Abstract PO1-19-06: Physical exercise during neoadjuvant chemotherapy for breast cancer as a mean to increase pathological complete response rates: the randomized Neo-ACT trial
Authors: de Boniface Jana , Ringborg Cecilia Haddad , Altena Renske , Wengström Yvonne 
Published: May 2024

Abstract
Introduction
In early breast cancer, neoadjuvant chemotherapy (NACT) is increasingly used. The proof of efficacy is pathologically complete response (pCR), i.e. the absence of invasive tumour in breast and lymph nodes at surgery. Today, pCR is a common endpoint in pharmaceutical trials since it is significantly associated with survival especially in triple-negative and HER2-positive subtypes. Apart from the mitigation of treatment-related toxicity and symptoms, physical exercise mediates anti-tumoral systemic effects associated with tumour regression in preclinical and clinical models. The aim of Neo-ACT is to test the hypothesis that physical exercise can improve pCR rates in breast cancer patients receiving NACT.
Method
The Neo-ACT trial is an international prospective clinical trial, randomising T1-3N0-2 breast cancer patients planned for NACT to either a home-based physical exercise intervention supported by a mobile application or routine care. The primary endpoint is pCR; secondary endpoints are patient-reported quality of life, toxicity-related outcomes, and oncological outcomes such as Residual Cancer Burden, objective radiological tumour response, as well as overall, breast cancer-specific and disease-free survival at 2, 5 and 10 years. The intervention consists of a combination of high-intensity interval and resistance training of progressing intensity, and includes two weekly 60-min exercise sessions plus at least 150 min of moderate to vigorous physical activity per week. The Neo-ACT has been registered at clinicaltrials.gov on January 11, 2022 (NCT05184582).
Statistical methods
Patients will be randomized in a 1:1 fashion. It is anticipated that the rate of the primary endpoint pCR will be approximately 30% in the control arm (all subtypes). We aim to increase the rate of pCR in the experimental arm to 40%, i.e. a 10 percentage points increase, which is regarded clinically relevant since it would translate into improved disease-related outcomes. With a power of 80% and an alpha of 5%, a total of 712 patients have to be included; 356 in each arm. Accounting for a drop-out of 10%, we aim to include 790 patients. Stratification at the moment of computerized randomization is based on site of treatment (hospital) and biological tumour subtype (ER+HER2-, ER+HER2+, ER-HER2+, ER-HER2-).
All outcomes will primarily be analysed using an intention-to-treat approach, i.e. all study subjects will belong to the treatment group (exercise intervention or control) they were assigned to, disregarding compliance. As sensitivity analysis, all outcomes will also be analysed using a per-protocol approach, meaning that participants in the intervention group who comply with less than 65% of the prescribed physical exercise program, and participants who complete less than 40% of the planned neoadjuvant systemic therapy (around two 3-weekly courses) will be excluded from analysis.
Present accrual
The Neo-ACT trial has started enrolment at the first site in December 2022 and since then initiated a further five Swedish and one Finnish site. Until June 15, 2023, 26 participants had been randomized in the trial. A feasibility questionnaire is distributed via the EUBREAST network which officially supports this trial and has added the designation EUBREAST12-R. Further participating sites can be accommodated depending on volume, competing trials and language requirements for the mobile application. Contact: jana.de-boniface@ki.se
Citation Format: Jana de Boniface, Cecilia Haddad Ringborg, Renske Altena, Yvonne Wengström. Physical exercise during neoadjuvant chemotherapy for breast cancer as a mean to increase pathological complete response rates: the randomized Neo-ACT trial [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-19-06.