Abstract OT3-17-01: OPTIMA: A prospective randomized trial to validate the clinical utility and cost-effectiveness of gene expression test-directed chemotherapy decisions in mostly node-positive early breast cancer

Background: Multi-parameter tumour gene expression assays (MPAs) are widely used to estimate individual patient risk and to guide chemotherapy use in hormone-sensitive, HER2-negative early breast cancer. The TAILORx trial supports MPA use in a node-negative population. Evidence in node-positive breast cancer is limited. OPTIMA (Optimal Personalised Treatment of early breast cancer usIng Multi-parameter Analysis) (ISRCTN42400492) is a prospective international randomised controlled trial (RCT) designed to validate MPA’s as predictors of chemotherapy sensitivity in a largely node-positive breast cancer population. Methods: OPTIMA is a partially blinded study with an adaptive two-stage design. The main eligibility criteria are women and men age 40 or older with resected ER-positive, HER2-negative invasive breast cancer and up to 9 involved axillary lymph nodes. Randomisation is to standard management (chemotherapy and endocrine therapy) or to MPA-directed treatment using the Prosigna (PAM50) test. Those with a Prosigna tumour Score (ROR_PT) >60 receive standard management whilst those with a low score (≤60) are treated with endocrine therapy alone. Endocrine therapy for pre-menopausal women includes ovarian suppression. Prosigna tests are currently performed only for participants randomised to MPA-directed treatment. More than 1 tumour may be tested if participants have multi-focal tumours with discordant features and/or are considered clinically significant. The co-primary outcomes are: (1) Invasive Disease Free Survival (IDFS) and (2) cost-effectiveness. Secondary outcomes include IDFS in patients with low-score tumours and quality of life. Recruitment of 4500 patients over 5 years will permit demonstration of 3% non-inferiority of test-directed treatment, assuming 5-year IDFS of 85% with standard management. An integrated qualitative recruitment study addresses challenges to consent and recruitment, building on experience from the feasibility study which found that a multidisciplinary approach is important for recruitment success. Results: The OPTIMA main trial opened in January 2017. Overall recruitment as of 1 July 2019 was 1123 (1100 from UK, 13 from Norway); 91% had axillary node macro-metastases. Median time from consent to treatment allocation was 12 days (interquartile range 10-14 days). The withdrawal rate from trial treatment is 3%; 50% of these continue with follow up. Prosigna tests have been performed on 608 tumours for 549 participants; 59% were luminal A, 38% were luminal B and 3% non-luminal (6 patients with non-luminal tumours [1% overall] were ineligible on receptor retesting). Of the 53 (10%) participants with >1 tumour tested, 3 (6%) had discordant scores only, 7 (13%) had discordant subtypes only and 8 (15%) had both discordant scores and subtypes. Two thirds of the MPA-directed arm participants have been allocated to endocrine therapy only. The test failure rate is Conclusion: OPTIMA is one of two large scale prospective trials validating the use of test-guided chemotherapy decisions in node-positive early breast cancer. It is expected to have a global impact on breast cancer treatment. Funding: OPTIMA is funded by the UK NIHR HTA Programme (10/34/501). Views expressed are those of the authors and not those of the HTA Programme, NIHR, NHS or the Department of Health. Trial Inquiries: OPTIMA@warwick.ac.uk Citation Format: Robert C Stein, Andrea Marshall, Andreas Makris, Luke Hughes-Davies, Iain R MacPherson, Carmel Conefrey, Leila Rooshenas, Sarah E Pinder, Abeer M Shaaban, Bjorn Naume, David A Cameron, Daniel W Rea, Helena M Earl, Christopher J Poole, Peter S Hall, Georgina Dotchin, Stuart A McIntosh, Victoria Harmer, Adrienne Morgan, Bethany Shinkins, Nigel Stallard, Christopher McCabe, Jenny L Donovan, John MS Bartlett, Janet A Dunn. OPTIMA: A prospective randomized trial to validate the clinical utility and cost-effectiveness of gene expression test-directed chemotherapy decisions in mostly node-positive early breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr OT3-17-01.