HUYA Bioscience International Announces Epigenetic Breast Cancer Program

Expansion marked by clinical development for multiple HER2 subtypes of breast cancer

San Diego, CA, USA – September 3, 2015 –HUYA Bioscience International (HUYA) today announced expanding clinical trials with its lead cancer drug, HBI-8000, starting with a Phase 1 combination trial in support of a breast cancer program to be conducted in the United States.

HBI-8000 is a novel class I-selective oral histone deacetylase (HDAC) inhibitor which will be among the first to be included in a clinical trial involving HER-2 positive advanced or metastatic cancer patients.

The inclusion of HBI-8000 combination therapy for breast cancer as a potential target is a logical extension of the drug’s clinical development since it is currently in Phase 1 in Japan for Non-Hodgkin’s Lymphoma, has been in several other clinical trials involving solid tumors and is now marketed in China as Epidaza for the treatment of PTCL.

HUYA reached agreement with Quantum Leap Healthcare Collaborative to obtain the I-SPY (Investigation of Serial Studies to Predict Your Therapeutic Response with Imaging and Molecular Analysis) Phase 1 trial synopsis. HUYA will now conduct a clinical study to establish safety, tolerability and recommended dose for investigational agents in combination with a taxane-based chemotherapy ( paclitaxel) and the targeted therapy Herceptin® (trastuzumab) for Human Epidermal growth factor Receptor 2-positive (HER2+) metastatic cancer.

“This is an important step in the global development of this promising oral molecule as a combination therapy in solid tumors,” said Mireille Gillings, Ph.D., CEO of HUYA. “What makes this line of investigation particularly interesting is the potential for an additional mode of action in the form of the immunomodulatory effects shown to be mediated by HBI-8000.”

HBI-8000 inhibits tumor growth via multiple mechanisms of action, including epigenetic regulation of tumor cell division and apoptosis, immune effects such as activation of NK and CD8 T-cell-mediated antitumor activity, as well as repression of genes associated with drug resistance. Under the Tripartite Cooperation on Health between China, South Korea and Japan and given the recent approval of the drug for the treatment of PTCL in China, HUYA launched development of HBI-8000 in Japan and is now completing the first Phase 1 clinical trial in patients with NHL. The Company plans to begin a Phase 2 registration trial in 2016 based on the Pharmaceutical and Medical Devices Agency’s (PMDA) acceptance of HUYA’s accelerated development strategy for Japan.

About Breast Cancer
An estimated 231,840 new cases of invasive breast cancer are expected to be diagnosed among women in the U.S. during 2015; about 2,350 new cases are expected in men. Excluding cancers of the skin, breast cancer is the most frequently diagnosed cancer in women. Sixty-one percent of breast cancer cases are diagnosed at a localized stage (no spread to lymph nodes, nearby structures or other locations outside the breast), for which the five-year relative survival rate is 99 percent. If the cancer has spread to tissues or lymph nodes under the arm (regional stage), the survival rate is 85 percent. If the spread is to lymph nodes around the collarbone or to distant lymph nodes or organs (distant stage), the survival rate falls to 25 percent.

About HBI-8000
HBI-8000 is a member of the benzamide class of histone deacetylase (HDAC) inhibitors designed to block the catalytic pocket of Class I HDACs. HBI-8000 is an orally bioavailable, low-nanomolar inhibitor of cancer-associated HDAC enzymes with favorable pharmacology and safety profiles. HBI-8000 inhibits cancer-associated Class I HDAC1, HDAC2, HDAC3, as well as Class IIb HDAC10 at nanomolar concentrations and stimulates accumulation of acetylated histones H3 and H4 in tumor cells. Studies with human-derived tumor cell lines have demonstrated that HBI-8000 inhibits the growth of many tumor cell lines via multiple mechanisms of action, including epigenetic regulation of tumor cell growth and apoptosis, immunomodulatory effects such as activation of NK- and CD8 T-cell-mediated antitumor activity, as well as repression of genes associated with drug resistance. To date, HBI-8000 has been dosed in various types of hematological and solid tumors in several clinical trials, including a Phase 1 trial completed in the United States.

About HUYA Bioscience International
HUYA Bioscience International is a leader in enabling and accelerating the global development of novel biopharmaceutical product opportunities originating in China. HUYA has established extensive collaborations with Chinese biopharmaceutical, academic and commercial organizations to speed development and value creation in worldwide markets for China-sourced product candidates. With the largest Chinese compound portfolio covering all therapeutic areas, HUYA has emerged as the partner-of-choice for building and maximizing the value of biopharmaceutical innovation in China. HUYA has offices in the U.S., Japan and eight strategic locations across China, with joint headquarters in San Diego and Shanghai. With the largest team of scientists working with Chinese innovators, HUYA identifies and advances promising drug candidates globally. Earlier this year, HUYA was named the winner of a Stevie® Award in the Health Products & Services and Pharmaceuticals category in the Asia-Pacific Stevie Awards. www.huyabio.com

Contact Details:
Yiota Merianos
HUYA Corporate Communications
+1.858.353.1217
ymerianos@huyabio.com