• Preliminary efficacy analysis from the elacestrant plus everolimus and ribociclib cohorts of the ELEVATE study, along with updated safety data from additional cohorts of elacestrant plus targeted therapy combination arms, will be presented.
• These data highlight elacestrant’s potential role as an endocrine therapy backbone in combination with various targeted agents for patients with ER+/HER2- mBC.
• The robust elacestrant clinical development program across wide-ranging studies further solidifies its potential in monotherapy and combination settings, in mBC and in early breast cancer.

FLORENCE, Italy and NEW YORK, May 22, 2025 – The Menarini Group (“Menarini”), a leading international pharmaceutical and diagnostics company, and Stemline Therapeutics, Inc. (“Stemline”), a wholly-owned subsidiary of the Menarini Group, focused on bringing transformational oncology treatments to cancer patients, will present updated preliminary efficacy and safety results from the Phase 1b/2 ELEVATE study in patients with estrogen receptor-positive (ER+), HER2-negative (HER2-) locally advanced or metastatic breast cancer (mBC). The ELEVATE study was designed to evaluate the safety and efficacy of oral-oral combination treatment options to overcome different resistance mechanisms observed in ER+/HER2- mBC and improve patient outcomes. Additionally, various other trial-in-progress updates will be presented, investigating elacestrant’s potential to become an endocrine therapy (ET) backbone across the spectrum of breast cancer. These data will be presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting.

The ELEVATE study is comprised of six treatment regimens evaluating elacestrant in combination with CDK4/6 inhibitors (palbociclib, abemaciclib and ribociclib) and with inhibitors of the PI3K/AKT/mTOR pathway (everolimus, alpelisib and capivasertib). ELEVATE results reported at ASCO 2025 (abstract 1070/49) include updated efficacy data which demonstrate favorable preliminary progression-free survival (PFS) from the elacestrant plus ribociclib and the elacestrant plus everolimus cohorts. A recommended phase 2 dose (RP2D) was determined to be elacestrant 345 mg plus ribociclib 400 mg. The RP2D of elacestrant 345 mg plus everolimus 7.5 mg was previously reported.

“It is encouraging to see the positive preliminary efficacy and safety results when everolimus and ribocilib, respectively, are combined with elacestrant. These findings are consistent with the promising elacestrant plus abemaciclib cohort data from the same study that was presented last December, which also demonstrated favorable preliminary efficacy and safety in this setting,” said Hope S. Rugo, MD, Director, Women's Cancers Program and Division Chief, Breast Medical Oncology, City of Hope Comprehensive Cancer Center. “As the progression-free survival data and safety data continue to mature across the various cohorts of the ELEVATE study, we are encouraged by elacestrant’s potential to become an endocrine therapy backbone in combination regimens for the treatment of metastatic breast cancer.”

Additional data reported separately (abstract 1079/58) provided updated Phase 1b/2 safety results from four cohorts of the ELEVATE study, including elacestrant plus ribociclib, everolimus, alpelisib, and capivasertib. These updated preliminary results show that the combinations are consistent with the known safety profiles of each targeted therapy plus standard of care endocrine therapy.

“These data continue to underscore the potential value of elacestrant as a combination partner in the ER+/HER2- metastatic breast cancer treatment landscape,” said Elcin Barker Ergun, CEO of the Menarini Group. “We are also exploring the potential of elacestrant in other patient populations, including our currently enrolling ELEGANT study, which is designed to assess its potential benefit in early breast cancer patients with high risk of recurrence.”

In addition, the company will be presenting other data at the ASCO Annual Meeting. See below for a complete list of Menarini Stemline abstracts.

Menarini Stemline Abstracts:

Presentation Title: Elacestrant (Ela) combinations with ribociclib (Ribo) and everolimus (Eve) in patients (pts) with ER+/HER2- locally advanced or metastatic breast cancer (mBC): Update from ELEVATE, a phase (Ph) 1b/2, open-label, umbrella study.
Abstract Number: 1070
Presentation Date & Time: Monday, June 2, 9:00 AM – 12:00 PM CT
Location: Poster Bd 49
Presenting Author: Hope S. Rugo

Presentation Title: Elacestrant combinations in patients (pts) with ER+/HER2- locally advanced or metastatic breast cancer (mBC): Safety update from ELEVATE, a phase (Ph) 1b/2, open-label, umbrella study.
Abstract Number: 1079
Presentation Date & Time: Monday, June 2, 9:00 AM – 12:00 PM CT
Location: Poster Bd 58
Presenting Author: Nancy Chan

Presentation Title: ADELA: a double-blind, placebo-controlled, randomized phase 3 trial of Elacestrant (ELA) + everolimus (EVE) versus ELA + placebo (PBO) in ER+/HER2- advanced breast cancer (aBC) patients with ESR1-mutated tumors progressing on endocrine therapy (ET) + CDK4/6i.
Abstract Number: TPS1129
Presentation Date & Time: Monday, June 2, 9:00 AM – 12:00 PM CT
Location: Poster Bd 103b
Presenting Author: Antonio Llombart-Cussac

Presentation Title: ELCIN: Elacestrant in women and men with CDK4/6 Inhibitor (CDK4/6i)-naïve estrogen receptor-positive (ER+), HER2-negative (HER2-) metastatic breast cancer (mBC): an open-label multicenter phase 2 study.
Abstract Number: TPS1127
Presentation Date & Time: Monday, June 2, 9:00 AM – 12:00 PM CT
Location: Poster Bd 102b
Presenting Author: Virginia G. Kaklamani

Presentation Title: ELEGANT: Elacestrant versus standard endocrine therapy (ET) in women and men with node-positive, estrogen Receptor-positive (ER+), HER2-negative (HER2-), early breast cancer (eBC) with high risk of recurrence in a global, multicenter, randomized, open-label phase 3 study.
Abstract Number: TPS619
Presentation Date & Time: Monday, June 2, 9:00 AM – 12:00 PM CT
Location: Poster Bd 210a
Presenting Author: Aditya Bardia

Presentation Title: EORTC-2129-BCG: Elacestrant for treating ER+/HER2- breast cancer patients with ctDNA relapse (TREAT ctDNA)
Abstract Number: TPS620
Presentation Date & Time: Monday, June 2, 9:00 AM – 12:00 PM CT
Location: Poster Bd 210b
Presenting Author: Michail Ignatiadis

About The Elacestrant Clinical Development Program
Elacestrant is also being investigated in several company-sponsored clinical trials in metastatic breast cancer disease, alone or in combination with other therapies. ELEVATE (NCT05563220) is a phase 1b/2 clinical trial evaluating the safety and efficacy of elacestrant combined with alpelisib, everolimus, capivasertib, palbociclib, ribociclib or abemaciclib. ELECTRA (NCT05386108) is an open-label phase 1b/2, multicenter study evaluating elacestrant in combination with abemaciclib in patients with ER+, HER2- breast cancer. The phase 2 portion evaluates this treatment regimen in patients with brain metastases. ELCIN (NCT05596409) is a phase 2 trial evaluating the efficacy of elacestrant in patients with ER+, HER2- advanced/metastatic breast cancer who received one or two prior hormonal therapies and no prior CDK4/6 inhibitors in the metastatic setting. ADELA (NCT06382948) is a phase 3 randomized, double-blinded trial evaluating elacestrant in combination with everolimus in patients with ER+, HER2- mBC with ESR1-mut tumors. Elacestrant is also being evaluated in additional investigator-led trials, in trials conducted in collaboration with other companies, in metastatic breast cancer as well as in early disease.

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.

About The Menarini Group
The Menarini Group is a leading international pharmaceutical and diagnostics company, with a turnover of $4.7 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 bringing transformational oncology treatments to patients. Stemline commercializes elacestrant, 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, in the U.S., Europe, and other global regions. Stemline also commercializes tagraxofusp-erzs, a novel targeted therapy directed to CD123, for patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN), an aggressive hematologic cancer, in the United States, Europe, and other global regions. In addition, Stemline commercializes selinexor, an XPO1 inhibitor for multiple myeloma, in Europe. The company is also conducting multiple label-expansion studies with elacestrant and tagraxofusp in breast and hematologic cancer indications, respectively, and has an extensive clinical pipeline of additional drug candidates in various stages of development for a host of solid and hematologic cancers.

Media Contacts
The Menarini Group
Valeria Speroni Cardi
Email: pressoffice@menarini.com

Stemline Therapeutics, Inc.
Cheya Pope
Email: media@menarinistemline.com