JPRN-jRCT2071260044 Elacestrant hydrochloride ER-positive/HER2-negative Breast Cancer Clinical Landscape Report 2026: Design, Endpoints, Sponsor and Readout Outlook
Turn a newly registered trial into a decision-ready clinical landscape. This report examines JPRN-jRCT2071260044 using PatSnap Clinical Trials MCP for protocol design and endpoint evidence, with Drug & Asset MCP and Company & Deal Intelligence MCP used as the companion asset and sponsor enrichment workflow. Explore PatSnap MCP Servers to reproduce the research sequence inside an AI workflow.
MCP evidence snapshot: 4 August 2026. Trial records, recruitment status and projected dates can change after the snapshot and should be rechecked before operational decisions.
Why JPRN-jRCT2071260044 is a hot trial to watch
ER-positive/HER2-negative Breast Cancer is being segmented by mechanism, treatment setting, geography and endpoint architecture. JPRN-jRCT2071260044 is notable because it evaluates Elacestrant hydrochloride in a Phase 2 design sponsored by Stemline Therapeutics, Inc.. The main development question is whether the protocol can translate its rationale into a clinically interpretable and operationally credible readout.
Trial landscape snapshot
| Field | Indexed detail |
|---|---|
| Registration | JPRN-jRCT2071260044 |
| Official title | A Phase 2 Open-Label, Single-Arm, Multicenter Trial to Evaluate the Efficacy and Safety of Elacestrant Monotherapy for the Treatment of Japanese Participants with ER+/HER2- Advanced or Metastatic Breast Cancer with ESR1-mutation Following CDK4/6 Inhibitor Therapy |
| Phase / status | Phase 2 / 募集中 |
| Intervention | Elacestrant hydrochloride |
| Sponsor | Stemline Therapeutics, Inc. |
| Geography | Japan |
| Enrollment | [object Object] |
| Primary endpoint | IRC-assessed PFS |
| Endpoint time frame | Not reported |
| Primary completion / readout proxy | [object Object] |
Protocol design and endpoint interpretation
The indexed record describes a Phase 2 study of Elacestrant hydrochloride in ER-positive/HER2-negative Breast Cancer.
Allocation is Non-Randomized, masking is Open Label, and the intervention model is Single Group Assignment. Planned enrollment of [object Object] participants across Japan shapes statistical precision, execution risk and external validity. Interpretation should account for baseline risk, prior therapy, assessment schedule, missing-data handling and clinical relevance—not only statistical significance.
- IRC-assessed PFS (time frame not reported)
- IRC評価に基づくPFS (time frame not reported)
Readout outlook and evidence gap
The current protocol points to [object Object] as the best available readout proxy. Because this is an active or newly posted study, a trial-specific result citation is not included until a normalized clinical-trial-result record becomes available. That gap is itself operationally important: teams should monitor first result indexing, conference abstracts, protocol amendments and changes to the primary-completion date.
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Asset and sponsor context
Drug & Asset MCP profile: Elacestrant hydrochloride is indexed as No normalized modality returned, with target No normalized target returned, mechanism No normalized mechanism returned, and global highest development status No normalized global status returned.
Company & Deal Intelligence MCP profile: Stemline Therapeutics, Inc. is resolved to a normalized organization record in United States. The organization workflow adds identity, location, portfolio and partnering context where available.
The sponsor profile matters because scientific rationale alone does not determine development value. Manufacturing readiness, portfolio fit, geographic reach, partnering capacity and the ability to fund confirmatory development can determine whether a positive signal becomes a competitive asset.
White space around this program
- Sharper patient selection: prospective biomarker or phenotype definitions that identify who is most likely to benefit.
- Clinically interpretable endpoints: outcomes connecting activity with function, symptoms, survival or treatment burden.
- Comparator relevance: evidence against the most decision-relevant contemporary standard of care.
- Broader external validity: evidence across additional geographies, demographic groups and real-world settings.
- Operational differentiation: a development path that closes the readout gap without sacrificing safety or durability.
What to monitor next
Monitor recruitment, enrollment changes, protocol amendments, endpoint hierarchy, primary-completion timing, first result indexing, asset ownership and sponsor partnerships. A change in endpoint, population or ownership can alter the probability of success before a headline data release.
Bottom line
JPRN-jRCT2071260044 provides a focused lens on ER-positive/HER2-negative Breast Cancer development. Its value will be determined by whether Elacestrant hydrochloride can convert the current Phase 2 design into evidence that is clinically meaningful, operationally credible and differentiated from competing programs.
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