Until now, cancer treatment has been focused on three main areas: drug therapy, surgery (surgery), and radiation therapy. In addition to those, a therapeutic method (immunotherapy) that originally enhances the function of human immunity against cancer has been found in recent years, and immune checkpoint inhibitors have been used clinically.
Cancer cells create barriers (such as PD-L1) to prevent attacks from immune cells. Immune checkpoint inhibitors are antibody drugs that block the barriers and activate the immune cells (T cells) that can attack the cancer.
Immune checkpoint drugs are effective for many types of cancer as well as advanced cancers, but the problem is that single drugs are not effective enough. In addition, since it is an antibody drug, there are also issues such as its inability to be administered orally, difficulty in treating solid cancer (hard to reach inside the cancer), side effects, and high cost.
RS5614, which we are developing, is a small molecule drug that can be administered orally. Co-administration of RS5614 with an immune checkpoint inhibitor has shown that tumor size in mouse models of malignant melanoma is significantly reduced. When it is used in cancer patients in combination with immune checkpoint inhibitors, a stronger cancer reduction effect is expected.
We are preparing a Phase II study (investigators-initiated clinical trial) to confirm the therapeutic effects and side effects of RS5614 in patients with inoperable refractory malignant melanoma (Planning to include Tohoku University, University of Tsukuba, Kyoto University, Kagoshima University, Tokyo Metropolitan Komagome Hospital, etc.).