Antengene Announces Submission of IND Application in China for a Global Phase 3 Trial of ATG-010 (Selinexor) in Advanced or Recurrent Endometrial Cancer

Antengene Corporation Limited, 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, announced that it submitted an Investigational New Drug (IND) application to the National Medical Products Administration (NMPA) for ATG-010 (selinexor) in the treatment of Endometrial Cancer. This is a global Phase 3, multicenter, randomized, double-blind trial (SIENDO) aiming to evaluate the efficacy of ATG-010 compared to placebo as maintenance therapy in patients with advanced or recurrent endometrial cancer after combination chemotherapy and is being conducted at approximately 80 investigative sites around the world, including North America, Europe and Asia.

Endometrial cancer is the most common cancer of the female reproductive tract and for patients who progress following initial chemotherapy there are limited treatment options with poor prognosis. The highest incidence rates are reported in developed countries and some economically developed areas of China. In recent years, with an increase in the prevalence of obesity, diabetes and hypertension, the incidence and mortality rate of endometrial cancer has been increasing with a trend towards younger women.

ATG-010 is a first-in-class and only-in-class oral selective inhibitor of nuclear export, developed by Antengene and Karyopharm Therapeutics Inc. (NASDAQ: KPTI). It has been approved by the US Food and Drug Administration (FDA) for use in both multiple myeloma and diffuse large B-cell lymphoma, which are two major indications in hematological malignancies. In addition, the Phase 3 SIENDO trial of ATG-010 in patients with endometrial cancer has passed the planned interim futility analysis and the Data and Safety Monitoring Board (DSMB) recommended the trial should proceed as planned without any modification.

"The positive data of the Phase 3 SEAL trial in liposarcoma and the ongoing Phase 3 SIENDO trial in endometrial cancer which just passed the interim analysis have suggested substantial potential of ATG-010 across multiple solid tumors. Filing an IND with the NMPA in China is an important step in the clinical development of ATG-010 as we expect to explore additional therapeutic areas of our novel oral drug candidate," said Dr. Jay Mei, Founder, Chairman and CEO of Antengene. "We look forward to initiating the Phase 3 global trial in patients with advanced or recurrent endometrial cancer in China, to provide Chinese patients with better treatment options."

Professor Qi Zhou from the Gynecological Oncology Center of Chongqing University Cancer Hospital, the leading clinical investigator, said: "R&D capability in China has improved significantly in recent years. There are more innovative anti-tumor drugs moving towards clinical research and commercialization, and they are widely used in clinical practice. The emergence of targeted and immunotherapy drugs effectively improved the prognosis of patients. I look forward to advancing the research of ATG-010, a first-in-class selective nuclear export inhibitor, with Antengene, to improve the effect and increase the accessibility of treatment, so that patients can benefit from clinical results as soon as possible."

About ATG-010 (selinexor, XPOVIO®)

ATG-010 (selinexor, XPOVIO®), a first-in-class and only-in-class oral selective inhibitor of nuclear export compound discovered and developed by Karyopharm, is currently being developed by Antengene, which has the exclusive development and commercial rights in certain Asia-Pacific markets, including the Greater China, South Korea, Australia, New Zealand and the ASEAN countries. In July 2019, the US Food and Drug Administration (FDA) approved ATG-010 in combination with low-dose dexamethasone for the treatment of relapsed/refractory multiple myeloma (rrMM) and in June 2020 approved ATG-010 as a single-agent for the treatment of relapsed/refractory diffuse large B-cell lymphoma (rrDLBCL). A Marketing Authorization Application (MAA) has also been submitted to the European Medicines Agency (EMA) with a request for conditional approval of ATG-010 in this same rrMM indication. On December 18, 2020, the supplemental New Drug Application (sNDA) requesting an expansion of its indication to include the treatment for patients with multiple myeloma after at least one prior therapy was approved by the FDA. ATG-010 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. ATG-010 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 3 randomized, double blind, placebo controlled, cross-over SEAL trial evaluating single agent, oral ATG-010 versus matching placebo in patients with liposarcoma. Karyopharm also recently announced that the ongoing Phase 3 SIENDO trial of ATG-010 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 conducting two registrational Phase 2 clinical trials of ATG-010 in China for relapsed/refractory multiple myeloma (MARCH) and for relapsed/refractory diffuse large B-cell lymphoma (SEARCH), and has initiated clinical trials for high prevalence cancer types in the Asia Pacific region including peripheral T-cell lymphoma and NK/T-cell lymphoma (TOUCH) and KRAS-mutant non-small cell lung cancer (TRUMP).

About Antengene

Antengene Corporation Limited ("Antengene", SEHK: 6996.HK) is a leading clinical-stage Asia-Pacific biopharmaceutical company focused on innovative oncology medicines. Antengene aims to provide the most advanced anti-cancer drugs to patients in China, the Asia Pacific Region and around the world. Since its establishment, Antengene has built a pipeline of 12 clinical and pre-clinical stage assets and obtained 11 investigational new drug approvals in Asia Pacific. The vision of Antengene is to "Treat Patients Beyond Borders". Antengene aims to address significant unmet medical needs by discovering, developing and commercializing first-in-class/best-in-class therapeutics.