Menarini Group and SciClone Pharmaceuticals Announce Exclusive Sub-Licensing Collaboration to Develop and Commercialize ORSERDU® (Elacestrant) in China to Address Advanced or Metastatic Breast Cancer

• ORSERDU is the first treatment specifically approved for patients with ER+, HER2- advanced or metastatic breast cancer tumors that harbor ESR1 mutations, representing the first innovation in endocrine therapy in nearly 20 years.
• ESR1 mutations are present in up to 40% of ER+, HER2- advanced or metastatic breast cancers, and are a known driver of resistance to standard endocrine therapy, making these tumors more difficult to treat.
• This agreement includes undisclosed upfront, milestone payments and sales royalties.

FLORENCE, Italy and HONG KONG, Nov. 7, 2023 /PRNewswire/ -- The Menarini Group ("Menarini"), a leading international pharmaceutical and diagnostics company, and SciClone Pharmaceuticals (Holdings) Ltd. ("SciClone"), an international biopharmaceutical company, today announced that they have entered into an exclusive sub-licensing agreement to develop and commercialize ORSERDU® (elacestrant) in the People's Republic of China (China), in an effort to expand treatment options for appropriate metastatic breast cancer (mBC) patients.

ORSERDU, a once-daily oral endocrine monotherapy, for the treatment of postmenopausal women or adult men, with ER+, HER2-, ESR1-mutated advanced or metastatic breast cancer with disease progression following at least one line of endocrine therapy, was approved by the U.S. Food and Drug Administration in January 2023 under its priority review and fast track designation. In September 2023, ORSERDU was approved by the European Commission. Stemline Therapeutics, a wholly-owned subsidiary of the Menarini Group, focused on bringing transformational oncology treatments to cancer patients, commercializes ORSERDU in the U.S. and E.U.

Under the Sub-Licensing agreement, SciClone will pursue the development and registration of ORSERDU in China and commercialise ORSERDU upon its regulatory approval in China.

"Patients living with metastatic breast cancer need effective and tolerable options," said Elcin Barker Ergun, CEO of the Menarini Group. "We are proud to partner with SciClone in an effort to register a new breast cancer treatment for patients in China that can offer efficacy in a once-daily pill."

Approximately 70% of breast cancer cases are ER+, HER2-, and up to 40% of ER+, HER2- advanced or mBC tumors harbor ESR1 mutations, which develop as result of exposure to endocrine therapy in the metastatic setting. These mutations are a known driver of resistance to standard endocrine therapy, and until now, the tumors that harbor these mutations have been more difficult to treat. 

"China accounts for 20% of breast cancer prevalence worldwide,¹ and we know that these patients need new therapeutic options, particularly in the metastatic setting," said Zhao Hong, Executive Director, President and CEO of SciClone. "We believe that this agreement will enable us to work toward providing oncologists with an important option in the treatment armamentarium for their ER+, HER2- mBC patients whose tumors have an ESR1 mutation."

The approval of ORSERDU in the U.S. and E.U. is supported by data from the Phase 3 EMERALD trial, which demonstrated statistically significant progression-free survival (PFS) with elacestrant versus standard-of-care (SOC), defined as investigator's choice of an approved endocrine monotherapy. The primary endpoints of the study were PFS in the overall patient population and in patients with ESR1 mutations. In the group of patients whose tumors had ESR1 mutations, elacestrant achieved a median PFS of 3.8 months vs 1.9 months on the SOC, and reduced the risk of progression or death by 45% (PFS HR=0.55, 95% CI: 0.39, 0.77) vs SOC.

A post hoc subgroup analysis of the EMERALD PFS results, which was presented at the San Antonio Breast Cancer Symposium (SABCS) 2022, demonstrated that the duration of prior CDK4/6i treatment was positively associated with longer PFS on elacestrant but not with SOC. For patients with ESR1 mutations who were treated with CDK4/6i for ≥12 months prior to randomization on EMERALD, elacestrant achieved a median PFS of 8.6 months versus 1.9 months on SOC, with a 59% reduction in the risk of progression or death (HR=0.41 95% CI: 0.26-0.63).²

Safety data were consistent with previously reported results. The most common adverse reactions with ORSERDU were musculoskeletal pain, nausea, triglycerides increased, cholesterol increased, vomiting, fatigue, dyspepsia, diarrhea, calcium decreased, back pain, creatinine increased, arthralgia, sodium decreased, constipation, headache, hot flush, abdominal pain, anemia, potassium decreased, and alanine aminotransferase increased. Important Safety Information for ORSERDU is provided below.

About the EMERALD Phase 3 Study (NCT03778931)
The EMERALD Phase 3 trial is a randomized, open label, active-controlled study evaluating elacestrant as second- or third-line monotherapy in ER+, HER2- advanced/metastatic breast cancer patients. The study enrolled 478 patients who had received prior treatment with one or two lines of endocrine therapy, including a CDK4/6 inhibitor. Patients in the study were randomized to receive either elacestrant or the investigator's choice of an approved hormonal agent. The primary endpoints of the study were progression-free survival (PFS) in the overall patient population and in patients with estrogen receptor 1 gene (ESR1) mutations. In the group of patients whose tumors had ESR1 mutations, elacestrant achieved a median PFS of 3.8 months vs 1.9 months on the SOC, and reduced the risk of progression or death by 45% (PFS HR=0.55, 95% CI: 0.39, 0.77) vs SOC.

About ORSERDU (elacestrant)
U.S. Indication: ORSERDU (elacestrant), 345 mg tablets, is indicated for the treatment of postmenopausal women or adult men with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative, ESR1-mutated advanced or metastatic breast cancer with disease progression following at least one line of endocrine therapy.

Full prescribing information for the U.S. can be found at www.orserdu.com.

Important Safety Information
Warning and Precautions

Dyslipidemia: Hypercholesterolemia and hypertriglyceridemia occurred in patients taking ORSERDU at an incidence of 30% and 27%, respectively. The incidence of Grade 3 and 4 hypercholesterolemia and hypertriglyceridemia were 0.9% and 2.2%, respectively.  Monitor lipid profile prior to starting and periodically while taking ORSERDU.
Embryo-Fetal Toxicity: Based on findings in animals and its mechanism of action, ORSERDU can cause fetal harm when administered to a pregnant woman.  Advise pregnant women and females of reproductive potential of the potential risk to a fetus. Advise females of reproductive potential to use effective contraception during treatment with ORSERDU and for 1 week after the last dose. Advise male patients with female partners of reproductive potential to use effective contraception during treatment with ORSERDU and for 1 week after the final dose.

Adverse Reactions

Serious adverse reactions occurred in 12% of patients who received ORSERDU. Serious adverse reactions in >1% of patients who received ORSERDU were musculoskeletal pain (1.7%) and nausea (1.3%). Fatal adverse reactions occurred in 1.7% of patients who received ORSERDU, including cardiac arrest, septic shock, diverticulitis, and unknown cause (one patient each).
The most common adverse reactions (>10%), including laboratory abnormalities, of ORSERDU were musculoskeletal pain (41%), nausea (35%), increased cholesterol (30%), increased AST (29%), increased triglycerides (27%), fatigue (26%), decreased hemoglobin (26%), vomiting (19%), increased ALT (17%), decreased sodium (16%), increased creatinine (16%), decreased appetite(15%), diarrhea(13%), headache (12%), constipation (12%), abdominal pain (11%), hot flush (11%), and dyspepsia (10%).

Drug interactions

Concomitant use with CYP3A4 Inducers and/or inhibitors:  Avoid concomitant use of strong or moderate CYP3A4 inhibitors with ORSERDU. Avoid concomitant use of strong or moderate CYP3A4 inducers with ORSERDU.

Use in specific populations

Lactation: Advise lactating women to not breastfeed during treatment with ORSERDU and for 1 week after the last dose.
Hepatic Impairment: Avoid use of ORSERDU in patients with severe hepatic impairment (Child-Pugh C). Reduce the dose of ORSERDU in patients with moderate hepatic impairment (Child-Pugh B).
The safety and effectiveness of ORSERDU in pediatric patients have not been established.

To report SUSPECTED ADVERSE REACTIONS, contact Stemline Therapeutics, Inc. at 1-877-332-7961 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Elacestrant is also being investigated in several clinical trials in metastatic breast cancer disease, alone or in combination with other therapies: ELEVATE (NCT05563220); ELECTRA (NCT05386108); and ELCIN (NCT05596409). Elacestrant is also being evaluated in early breast cancer disease.

About The Menarini Group
The Menarini Group is a leading international pharmaceutical and diagnostics company, with a turnover of over $4.4 billion and over 17,000 employees. Menarini is focused on therapeutic areas with high unmet needs with products for cardiology, oncology, pneumology, gastroenterology, infectious diseases, diabetology, inflammation, and analgesia. With 18 production sites and 9 Research and Development centers, Menarini's products are available in 140 countries worldwide. For further information, please visit www.menarini.com.

About Stemline Therapeutics Inc.
Stemline Therapeutics, Inc. ("Stemline") a wholly-owned subsidiary of the Menarini Group, is a commercial-stage biopharmaceutical company focused on the development and commercialization of novel oncology therapeutics. Stemline commercializes ORSERDU® (elacestrant) in the U.S. and in the E.U., an oral endocrine therapy indicated for the treatment of postmenopausal women or adult men with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative, ESR1-mutated advanced or metastatic breast cancer with disease progression following at least one line of endocrine therapy. Stemline also commercializes ELZONRIS® (tagraxofusp-erzs), a novel targeted treatment directed to CD123 for patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN), an aggressive hematologic cancer, in the United States and Europe, which is the only approved treatment for BPDCN in the US and EU to date. Stemline also commercializes NEXPOVIO® (selinexor) in Europe, an XPO1 inhibitor for multiple myeloma. Stemline also has an extensive clinical pipeline of small molecules and biologics in various stages of development for a host of solid and hematologic cancers.

About SciClone Pharmaceuticals (Holdings) Limited
SciClone Pharmaceuticals (Holdings) Limited ("SciClone Pharmaceuticals", HKEX: 6600) is a global biopharmaceutical company with an integrated platform for the development and the commercialization of innovative therapies for cancer and severe infection. With an innovation-driven strategic transformation, SciClone has established a product portfolio with differentiated advantages, including a number of first-in-class and best-in-class potential products/pipelines. Staying true to the Group's original aspiration of "SciClone gives life hope", SciClone is dedicated to improving patients' health by providing top-tier healthcare products and services with global standards of care. For more information about SciClone, please visit www.sciclone.com.

¹ Ferlay J, Ervik M, Lam F, Colombet M, Mery L, Piñeros M, Znaor A, Soerjomataram I, Bray F (2020). Global Cancer Observatory: Cancer Today. Lyon, France: International Agency for Research on Cancer. Available from: https://gco.iarc.fr/today, accessed [01 Nov 2023].

² Bardia et al. EMERALD phase 3 trial of elacestrant versus standard of care endocrine therapy in patients with ER+/HER2- metastatic breast cancer: Updated results by duration of prior CDK4/6i in metastatic setting. SABCS 2022. GS3-01

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