Antengene Announces Acceptance of IND Application in China for the Phase II Clinical Trial of Single-Agent Selinexor for the Treatment of Myelofibrosis (MF)

SHANGHAI and HONG KONG,July 6,2021 -- Antengene Corporation Limited ("Antengene",SEHK: 6996.HK),a leading innovative biopharmaceutical company dedicated to discovering,developing and commercializing global first-in-class and/or best-in-class therapeutics in hematology and oncology,recently announced that China's National Medical Products Administration (NMPA) has accepted the Investigational New Drug (IND) application for single agent selinexor,a first-in-class orally available Exportin 1 (XPO1) inhibitor,for the treatment of patients with myelofibrosis (MF) in China.

MF is a clonal hematologic neoplasm which can emerge either as primary MF,polycythemia vera (PV) or essential thrombocythemia (ET)[1]. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is currently the only curative treatment for MF. However,such treatment is difficult to carry out and has a low rate of success. According to the National Comprehensive Cancer Network (NCCN®) Guidelines for the Treatment of MF,patients with intermediate-2 or high-risk MF ineligible for allo-HSCT and with a platelet count of ≥50×109/L should be treated with ruxolitinib or fedratinib,while there are few follow-on treatment alternatives for patients failed or resistant to ruxolitinib. At present,only ruxolitinib has been approved for clinical treatment in China,and as a result,MF remains a disease with limited treatment options,representing an urgent unmet medical need.

This randomized,open-label,multicenter Phase II study is designed to evaluate the safety and efficacy of selinexor versus physician's choice (PC) in patients with MF who had at least six months of treatment with a JAK1/2 inhibitor. Approximately 112 patients with MF from 75 trial centers across the world will be randomized in a 1:1 ratio into one of the two treatment arms.

"This acceptance by the NMPA of the IND application for the China study of selinexor in patients with MF marks another major step forward in our effort to develop selinexor into a novel cancer drug. It also paves the way for our on-going exploration of additional indications for Antengene's novel assets," said Dr. Jay Mei,Founder,Chairman and CEO of Antengene. "We are hopeful that,through this novel drug candidate with strong potential in this disease,coupled with our deep expertise in the field of hematologic malignancies,we will be able to bring renewed hope to patients with MF in China. Moving forward,we will work closely with the NMPA to advance this trial in China,and strive to bring this innovative therapeutic to patients in the region and beyond."

About Selinexor (XPOVIO®)

Selinexor is a first-in-class oral selective inhibitor of nuclear export (SINE) compound discovered and developed by Karyopharm Therapeutics Inc. (NASDAQ: KPTI),Selinexor is currently being developed by Antengene,which has the exclusive development and commercial rights in certain Asia-Pacific markets,including Greater China,South Korea,Australia,New Zealand and the ASEAN countries.

In July 2019,the US Food and Drug Administration (FDA) approved selinexor in combination with low-dose dexamethasone for the treatment of relapsed/refractory multiple myeloma (RRMM) and in June 2020 approved selinexor as a single-agent for the treatment of relapsed/refractory diffuse large B-cell lymphoma (RR DLBCL). In December 2020,selinexor also received FDA approval as a combination treatment for multiple myeloma after at least one prior therapy. In February 2021,selinexor was approved by the Israeli Ministry of Health for the treatment of patients with RRMM or RR DLBCL and in March 2021,the European Commission (EC) has granted conditional marketing authorization for selinexor (NEXPOVIO) for the treatment of adult patients with RRMM.

Selinexor is so far the first and only oral SINE compound approved by the FDA and is the first drug approved for the treatment of both MM and DLBCL. Selinexor is also being evaluated in several other mid-and later-phase clinical trials across multiple solid tumor indications,including liposarcoma and endometrial cancer. In November 2020,at the Connective Tissue Oncology Society 2020 Annual Meeting (CTOS 2020),Antengene's partner,Karyopharm,presented positive results from the Phase III randomized,double blind,placebo controlled,cross-over SEAL trial evaluating single agent,oral selinexor versus matching placebo in patients with liposarcoma. Karyopharm also announced that the ongoing Phase III SIENDO trial of selinexor in patients with endometrial cancer passed the planned interim futility analysis and the Data and Safety Monitoring Board (DSMB) recommended the trial should proceed as planned without any modifications. Top-line SIENDO trial results are expected in the second half of 2021.

Antengene is currently conducting five late-stage clinical trials of selinexor for the treatment of MM,DLBCL,non-small cell lung cancer,and peripheral T and NK/T-cell lymphoma. Furthermore,Antengene has submitted New Drug Applications (NDAs) for selinexor in multiple Asia-Pacific markets including China,and Singapore,and was granted the Priority Review status by China's NMPA and an Orphan Drug Designation by the Ministry of Food and Drug Safety of South Korea (MFDS).

About Antengene

Antengene Corporation Limited ("Antengene",SEHK: 6996.HK) is a leading clinical-stage R&D driven biopharmaceutical company focused on innovative medicines for oncology and other life threatening diseases. Antengene aims to provide the most advanced anti-cancer drugs to patients in the Asia-Pacific Region and around the world. Since its establishment in 2017,Antengene has built a broad and expanding pipeline of clinical and pre-clinical stage assets through partnerships as well as in-house drug discovery,and obtained 15 investigational new drug (IND) approvals and submitted 5 new drug applications (NDA) in multiple markets in Asia Pacific. Antengene's vision is to "Treat Patients Beyond Borders". Antengene is focused on and committed to addressing significant unmet medical needs by discovering,developing and commercializing first-in-class/best-in-class therapeutics.

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[1] J. Mascarenhas,B.K. Marcellino,M. Lu,M. Kremyanskaya,F. Fabris,L. Sandy,M. Mehrotra,J. Houldsworth,V. Najfeld,S. El Jamal,B. Petersen,E. Moshier,R. Hoffman,A phase I study of panobinostat and ruxolitinib in patients with primary myelofibrosis (PMF) and post-­polycythemia vera/essential thrombocythemia myelofibrosis (post-­PV/ET MF).