OBP-801 is a histone deacetylase (HDAC) inhibitor, having specific and strong activity on HDAC, which is expected to show anticancer effect by promoting an expression of tumor suppressor genes in cancer cell and inducing apoptotic and autophagic cell death.
The results of pre-clinical studies on OBP-801 indicated the most potent HDAC inhibitory activity as compared to other HDAC inhibitors including and Zolinza® and Istodax®, and its efficacy on a wide range of cancers is expected.
Furthermore, Oncolys has been exploring the potential ophthalmic use of OBP-801 in collaboration with Kyoto Prefectural University of Medicine.


Target indication

Lung cancer, lymphoma, kidney cancer, and glaucoma

Current status

We concluded a worldwide exclusive license agreement with Astellas Pharma Inc. on October 2009 to develop, manufacture and commercialize OBP-801.
After completion of preclinical and CMC works, we filed an IND to the US FDA in 2014 and have been conducting phase 1 clinical study for solid tumor.
For the ophthalmic use, we initiated to explore the possibility of using OBP-801 as an alternate drug of mitomycin C in glaucoma operation in collaboration with Kyoto Prefectural University of Medicine.


The novel HDAC inhibitor OBP-801/YM753 enhances the effects of 5-fluorouracil with radiation on esophageal squamous carcinoma cells.

Furutani A, Sowa Y, Fujiwara H, Otsuji E, Sakai T.
Oncol Res. 2014;21(5): 281-286. doi:, 2014

A novel HDAC inhibitor OBP-801 and a PI3K inhibitor LY294002 synergistically induce apoptosis via the suppression of survivin and XIAP in renal cell carcinoma.

Yamada T, Horinaka M, Shinnoh M, Yoshioka T, Miki T, Sakai T.
013 Oct;43(4): 1080-1086. doi: 1, 2013

Combination of a novel HDAC inhibitor OBP-801/YM753 and a PI3K inhibitor LY294002 synergistically induces apoptosis in human endometrial carcinoma cells due to increase of Bim with accumulation of ROS.

Yoshioka T, Yogosawa S, Yamada T, Kitawaki J, Sakai T.
2013 May;129(2): 425-32. doi:, 2013

YM753, a novel histone deacetylase inhibitor, exhibits antitumor activity with selective, sustained accumulation of acetylated histones in tumors in the WiDr xenograft model.

Shindoh N, Mori M, Terada Y, Oda K, Amino N, Kita A, Taniguchi M, Sohda KY, Nagai K, Sowa Y, Masuoka Y, Orita M, Sasamata M, Matsushime H, Furuichi K, Sakai T.
2008 Mar;32(3): 545-55, 2008