Inmagene and Kissei Enter into an Exclusive License Agreement for Fostamatinib in China

SHANGHAI andSAN DIEGO and NAGANO,Japan,Aug. 5,2021 -- Inmagene Biopharmaceuticals ("Inmagene") and Kissei Pharmaceutical Co.,Ltd. ("Kissei") announced today that they have entered into an exclusive license agreement for the development and commercialization of fostamatinib in mainland China,Hong Kong and Macau.

Under the terms of the agreement,Inmagene will obtain exclusive rights to develop and commercialize fostamatinib in all potential indications in China. In return,Kissei will receive an upfront payment and milestone payments based on the progress of development and commercialization.

"Fostamatinib should greatly benefit Chinese ITP patients and is a valuable addition to our portfolio," said Jonathan Wang,Inmagene's Chairman and CEO. "Inmagene will bring fostamatinib to China via an accelerated development and registration pathway. We are delighted to collaborate with Kissei,a highly reputable company."

About Fostamatinib

Fostamatinib is the first and only spleen tyrosine kinase (SYK) inhibitor indicated for the treatment of chronic immune thrombocytopenia (ITP) in adult patients who have had an insufficient response to a previous treatment. SYK is a key signaling member in the immune process that leads to platelet destruction in ITP. Unlike other therapies that modulate the immune system in different ways or stimulate platelet production,fostamatinib may address an underlying autoimmune cause of ITP by impeding platelet destruction.

Discovered and developed by Rigel Pharmaceuticals,a biotech company in South San Francisco,fostamatinib has been approved in the US,Europe and Canada. In October 2018,Kissei acquired the development and commercialization rights for fostamatinib in Japan,the Greater China and Korea from Rigel.

About ITP

In patients with ITP,the immune system attacks and destroys the body's own blood platelets,which play an active role in blood clotting and healing. ITP accounts for about one-third cases of total bleeding disorders. The adult annual incidence rate in China is approximately 5-10 per 100,000 population.

Common symptoms of ITP are excessive bruising and bleeding. People suffering with chronic ITP may live with an increased risk of severe bleeding events that can result in serious medical complications or even death. Current therapies for ITP include steroids,blood platelet production boosters (TPOs) and splenectomy. However,not all patients respond to existing therapies. As a result,there remains a significant medical need for additional treatment options for patients with ITP.

About Inmagene

Inmagene,with wholly owned subsidiaries in San Diego,Shanghai,Hangzhou and Wuhan,is a leading biotech company focused on developing therapeutics for immunology-related diseases. Believing in "borderless innovation",the Inmagene team integrates efficient resources worldwide to make such therapeutics available to patients globally.

The company is building a robust pipeline of nearly 20 drug candidates. Izokibep (IMG-020),Inmagene's most advanced drug candidate,is entering the global phase 2 or 3 trials for multiple indications.

Inmagene has formed strategic partnerships with Affibody AB and HUTCHMED (Nasdaq/AIM: HCM) to develop and commercialize highly innovative drug candidates. Inmagene is operating 12 "Smart Innovation" programs to create and develop novel drug candidates for the global market. It also in-licenses clinical stage products and,together with its partners,carries out global development activities,including multi-center clinical trials.

For more details about Inmagene,please visit www.inmagenebio.com

About Kissei

Under the management philosophy "contribute to society through high-quality,innovative pharmaceutical products" and "serve society through our employees",Kissei provides unique innovative pharmaceutical products for patients in the world. A drug discovery and R&D-oriented company,Kissei has a special focus on urology,nephrology,dialysis,diabetes,gastroenterology and rare diseases.

For more details about Kissei,please visit www.kissei.co.jp