⁸F] FBPA. It also aims to exploratory evaluate^*4 the usefulness of [¹⁸F] FBPA-PET in determining the appropriateness of BNCT.

BNCT is a therapy that selectively kills cancer cells by utilizing the principle that the boron compound BPA is specifically taken up by cancer cells. Currently, [¹⁸F] FBPA, which is an application of BPA to a drug used in PET examinations, is also being developed for [¹⁸F] FBPA-PET to confirm how much BPA accumulates in cancer cells, which is necessary to target cancer cells.

The study is the world’s first BNCT clinical study targeting multiple cancers that occur in the thoracic region. By using the same normal tissues irradiated with neutrons, multiple cancers can be grouped together, which is expected to shorten the development period compared to conducting studies for each individual cancer. In addition, we expect that the [¹⁸F] FBPA-PET will enable us to determine the suitability of BNCT before the procedure and to consider the most appropriate treatment for each patient.

In the case of thoracic malignancies, when standard treatment is administered for the first treatment, chemotherapy is the only treatment of choice at the time of recurrence, and there is no choice of local treatment. Under these circumstances, we will continue to develop BNCT to meet unmet medical needs.

The term of the Agreement is until October 31, 2028.

For details of the clinical study protocol, please refer to the Japan Registry of Clinical Trials.

*1 CICS-1:
　CICS-1 is an accelerator-based BNCT system developed by CICS Inc. An RFQ (radio frequency
　quadrupole) linear accelerator leads to the collision of protons with a lithium target, and generates
　neutrons characterized by low mix of fast neutrons that are harmful to the human body. Because the
　neutrons energy of less than 800 keV is low, it is possible to downsize the moderator system to
　decelerate the neutron energy to about 10 keV, suitable for BNCT.

*2 Thoracic solid malignant tumors:
　Esophageal cancer, non-small cell lung cancer, breast cancer, malignant soft tissue sarcoma occurring
　in thoracic area, malignant pleural mesothelioma, etc.

*3 [¹⁸F] FBPA-PET:
　A PET test using [¹⁸F] FBPA (L-2-fluoro-4-boronophenylalanine) to measure the selective accumulation
　of the boron compound L-4-boronophenylalanine (BPA), used in BNCT, in the target tumor.

*4 Exploratory evaluation:
　Various evaluations in preparation for the next stage of testing, etc.
　Evaluation that is the preliminary stage of a validation evaluation to test a hypothesis and to formulate
　 a hypothesis.