• The collaboration of lasofoxifene (HLX78) between Henlius and Sermonix now include all of Asia

• Sermonix and Henlius will subsequently engage with PMDA and collaborate on expedited co-development of oral lasofoxifene in Japan

• IND approval in China allows Shanghai Henlius Biotech to enroll ELAINE-3 trial patients in China

SHANGHAI, China - June 7, 2024 - Shanghai Henlius Biotech, Inc. (2696.HK) has expanded its license from Sermonix Pharmaceuticals Inc., a privately held biopharmaceutical company developing innovative therapeutics to specifically treat metastatic breast cancers (mBC), to add additional Asia territories for HLX78 (oral lasofoxifene). The agreement also allows Henlius to share with Sermonix expedited co-development of HLX78 in Japan. Sermonix has completed a Phase 1 Japanese PK study and, together with Henlius, will begin engagement with the Pharmaceuticals and Medical Devices Agency (PMDA) to address a regulatory path in Japan.

Last month, Henlius announced that China’s National Medical Products Administration (NMPA) approved the investigational new drug application (IND) for HLX78 (oral lasofoxifene). The IND approval allows Henlius to join the ongoing global registrational ELAINE-3 trial with responsibility in China. ELAINE-3 (NCT05696626), the third Evaluation of Lasofoxifene in ESR1 Mutations (ELAINE) trial, is assessing the efficacy of oral lasofoxifene and a CDK4/6 inhibitor in 400 pre- and post-menopausal subjects with locally advanced or metastatic ER+/HER2- breast cancer with an ESR1 mutation.

 “The collaboration between Henlius and Sermonix started in January 2024,” Ms. Ping Cao, Chief Business Development Officer, and SVP of Business Development of Henlius, said, “In mere months from agreement to amendment, our unified dedication shines, turning swift collaboration and full-hearted implementation into tangible success - as underscored by our product's IND approval in China."

“With active ELAINE-3 enrollment already underway in the U.S., Canada, EU and Israel, we are pleased to announce that Sermonix and Henlius, our Chinese development partner for oral lasofoxifene, received approval for its investigational new drug application,” said Dr. David Portman, Sermonix founder and chief executive officer. “This milestone clears Henlius to enroll patients in ELAINE-3 in China, therefore further diversifying our patient population and potentially helping more people to better confront this terrible disease.”

HLX78 (Oral lasofoxifene) is an investigational novel targeted endocrine therapy in clinical development that has demonstrated robust target engagement as an ESR1 antagonist in the breast, particularly in the presence of ESR1 mutations.

In two completed Phase 2 clinical studies (ELAINE-1 and ELAINE-2), lasofoxifene demonstrated anti-tumor activity against tumors with ESR1 mutations as a monotherapy and in combination with a CDK4/6 inhibitor. Lasofoxifene’s bioavailability and potent activity in mutations of the estrogen receptor, in addition to its potential to improve sexual and urogenital health with a well-tolerated profile, could hold promise for patients who have acquired endocrine resistance due to ESR1 mutations, and, if approved, play a critical role in the precision medicine treatment of advanced ER+ breast cancer.

Breast cancer is the second most diagnosed cancer in the world, according to GLOBOCAN 2022. There were around 2.3 million new cases of breast cancer in 2022 globally, including more than 357,000 in China.1 ER+ breast cancer comprises 60-70% of all breast cancers.2 Endocrine therapy remains the mainstay treatment for ER+ breast cancer and the most widely used class of aromatase inhibitor (AI) has been recommended by the National Comprehensive Cancer Network (NCCN) and Chinese Society of Clinical Oncology (CSCO) guidelines to be the adjuvant and first-line standard of care for patients with ER+/HER2- breast cancer.3,4 However, almost all patients treated with AIs in the advanced setting develop resistance5, with ESR1 mutations being one of the most prevalent alterations, present in up to 40% of patients and a significant mechanism of resistance to endocrine therapy6. Currently, there are limited treatment options for ER+/HER2- breast cancer with ESR1 mutations, and thus a large clinical need exists.

【Reference】

[1] Sung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A, Bray F. Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and MortalityWorldwide for 36 Cancers in 185 Countries. CA Cancer J Clin. 2021 May;71(3):209-249.

[2] Ignatiadis M, Sotiriou C. Luminal breast cancer: from biology to treatment[J]. Nat Rev Clin Oncol, 2013, 10(9): 494-506. doi: 10.1038/nrclinonc.2013.124.

[3] 《中国临床肿瘤学会（CSCO）乳腺癌诊疗指南2023》

[4] NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Breast Cancer V.5.2023

[5] Rozeboom B, Dey N, De P. ER+ metastatic breast cancer: past, present, and a prescription for an apoptosis-targeted future. Am J Cancer Res. 2019;9(12):2821-2831. Published 2019 Dec 1.

[6] Spoerke JM, Gendreau S, Walter K, et al. Heterogeneity and clinical significance of ESR1 mutations in ER-positive metastatic breast cancer patients receiving fulvestrant. Nat Commun. 2016;7:11579. Published 2016 May 13. doi:10.1038/ncomms11579

About Sermonix

Sermonix Pharmaceuticals Inc. is a privately held biopharmaceutical company focused on the development of female-specific oncology products and is currently undertaking a Phase 3 clinical studies of lasofoxifene, its lead investigational drug. The Sermonix management team, led by founder Dr. David Portman, has significant experience in all stages of the drug development, regulatory and commercialization processes in the breast cancer drug development arena. Learn more at SermonixPharma.com. To learn more about the ELAINE studies, visit DiscoverElaine.com.