On May 29, 2026 Veracyte, Inc. (Nasdaq: VCYT), a leading cancer diagnostics company, reported results from the independent OPTIMA (Optimal Personalised Treatment of early breast cancer using Multi-parameter Analysis) trial, led by University College London (UCL). The results, which will be presented at the ASCO (Free ASCO Whitepaper) Annual Meeting, conclude that the Prosigna Breast Risk of Recurrence (ROR) test safely guides adjuvant chemotherapy decisions in patients with early-stage, ER-positive HER2-negative breast cancer.

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"Behind every breast cancer treatment decision is a patient asking, ‘Do I really need chemotherapy?’" said Prof. Robert Stein, Lead Investigator, University College London. "OPTIMA answers this question with robust evidence. These study results can be practice-changing – we can now use the Prosigna test to predict which high-risk patients can safely avoid chemotherapy and its lasting side effects without compromising outcomes. That is a profound shift for patients and the clinicians who care for them."

The Phase III prospective, randomized controlled trial compared standard of care – chemotherapy followed by hormone therapy – to treatment guided by Prosigna test results: patients with high ROR scores (>60) received chemotherapy followed by hormone therapy while those with low ROR scores (≤60) received hormone therapy alone.

Key Trial Findings

The OPTIMA trial results demonstrate:

Chemotherapy can be safely avoided for many patients: The Prosigna test identified that 68% of patients with clinically high-risk node-positive breast cancer, who previously would have received chemotherapy, could safely forgo it entirely. These patients achieved 5-year cancer-free survival rates of 93.7% — statistically noninferior to the 94.9% achieved with chemotherapy — demonstrating that omitting treatment for these patients does not compromise outcomes or increase recurrence risk.
Robust results across broadest range of high-risk subgroups: Non-inferiority was confirmed in previously under-studied populations where treatment guidance has been most uncertain, demonstrating that tumor biology, vs clinical factors alone, can guide chemotherapy decisions for:
Premenopausal women treated with ovarian function suppression (HR 1.04; 90% CI 0.60–1.80)
Patients with extensive nodal involvement (4–9 positive nodes, or pN2 disease) (HR 1.19; 95% CI 0.62–2.29)
Highest level of prospective evidence: With 4,429 patients and 4.0-year median follow-up, OPTIMA provides Level 1A evidence, showing that the Prosigna test can accurately predict chemotherapy benefit and guide safe de-escalation across patient populations.
The Impact on Patients with Breast Cancer

Breast cancer remains the most commonly diagnosed cancer worldwide, affecting 1 in 8 women in the U.S.,1 with over 225,000 new HR+/HER2- breast cancer cases diagnosed annually.2 Treatment decisions play a critical role in preventing recurrence and improving long-term outcomes.

For many of these patients, chemotherapy decisions have historically been driven by clinical factors alone – age, tumor size, and lymph node status – and its potential for multiple, severe side effects. Up to 43% of breast cancer survivors experience persistent nerve damage years after chemotherapy, with studies showing a broader range of treatment-related side effects impacting the majority of patients during and after care.3

The Prosigna test is a genomic test that uniquely combines intrinsic subtypes and proliferation score with clinical pathological factors to calculate a patient’s Risk of Recurrence (ROR) score. In OPTIMA, an ROR score < 60 enabled clinicians to identify patients who could safely avoid chemotherapy. The results from the OPTIMA trial are in a position to transform how clinicians approach breast cancer treatment decisions using the Prosigna ROR score to confidently de-escalate therapy in a high percentage of high-risk patients.

"OPTIMA sets a new standard for how chemotherapy decisions are made in breast cancer," said Phillip Febbo, M.D., Chief Scientific and Medical Officer, Veracyte. "Prosigna now has the strongest prospective evidence of any genomic test to predict which patients with clinically high-risk hormone-receptor positive breast cancer can safely avoid chemotherapy. For patients, that means the option to choose a treatment with fewer unnecessary side effects, and for clinicians, the confidence to act on it."

ASCO Annual Meeting Presentation

The OPTIMA trial results are being presented this Saturday, May 30 at the 2026 ASCO (Free ASCO Whitepaper) Annual Meeting during the Breast Cancer—Local/Regional/Adjuvant Oral Abstract Session (1:15 PM CDT, Hall B1, Abstract 500). Prof. Robert C. Stein from University College London is presenting the findings, which will also be livestreamed via the ASCO (Free ASCO Whitepaper) conference platform.

About the OPTIMA Trial

OPTIMA (Optimal Personalised Treatment of early breast cancer using Multi-parameter Analysis) is an international, multicenter randomized controlled trial led by University College London and funded by U.K. National Institute for Health and Care Research. The independent study enrolled 4,429 women and men aged ≥40 years with ER-positive HER2-negative early breast cancer and 0–9 involved axillary lymph nodes. Participants were randomly assigned to either the control arm for standard chemotherapy followed by hormone therapy or to the Prosigna test-directed arm of standard chemotherapy followed by hormone therapy for patients with Prosigna high ROR test results (>60), versus hormone therapy alone for patients with Prosigna low ROR test results (≤60). All premenopausal women were required to have ovarian function suppression.

(Press release, Veracyte, MAY 29, 2026, View Source [SID1234666204])