Cutaneous angiosarcoma is a cancerous transformation of the inner cells of blood vessels (vascular endothelial cells). Angiosarcoma is an extremely rare tumor, and its treatment consists of four major therapies: immunotherapy, surgery, radiation therapy, and chemotherapy. Because of the high likelihood of the aggravation, physicians consider that a combination of various therapies should be implemented immediately, and each medical facility currently conducts any available treatments, regardless of the stage of the disease.
Paclitaxel, one of anticancers, is the first-line chemotherapy for the initial treatment of angiosarcoma. However, even with the combination of the chemotherapy and radiation therapy, it is difficult to achieve long-term regression or disappearance of cancer. Therefore, the development of highly effective and safe treatments and therapeutics is eagerly anticipated as the second-line treatment.
PAI-1 is expressed on vascular endothelial cells, and its tumor, angiosarcoma, also expresses high levels of PAI-1. It has been reported that patients with high expression of PAI-1 are less likely to respond to paclitaxel in first-line treatment. Paclitaxel induce apoptosis, a type of cell death in angiosarcoma, but cancer cells that express high levels of PAI-1 are less likely to undergo apoptosis. The combination of paclitaxel and the PAI-1 inhibitor RS5614 may enhance the therapeutic effect of paclitaxel on angiosarcoma.
In collaboration with Tohoku University, a Phase II investigator-initiated clinical trial is being conducted to evaluate the efficacy and safety of the combination of paclitaxel and RS5614 in patients with cutaneous angiosarcoma who are refractory to paclitaxel.
In April 2023, we concluded an agreement on comprehensive research collaboration with Hiroshima University. This clinical trial has been conducted under the support of Hiroshima University Renascience Open Innovation Labo (HiREx) and the Clinical Research Center in Hiroshima. This project can bring the new second-line treatment for angiosarcoma, currently with no effective therapeutics.