NCT07691333 Letrozole PIK3CA mutation/HR-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 NCT07691333 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: 21 July 2026. Trial records, recruitment status and projected dates can change after the snapshot and should be rechecked before operational decisions.

Why NCT07691333 is a hot trial to watch

PIK3CA mutation/HR-positive/HER2-negative Breast Cancer is being segmented by mechanism, treatment setting, geography and endpoint architecture. NCT07691333 is notable because it evaluates Letrozole in a Phase 2 design sponsored by Fujian Cancer Hospital. The main development question is whether the protocol can translate its rationale into a clinically interpretable and operationally credible readout.

Trial landscape snapshot

Protocol design and endpoint interpretation

This study is a single-center, prospective, open-label exploratory clinical study to assess the efficacy and safety of kumorixilib combined with capecitabine and letrozole as neoadjuvant therapy in patients with HR+/HER2- stage II-III invasive breast cancer. The study plans to enroll 35 eligible patients, and all participants will receive the triple-drug combination regimen without randomization. The treatment regimen: kumorixilib 180 mg orally once daily, capecitabine 500 mg orally three times daily, and letrozole 2.5 mg orally once daily; each cycle lasts 28 days, for a total of 6 cycles. Breast MRI will be used to evaluate radiological tumor response. Surgical resection will be arranged 2-4 weeks after neoadjuvant treatment ends. The primary endpoint is the percentage change in Ki-67 score from baseline to Cycle 1 Day 28. Secondary endpoints include the complete cell cycle arrest rate (CCCA, Ki-67 ≤ 2.7%) on Day 28, the reduction rat

Allocation is N/A, masking is None (Open Label), and the intervention model is Single Group Assignment. Planned enrollment of 35 participants across China 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.

• Percentage change in Ki-67 score from baseline to Cycle 1 Day 28 (At the end of Cycle 1 (each cycle is 28 days)) — The percentage reduction of Ki-67 proliferation index in tumor tissue between baseline and Cycle 1 Day 28 after treatment initiation.

Readout outlook and evidence gap

The current protocol points to 2028-01-30 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

Trial-sourced asset: Letrozole. The Drug & Asset MCP enrichment step is designed to add normalized targets, modality and global development status when an exact asset match is available.

Trial-sourced sponsor: Fujian Cancer Hospital. Company & Deal Intelligence MCP is the companion workflow for resolving organization identity, corporate profile and partnering context.

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

NCT07691333 provides a focused lens on PIK3CA mutation/HR-positive/HER2-negative Breast Cancer development. Its value will be determined by whether Letrozole can convert the current Phase 2 design into evidence that is clinically meaningful, operationally credible and differentiated from competing programs.

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