Interim Analysis Research Articles

An open-label long-term Phase 3 study of CAM2029, an octreotide subcutaneous depot, in patients with acromegaly (ACROINNOVA 2): interim analysis of patient-reported outcomes

An open-label long-term Phase 3 study of CAM2029, an octreotide subcutaneous depot, in patients with acromegaly (ACROINNOVA 2): interim analysis of patient-reported outcomes

Assessing long-term safety and efficacy of osilodrostat in prior- and new-use patients with endogenous cushing's syndrome: a 1-year real-world interim analysis of the non-interventional, multinational LINC 6 study

Assessing long-term safety and efficacy of osilodrostat in prior- and new-use patients with endogenous cushing's syndrome: a 1-year real-world interim analysis of the non-interventional, multinational LINC 6 study

An open-label long-term Phase 3 study of CAM2029, an octreotide subcutaneous depot, in patients with acromegaly (ACROINNOVA 2): interim analysis of the ACROINNOVA 1 roll-over patients subgroup

An open-label long-term Phase 3 study of CAM2029, an octreotide subcutaneous depot, in patients with acromegaly (ACROINNOVA 2): interim analysis of the ACROINNOVA 1 roll-over patients subgroup

Semaglutide combined with empagliflozin vs. monotherapy for non-alcoholic fatty liver disease in type 2 diabetes: Study protocol for a randomized clinical trial.

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with type 2 diabetes mellitus (T2DM). Lifestyle intervention remains a preferred treatment modality for NAFLD. The glucagon-like peptide (GLP-1) receptor agonists and sodium-glucose cotransporter-2 (SGLT-2) inhibitors have been developed as new glucose-lowering drugs, which can improve fatty liver via an insulin-independent glucose-lowering effect. However, studies exploring the efficacy of GLP-1 receptor agonists combined with SGLT-2 inhibitors in patients with NAFLD and T2DM are scanty. Thus, the present randomised controlled trial aims at comparing the efficacy and safety of semaglutide plus empagliflozin with each treatment alone in patients with NAFLD and T2DM. This 52-week double-blinded, randomised, parallel-group, active-controlled trial evaluates the effects of semaglutide, empagliflozin and semaglutide + empagliflozin in 105 eligible overweight/obese subjects with NAFLD and T2DM. The primary outcome will be a change from baseline to week 52 in the controlled attenuation parameter, free fatty acid and glucagon. Secondary endpoints include changes in liver stiffness measurement, liver enzymes, blood glucose, lipid levels, renal function, electrolyte balances, minerals and bone metabolism, cytokines, high-sensitivity C-reactive protein, ferritin, anthropometric indicators, nonalcoholic fatty liver fibrosis score, fibrosis 4 score and homeostatic model assessment for insulin resistance. In addition, intention-to-treat, interim analysis and safety analysis will be performed. This double-blinded, randomised, clinical trial involves a multi-disciplinary approach and aims to explore the synergistic effects of the combination of semaglutide and empagliflozin. The results can provide important insights into mechanisms of GLP-1 receptor agonists and/or SGLT-2 inhibitors in patients with NAFLD and T2DM. This study has been registered with Chinese Clinical Trial Registry (ChiCTR2300070674).

Abstract PO3-17-07: Real-world experience with trastuzumab deruxtecan in patients with breast cancer: 6 month-interim analysis of an all-patient postmarketing surveillance in Japan

Abstract Background: Trastuzumab deruxtecan (T-DXd) is an anti-human epidermal growth factor receptor 2 (HER2) antibody-drug conjugate. T-DXd has shown great efficacy in HER2-positive breast cancer, hence receiving approval in Japan in March 2020. In Japan, all-patient postmarketing surveillance (PMS) is underway to evaluate the risk of interstitial lung disease/pneumonitis (ILD/p) in patients with breast cancer treated with T-DXd. Due to the limited generalizability of results from clinical trials, there is a need for more information about ILD/p in a real-world setting. Herein we present an interim analysis of the large-scale all-patient PMS. Methods: This is an observational, multicenter, all-patient PMS (jRCT1080225197) with an observation period of 18 months that enrolled all patients treated with T-DXd for recurrent/advanced HER2-positive breast cancer. Patients who initiated T-DXd treatment between May 2020 (launch date of T-DXd) and May 2021 were included in the interim analysis to ensure the observation period of 6 months from the initial treatment of T-DXd. This interim analysis is based on safety data from the first 6 months of 1204 patients. Data collected includes baseline characteristics and information on ILD/p. All potential ILD/p (identified based on the AE terms) reported by physicians were adjudicated by an independent ILD adjudication committee. The incidence of ILD/p was calculated from adjudicated drug-related ILD/p. Results: The interim analysis set included 1204 patients with median age of 60 years. Three of the 1204 patients (0.2%) received T-DXd as a first-line treatment, 30 (2.5%) as second-line, 1159 (96.3%) as third- line or later treatment. At baseline, 105 (8.7%) of patients had an Eastern Cooperative Oncology Group performance status (ECOG PS) 2 or greater, 8 (0.7%) had severe renal impairment (15≤ creatinine clearance (CLcr) < 30 mL/min), 4 (0.3%) had end-stage renal disease (CLcr < 15 mL/min), 5 (0.4%) had severe liver impairment (total bilirubin >4.5 mg/dL), and 32 (2.7%) had comorbid ILD/radiation pneumonitis. Those were defined as exclusion criteria in clinical trials of T-DXd. The median dose at the start of administration of T-DXd was 5.4 mg/kg (range:2.7-5.4). During the first 6 months from the initial treatment, T-DXd was discontinued in 403 (33.5%) of the 1204 patients. The most common reasons for discontinuation were disease progression in 232 (57.6%) of the discontinued 403 patients followed by ILD/p in 97 (24.1%) of the 403 patients. In the first 6 months, the incidence of all grade, grade ≥3, and grade 5 ILD/p were 8.2% (n=99), 1.7% (n=20) and 0.4% (n=5), respectively. The incidence of ILD/p stratified by baseline characteristics identified as potential risk factors of drug-related ILD/p is shown in Table. Conclusion: This is the first report demonstrating real-world experience with T-DXd in Japan. The interim analysis revealed useful information including patient and treatment profiles of T-DXd and the incidence of ILD/p during the first 6 months from the initial treatment in a real-world setting in Japan. The final analysis of the ongoing PMS is warranted for further evaluation. Incidence of interstitial lung disease/pneumonitis by patient baseline characteristics XX XX ILD/p: interstitial lung disease/pneumonitis, 95% CI: 95% confidence interval, CLCr: creatinine clearance using the Cockcroft-Gault equation * includes ILD/p, pulmonary fibrosis, radiation pneumonitis, chronic obstructive pulmonary disease, emphysema, and Asthma (Source: Powell CA, Modi S, Iwata H, et al. Pooled analysis of drug-related interstitial lung disease and/or pneumonitis in nine trastuzumab deruxtecan monotherapy studies. ESMO Open 2022;7(4):100554) Citation Format: Junji Tsurutani, Hideki Mizutani, Ayumi Tanabe. Real-world experience with trastuzumab deruxtecan in patients with breast cancer: 6 month-interim analysis of an all-patient postmarketing surveillance in Japan [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 PO3-17-07.

Abstract PO3-16-12: European real-world experience of patients with HER2+ advanced/metastatic breast cancer accessing trastuzumab deruxtecan through a named patient program: first interim analysis of EUROPA T-DXd

Abstract Background: In 2021, trastuzumab deruxtecan (T-DXd) monotherapy was conditionally approved in the EU for adult patients with human epidermal growth factor receptor 2-positive (HER2+) advanced/metastatic breast cancer (mBC). A named patient program (NPP) was initiated (March 2021) to enable eligible patients with an unmet medical need to gain access to T-DXd when not yet available locally, either commercially or through an appropriate clinical trial. Centers that treated/are treating patients under this NPP were invited to participate in EUROPA T-DXd real-world data (RWD) collection. Methods: EUROPA T-DXd is an ongoing, multicenter (Ireland, Italy, and Spain), observational (retro- and prospective) study of RWD from approximately 200 adult patients with HER2+ advanced/mBC who had received ≥2 prior anti-HER2 regimens and for whom T-DXd was initiated through the NPP. Collection of RWD is optional and independent of eligibility for the NPP. The primary objective is to estimate real-world time to treatment discontinuation (rwTTD). Secondary objectives include real-world progression-free survival (rwPFS), reasons for T-DXd discontinuation, safety, and prior anti-HER2 treatment patterns. Results: This first interim analysis included 84 evaluable patients. Patients had a mean (standard deviation) age of 53.4 (11.1) years; most were female (97.6%) and had HER2 immunohistochemistry 3+ (70.2%), and 44% had received >3 prior lines of anti-HER2 therapy in the metastatic setting (Table). At data cutoff (June 5, 2023), 50 (59.5%) patients were still receiving T-DXd. In total, 34 patients (40.5%) discontinued T-DXd (death, n=1 [1.2%]; adverse event, n=3 [3.6%]; disease progression, n=26 [31%]; or other, n=4 [4.8%]). Median rwTTD was 21.4 months (95% confidence interval 17.6, not estimated), and median rwPFS was not reached. The results of the wider cohort will be presented at the meeting, including adverse events. Conclusion: Results from this first interim analysis confirm the efficacy of T-DXd in heavily pretreated patients with HER2+ mBC. Baseline characteristics and demographics are comparable to the clinical trial setting. Analyses are ongoing and will provide more mature rwTTD and rwPFS. XX XX Citation Format: Michelino De Laurentiis, José Ángel García-Sáenz, Giampaolo Bianchini, Cristina Saura, Hans Wildiers, Arthur Allignol, Amanda Logue, Markus Lucerna, Sabine Stamenitis. European real-world experience of patients with HER2+ advanced/metastatic breast cancer accessing trastuzumab deruxtecan through a named patient program: first interim analysis of EUROPA T-DXd [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 PO3-16-12.

Abstract PO3-19-05: Phase III study to evaluate the efficacy and safety of GLSI-100 (GP2 + GM-CSF) in breast cancer patients with residual disease or high-risk PCR after both neo-adjuvant and postoperative adjuvant anti-HER2 therapy, Flamingo-01

Abstract Background: GP2 is a biologic nine amino acid peptide of the HER2/neu protein delivered in combination with Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) that stimulates an immune response targeting HER2/neu expressing cancers, the combination known as GLSI-100. In a prospective, randomized, single-blinded, placebo-controlled, multicenter Phase IIb study, no recurrences were observed in the HER2+ population after 5 years of follow-up, if the patient was treated with GLSI-100, survived, and was followed for more than 6 months (p = 0.0338). Immunotherapy elicited a potent response measured by skin tests and immunological assays. Of the 146 patients that have been treated with GLSI-100 over 4 clinical trials, GLSI-100 was well-tolerated and no serious adverse events observed were considered related to the immunotherapy. Methods: This Phase III trial is a prospective, randomized, double-blinded, multi-center study. After 1 year of trastuzumab-based therapy, 6 intradermal injections of GLSI-100 or placebo will be administered over the first 6 months and 5 subsequent boosters will be administered over the next 2.5 years for a total of 11 injections over 3 years. The participant duration of the trial will be 3 years treatment plus 1 additional year follow-up for a total of 4 years following the first year of treatment with trastuzumab-based therapy. Patients will be stratified based on residual disease status at surgery, hormone receptor status and region. Study Size – Interim Analysis: Approximately 498 patients will be enrolled. To detect a hazard ratio of 0.3 in invasive breast cancer free survival (IBCFS), 28 events will be required. An interim analysis for superiority and futility will be conducted when at least 14 events have occurred. This sample size provides 80% power if the annual rate of events in placebo patients is 2.4% or greater. Up to 100 non-HLA-A*02 subjects will be enrolled in an open-label arm. Eligibility Criteria: The patient population is defined by these key eligibility criteria: Objectives: Study Status: The study has been initiated at a number of sites in the US. The study is also expected to be opened in Spain, Germany, and France. Contact Information: Greenwich LifeSciences, Inc. Stafford, TX Email: Flamingo-01@greenwichlifesciences.com Website: greenwichlifesciences.com Funding: This trial is supported by Greenwich LifeSciences. Citation Format: Snehal Patel, Jaye Thompson, Mira Patel, F. Joseph Daugherty, Mothaffar Rimawi. Phase III study to evaluate the efficacy and safety of GLSI-100 (GP2 + GM-CSF) in breast cancer patients with residual disease or high-risk PCR after both neo-adjuvant and postoperative adjuvant anti-HER2 therapy, Flamingo-01 [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 PO3-19-05.

Abstract PO2-16-08: Adjuvant Treatment Selection for County-Level Patients with HR+/HER2- Early Breast Cancer in a Real-Life Setting in China

Abstract Background: CHASE001 (NCT05544123), a prospective, non-interventional multicenter study exploring real-world treatment and referral behavior of Chinese county patients (pts) with HER2+ or HR+/HER2– breast cancer is ongoing since September 2022. A prespecified interim analysis (IA) on 750 HER2+ and HR+/HER2- early breast cancer (eBC) was reported at the ESMO Congress 2023. In the 2nd IA from CHASE001, adjuvant treatment selection for patients with HR+/HER2- eBC will be evaluated. Methods: The study was designed to enroll 2500 pts, including four cohorts (HER2+ eBC, HR+/HER2-eBC, HER2+ advanced BC, and HR+/HER2- aBC). In this IA, HR+/HER2- eBC pts after surgery were included. Descriptive statistics reported patient demographics, clinical and disease characteristics and treatment patterns. To investigate the factors associated with chemotherapy-free regimen, non-anthracycline chemotherapy regimen and ovarian function suppression (OFS), univariate and multivariate logistic regression analyses were conducted. Results: At data cutoff (May 17, 2023), 697 HR+/HER2- eBC pts (median age 52 years, 45.77% pT2, 50.93% pN0, 56.10% G2) were included from 26 institutions in China county areas, 338 (48.49%) were premenopausal. 584 (83.79%) received adjuvant chemotherapy, with a few (47/584, 8.05%) initially developing their treatment plan at a higher level hospital (national or provincial tertiary hospital). AC-T (309/584, 52.91%) was the most commonly used regimen. 181 (30.99%) pts received non-anthracycline chemotherapy regimen (mainly TC), and pts with N0, age≥65 years and ki67 < 20% had the strongest association to this regimen (multivariate OR=0.082, 95%CI [0.037,0.179], OR=0.463, 95%CI [0.250,0.859], and OR=0.642, 95%CI [0.418,0.985], respectively). Interestingly, on univariate analysis pts initially diagnosed in a higher level hospital were significantly associated with non-anthracycline regimen (P=0.0109), however on multivariate analysis it was no longer significant. 483 pts received endocrine therapy, including 234 (48.45%) premenopausal pts. The most commonly used endocrine regimen for premenopausal pts was OFS/OFS+ (122/234, 52.14%) ,of which half (61, 50%) were prescribed OFS+TAM/TOR; followed by TAM/TOR monotherapy (69/234, 29.49%). The proportions of patients classified as low, intermediate, and high clinical risk for recurrence (investigator assessed)were 33.62%, 42.67% and 23.71%. The OFS rate were 39.74% in low, 61.62% in intermediate and 70.91% in high risk pts, respectively. Multivariable analyses found that high clinical risk, age < 45 years and ki67 < 20% were strongly associated with the use of OFS (OR=0.210, 95%CI [0.066,0.674], OR=0.327, 95%CI [0.165,0.649], and OR=0.405, 95%CI [0.194,0.845], respectively). For postmenopausal pts, AI monotherapy (84.74%) was the most commonly used endocrine regimen. Conclusions: To our knowledge, this is the first real-world study evaluating the treatment patterns and referral behavior of BC pts in China counties. The 2nd IA results presented showed the current systemic adjuvant treatment preferences and influence factors from a large sample of HR+/HER2- eBC pts in China counties, which were generally consistent with China BC treatment guidelines. Table 1. Utilization of adjuvant systemic therapy regimens in 697 HR+/HER2− eBC pts, China counties AC-T: (dd)doxorubicin/epirubicin, cyclophosphamide, followed by (dd)paclitaxel/docetaxel; TC: paclitaxel/docetaxel, cyclophosphamide; AC: doxorubicin/epirubicin, cyclophosphamide; TAC: docetaxel, doxorubicin/epirubicin, cyclophosphamide; TAM: tamoxifen; OFS: ovarian function suppression; AI: aromatase inhibitors; TOR: toremifene; CDK4/6i: cyclin-dependent kinase 4/6 inhibitors; “Other” category includes various therapies used in <1% of patients each Citation Format: Yinghua Ji, Honglan Qu, Feidu Zhou, Juan Wang, Qianfu Wu, Guohua Dai, Mengyou Liu, Wenbo He, Wei Liang, Qiuli Meng, Yun Ren, Guoxiang Luo, Hongjian Wang, Hui Liu, Zien Qin, Yingguo Tian, Huali Tang, Hongmei Liu, Jun Luo, Zengfeng Yu, Guinv Hu, Jianzhi Gao, Xiang Tan, Yi Liu, Yuanjiang Zhang, Ming Wang, Min Zhang, Ping Lu. Adjuvant Treatment Selection for County-Level Patients with HR+/HER2- Early Breast Cancer in a Real-Life Setting in China [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 PO2-16-08.

Abstract PO3-16-10: Real-world outcomes with first-line ribociclib + endocrine therapy in patients with metastatic HR+, HER2– breast cancer: Fourth interim analysis of REACH AUT trial

Abstract Background: Ribociclib (RIB), a cyclin-dependent kinase 4 and 6 inhibitor (CDK4/6i) in combination with endocrine therapy (ET) yielded significant improvement in progression-free survival (PFS) and overall survival (OS) across three phase III MONALEESA trials including patients (pts) with hormone receptor–positive (HR+), human epidermal growth factor receptor 2–negative (HER2–) metastatic breast cancer (MBC) in first-line (1L) and second-line (2L) setting. In the previous interim analyses of REACH AUT trial, 1L RIB + ET showed tolerable safety and favorable PFS results in a real-world setting. Results from the preplanned fourth interim analysis are reported here. Methods: REACH AUT is a noninterventional study conducted in Austria reporting data on the real-world clinical experience of RIB + ET (aromatase inhibitor [AI] or fulvestrant [FUL]) in premenopausal, perimenopausal, or postmenopausal pts with HR+, HER2– MBC. Pts with no prior ET for advanced disease and maximum up to 1 prior line of chemotherapy (CT) in the advanced setting were included. Results: At data cutoff (March 27, 2023) with a median duration of follow-up of 23.8 months, out of 281 analyzed pts (12.5% of premenopausal/perimenopausal and 85.1% of postmenopausal, 2.5% of unknown status) 31.7% of pts were receiving ongoing treatment. The most common reasons for treatment discontinuations (68.3%) were disease progression (39.1%) and adverse events (AEs, 22.1%). The median age was 63 years (< 65 years, n=156, 55.5%; ≥65 years, n=125, 44.5%) and ECOG PS ≥2: 1.8%. In 106 pts (37.7%), de novo metastatic disease was reported. Visceral metastases (lung, liver) were present in 116 pts (41.3%) and bone-only metastases in 80 pts (28.5%). Prior adjuvant therapy was received by 139 pts (49.5%): AI ± GnRH: n=80 (26.7% without and 1.8% with GnRH); tamoxifen ± GnRH: n=74 (21.7% without and 4.6% with GnRH); CT: n=56 (19.9%); antibody therapy n=3 (1.1%). In the metastatic setting, 1L RIB was prescribed in combination with an AI in 223 pts (79.4%; letrozole: n=139 [49.5%]; anastrozole: n=48 [17.1%]; exemestane: n=47 [16.7%]) and with FUL in 52 pts (18.5%). Prior CT for MBC was received by 5 pts (1.8%). The median PFS was 29.7 months in the overall population; 28.3 months in pts with bone only and 26.9 months in pts with visceral metastatic disease. In pts evaluable for response, the objective response rate and clinical benefit rate were 31.3% and 60.9%, respectively. The OS rates were 91.9%, 81.7%, and 63.7% at 12 months, 24 months, and 36 months, respectively. The trial is ongoing with ~40% of subjects end of documentation and ~27% of deaths. In total, 69.4% of pts had RIB dose interruptions and 48.8% of pts had a RIB dose reduction. The majority of all reported AEs were grade 1 (50.1%) or grade 2 (31.2%); the median time to first AE was 0.5 months. The most common AE was neutropenia (all grades: n=143, 50.9%; grade 1: n=39, 13.9%; grade 2: n=68, 24.2%; grade 3: n=98, 34.9%; grade 4: n=5, 1.8%). QTc prolongation of any grade was observed in 32 pts (11.4%; grade 1: n=24, 8.5%; grade 2: n=11, 3.9%; grade 3: n=1, 0.4%). Hepatobiliary toxicity of any grade was observed in 42 pts (14.9%; grade 1: n=12, 4.3%; grade 2: n=18, 6.4%; grade 3: n=22, 7.8%; grade 4: n=3, 1.1%). Overall, currently 101 pts (35.9%) received a follow-up therapy after progression on RIB + ET. The most common first subsequent therapies were targeted therapies + ET (40.0%), followed by cytotoxic chemotherapy (22.0%) and endocrine monotherapy (19.0%). Conclusion: 1L RIB + ET continues to show favorable efficacy and a tolerable safety profile in the routine clinical practice. The results are consistent with the data from MONALEESA trials. The OS is showing a positive trend but is still immature during this study follow-up. Efficacy Outcomes With RIB + ET in Patients With HR+, HER2– MBC (Overall Population, Nf281) XX XX Citation Format: Christian F. Singer, Daniel Egle, Richard Greil, Edgar Petru, Leopold Oehler, Marija Balic, Laurenz Schöffmann, Georg Pfeiler, Maximilian Marhold, Christine Brunner, Karin Haider, Arik Galid, Ursula Pluschnig, Ferdinand Haslbauer, Michael Hubalek, Andreas Redl, Julia Flatschacher, Shanow Uthman, Bernhard Mraz, Rupert Bartsch. Real-world outcomes with first-line ribociclib + endocrine therapy in patients with metastatic HR+, HER2– breast cancer: Fourth interim analysis of REACH AUT 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 PO3-16-10.

Abstract PO4-20-05: An open label phase III randomized trial to evaluate the efficacy of Post-chemotherapy Axillary Conservation Surgery in breast cancer (PACS)

Abstract Background- Axillary lymph nodes (ALN) status is the most important prognostic factor in breast cancer. Traditionally, a complete axillary lymph node dissection (ALND) has been standard of care for those patients who have a positive node pre-chemotherapy. However, lately axillary conservation is paving its way in the post-chemotherapy setting as well to avoid significant morbidity of ALND. Most sentinel node biopsy studies have failed to achieve the desired false negative rate(FNR). (Boughey JC et al, JAMA. 2013 Oct; Kuehn T et al, Lancet Oncol. 2013; Boileau JF et al, J Clin Oncol. 2015 Jan).We previously reported a low FNR of low axillary sampling (LAS) in the post-chemotherapy setting. (Parmar et al, JCO-GO, 2021) We are conducting a phase III, randomised controlled trial of LAS versus complete ALND in post-chemotherapy negative (ypN0) axilla. Aims and objectives- The primary objective is to assess the non-inferiority of LAS in patients who are rendered ypN0 by pre-operative chemotherapy with disease-free survival as primary end point. The secondary objectives are comparing the morbidity of ALND (lymphedema, paraesthesia, and shoulder dysfunction) in the LAS and ALND arms, and to evaluate the impact on overall survival, local, regional, and distant recurrence free survival and quality of life. Trial design- This is a prospective, open label, randomised, phase III trial where histologically proven, non-metastatic, cT1-4,N0-2 breast cancer patients who are rendered ycN0 after pre-operative systemic chemotherapy are being accrued. Patients with prechemo N3 disease, inflammatory breast cancer, recurrent disease, pregnancy associated breast cancer are being excluded from the study. The chemotherapy regimens and surgical assessment is as per standard institutional protocols. After obtaining informed consent, patients undergo LAS during surgery and lymph nodes(LN) are sent for frozen section analysis. If any LN is found to be involved, a complete ALND is carried out. If the staging procedure is negative, then patients are randomised into 2 groups- observation v/s complete ALND. Stratification factors are T stage, N stage, Hormone receptor status, Her2 receptor status and number of chemotherapy cycles taken. Morbidity assessment is done with- Constans shoulder score, arm volumetry, paraesthesia assessment, and a QOL questionnaire- Self-reported Breast cancer Lymphedema Symptom Experience Index (BCLSEI). A baseline assessment pre-surgery is followed by 6 monthly morbidity assessments and regular oncologically relevant follow-up up to 5 years. A two-sided log-rank test with an overall sample size of 2316 with a 10% dropout rate (1158 in ALND and 1158 in LAS group) achieves 80% power at a 0.05 significance level to detect a hazard ratio of 1.16 (upper limit of non-inferiority) when the proportion surviving in the control group is 0.71. An interim analysis will be carried out at 25% events and conditional power will be calculated. If the conditional power is below 20%, then the study will be discontinued for futility. The study has been approved by Institutional Ethics Committee (CTRI/2022/07/044461) Expected Study and Results- We started accrual in February 2023 and have screened 63 and randomized 45 patients until now. Ours is a first large randomised prospective study in the post-chemotherapy axillary management setting which will help us understand the efficacy of axillary conservation surgery in patients who are node negative post neoadjuvant chemotherapy. In future, lesser morbid procedures than LAS like targeted axillary dissection can be tested in the same trial. However, LAS as a technique of axillary conservation suits resource constraints and high volume setting such as ours. Citation Format: Shalaka Joshi, Jessicka Shah, Pallavi Daphale, Rohini Hawaldar, Anuradha Daptardar, Ayushi Sahay, Tanuja Shet, Palak Popat, Tabassum Wadasadawala, Nita Nair, Vani Parmar, Bipin Bandre, Shabina Siddique, Vaibhav Vanmali, Sudeep Gupta, Rajendra Badwe. An open label phase III randomized trial to evaluate the efficacy of Post-chemotherapy Axillary Conservation Surgery in breast cancer (PACS) [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 PO4-20-05.

Abstract PO3-11-03: A Randomized Controlled Trial to Assess the Benefit of Art & Music Therapy on Quality of Life in Patient with Breast Cancer

Abstract Introduction: Quality of life (QoL) in oncology captures the well-being of a patient and is considered a significant outcome criterion. Breast cancer (BC) is the most diagnosed cancer in women, however, standardizing integrative therapies to alleviate the burden of cancer and improve QoL is still an unmet need. Art and music therapy might mitigate psychological and emotional distress. We sought to evaluate their efficacy compared to control among patients with BC during or after active therapy. Methods: Seventy-six treated patients with Stages I-III BC were randomly assigned to art, music therapy, or routine oncology care standard of care arm (SOC) for 3 months and received two sessions per month by a licensed therapist (including in-person/virtual and group sessions). The primary outcome was an improvement in QoL measured by the Functional Assessment of Cancer Therapy–Breast (FACT-B) questionnaire and secondary outcomes included: cognitive function measured by Functional Assessment of Cancer Therapy–Cognition (FACT-Cog), response to a 4-component Cleveland Clinic Visual Analog Scale (CCVAS), indicators of anxiety and depression assessed by the Generalized Anxiety Disorder-7 item (GAD-7) and Patient Health Questionnaire-9 item (PHQ-9). All questionnaires were assessed at baseline, 30, 90, and 180 days. Statistical considerations included stratified randomization, and a mean difference in 15 points between either of the interventions. SOC arm was considered relevant at the 3-month mark. Mean improvement within groups was performed using paired t-tests whereas independent t-tests were used to evaluate mean improvement between interventions (1 or 2 vs. SOC arm). All analyses were performed using SPSS version 26 (IBM, Armonk, NY). Results: Forty-five participants completed the study to date and were included in the interim analysis. Median age was 58 (57-59), white race (51.1%), patients on active treatment (45%), art therapy group (n=16), music therapy (n=15) and standard of care (n=14). Significant improvement was noted in the art therapy arm at 3 months in FACT-B physical well-being (p=0.04), functional well-being (p=0.008) domains as well as GAD-7 (p=0.003), PHQ-9 (p=0.04) and FACT-Cog section “impact on quality of life” (p=0.03). At 6 months, the art therapy arm demonstrated lower scores in the CCVAS questionnaire total score, emotional distress (p=0.01) and anxiety (p=0.004) scales. Music therapy participants reported a significant improvement only in GAD-7 index(p=0.04) at 3 and 6 months compared to SOC. No significant difference was found between art and music therapy arms. Conclusion: Art therapy patients exhibited significant improvement in overall QoL (including anxiety, depression, improvement in cognitive function) and 4-scale CCVAS (emotional distress, anxiety, depression, and pain). Music therapy improved anxiety scores (GAD-7). Art and music therapy should be considered in the care of patients to manage cancer associated distress and improve their quality of life. Table 1. Comparison of test changes from 3 months to baseline within groups Table 2. Comparison of test changes from 6 months to baseline within groups Citation Format: Maria Herran, Mohamed Mohanna, Saad Sabbagh, Barbara Dominguez, Kaylee Sarna, Rachel Upton-Rice, Angie Burdine, Zeina Nahleh. A Randomized Controlled Trial to Assess the Benefit of Art & Music Therapy on Quality of Life in Patient with Breast Cancer [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 PO3-11-03.

Abstract RF02-04: A phase III study comparing trastuzumab emtansine with trastuzumab, pertuzumab, and docetaxel in older patients with metastatic HER2-positive breast cancer. (JCOG1607 HERB TEA study)

Abstract Background A combination of trastuzumab, pertuzumab, and docetaxel (HPD) is recommended as first-line treatment for patients with HER2-positive metastatic breast cancer. For older patients, it is difficult to maintain a relative dose intensity, which often impairs their quality of life. A new standard treatment option for older patients is required with less toxicity and non-inferior efficacy compared to HPD. Methods The eligibility criteria were as follows: age 65 years and older, HER2-positive metastatic breast cancer, no previous systemic treatment with chemotherapy and anti-HER2 targeted drugs, ECOG PS 0–2 for 65–74 years or 0–1 for 75 years or older, and adequate organ function. Treatment consisted of trastuzumab emtansine (T-DM1) 3.6 mg/kg every 3 weeks or HPD (trastuzumab 8 mg/kg, then 6 mg/kg, pertuzumab 840 mg, then 420 mg/body, and docetaxel 60 mg/m2, could be escalated to 75 mg/m2 if there were no unmanageable toxicity) every 3 weeks after a 1:1 ratio randomization. The trial was designed to achieve 70% power to confirm the non-inferiority of T-DM1 to HPD at a one-sided alpha of 5% with a non-inferiority margin of 1.35 in terms of the hazard ratio (HR) for overall survival (OS) as the primary endpoint. With a median OS of 30 months in both arms, 6.5 years of accrual, and 5 years of follow-up, the planned sample size was 250. Secondary endpoints were progression-free survival (PFS), response rate (RR), adverse events, cumulative breast cancer-specific mortality (BCSM), safety, and deterioration of activities of daily living. (Clinical Trial Information: UMIN000030783). Results In total, 148 patients were enrolled between January 2018 and March 2023. A total of 135 patients were assessed in the preplanned first interim analysis. The median patient age was 72 years (range 65-88) in the T-DM1 arm and 71 (65-84) in the HPD arm. The proportion of estrogen receptor-positive (10%) patients was well balanced between both arms (49.3 and 55.6%, respectively). Of these patients, 64.8% had stage IV disease and 35.2% had recurrent disease. T-DM1 was not non-inferior to HPD (HR 1.487; 99.9% CI, 0.288 to 7.678) in terms of OS. The median PFS was 9.8 months in the T-DM1 arm and 18.4 months in the HPD arm (HR 1.749; 95%CI, 1.124-2.723). Response rates were lower in the T-DM1 arm than that of the HPD arm (52.7% [95% CI, 38.8-66.4] and 76.8% [95% CI, 63.6-87.0], respectively) (p=0.099). BCSM was higher in the T-DM1 arm than that of the HPD arm (HR 1.617; 95% CI, 0.764-3.425). Grade 3 and higher neutropenia were less common in the T-DM1 arm than in the HPD arm (0 vs. 30.4%); however, thrombocytopenia was more common in the T-DM1 arm than in the HPD arm (16.9 vs. 0%). Grade 3 or more non-hematological adverse events were less common and lower in the T-DM1 arm (35.2%) than in the HPD arm (58.6%), including fatigue (5.6% vs. 22.9%), diarrhea (0% vs. 11.4%), appetite loss (8.5% vs. 11.4%), and febrile neutropenia (0% vs. 10.0%), which reduced the quality of life in older patients with HER2-positive metastatic breast cancer. Conclusion T-DM1 was not non-inferior to HPD in terms of OS. However, T-DM1 showed better tolerability in terms of frequency and severity of adverse events. HPD will continue to be the standard of care as the first-line treatment for older patients with HER2-positive metastatic breast cancer. Older patients with breast cancer have heterogeneous health conditions. A subset analysis according to age or geriatric assessment may identify the subpopulation of older patients with HER2-positive metastatic breast cancer for whom T-DM1 is an optional treatment. Citation Format: Akihiko Shimomura, Kenji Tamura, Keita Sasaki, Ryo Sadate, Akihiko Suto, Masataka Sawaki, Naohito Yamamoto, Tomoyuki Yoshiyama, Takako Hayashi, Eriko Tokunaga, Takashi Yamanaka, Chikako Shimizu, Tadahiko Shien, Hiroji Iwata. A phase III study comparing trastuzumab emtansine with trastuzumab, pertuzumab, and docetaxel in older patients with metastatic HER2-positive breast cancer. (JCOG1607 HERB TEA study) [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 RF02-04.

Abstract PO4-22-12: Robot-assisted nipple-sparing mastectomy using da Vinci SP single-port system: primary results from the pilot trial RASPIM-01

Abstract Background Robot-assisted breast surgery was developed in 2014 for nipple-sparing mastectomy through a concealable lateral chest wall incision smaller. Although successful experiences have been reported using a multi-arm surgical robotic system, collisions between robotic arms and instruments often result in the discontinuation of console workflow and limit the performance of the surgical robot. Compared to multi-armed robot systems, the SP system is single-armed, equipped with flexible instruments containing multiple joints that may avoid instrument collision, a controllable camera reducing visual dead spots, and a designated non-third-party port that allows single-port entry and full deployment of the instrument. The RASPIM-01 trial (NCT05448963) is a single-armed pilot study assessing the feasibility of robot-assisted nipple-sparing mastectomy (NSM) using a new SP system. Method This study is a pilot trial conducted in a single-arm, non-randomized design with a recruitment of 30 participants. The SP surgical robot is used in NSM through the lateral chest wall incisions. The major inclusion criteria are 1) Breast cancer with preoperative clinical tumor sizes less than 5 cm, with an adequate tumor-skin distance of at least 3mm, and without nipple-areolar involvement in at least 1cm around the nipple by image, 2) Breast cancer up to clinical stage IIIA (T3, N1-2) showing adequate response to neoadjuvant therapy and meeting criteria 1), 3) Germline pathogenic/likely pathogenic BRCA1 or 2 variant carriers with or without a breast cancer diagnosis, requiring unilateral or bilateral therapeutic mastectomy or prophylactic mastectomy. Exclusion criteria include extensive breast skin or nipple involvement such as inflammatory breast cancer, Paget’s disease, nipple discharge associated with malignancy, image suggestive of cancer involvement of the nipple and subareolar tissue, and stage III breast cancer without response to neoadjuvant therapy, and previous radiotherapy of the surgical side breast. The endpoint measurements include Primary endpoint: The ability to complete nipple-sparing mastectomy with an SP system in the per-protocol population without additional assistant port or conversion to open surgery. Statistical analysis includes point estimation with a 95% confidence interval to analyze the mean or proportion of key performance parameters. No interim analysis will be performed due to the limited number intended to recruit. Results The study recruited 30 breast cancer patients and conducted 30 NSMs, while no prophylactic mastectomy case was recruited. The median age was 44 years old, BMI was 22.4 (18.9-30.0) kg/m2. Median tumor size was 3.0 (1.0-14.6) cm, and axillary lymph node metastases were present in 7 cases (23.3%). T2 (13 cases, 43.3%) tumors were the majority, followed by Tis (10 cases, 33.3%), T1 (5 cases, 16.7%), and T3 (2 cases, 6.7%). The anatomical stages of invasive cancer were Ia (16.7%), IIa (26.7%), IIb (16.7%), and IIIa (6.7%), among them 9 (30.3%) received neoadjuvant chemotherapy before surgery. All NSMs met the primary endpoint of successful completion using the SP robot system without conversion to open mastectomy or the addition of an assistant port. Median console time was 108.5 (73-285) min and docking time was 2.5 (1-9) min. Specimen weight was 311.6 (107-838) gm, while 2 (6.7%) cases had their nipple excised due to cancer-involved margin reported from the frozen section. Twenty-six (86.6%) cases received autologous free flap reconstruction, among which 25 (83.3%) cases received DIEP, and 1 (3.3%) received PAP reconstruction. Four cases received implant (2 cases, 6.7%) or tissue expander (3 cases, 6.7%). Conclusion This is the first NSM clinical trial operated with SP surgical robot system and met its primary endpoint showing the feasibility to conduct NSM. Secondary and exploratory endpoints data will be reported after the completion of clinical follow-ups. Citation Format: Wen-Ling Kuo, Chia-Huei Chu, Jung-ju Huang. Robot-assisted nipple-sparing mastectomy using da Vinci SP single-port system: primary results from the pilot trial RASPIM-01 [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 PO4-22-12.

Abstract PO5-25-11: Appropriate use of interventional cohort studies with threshold-crossing designs for de-escalation trials in breast cancer

Abstract For some populations of patients with early breast cancer (BC), clinical outcomes have improved such that the focus has shifted to identifying aspects of therapy that can be reduced or omitted to spare patients toxicity without compromising outcomes. For example, in patients with HER2+ disease, introduction of HER2-targetted therapy significantly reduced event rates but at increased exposure to toxicity. For those with a pathological complete response (pCR) to neo-adjuvant anti-HER2 therapy, the absolute gain from continued adjuvant therapy is likely to be small and the event rate sufficiently low such that any deviation from the expected prognosis would be sufficient to infer failure of a reduced treatment strategy. Previous studies would usually adopt a non-inferiority (NI) trial randomising patients between standard of care (SOC) and reduced therapy. The reduced therapy would be declared non-inferior if the difference between the groups does not exceed a pre-agreed NI margin. Some populations, such as those described, have a very low rate of recurrence and thus large sample sizes are required to gain sufficient power resulting in several issues. In these situations, threshold-crossing designs, also known as interventional cohort studies (ICS), provide an alternative to traditional NI trials. In ICS, a single cohort is recruited and receives the reduced therapy. The event rate is compared to a pre-defined fixed threshold, above which recurrence rates would be considered unacceptable. When conducted appropriately, such studies are statistically and logistically efficient, and should be considered definitive. ICS can be used when 1. A stable background of SOC exists with robust data from which an appropriate crossing-boundary can be defined. Critically, the historical control population used to define the boundary must closely reflect the study population and those seen in clinical practice. 2. The event rate is sufficiently low and consequently has low variability, so a concurrent control group is not required because an accurate estimate of the event rate with SOC already exists. 3. The primary endpoint of interest is reliable, sensitive to treatment and timely to allow early stopping if interim analyses indicate an issue. The well-defined excellent prognosis of patients with HER2+ BC who have a pCR to contemporary neo-adjuvant therapy, coupled with the pattern of relapse rates dropping off rapidly after 3 years, makes this an appropriate setting for implementing such designs. Three recently initiated studies testing reduced therapy in this patient population, HER2-RADiCAL (NIHR131362), CompassHER2 (NCT04266249) and DECRESCENDO (NCT04675827), all have an ICS design. An ICS approach is also valid for trials testing avoidance of radiotherapy in very low-risk populations, where the absolute benefit is likely low and occurrence of late local events is salvageable so as not to impact on overall survival, such as in PRIMETIME (ISRCTN 41579286). In contrast, there are several settings where these designs should not be used. For example, in the assessment of systemic therapy in ER+ HER2- BC the recurrence rate is constant beyond 3 years meaning events cannot be picked up in a timely manner and a fixed threshold defined at 3/5 years would not allow preclusion of a later drop-off in efficacy. It would also be premature to use ICS in TNBC following immunotherapy as outcome data is not yet sufficiently mature to accurately define a suitable threshold. Finally, if relapse rates are not sufficiently low, natural variation in control group incidence rates would prevent setting a suitable fixed threshold. We will discuss the key requirements and design features for using ICS to efficiently evaluate avoidance of treatment in BC and highlight the importance of patient involvement in the development of such trials. Citation Format: Holly Tovey, Laura Finneran, Lucy Kilburn, Iain Macpherson, Andrew Wardley, Hilary Stobart, Lesley Turner, Mairead MacKenzie, Charlotte Coles, Cliona Kirwan, Judith Bliss. Appropriate use of interventional cohort studies with threshold-crossing designs for de-escalation trials in breast cancer [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 PO5-25-11.

Abstract PO3-20-05: Phase II Study of Genomically Guided Radiation Dose Personalization in the Management of Triple Negative Breast Cancer

Abstract Background: Our group has previously developed the radiosensitivity index (RSI) using a multigene expression model that is directly proportional to tumor radioresistance (high RSI = increased radioresistance). RSI has been previously validated in two datasets of patients with triple negative breast cancer (TNBC). In this study, we will run a selective dose personalization study in TNBC patients undergoing breast conservation therapy (BCT). Based on patients RSI scores, they will either receive a radiation therapy (RT) boost of 10 Gy to the tumor cavity or not. Given our data in two independent datasets, the current study will reveal the feasibility and benefit of selective genomic dose personalization in TNBC following BCT. Trial Design: The study is designed as a prospective, nonrandomized, phase II trial of genomically guided RT in the management of TNBC undergoing BCT. Patients will be allocated to one of two groups based on their RSI determination from fresh frozen tissue collected by biopsy or at the time of BCT. These groups will be Group A, RSI optimized whole breast radiotherapy alone or with a 10 Gy boost or Group B, RSI not optimized whole breast radiotherapy with a boost of 10 Gy to tumor cavity. Patients will receive standard of care chemotherapy, neoadjuvant or adjuvant. Eligibility: TNBC patients undergoing BCT. Specific Aims: To determine the three-year local control following genomically guided dose personalization in the management of TNBC following BCT. Secondary objectives include determination of overall survival (OS), progression free survival (PFS), and quality of life (QOL) following genomically guided dose personalization. Statistical Methods: The primary hypothesis is the three-year local control rates differ for groups A and B, against the null hypothesis that the two rates are identical. Patients will allocate approximately 78% in group A and 22% in group B and local control rates are expected to be 96% and 75%, respectively. Assuming 80% power and 10% type I error for a log-rank test, 86 patients are needed. An interim analysis will be completed when 4 disease progression events are observed. There will be approximately 43 patients at the time of interim analysis. Patient Accrual: This study is open with 1 patient enrolled at the time of submission. A total of 86 patients will be enrolled. Contact Information: Kamran A. Ahmed MD, Moffitt Cancer Center, email: kamran.ahmed@moffitt.org, Clinical trial information: NCT05115474. Funding: Moffitt and Morton Plant Mease Foundations. Citation Format: Kamran Ahmed, Iman Washington, Matthew Mills, Michelle DeJesus, Youngchul Kim, Ronica Nanda, Javier Torres-Roca, Steven Eschrich, Janis De La Iglesia, John Puskas, Marilin Rosa, Jason Wilson, Paula Lundgren, Negar Golesorkhi, Nazanin Khakpour, Susan Hoover, Marie Lee, John Kiluk, Melissa Mallory, Christine Laronga, Laura Kruper, Brian Czerniecki, Roberto Diaz. Phase II Study of Genomically Guided Radiation Dose Personalization in the Management of Triple Negative Breast Cancer [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 PO3-20-05.

Abstract PS12-08: MORPHEUS Hormone Receptor-Positive Breast Cancer: interim analysis of a Phase Ib/II, study of fulvestrant ± atezolizumab and abemaciclib triplet treatment in patients metastatic disease

Abstract BACKGROUND Endocrine therapy (ET) is the mainstay of treatment for metastatic hormone receptor-positive breast cancer (HR+ BC). ET resistance and disease progression are expected, thus novel therapies, like cancer immunotherapy, are needed. Prior data suggest that abemaciclib (abema), a cyclin-dependent kinase 4/6 (CDK4/6) inhibitor, has immunomodulatory activity. In the MORPHEUS HR+ BC study (NCT03280563), atezolizumab (atezo; anti–programmed death-ligand 1 [PD-L1]) was tested in combination with fulvestrant (FUL), with and without abema, in patients (pts) with HR+ metastatic BC. We present 24-week interim analyses. METHODS Pts with measurable disease progression during first- or second-line therapy for metastatic or inoperable locally advanced HR+ BC and prior treatment with a CDK4/6 inhibitor were randomized to receive FUL (control) or FUL + atezo (1200 mg intravenous every 3 weeks) or FUL + atezo + abema (150 mg twice a day); prior FUL was not permitted. Pts were treated until loss of clinical benefit or unacceptable toxicity. Primary endpoints were objective response rate (ORR) per Response Evaluation Criteria in Solid Tumours (RECIST) v1.1 and safety. Progression-free survival (PFS) was a secondary endpoint. Baseline tumor samples were analyzed for PD-L1 expression (SP263), CD8 T cell infiltration, and gene expression by RNAseq. RESULTS As of Dec 2022, 40, 31, and 25 pts (38, 30, and 20 evaluable pts) were randomized to atezo + abema + FUL, atezo + FUL, and FUL, respectively. Pts were followed for ≥ 24 weeks. Demographics were similar among the groups, with most pts receiving prior palbociclib (palbo) as part of their only prior metastatic therapy. Details and best confirmed ORRs are shown in the table. Median PFS was 6.34 months (95% confidence interval [CI] 5.52, 16.03) in the atezo + abema + FUL arm, 3.15 months (95% CI 1.51, 7.79) in the atezo + FUL arm, and 1.95 months (95% CI 1.45, 4.93) in the FUL arm. The hazard ratio of atezo + abema + FUL vs FUL was 0.43 (95% CI 0.24, 0.78). Safety data are shown in the table. Mild/moderate (grade 1/2) interstitial lung disease (ILD)/pneumonitis (7.7%) was observed in the atezo + abema + FUL arm. At baseline, tumors exhibited low prevalence of PD-L1 (median immune cells: 0.5%, tumor cells: 0%) and CD8 infiltration (12% inflamed phenotype), which did not associate with response in any arm. RNAseq analysis indicated that response to atezo + abema + FUL was strongly associated with low baseline expression levels of proliferation and metabolism signatures and trended with high expression of some immune signatures. CONCLUSIONS The triplet therapy of atezo + abema + FUL showed improved ORR and PFS compared with FUL monotherapy in the second- or third-line setting post-CDK4/6 inhibitor. This combination of atezo + abema + FUL was tolerable, with no unexpected safety signals, including no high-grade ILD/pneumonitis. Efficacy and safety Data are number of patients (%), unless otherwise specified. * Patient was treated in the second line and incorrectly included in this group. Abema, abemaciclib; AE, adverse event; ALT, alanine aminotransferase; AST, aspartate aminotransferase; atezo, atezolizumab; CDK4/6, cyclin-dependent kinase 4/6; CI, confidence interval; ful, fulvestrant; irAE, immune-related adverse event; L, line; ORR, objective response rate; PFS, progression-free survival; TRAE, treatment-related adverse event. Citation Format: Kyung Hae Jung, Seock-Ah Im, Denise Yardley, Sara Hurvitz, Keun Seok Lee, Amir Sonnenblick, Shlomit Shachar, Antoinette Tan, Elizabeth Comen, Einav Gal-Yam, Adam Brufsky, Hope Rugo, Jing Zhu, Kelly DuPree, Vanessa Breton, Fiona Young, Richard Schwab, Edward Cha, Melinda Telli. MORPHEUS Hormone Receptor-Positive Breast Cancer: interim analysis of a Phase Ib/II, study of fulvestrant ± atezolizumab and abemaciclib triplet treatment in patients metastatic disease [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 PS12-08.

Abstract PS16-01: Comparison of an Atezolizumab monotherapy window followed by Atezolizumab and chemotherapy vs. Atezolizumab and chemotherapy alone in triple negative breast cancer (TNBC) – final analysis of the neoadjuvant neoMono trial

Abstract Background: Improvement of systemic therapy of TNBC still is a medical need. Exploratory data from the neoadjuvant GeparNuevo trial suggested a benefit from an immune checkpoint inhibitor (ICI) monotherapy window in TNBC. The neoMono trial prospectively analyzed whether the addition of a preceding Atezolizumab monotherapy window prior to Atezolizumab and chemotherapy (CTX) improves pCR rates among patients (pts) with early TNBC. In an interim analysis after 100 pCR events, patients with unselected TNBC did not show a significant benefit from an Atezolizumab monotherapy window, while an exploratory analysis suggested a highly clinically relevant benefit among pts with PD-L1 positive TNBC. Here we present the final primary endpoint analysis. Methods: NeoMono is a phase 2 randomized multicenter trial that was planned to recruit a maximum of 458 female and male pts with primary TNBC (defined as ER/PR < 10% and HER2 negative) with tumor stages cT1c – cT4d (cN0 and cN+). As the protocol mandated termination of trial recruitment based on the results of the interim analysis, the final ITT population was limited to 359 pts. PD-L1 status had to be identifiable by central pathology by means of the VENTANA PD-L1 (SP142) assay and was defined by PD-L1 expression on immune cells (IC). Neoadjuvant treatment in both study arms consisted of Atezolizumab 1200 mg every 3 weeks in addition to neoadjuvant CTX (12 x Carboplatin/Paclitaxel q1w followed by 4x Epirubicin/Cyclophosphamide q3w). Combination therapy in arm A was preceded by an Atezolizumab monotherapy window of 840 mg once two weeks prior to initiation of combination therapy, while patients in arm B received no immune monotherapy window. Study goals are to compare the efficacy of neoadjuvant CTX + Atezolizumab with versus without a two-week atezolizumab monotherapy window preceding CTX + ICI (primary endpoint: pCR) and to identify biomarkers for response and resistance through analysis of sequential tissue and liquid biopsies. The neoMono statistical design uses Bayesian posterior probabilities (uniform prior distribution) and logistic regression to analyze the primary endpoint. Results: 180 pts in arm A and 179 in arm B from 34 study sites were included in the final primary endpoint analysis. Demographics and baseline characteristics as well as drug exposure were well-balanced in both arms. Posterior mean pCR rates in the ITT population in study arms A and B were 65.7% (95% high posterior density interval (HPDI): 58.5%, 72.5%) and 69% (62.2%, 75.9%), respectively. In an exploratory analysis stratified by PD-L1 IC status (negative: < 1% versus positive: ≥ 1%), pCR rates in arm A were 91.5% in the PD-L1 IC-positive group and 56.1% in the PD-L1 IC-negative group, the corresponding pCR rates in arm B were 82.2% and 64.5%, respectively. In a multivariate analysis of the ITT population including tumor size, nodal status, tumor grade, age and PD-L1 status, the odds ratio for achieving a pCR was 4.77 (p < 0.001) for PD-L1-positive and 2.36 (p=0.023) for grade 3 tumors. In an exploratory analysis including HER2 status, odds for achieving a pCR were significantly higher for patients with HER2-negative (IHC 0) vs. HER2-low tumors (OR 1.73, p=0.036). No new safety signals were observed. Conclusion: The final primary endpoint analysis of the neoMono trial demonstrated the highest pCR rates ever reported in a phase II/III trial in TNBC. While a significant impact of an ICI monotherapy window on the pCR rate after combination of CTX + ICI in an unselected ITT population could not be demonstrated, neoMono indicates for the first time in a randomized prospective setting that patients with immune active TNBC might derive particular benefit from a preceding ICI monotherapy window. The results of the neoMono trial are mainly justifying the conduction of a confirmative trial in immune active TNBC. However, our results underscore the potential role of pre-therapeutic ICI monotherapy window as part of future therapeutic concepts in TNBC. Citation Format: Hans-Christian Kolberg, Johannes Schumacher, Ramona Erber, Michael Braun, Peter A. Fasching, Eva-Maria Grischke, Christian Schem, Michael P. Lux, Mustafa Deryal, Oliver Hoffmann, Bernhard Heinrich, Georg Kunz, Kristina Lübbe, Petra Krabisch, Arndt Hartmann, Philip Raeth, Sabine Kasimir-Bauer, Cornelia Kolberg-Liedtke. Comparison of an Atezolizumab monotherapy window followed by Atezolizumab and chemotherapy vs. Atezolizumab and chemotherapy alone in triple negative breast cancer (TNBC) – final analysis of the neoadjuvant neoMono 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 PS16-01.

Abstract GS03-03: Ribociclib (RIB) + nonsteroidal aromatase inhibitor (NSAI) as adjuvant treatment in patients with HR+/HER2− early breast cancer: final invasive disease–free survival (iDFS) analysis from the NATALEE trial

Abstract Background: Interim results from the phase 3 NATALEE trial demonstrated that adding RIB to standard-of-care adjuvant NSAI had a statistically significant iDFS benefit in patients with stage II and III HR+/HER2− early breast cancer at risk of recurrence, including those with node-negative disease (Slamon et al, ASCO 2023). We present the final protocol-specified analysis of the primary endpoint of iDFS. Methods: A total of 5101 pre-/postmenopausal women and men underwent 1:1 randomization to receive RIB (400 mg/day; 3 weeks on/1 week off for 36 months) + NSAI (letrozole 2.5 mg/day or anastrozole 1 mg/day for ≥60 months) or NSAI alone. Men and premenopausal women received goserelin (3.6 mg once every 28 days). Patients were required to have anatomic stage IIA (either N0 with additional risk factors or N1), IIB, or III breast cancer per the AJCC (8th edition). Patients remained on trial as long as they were continuing on NSAI (≤5 years), regardless of RIB discontinuation. The primary endpoint was iDFS according to STEEP v1.0 criteria, and the secondary efficacy endpoints were recurrence-free survival (RFS), distant disease–free survival (DDFS), and overall survival (OS). This final analysis was planned after approximately 500 iDFS events. iDFS was evaluated by the Kaplan-Meier method, and statistical comparison was made by a stratified log-rank test. P values were not corrected for multiple comparisons. Results: At the data cutoff (July 21, 2023), among the 2549 patients in the RIB + NSAI arm, 1091 (42.8%) completed 3 years of RIB treatment, and 905 (35.5%) discontinued RIB or RIB + NSAI early and 528 patients (20.7%) remained on RIB. 1748 patients (68.5%) remain on treatment in the NSAI arm. Median follow-up for iDFS was 33.3 months, an additional 5.6 months from the previous interim analysis. A total of 509 iDFS events were observed, 226 (8.9%) in the RIB + NSAI arm and 283 (11.1%) in the NSAI alone arm. RIB + NSAI demonstrated a significant iDFS benefit over NSAI alone (HR, 0.749; 95% CI, 0.628-0.892; P=.0006). The 3-year iDFS rates were 90.7% (95% CI, 89.3%-91.8%) vs 87.6% (95% CI, 86.1%-88.9%). A consistent benefit was observed across patient subgroups, including those with node-negative, stage II, or stage III disease (Table). Secondary endpoints of DDFS and RFS favored RIB + NSAI over NSAI alone (Table). OS data were immature, with 84 (3.3%) and 88 (3.4%) total events in the RIB + NSAI and NSAI alone arms, respectively. No new safety signals were observed since the prior interim analysis. Discontinuation of RIB due to adverse events was observed in 19.5% of patients (a <1% increase from the prior interim analysis). Conclusions: With a substantial proportion of patients completing 3 years of RIB treatment, NATALEE continues to demonstrate a significant iDFS improvement with RIB + NSAI over NSAI alone. Efficacy results confirm continued improvement in benefit across subgroups, including stage II disease. Safety findings support the manageable toxicity profile of RIB at the 400-mg starting dose in early breast cancer. Table. Citation Format: Gabriel Hortobagyi, Daniil Stroyakovsky, Denise Yardley, Chiun-Shen Huang, Peter A. Fasching, John Crown, Aditya Bardia, Stephen Chia, Seock-Ah Im, Miguel Martín, Sherene Loi, Binghe Xu, Sara Hurvitz, Carlos Barrios, Michael Untch, Rebecca Moroose, Frances Visco, Federico Parnizari, Farhat Ghaznawi, Zheng Li, Sorcha Waters, Arunava Chakravartty, Dennis Slamon. Ribociclib (RIB) + nonsteroidal aromatase inhibitor (NSAI) as adjuvant treatment in patients with HR+/HER2− early breast cancer: final invasive disease–free survival (iDFS) analysis from the NATALEE 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 GS03-03.

Abstract PO3-05-12: Randomized Phase 2 of Bria-IMT, an Allogenic Human Cell Line with Antigen Presenting Activity, in Heavily Pretreated Metastatic Breast Cancer

Abstract Introduction Despite progress in MBC, too many continue to succumb due to treatment resistance or intolerance. SV-BR-1-GM is an allogenic human breast cancer cell line with antigen presenting cell activity designed to overcome the immune-suppressive tumor microenvironment while being acceptable to extensively pretreated contemporary MBC patients. We report interim exploratory analysis of the ongoing RCT of the Bria-IMT regimens. Methods An interim exploratory analysis using preliminary partially available evaluable data of the ongoing prospective, randomized phase 2 (NCT03328026; 2018-present) of Bria-IMT (irradiated SV-BR-1-GM) with a PD-1check point inhibitor (CPI) every 3 weeks (25 patients dosed to date). Both regimens include cyclophosphamide 300 mg/m2 48-72 hours prior to intradermal Bria-IMT (~20 x 106 cells) followed by interferon-alpha at the inoculation sites 2 days later. The control arm used the original sequence with simultaneous start of Bria-IMT and CPI in cycle 1. The experimental arm started CPI in cycle 2 after the 2nd inoculation. Candida skin test was performed before cycle 1 to determine anergy status while delayed-type hypersensitivity skin test (DTH), defined as >5mm erythema & induration, was done at every cycle by intradermal injection of a small test dose of Bria-IMT prior to full dose inoculation. Results Median age: 58 (range 37-81); median prior therapies: 8 lines (range 4-18); 89% were grade 2/3 (n=18); 68% hormone receptor positive; 61% HER2 negative, 33% HER2 low, and 6% HER2 high; 33% triple negative. Overall, 53% of subjects had a clinical benefit as best response by BICR, PI or target lesion measurement. The two treatment arms were similar with a trend showing longer median durations on therapy (mDOT) of 3.7 mo in the experimental delayed CPI arm compared with mDOT = 2.9 for original sequence control arm. 47% of patients were anergic to candida. Among all anergic subjects, the mDOT was 3.5 compared to 2.5 mo for non-anergic patients. However, among anergic subjects, the alternative treatment arm had a lower risk of treatment discontinuation (improved HR) with mDOT of 3.7 compared to the 3.3 mo mDOT of the original treatment. 50% of anergic subjects eventually developed DTH to SV-BR-1-GM. mDOT was 4.0 mo for DTH+ pts vs 3.0 mo for those who did not mount DTH. Median OS was not yet reached; mean OS was higher in non-anergic vs anergic pts. Among those who developed an inoculation site reaction to Bria-IMT, OS was greater than for those who did not. Time on the Bria-IMT regimen exceeded the time on penultimate treatment in 22% of subjects while 33% of subjects with prior CPI use exceeded last therapy. AEs were mild with 28% of subjects (n=7) having > grade 3 events. The most common grade 3+ AE was lipase increase (n=3). One subject with encouraging changes in peripheral blood tumor markers and CTCs completed a PET study using Zr-89 crefmirlimab berdoxam, a zirconium-89 labelled truncated antibody specific to human CD8α (CD8 Immuno-PET) and demonstrated increased uptake in some metastatic lesions and draining lymph nodes. Updated results will be provided at the meeting. Conclusion Sequencing of CPI with Bria-IMT is associated with differential clinical outcome trends but not statistically significant in this interim preliminary exploratory analysis regardless of prior CPI use. Bria-IMT is immunogenic with clinical benefit demonstrated for both treatment schedules among patients with inducible DTH reactions. Patients who develop an immune response to Bria-IMT had an increase in OS compared to those who did not. The nodal localization of CD8+ cells on PET may indicate a systemic activation of CD8 positive lymphoid cells. It also provides support that the Bria-IMT + CPI combination immune-based therapy can result in an increase of CD8+ tumor infiltrating lymphocytes in breast cancer metastatic sites. These preliminary results will be evaluated in the ongoing randomized phase 3 pivotal registrational trial. Citation Format: Carmen Calfa, Chaitali Nangia, Minal Barve, John Knecht, Jarrod Holmes, Kendrith Roland, Ralph Boccia, Frances Valdes-Albini, Zach Gostout, Mingjin Chang, William Williams, Charles Wiseman, Bonnie Guerin, Shaker Dakhil, Giuseppe Del Priore, Saranya Chumsri. Randomized Phase 2 of Bria-IMT, an Allogenic Human Cell Line with Antigen Presenting Activity, in Heavily Pretreated Metastatic Breast Cancer [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 PO3-05-12.

Recombinant ADAMTS13 in Congenital Thrombotic Thrombocytopenic Purpura

BackgroundCongenital thrombotic thrombocytopenic purpura (TTP) results from severe hereditary deficiency of ADAMTS13. The efficacy and safety of recombinant ADAMTS13 and standard therapy (plasma-derived products) administered as routine prophylaxis or on-demand treatment in patients with congenital TTP is not known.MethodsIn this phase 3, open-label, crossover trial, we randomly assigned patients in a 1:1 ratio to two 6-month periods of prophylaxis with recombinant ADAMTS13 (40 IU per kilogram of body weight, administered intravenously) or standard therapy, followed by the alternate treatment; thereafter, all the patients received recombinant ADAMTS13 for an additional 6 months. The trigger for this interim analysis was trial completion by at least 30 patients. The primary outcome was acute TTP events. Manifestations of TTP, safety, and pharmacokinetics were assessed. Patients who had an acute TTP event could receive on-demand treatment.ResultsA total of 48 patients underwent randomization; 32 completed the trial. No acute TTP event occurred during prophylaxis with recombinant ADAMTS13, whereas 1 patient had an acute TTP event during prophylaxis with standard therapy (mean annualized event rate, 0.05). Thrombocytopenia was the most frequent TTP manifestation (annualized event rate, 0.74 with recombinant ADAMTS13 and 1.73 with standard therapy). Adverse events occurred in 71% of the patients with recombinant ADAMTS13 and in 84% with standard therapy. Adverse events that were considered by investigators to be related to the trial drug occurred in 9% of the patients with recombinant ADAMTS13 and in 48% with standard therapy. Trial-drug interruption or discontinuation due to adverse events occurred in no patients with recombinant ADAMTS13 and in 8 patients with standard therapy. No neutralizing antibodies developed during recombinant ADAMTS13 treatment. The mean maximum ADAMTS13 activity after recombinant ADAMTS13 treatment was 101%, as compared with 19% after standard therapy.ConclusionsDuring prophylaxis with recombinant ADAMTS13 in patients with congenital TTP, ADAMTS13 activity reached approximately 100% of normal levels, adverse events were generally mild or moderate in severity, and TTP events and manifestations were rare. (Funded by Takeda Development Center Americas and Baxalta Innovations; ClinicalTrials.gov number, NCT03393975.)