Abstract A50: Circulating tumor DNA (ctDNA) and magnetic resonance imaging (MRI) for monitoring and predicting response to neoadjuvant therapy (NAT) in high-risk early breast cancer patients in the I-SPY 2 TRIAL

Background: MRI measurements (Li et al., Magn Reson Imaging 2019; Hylton et al., Radiology 2016) and ctDNA (Magbanua et al., SABCS 2018) have both been independently shown to associate with response to NAT. We performed a retrospective study to examine correlation between ctDNA and MRI and to investigate whether information from these two measurements can be combined to improve early prediction of response.

Methods: We analyzed serial ctDNA and MRI data from 84 high-risk (stage II/III) breast cancer patients collected at baseline (T0), 3 weeks after initiation of paclitaxel-based NAT (T1), between paclitaxel and anthracycline regimens (T2), and after NAT prior to surgery (T3). The response variable was pathologic complete response (pCR), defined as the absence of invasive tumor in the breast and lymph nodes after NAT. We examined correlations between MR functional tumor volume (FTV) and ctDNA using Spearman's rho (r). Mean FTV between ctDNA+/- groups were compared using t-test. Monte Carlo simulation was used to assess correlation between FTV and ctDNA trajectories in individual patients. We investigated the impact of adding ctDNA information to MR FTV-based predictors using receiver operating characteristic curves to calculate area under the curve (AUC), logistic regressions, and decision trees using recursive partitioning.

Results: The mean levels of ctDNA (mutant molecules/mL plasma) were significantly correlated with FTV at all timepoints [T0 (r=0.49), T1 (r=0.42), T2 (r=0.42), T3 (r=0.43), all p<0.05]. The mean FTV in patients who had detectable ctDNA was significantly higher compared to those who were negative (all timepoints, all p<0.05). FTV and ctDNA trajectories in individual patients over the course of therapy were correlated (empirical 1-sided p=0.046). Adding continuous ctDNA information (mutant molecules/mL plasma) to FTV at T1 improved AUC in the pCR-prediction model, but the increase was not statistically significant (FTV: 0.59, FTV+ctDNA: 0.69, p=0.25). No improvements in AUCs were observed at other timepoints. Treated as a dichotomous variable, ctDNA positivity at T1 trended toward association with non-pCR in logistic regression models at T2 and T3 with MR-based prediction scores as a covariate (0.05).

Citation Format: Mark Jesus M. Magbanua, Laura H. Hendrix, Terry Hyslop, William T. Barry, Eric P. Winer, Clifford Hudis, Deborah Toppmeyer, Lisa Anne Carey, Ann H. Partridge, Jean-Yves Pierga, Tanja Fehm, José Vidal-Martínez, Dimitrios Mavroudis, Jose A. Garcia-Saenz, Justin Stebbing, Paola Gazzaniga, Luis Manso, Rita Zamarchi, María Luisa Antelo, Leticia De Mattos-Arruda, Daniele Generali, Carlos Caldas, Elisabetta Munzone, Luc Dirix, Amy L. Delson, Harold Burstein, Misbah Qadir, Cynthia Ma, Janet H. Scott, François-Clément Bidard, John W. Park, Hope S. Rugo. Circulating tumor DNA (ctDNA) and magnetic resonance imaging (MRI) for monitoring and predicting response to neoadjuvant therapy (NAT) in high-risk early breast cancer patients in the I-SPY 2 TRIAL [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr A50.

Abstract P2-12-06: The clinical benefit index: A pilot study integrating treatment efficacy and quality of life in oncology clinical trials

Background: Breast cancer remains the most frequently diagnosed cancer among women worldwide, accounting for a quarter of all diagnoses. Despite advances in treatment and symptom management, the majority of women will experience some form of drug-related toxicity, psychosocial distress, and subsequent impairments in their quality of life (QoL). Distress and impairments in QoL can interfere with treatment adherence, while engagement in health promoting behaviors and effective management of symptoms has been associated with improved QoL, adherence and increased survival. The utilization of QoL or other Patient Reported Outcome (PRO) measures in clinical trials remains inconsistent, and no uniformly accepted measure exists to integrate QoL data into the assessment of therapeutic agents. There are two goals of the I-SPY 2 QoL Pilot Study: 1) To demonstrate the reporting of an integrated utility-based QOL score, the PROPr, within a novel longitudinal approach that provides a single numerical index of QoL; 2) Generate a Clinical Benefit Index (CBI), a single composite score that integrates the longitudinal PROPr score with a clinical efficacy score, RCB index, to provide a measure that could go beyond clinical efficacy in the evaluation of therapeutic agents in the I-SPY 2 TRIAL. Methods: Study participants were part of the I-SPY 2 TRIAL assessing novel neoadjuvant therapies added to standard chemotherapy in the treatment of Stage 2/3 breast cancer. Participants completed a validated QoL measure at three time points: baseline, prior to surgery, and 1-month post-surgery. QoL was assessed using the NIH PROMIS measure (physical function (four items), anxiety (eight items), depression (eight items), fatigue (eight items), applied cognition (eight items) and social roles (four items)) and results at each time point used to calculate the PROPr, a single utility-based index score to assess overall quality of life. PROPr index utility scores were used to generate a single longitudinal QoL score based on area under the curve modeling. Clinical efficacy was assessed based on the residual cancer burden (RCB) observed at the time of surgery. The CBI was generated by plotting RCB index against the longitudinal PROPr index for each participant and study arm. Results: Only a fraction (n=107) of all patients had complete data across study timepoints and were included in our analyses, and thus our data represent a proof of concept. Patients on the control arm were treated with Paclitaxel followed by anthracycline (AC). Patients in the pilot were assigned either the control arm or six experimental drug arms. The longitudinal PROPr utility index demonstrated a range of outcomes, with some arms more challenging to tolerate, and others much better, ranging from 0.67 to 1.16. The RCB index of the seven study arms ranged from 0.49 to 1.99. The CBI, an integration of the longitudinal PROPr and RCB indexes, also demonstrated a range from 0.43 to 1.60. Conclusion: We are reporting the development of a novel, valid and standardized QoL assessment that should be a routine part of clinical trials in oncology. This proof of concept study suggests that that calculation of the CBI is feasible and can reveal differences in the clinical profiles of therapeutic agents, both in terms of QoL and overall integration of clinical efficacy and QoL. The CBI represents a novel approach to providing summary data that can be easily interpreted as part of clinical trial outcome data. Ideally, these integrated assessments would provide a more comprehensive evaluation of investigational therapies, and ultimately help inform treatment decision discussions between patients and providers. Moving forward, electronic PRO data will be collected as part of routine care in the I-SPY 2 TRIAL, thus enabling the longitudinal PROPr and CBI scores to be generated for every agent evaluated.

Citation Format: Amrita Basu, Errol J. Philip, Barry Dewitt, Janel Hanmer, Aheli Chattopadhyay, Christina Yau, Smita Asare, Karyn Digiorgio, Ruby Singhrao, Adam Asare, Jane Perlmutter, I-SPY 2 Consortium, Michelle Melisko, Laura Esserman. The clinical benefit index: A pilot study integrating treatment efficacy and quality of life in oncology clinical trials [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 P2-12-06.

Abstract 2679: Integration of DNA repair deficiency and immune biomarkers to predict which early-stage triple-negative breast cancer patients are likely to respond to platinum-containing regimens vs. immunotherapy: The neoadjuvant I-SPY 2 trial

Background: Triple negative breast cancer (TNBC), generally considered aggressive with few options beyond standard chemotherapy, is currently experiencing a period of optimism, with multiple trials showing increased efficacy of platinum containing regimens (with and without PARP-inhibition), and more recently, immunotherapy. In I-SPY 2, veliparib/carboplatin (VC) and the immune checkpoint inhibitor pembrolizumab (Pembro) graduated in the TN subtype. As part of the I-SPY 2 biomarker program, we previously identified the signature PARPi7, a measure of DNA repair deficiency (DRD), as predicting response to VC. As well, immune signatures, including one representing dendritic cells, predicted response to Pembro. Here we investigate the overlap between these biomarkers to identify patient subgroups more likely to respond to immunotherapy or platinum-based therapy and estimate response rates to VC and Pembro in patients positive for one, both, or neither biomarker.

Methods: 153 TNBC patients (Control: 85; VC: 39; Pembro: 29) were considered in this analysis. Continuous DNA repair deficiency and immune signatures assayed at the pre-treatment time point were evaluated as published (Wolf, 2017; Danaher, 2017). To identify optimal dichotomizing thresholds, 2-fold cross-validation was repeated 500 times. Bayesian logistic regression was used to estimate pCR rates by arm for patient subsets defined by biomarker combinations. Our study is exploratory with no claims for generalizability; and this analysis does not adjust for multiplicities.

Results: Using the optimal dichotomizing cutpoints, 54% of TNBC patients are classified as DRD+, and 67% Immune+. As expected, DRD+ patients have a high estimated pCR rate to VC (75%); and Immune+ patients have a high estimated pCR rate to Pembro (82%). Combining these biomarkers, 40% of TNBC are positive for both biomarkers, 40% for only one biomarker (26% Immune+/DRD-, 14% Immune-/DRD+), and 20% for neither. The Immune+/DRD+ TN subset predicted sensitive to both VC and Pembro has a higher estimated pCR rate to both VC and Pembro relative to control (estimated pCR rates: VC: 75%, Pembro: 73% vs. control: 18%). In contrast, the Immune+/DRD- group, predicted to be sensitive to Pembro, has the highest pCR rate to Pembro (VC: 48%, Pembro: 83% vs. control 21%), whereas the Immune-/DRD+ group is most responsive to VC (VC: 63%, Pembro: 41% vs. control 29%). For the 20% of Immune-/DRD- TNBC patients, their estimated response rates are lower than the biomarker-positive patients (VC: 27%, Pembro: 43% vs. control: 19%).

Conclusion: Molecular phenotypes capturing immune activation and DNA repair deficiency may predict response of TNBC and help prioritize selection of platinum or immunotherapy containing regimens.

Citation Format: Denise M. Wolf, Christina Yau, Julia Wulfkuhle, Emanuel Petricoin, Lamorna Brown-Swigart, Gillian Hirst, Smita Asare, I-SPY 2 Consortium, Douglas Yee, Angela DeMichele, Hope Rugo, Olufunmilayo Olopade, Rita Nanda, Minetta Liu, Laura Esserman, Laura van t' Veer. Integration of DNA repair deficiency and immune biomarkers to predict which early-stage triple-negative breast cancer patients are likely to respond to platinum-containing regimens vs. immunotherapy: The neoadjuvant I-SPY 2 trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2679.

Abstract P1-15-02: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Schwab R, Clark A, Yau C, Wolf D, Chien AJ, Majure M, Ewing C, Wallace A, Roesch E, Helsten T, Forero A, Stringer-Reasor E, Vaklavas C, Nanda R, Jaskowiak N, Boughey J, Haddad T, Han H, Lee C, Albain K, Isaacs C, Elias A, Ellis E, Shah P, Lang J, Lu J, Tripathy D, Kemmer K, Yee D, Haley B, Korde L, Edmiston K, Northfelt D, Viscusi R, Khan Q, I-SPY 2 Consortium, Symmans WF, Perlmutter J, Hylton N, Rugo H, Melisko M, Wilson A, Singhrao R, Asare S, van't Veer L, DeMichele A, Berry D, Esserman L. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-15-02.