Yisheng Biopharma and Tavotek Biotherapeutics Announce Strategic Research Alliance for Development of YS-ON-001/002 and Tavo-301/303 Combination Therapy for Cancer Treatment

GAITHERSBURG,Md. andAMBLER,Pa.,Jan. 6,2020 --Yisheng Biopharma Co.,Ltd.("Yisheng Biopharma"),a biopharmaceutical company focusing on research,development,manufacturing,sales and marketing of immunological biologics and vaccines,and Tavotek Biotherapeutics,a biotech company focusing on novel multi-specific antibodies in immuno-oncology and autoimmune diseases,announced today that the companies have entered into a strategic research alliance and collaborate in the development involving their lead assets in oncology. The objective of the alliance is to co-develop a combination therapy of YS-ON-001/002 and Tavo-301/303 for cancer treatment. The two companies are also in discussions regarding additional research and development collaborations beyond oncology.

"We are excited to collaborate with Tavotek,which has a rich pipeline of multi-specific antibodies and advanced technology platforms in oncology and other therapeutic areas," commentedDr. David Shao,President and Chief Executive Officer of Yisheng Biopharma. "As potent agonists of TLR3,MDA5 and RIG-I pathways,YS-ON-001 and YS-ON-002 have demonstrated promising effects in activating the innate and adaptive immune systems and modulating the tumor microenvironment,and YS-ON-001 has shown an excellent safety profile with clinical data to date. By combining YS-ON-001/002 with multi-specific antibodies directed against tumors,we are well positioned in developing a first-in-class immunotherapy with potentially higher response rates. We look forward to working with the Tavotek team to explore the potential synergy of YS-ON-001/002 and Tavo-301/303."

"The collaboration with Yisheng aligns with Tavotek's mission to develop life-changing therapies for patients with significant unmet medical need," saidDr. Mann Fung,Chief Executive Officer of Tavotek. "Current immuno-oncology approaches such as PD1/PDL1 antibody achieve only approximately 20 to 30 percent response rates in clinical settings. A majority of cancer patients still are not seeing a benefit from current therapies. We believe a combination regimen of YS-ON-001/002 with multi-specific IO antibodies,such as Tavo-301/303,will have beneficial impact on cancer care."

YS-ON-001 and YS-ON-002areimmunotherapeutic productsbased on the TLR3/RIG-I/MDA-5 signaling pathways of PIKA® immunomodulating technology. They arecapable of both reducing the immunosuppressive effect of tumor microenvironment and enhancing the anti-tumor function of the immune system to tumor cells. YS-ON-001 is currently in clinical development in China and Singapore,and has received orphan drug designations from the U.S. FDA for treatment of pancreatic and liver cancers. The product has been approved in Cambodia for the treatment of advanced solid tumors. YS-ON-002 is a clinical candidate ready for IND submission. YS-ON-001/002 can be an integral immunotherapy component with standard of oncology care,such as chemotherapies,targeted therapies and checkpoint inhibitors or with emerging immunotherapies for additive or synergistic treatment benefits.

Tavo-301/303 is a series of novel multi-specific antibody-based Immuno-Oncology assets that was developed using Tavotek's proprietary TavoSelect™ Platform. Novel protein engineering employing TavoSelect™ technology generates multi-specific biologics with optimal molecular profiles for targeting multiple relevant epitopes simultaneously to manage difficult-to-treat solid tumors. These biologics modulate the immunosuppressive pathway by multiple mechanisms of action to promote anti-tumor response and efficacy. The TavoSelec™ technology also provides biologic molecules with favorable pharmacokinetic profiles and stable formats for ease of development and manufacturing.

About Yisheng Biopharma Co.,Ltd.

Yisheng Biopharma is a fully integrated biopharmaceutical company with a global footprint that is discovering,developing and commercializing innovative biotherapeutics for cancer and infectious disease using its novel PIKA® immunomodulating technology. PIKA technology augments both innate and adaptive immune responses through the TLR3,RIG-I and MDA5 pathways. Products in clinical development include YS-ON-001 for the treatment of advanced solid tumors,YS-HBV-001 hepatitis B vaccine,and the PIKA rabies vaccine for accelerated protection against rabies infection. The Company has two marketed products in China and South Asia market. Yisheng Biopharma is headquartered in Beijing and has approximately 500 employees in China,U.S.,Singapore and other countries in Asia. For more information on Yisheng,please visit www.yishengbio.com.

About PIKA Technology

Proprietary PIKA technology originated from research in a class of well-defined synthetic dsRNA molecules. Endosomal dsRNA can be recognized by TLR3 while cytosolic dsRNA can be sensed by the RIG-I-like receptor family which include RIG-I and MDA-5. Through TLR3,RIG-I and MDA-5 signaling,PIKA technology can induce prompt production of interferon,cytokines,chemokines and costimulatory factors. The antiviral and antitumor effects of interferon have been well established. Production of type I interferon upon PIKA administration facilitates antigen cross-presentation by dendritic cells and augments CD4+ T-cell,CD8+ T-cell and natural killer cell responses,which makes PIKA-based therapeutics suitable for both antiviral and antitumor applications.

About Tavotek

Tavotek is a biopharmaceutical company focused on discovering,acquiring,developing,and commercializing therapeutic medicines for patients suffering from debilitating diseases with significant unmet medical need. Tavotek has a rich pipeline of product candidates in various stages of development,focused on cancers,autoimmune conditions,and infectious diseases. For more information,please visit www.tavotek.com

About TavoSelect™Platform

The TavoSelect™ Platform offers highly diversified human antibody sequences that can be utilized in different formats: VHH,scFv,IgG,multi-specific antibodies,fusion proteins,and the engineering of host defense cell surface receptors.TavoSelect™ of leads emphasize creative screening procedures,NGS analyses,and utilization of proprietary AI software to capture and optimize the best candidates rapidly.The efficiency of the TavoSelect™ Platform generates novel diverse therapeutic biologic molecules and medical diagnostics for patients.

Yisheng Contact:

Solebury Trout

Rich Allan (media)

Tel: +1 646-378-2958

Email: rallan@soleburytrout.com

Bob Ai (investors)

Tel +1 646-378-2926

Email: bai@soleburytrout.com

Tavotek Contact:

Wei Zhang,Investors and Media

Tel: +1 267-405-9426

Email: info@tavotek.com