Stemline Therapeutics
Stemline Therapeutics is a commercial-stage biopharmaceutical subsidiary of Menarini Group developing and marketing oncology therapeutics. It commercializes three approved products—ORSERDU, ELZONRIS, and NEXPOVIO—and advances an AI-discovered oncology pipeline through partnerships with Insilico Medicine and others.
- Company typePrivate
- Founded2003
- HeadquartersNew York, United States
- Headcount501–1,000
- GTM typeB2B
- OfferingHardware or Manufacturing
What Stemline Therapeutics does
Stemline Therapeutics is a commercial-stage biopharmaceutical company focused on oncology therapeutics, operating as a wholly-owned subsidiary of Menarini Group. The company markets three approved products: ORSERDU (elacestrant), an oral selective estrogen receptor degrader (SERD) approved by FDA in January 2023 as the first and only treatment specifically indicated for ESR1-mutated ER+/HER2- advanced or metastatic breast cancer; ELZONRIS (tagraxofusp-erzs), a CD123-directed diphtheria toxin fusion protein approved in 2018 (FDA) and 2021 (EMA) as the only approved treatment for blastic plasmacytoid dendritic cell neoplasm (BPDCN) in the US and EU; and NEXPOVIO (selinexor), a first-in-class oral XPO1 inhibitor for multiple myeloma, commercialized in Europe under a licensing arrangement with Karyopharm Therapeutics. Beyond approved products, the pipeline includes SL-801 (reversible XPO1 inhibitor in Phase 1 for solid tumors), SL-701 (immunotherapy in glioblastoma), and AI-discovered candidates MEN2312 (KAT6 inhibitor) and MEN2501 (KIF18A inhibitor) sourced through a multi-asset exclusive license partnership with Insilico Medicine, plus a third preclinical AI-designed oncology candidate.
The business model centers on pharmaceutical product sales through wholesale and specialty pharmacy distribution to hospitals and cancer treatment centers, supported by field sales teams and medical science liaisons targeting oncologists and hematologists. Revenue streams include direct product sales (ORSERDU, ELZONRIS in US and EU), licensing royalties (NEXPOVIO from Karyopharm's ex-US selinexor arrangement), and milestone payments from the Insilico partnership, with MEN2501 first-in-patient dosing triggering a $5 million payment in February 2026 and combined Insilico deal value exceeding $550 million. Pricing follows standard monthly specialty pharmaceutical reimbursement, with the company leveraging parent Menarini Group's global distribution infrastructure spanning 18 production sites, 9 R&D centers, and operations in 140 countries.
Stemline pursues combination therapy expansion across its portfolio, including elacestrant plus abemaciclib (mPFS 14.3 months), elacestrant plus capivasertib (88.9% disease control rate), selinexor plus ruxolitinib (SENTRY Phase 3 hit first co-primary endpoint with 49.8% SVR35 versus 28% for ruxolitinib alone), and elacestrant plus everolimus (ADELA Phase 3 with MEDSIR). The company uses AI-driven diagnostic and trial infrastructure partnerships (Tempus Next, Medidata, VisualDx) to support patient identification and clinical execution. The product franchise is concentrated in rare and biomarker-defined oncology indications where the company holds first-in-class or only-approved positions.
Stemline Therapeutics firmographics
Firmographics- Name
- Stemline Therapeutics
- Legal name
- Stemline Therapeutics, Inc.
- Website
- https://stemline.com
- Company type
- Private
- Founded year
- 2003
- Operating status
- Operating
- Headcount range
- 501–1,000 employees
- Short description
- Stemline Therapeutics is a commercial-stage biopharmaceutical subsidiary of Menarini Group developing and marketing oncology therapeutics. It commercializes three approved products—ORSERDU, ELZONRIS, and NEXPOVIO—and advances an AI-discovered oncology pipeline through partnerships with Insilico Medicine and others.
- Ownership category
- akta.pro rank
Stemline Therapeutics industry classification
Industry- Product category
- Oncology Pharmaceuticals
- NAICS
- Biological Product (except Diagnostic) Manufacturing (325414), Pharmaceutical and Medicine Manufacturing (3254)
- SIC
- Pharmaceutical Preparations (2834)
- akta.pro primary industry
- Oncology Specialty Pharmaceuticals (HLAIACAA)
Keywords
Where Stemline Therapeutics is headquartered
LocationHeadquarters
- HQ city
- New York
- HQ country
- United States
- HQ region
- North America
Offices3 records
Markets served
Stemline Therapeutics business model
Business model- GTM type
- B2B
- Offering type
- Hardware or Manufacturing
- Cost components
- Technology or R&D, Marketing or Sales, Personnel, Operations, Supply Chain
Revenue model
- Product Sales - ORSERDU: Revenue from sales of ORSERDU (elacestrant) in the US and Europe for treatment of ER+/HER2-/ESR1-mutated advanced or metastatic breast cancer.
- Product Sales - ELZONRIS: Revenue from sales of ELZONRIS (tagraxofusp-erzs) in the US and Europe for treatment of BPDCN, the only approved treatment for this indication.
- Product Sales - NEXPOVIO: Revenue from sales of NEXPOVIO (selinexor) in Europe for multiple myeloma, marketed under licensing agreement with Karyopharm Therapeutics.
- Milestone Payments from AI Partnership: Revenue received from Insilico Medicine upon achievement of development milestones for AI-discovered compounds, including $5 million for MEN2501 first-in-human dosing. Combined agreement value exceeds $550 million.
Pricing tiers
| Model | Billing | Price |
|---|---|---|
| Subscription | Monthly | ORSERDU (elacestrant) 345mg tablets - approved indication pricing |
Go-to-market motion1 record
Distribution channels2 records
Marketing channels4 records
Stemline Therapeutics product offering
Product offeringCore offering
Stemline Therapeutics commercializes novel oncology therapeutics, including ORSERDU (elacestrant) for ER+/HER2-/ESR1-mutated advanced or metastatic breast cancer, ELZONRIS (tagraxofusp-erzs) for blastic plasmacytoid dendritic cell neoplasm (BPDCN), and NEXPOVIO (selinexor) for multiple myeloma in Europe. The company also develops a clinical pipeline of small molecule and biologic candidates, including AI-discovered assets in partnership with Insilico Medicine targeting oncology indications with high unmet medical need.
Product overview
Stemline Therapeutics is a commercial-stage biopharmaceutical company developing and commercializing novel oncology therapeutics. The company markets three approved products: ORSERDU (elacestrant), an oral SERD for ER+/HER2- ESR1-mutated metastatic breast cancer; ELZONRIS (tagraxofusp-erzs), a CD123-directed therapy for BPDCN; and NEXPOVIO (selinexor), an XPO1 inhibitor for multiple myeloma in Europe. The pipeline includes clinical-stage candidates SL-801 (XPO1 inhibitor for solid tumors), SL-701 (immunotherapy for glioblastoma), and MEN2501 (KIF18A inhibitor), plus AI-discovered assets from Insilico Medicine including MEN2312 (KAT6 inhibitor) and a second preclinical oncology asset. Multiple combination studies are ongoing for elacestrant across metastatic and early breast cancer settings.
Differentiator
Problem solved
Functional benefit
Brands
- ORSERDU: ORSERDU (elacestrant) - oral endocrine therapy for ER+, HER2- advanced or metastatic breast cancer with ESR1 mutations
- ELZONRIS
- NEXPOVIO
Products and services
- ORSERDU (elacestrant) Oral selective estrogen receptor degrader (SERD) approved for treatment of postmenopausal women or adult men with estrogen receptor-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer following disease progression on endocrine therapy. First and only oral SERD specifically indicated for ESR1-mutated tumors.
- ELZONRIS (tagraxofusp-erzs) Novel targeted therapy directed to CD123 (IL-3R) comprising human IL-3 recombinantly fused to a truncated diphtheria toxin payload. Indicated for treatment of blastic plasmacytoid dendritic cell neoplasm (BPDCN) in adults and pediatric patients 2 years and older. The only approved treatment for BPDCN in the US and EU.
- NEXPOVIO (selinexor) First-in-class oral exportin 1 (XPO1) inhibitor approved in Europe for multiple myeloma: (i) in combination with dexamethasone for adult patients who have received at least four prior therapies, and (ii) in combination with bortezomib and dexamethasone for adults who have received at least one prior therapy. Commercialized in Europe under licensing agreement with Karyopharm Therapeutics.
Quantifiable outcome
- SVR35 (spleen volume reduction ≥35%) achieved in 49.8% of myelofibrosis patients at week 24 with selinexor + ruxolitinib vs 28% with ruxolitinib alone
- +4 more outcomes
Companies that use Stemline Therapeutics
Customer profileNamed customers5 records
Segments4 records
Ideal customer profiles2 records
Stemline Therapeutics technology and API
TechnologyTechnology focussed No
API detail
- Has API
- No
- API docs
- API detail
Core technology
AI maturity
App detail
Integration2 records
Feature6 records
Stemline Therapeutics partnerships and signals
Strategic signalPartnerships
Nine partnerships are on record, tiered supporting, major and core.
- MedidatasupportingExpansion of 14-year partnership deploying Medidata's AI Study Build technology to power Stemline's oncology portfolio. Technology leverages data from more than 38,000 clinical trials to automate study configurations, reducing trial startup time from months to weeks.
- VisualDxsupportingCollaboration to aid in identifying people who may have Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN), supporting diagnosis of this rare aggressive hematologic malignancy.
- Tempus AImajorCollaboration to implement Tempus Next, AI-enabled care pathway intelligence platform for metastatic breast cancer patients. Platform analyzes clinical data and notifies clinicians when ESR1 testing is missing at disease progression, supporting appropriate testing integration into treatment journey.
- Insilico Medicine (Second Agreement)coreSecond exclusive global license agreement for AI-discovered preclinical asset targeting high unmet needs in oncology. $20 million upfront payment. Combined value of all agreements exceeds $550 million. MEN2501 (KIF18A inhibitor) achieved first-in-patient dosing milestone in 2026, triggering $5 million payment to Insilico.
- MEDSIRmajorClinical trial collaboration for ADELA Phase 3 study evaluating elacestrant + everolimus vs elacestrant alone in ER+/HER2- advanced breast cancer with ESR1 mutations. International study across Spain, Italy, France, Austria, Czech Republic, Greece, Germany, and UK. MEDSIR provides end-to-end clinical trial management.
- Insilico MedicinecoreGlobal exclusive license agreement for novel KAT6 inhibitor (MEN2312) for breast cancer and other oncology indications. Asset designed using Insilico's generative AI engine. Combined deal value exceeds $550 million including $20 million upfront payment, development milestones, and tiered royalties. MEN2312 advanced rapidly into clinical phase.
- Carrick TherapeuticssupportingClinical trial collaboration to evaluate samuraciclib and elacestrant combination in breast cancer, exploring novel therapeutic combination to overcome resistance mechanisms.
- EORTC (European Organisation for Research and Treatment of Cancer)majorCollaboration to launch new clinical trial in early-stage breast cancer, expanding elacestrant development into earlier disease stages and adjuvant treatment settings.
- Karyopharm TherapeuticscoreCollaboration on selinexor development. Karyopharm commercializes selinexor as XPOVIO in the US; Menarini Group holds global licensing rights for selinexor as NEXPOVIO outside US. Conducted pivotal Phase 3 SENTRY trial of selinexor + ruxolitinib in myelofibrosis presented at EHA 2026. SENTRY achieved first co-primary endpoint with 49.8% SVR35 vs 28% for ruxolitinib alone.
Scale indicators8 records
Recent moves6 records
Expansion highlights6 records
Stemline Therapeutics competitors and assessment
Company assessmentDirect peers
- Karyopharm Therapeutics: Direct partner and co-developer of selinexor (NEXPOVIO/XPOVIO). Both companies commercialize the same molecule in different geographies for multiple myeloma and other oncology indications, making them directly comparable oncology specialty pharma companies of similar size and stage.
- Olema Oncology: Direct competitor in the oral SERD space with OP-1250 in development for ER+/HER2- breast cancer. Both companies target the same patient population with similar mechanisms of action and are at similar clinical/commercial stages.
- Arvinas: Oncology specialty biotech developing targeted therapies including ER-targeted PROTAC degraders for breast cancer. Both companies operate in similar patient populations with novel targeted mechanisms and similar size/scale.
- Radius Health: Specialty pharma company that was acquired by Menarini Group for ~$890M in 2022, focused on osteoporosis and oncology. Now operates as part of Menarini alongside Stemline, representing the most directly comparable subsidiary within the same parent company.
- MacroGenics: Clinical-stage oncology specialty biopharmaceutical company developing antibody-based therapeutics for cancer including margetuximab. Similar size, oncology focus, and pipeline stage profile to Stemline.
Broad incumbents
- ImmunoGen: Oncology biotech now part of AbbVie focused on antibody-drug conjugates for cancer including ELAHERE for ovarian cancer. Similar oncology specialty focus with comparable commercial-stage profile before acquisition.
- Seagen: Large oncology specialty company (acquired by Pfizer for $43B) developing targeted cancer therapies including ADCs. Comparable in oncology focus but at much larger scale with broader pipeline.
- Exelixis: Commercial-stage oncology company focused on genitourinary cancers with cabozantinib. Comparable specialty oncology profile with multiple approved drugs and ongoing pipeline development, though focused on different therapeutic areas.
- AstraZeneca (Oncology Division): Large pharmaceutical company with significant oncology portfolio including competing oral SERD (camizestrant) and breast cancer therapies. Operates as broader incumbent in the same oncology space with far greater resources for label expansion studies.
Emerging players
- Mersana Therapeutics: Clinical-stage oncology company developing antibody-drug conjugates including XMT-1660. Comparable size and clinical-stage oncology focus with novel platform technology targeting similar patient populations.
Market position
Strengths5 records
Weaknesses5 records
Competitive moat5 records
Key risks6 records
Key highlights7 records
Customer concentration
Stemline Therapeutics social profiles
Digital presenceStemline Therapeutics financial estimates
Financial estimateRevenue estimate
Valuation estimate
Stemline Therapeutics leadership team
Management profileNumber of profiles
Profiles3 records
Stemline Therapeutics funding detail
Funding detailFunding overview
Funding rounds6 records
Investors1 record
Funding detail is available on the Subscription and Enterprise plan.Contact sales →
Stemline Therapeutics M&A and investment
M&A and investmentM&A
Investments
M&A and investment is available on the Subscription and Enterprise plan.Contact sales →
Frequently asked questions about Stemline Therapeutics
What does Stemline Therapeutics do?
Stemline Therapeutics commercializes novel oncology therapeutics, including ORSERDU (elacestrant) for ER+/HER2-/ESR1-mutated advanced or metastatic breast cancer, ELZONRIS (tagraxofusp-erzs) for blastic plasmacytoid dendritic cell neoplasm (BPDCN), and NEXPOVIO (selinexor) for multiple myeloma in Europe. The company also develops a clinical pipeline of small molecule and biologic candidates, including AI-discovered assets in partnership with Insilico Medicine targeting oncology indications with high unmet medical need.
Is Stemline Therapeutics a public or private company?
Stemline Therapeutics is a private company. It is classified as corporate owned and is currently operating.
When was Stemline Therapeutics founded?
Stemline Therapeutics was founded in 2003. It employs 501 to 1,000 people.
Where is Stemline Therapeutics based?
Stemline Therapeutics is headquartered in New York, United States, in the North America region.
How does Stemline Therapeutics make money?
Four revenue lines are on record. Product Sales - ORSERDU is the primary driver. The others are product Sales - ELZONRIS, product Sales - NEXPOVIO and milestone Payments from AI Partnership.
Who are Stemline Therapeutics's main competitors?
Direct peers on record are Karyopharm Therapeutics, Olema Oncology, Arvinas, Radius Health and MacroGenics. Broad incumbents are ImmunoGen, Seagen, Exelixis and AstraZeneca (Oncology Division). Mersana Therapeutics is listed as an emerging player.
Does Stemline Therapeutics have an API?
No public API is recorded for Stemline Therapeutics.
What industry is Stemline Therapeutics in?
Stemline Therapeutics's product category is Oncology Pharmaceuticals. Its primary akta.pro industry code is HLAIACAA, Oncology Specialty Pharmaceuticals. Its NAICS code is 325414 and its SIC code is 2834.