HengRui's HRS-6209 breast cancer trial pushes completion out two years
The Phase 1/2 dose-finding study now targets December 2027 completion, up from December 2025, extending the wait for a signal on HengRui's SERD franchise.
Executive Summary
- HengRui extended the primary completion date on its Phase 1/2 combination trial of HRS-6209 in breast cancer by two years, the largest timing revision the trial has logged since it started recruiting.
- Enrollment target and trial status stayed unchanged, and the study keeps recruiting at its original site, which points to a pacing shift rather than a program in distress.
- The trial is testing an oral selective estrogen receptor degrader in combination with multiple partner drugs across nine arms, with safety, tolerability, and dose-finding as the near-term bar and objective response rate reserved for a later efficacy-expansion stage.
- HRS-6209 sits in a breast cancer field crowded with later-stage, more advanced antibody-drug conjugates and targeted therapies, none of which share its mechanism, leaving this program's differentiation tied to how the combination performs rather than to novelty.
The change
HengRui's ClinicalTrials.gov record for NCT06555068 now lists a primary completion date of December 1, 2027, up from December 1, 2025. That is the single largest timing revision on the trial's history: an earlier amendment in mid-2025 had already pushed the date from August 2026 to December 2025, and the study's overall completion date, covering long-term follow-up, now stands at August 2028. The trial started recruiting in August 2024 and remains open at one site in China. NCT06555068A Trial of HRS-6209 in Combination With Fulvestrant, Letrozole, HRS-8080, or HRS-1358 in Breast Cancer PatientsNCT06555068
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
What the trial tests
The study is a Phase 1/2, open-label design testing HRS-6209 in combination with fulvestrant, letrozole, and two other HengRui-developed agents, HRS-8080 and HRS-1358, across nine treatment arms in ER-positive, PR-positive breast cancer. Its dose-exploration stage carries serious adverse events, dose-limiting toxicity, maximum tolerated dose, and recommended Phase 2 dose as primary endpoints; a later efficacy-expansion stage adds objective response rate as a primary measure. The design targets 528 patients with a life expectancy over three months and disease progression after prior systemic treatment, positioning the study as second-line-or-later. A HengRui document describing the update characterized the shift as a two-year extension from the previously anticipated date. NCT06555068+1A Trial of HRS-6209 in Combination With Fulvestrant, Letrozole, HRS-8080, or HRS-1358 in Breast Cancer PatientsNCT06555068Jiangsu HengRui Medicine Timeline Delayed for Phase 1/2 HRS-6209 Trial in Advanced Breast CancerJul 16, 2026
Reading the delay
Enrollment target held flat at 528 patients with no reduction, which the operational baseline for this trial type reads as within the routine range for a Phase 1/2 dose-finding study. The trial's registry-churn record shows one completion-date change against three total edits since 2024, a pace the protocol-stability read labels stable rather than volatile. Combined with the trial's nine dosing arms and ongoing recruitment, the extension is consistent with the added time a multi-combination, dose-escalation design typically needs to move through cohorts before an efficacy-expansion readout, rather than a signal of an enrollment shortfall. NCT06555068A Trial of HRS-6209 in Combination With Fulvestrant, Letrozole, HRS-8080, or HRS-1358 in Breast Cancer PatientsNCT06555068
Where it sits
HRS-6209 is one of three active HengRui trials testing the drug in breast cancer, alongside a Phase 1 study run with a separate collaborator and another Phase 1/2 combination study, both still recruiting. The wider breast cancer trial field includes Phase 3 programs for antibody-drug conjugates such as Daiichi Sankyo's trastuzumab deruxtecan and Merck's sacituzumab tirumotecan, and targeted agents including Novartis's ribociclib, none of which share HRS-6209's mechanism. That leaves this program without a same-target comparator in the tracked landscape, and its case for differentiation will rest on how the fulvestrant, letrozole, and HRS-8080/HRS-1358 combinations perform once dosing and safety data mature, not on mechanism novelty. NCT06555068A Trial of HRS-6209 in Combination With Fulvestrant, Letrozole, HRS-8080, or HRS-1358 in Breast Cancer PatientsNCT06555068
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.