HUYA Bioscience International, the leader in accelerating the global development of China's pharmaceutical innovations, announced today the Ministry of Health, Labour and Welfare (MHLW) granted HBI-8000 orphan drug designation (ODD) in Japan as monotherapy for relapsed or refractory Adult T-cell Leukemia-Lymphoma or (ATL). HBI-8000 already has ODD in Japan for peripheral T-cell lymphoma (PTCL).

ATL is caused by latent infection of the human t-cell leukaemia virus type 1 or HTLV-1 and is endemic in Japan with up to one million carriers and a disease incidence estimated at 0.05-0.10%. There are approximately 2,000 patients and as many as 700 - 1,000 deaths reported each year. It is primarily a disease of the elderly with poor prognosis, the three-year survival rate in aggressive ATL after chemotherapy is 25% and few effective treatment options other than allogeneic bone marrow transplantation and high dose chemotherapy in a subset of eligible patients.

"Effective treatment options for relapsed or refractory (R/R) aggressive ATL are very limited and the designation of ODD status recognizes the need for a new treatment for this difficult-to-manage disease, I hope that development of HBI-8000 could be accelerated with the ODD," said Dr. Kunihiro Tsukasaki, MD PhD, Principal Investigator of HBI-8000 clinical study & Professor, Department of Hematopoietic Tumor, Saitama Medical University, International Medical Center.

HBI-8000 is an epigenetic immunomodulator approved for the treatment of lymphoma and metastatic breast cancer in China. This oral agent targets class I histone deacetylase (HDAC) and suppresses the expression of the viral oncogene HTLV-I bZIP factor, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) and the inflammasome in ATL cells. Furthermore, HBI-8000 may induce latent viral antigen expression making ATL cells more sensitive to immune cytotoxicity targeting viral antigens. This is a novel mechanism of action and does not overlap with currently available drugs. Recent clinical studies conducted by HUYABIO in Japan suggest clinical efficacy of HBI-8000 in this rare disease setting of R/R aggressive ATL.

"The orphan drug designation of HBI-8000 recognizes the potential of this agent to meet an important unmet medical need and ATL is a critical public health issue in Japan," said Dr. Mireille Gillings, CEO & Executive Chair of HUYABIO. "The designation is appropriate for this rare malignancy, which afflicts an elderly population with such devastating effects. We are now preparing an application to the PMDA for approval of HBI-8000 as monotherapy for the treatment for R/R ATL."