On December 12, 2025 Natera, Inc. (NASDAQ: NTRA), a global leader in cell-free DNA and precision medicine, and MEDSIR (Medica Scientia Innovation Research), a global leader in oncology research, reported their collaboration on the MiRaDoR (NCT05708235) study, which is a multicenter, phase II clinical trial in hormone receptor-positive, HER2-negative (HR+/HER2-) breast cancer.

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Breast cancer is the most common cancer in women worldwide, with approximately 2.3 million new cases diagnosed in 2022.1 Despite advances in treatment, recurrence remains a key concern for patients with HR+/HER2- disease, which represents roughly 70% of all breast cancer cases.2

Funded by F. Hoffman-La Roche Ltd., and sponsored by MEDSIR, MiRaDoR will use Signatera Genome to evaluate the efficacy of different therapeutic approaches in early-stage HR+/HER2- breast cancer. Up to 60 patients who are Signatera-positive without clinical nor radiological evidence of disease recurrence will be sequentially enrolled into one of four treatment arms:

Arm A: Standard of care endocrine therapy given during the first 90-day period, then patients switch to Arms B, C or D
Arm B: Giredestrant (oral selective estrogen receptor degrader)
Arm C: Giredestrant plus Abemaciclib (CDK4/6 inhibitor)
Arm D: Giredestrant plus Inavolisib (PIK3CA inhibitor; for patients with PIK3CA mutations)
The trial will enable investigators to evaluate serial circulating-tumor DNA (ctDNA) levels in each treatment arm as a predictive marker of treatment response. The study’s primary endpoint is the proportion of patients who have achieved a 90% decrease or clearance in baseline ctDNA after three months of treatment. Participants will have additional Signatera testing at 6, 9 and 12 months, and every six months thereafter until study treatment discontinuation. Results may help determine if specific therapy combinations are more effective in terms of ctDNA decrease than standard of care endocrine treatment.

"Uniting Signatera Genome’s ability to detect molecular residual disease with genomic profiling creates a new standard for precision oncology clinical trials," said Angel Rodriguez, M.D., senior medical director of oncology at Natera. "In the MiRaDoR trial, investigators are moving beyond surveillance; they are also characterizing the specific genomic driver, PIK3CA, and no longer just asking ‘is the cancer back?’ but also answering ‘how do we treat it?’"

Enrollment for MiRaDoR is underway, with several U.K. sites already active and additional site activations expected in Europe in 2026.

(Press release, MedSIR, DEC 12, 2025, View Source [SID1234661410])