Subcutaneous vs Intravenous Trastuzumab/Pertuzumab: A Time and Motion Substudy of a Phase II Trial of Adjuvant Trastuzumab/Pertuzumab for Stage I HER2+ Breast Cancer (ADEPT trial).

PURPOSE: The time required for in-clinic drug administration can substantially affect breast cancer patients' quality of life. Subcutaneous (SC) drug administration, as opposed to intravenous (IV), may reduce this time commitment. This study sought to estimate the difference in time burden between IV and SC administration of trastuzumab and pertuzumab (HP). METHODS: We prospectively enrolled a subcohort of patients participating in the ADEPT trial (ClinicalTrials.gov identifier: NCT04569747, investigating adjuvant HP plus endocrine therapy for stage I human epidermal growth factor receptor 2-positive breast cancer) to this single-arm crossover time and motion substudy. Patients received two cycles of IV HP followed by two cycles of SC HP. During each cycle, time points in drug preparation and administration were captured. The primary end point was total patient time in the treatment chair. Additional end points included total patient treatment experience time and total pharmacy workflow time. A sample size of 22 patients was estimated to provide 90.7% power with two-sided alpha .05 to detect a difference of 70 minutes in the primary end point by treatment arm (IV v SC). RESULTS: Twenty-two patients were enrolled. The mean total patient time in the treatment chair was 61.8 minutes shorter with SC versus IV HP (22.5 v 84.3 minutes; P < .0001). The mean total patient treatment experience time (incorporating time spent waiting for treatment initiation and time spent in the treatment chair) was 81.8 minutes shorter for SC administration (96 v 177.8 minutes; P < .0001). The pharmacy workflow time was 78.2 minutes shorter for SC versus IV formulation (41 v 119.2 minutes; P < .0001). CONCLUSION: SC administration of HP shortened patient time burden by approximately 1 hour. SC drug administration can facilitate faster workflows for health care professionals and improve patients' breast cancer treatment experience.

Abemaciclib plus endocrine therapy for HR+, HER2-, node-positive, high-risk early breast cancer: a plain language summary of the monarchE study.

WHAT IS THIS SUMMARY ABOUT?: This article summarizes the most recent results of the monarchE study. This study was completed in participants with a type of breast cancer called HR+, HER2-, node-positive, high-risk early breast cancer. In this study, abemaciclib, a non-chemotherapy treatment, was administered with standard of care endocrine therapy after curative surgery. Most participants had received prior chemotherapy and/or radiotherapy. The study investigated if abemaciclib helped participants live longer without their cancer returning compared with participants who only received standard of care endocrine therapy. The study participants were assigned to 1 of 2 treatment groups. Participants in Group A were assigned to receive standard of care endocrine therapy with abemaciclib for 2 years, followed by endocrine therapy for a total of at least 5 years. Participants in Group B were assigned to receive standard of care endocrine therapy only for at least 5 years. The effect of treatment was compared between these 2 groups. WHAT WERE THE RESULTS?: Overall, the results showed that the cancer was 34% less likely to come back after surgery in the participants in Group A (abemaciclib plus endocrine therapy) compared with those in Group B (endocrine therapy only). At 4 years since the start of the study treatment, more participants who received the combination of abemaciclib plus endocrine therapy remained free of cancer compared with participants who received endocrine therapy alone (86% versus 79%). Participants who received abemaciclib plus endocrine therapy had more side effects than those who received endocrine therapy alone, but most of these effects were mild to moderate and reversible upon the end of therapy. The most common side effects in the abemaciclib group were diarrhea, infections, low number of white blood cells, and tiredness. WHAT DO THE RESULTS MEAN?: This study found that administering abemaciclib in combination with standard endocrine therapy after curative breast surgery helped lower the risk of cancer returning in people with HR+, HER2-, node-positive, high-risk early breast cancer. Abemaciclib is a new treatment option for people with this diagnosis. People with high-risk early breast cancer should always talk to their doctors and nurses before making any decisions about their treatment.Clinical Trial Registration: NCT03155997 (monarchE study).

OptimICE-RD: sacituzumab govitecan + pembrolizumab vs pembrolizumab (± capecitabine) for residual triple-negative breast cancer.

Patients with early-stage triple-negative breast cancer (TNBC) with residual invasive disease after neoadjuvant therapy have a high risk of recurrence even with neoadjuvant and adjuvant treatment with pembrolizumab. Sacituzumab govitecan, a Trop-2-directed antibody-drug conjugate with a topoisomerase I inhibitor payload, improved progression-free survival (PFS) and overall survival (OS) versus chemotherapy in patients with pre-treated metastatic TNBC. Moreover, preclinical data suggest that topoisomerase I inhibitors may enhance the effects of immune checkpoint inhibitors through activation of the cGAS-STING pathway. Here we describe the international randomized phase III AFT-65/ASCENT-05/OptimICE-RD trial, which evaluates the efficacy and safety of sacituzumab govitecan plus pembrolizumab versus treatment of physician's choice (pembrolizumab ± capecitabine) among patients with early-stage TNBC with residual invasive disease after neoadjuvant therapy.Clinical Trial Registration: NCT05633654 (ClinicalTrials.gov)Other Study ID Number(s): Gilead Study ID: GS-US-595-6184Registration date: 1 December 2022Study start date: 12 December 2022Recruitment status: Recruiting.

AFT-65/ASCENT-05/OptimICE-RD is an ongoing clinical trial that is testing a new treatment combination for patients with stage II or III triple-negative breast cancer (TNBC). Stage II­III means the cancer is confined to the breast and/or nearby lymph nodes and can be surgically removed. However, there remains a risk that the cancer could recur after surgery. To reduce this risk, patients with stage II­III TNBC receive anti-cancer medication before and after surgery. For some patients, receipt of anti-cancer medication before surgery produces a pathologic complete response (pCR), meaning there is no observable cancer left behind at surgery. Patients with a pCR have a lower risk of recurrence than patients with residual disease.The AFT-65/ASCENT-05/OptimICE-RD trial includes people with stage II-III TNBC who have residual cancer after completing their course of pre-surgery anti-cancer medication. All participants have any remaining cancer in their breast and/or lymph nodes removed surgically, after which they are randomly assigned to receive one of two treatments. The experimental therapy consists of pembrolizumab along with a medication called sacituzumab govitecan, which kills cancer cells directly and may strengthen the anti-cancer immune response. Pembrolizumab strengthens the anti-cancer immune response, so the hypothesis of this trial is that the two medications will be more effective together. The control therapy consists of pembrolizumab, alone or in combination with a chemotherapy medication called capecitabine, which is the current standard of care. To study the effectiveness of each treatment, the researchers are following up with all participants to learn if and when their breast cancer returns.

Adjuvant Trastuzumab Emtansine Versus Paclitaxel Plus Trastuzumab for Stage I Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer: 5-Year Results and Correlative Analyses From ATEMPT.

PURPOSE: Long-term outcomes of patients with stage I human epidermal growth factor receptor 2 (HER2)-positive breast cancer receiving adjuvant trastuzumab emtansine (T-DM1) remain undefined, and prognostic predictors represent an unmet need. METHODS: In the ATEMPT phase II trial, patients with stage I centrally confirmed HER2-positive breast cancer were randomly assigned 3:1 to adjuvant T-DM1 for 1 year or paclitaxel plus trastuzumab (TH). Coprimary objectives were to compare the incidence of clinically relevant toxicities between arms and to evaluate invasive disease-free survival (iDFS) with T-DM1. Correlative analyses included the HER2DX genomic tool, multiomic evaluations of HER2 heterogeneity, and predictors of thrombocytopenia. RESULTS: After a median follow-up of 5.8 years, 11 iDFS events were observed in the T-DM1 arm, consistent with a 5-year iDFS of 97.0% (95% CI, 95.2 to 98.7). At 5 years, the recurrence-free interval (RFI) was 98.3% (95% CI, 97.0 to 99.7), the overall survival was 97.8% (95% CI, 96.3 to 99.3), and the breast cancer-specific survival was 99.4% (95% CI, 98.6 to 100). Comparable iDFS was observed with T-DM1 irrespective of tumor size, hormone receptor status, centrally determined HER2 immunohistochemical score, and receipt of T-DM1 for more or less than 6 months. Although ATEMPT was not powered for this end point, the 5-year iDFS in the TH arm was 91.1%. Among patients with sufficient tissue for HER2DX testing (n = 187), 5-year outcomes significantly differed according to HER2DX risk score, with better RFI (98.1% v 81.8%, hazard ratio [HR], 0.10, P = .01) and iDFS (96.3% v 81.8%, HR, 0.20, P = .047) among patients with HER2DX low-risk versus high-risk tumors, respectively. CONCLUSION: Adjuvant T-DM1 for 1 year leads to outstanding long-term outcomes for patients with stage I HER2-positive breast cancer. A high HER2DX risk score predicted a higher risk of recurrence in ATEMPT.

Checkpoint inhibition for early-stage hormone receptor-positive breast cancer.

INTRODUCTION: Most patients with breast cancer have early-stage hormone receptor (HR)-positive, human epidermal growth factor receptor-2 (HER2)-negative disease. Even though the prognosis for most of these patients is good, there is a need to identify patients at risk for poor outcomes and to develop strategies to mitigate this risk. AREAS COVERED: The addition of immunotherapy to standard neoadjuvant chemotherapy represents a promising option for select patients with HR-positive early breast cancer. Three randomized clinical trials have shown favorable results to date. In this review, we discuss the findings of I-SPY2, CheckMate 7FL (NCT04109066), and KEYNOTE-756 (NCT03725059). EXPERT OPINION: Despite the promising results of these trials, there are unanswered questions that need to be considered before incorporating neo/adjuvant immunotherapy in the treatment paradigm of early-stage HR-positive breast cancer. One example of an unanswered question is patient selection. Because the regimens used in these protocols are associated with long-term toxicities, identifying the patients who are more likely to derive a benefit from these agents, such as through the use of biomarkers, is critical. A second example is the optimal integration of adjuvant therapies that improve invasive disease-free survival, such as abemaciclib and ribociclib, which are not safely administered concurrently with immunotherapy.

Clinical efficacy of CDK4/6 inhibitor plus endocrine therapy in HR-positive/HER2-0 and HER2-low-positive metastatic breast cancer: a secondary analysis of PALOMA-2 and PALOMA-3 trials.

BACKGROUND: Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors in combination with traditional endocrine therapy (ET) are now the recommended first-line treatment for hormone receptor (HR)-positive and HER2-negative metastatic breast cancer (MBC). However, the benefits of adding CDK4/6 inhibitors to ET in HER2-low-positive and HER2-0 subgroups remain unclear. We aimed to assess the effectiveness of CDK4/6 inhibitors in combination with ET in patients with HR-positive, HER2-low-positive and HER2-0 MBC. METHODS: This secondary analysis assessed progression-free survival (PFS) among HER2-low-positive and HER2-0 patients enrolled in the double-blind, placebo-controlled randomised clinical trials PALOMA-2 and PALOMA-3. The study included 1186 HER2-negative, HR-positive female patients, with available immunohistochemistry (IHC) and/or in situ hybridization (ISH) results, across 17 countries enrolled between February 2013 and August 2014. HER2-low-positive status was defined by IHC 1+ or 2+ with negative ISH, and HER2-zero by IHC 0. Data analyses were conducted between March and May 2023. In the PALOMA-2 trial, patients were randomly assigned to receive either palbociclib or placebo, in combination with letrozole in the first-line treatment for HR-positive MBC. Patients in the PALOMA-3 study, who had progression or relapse during previous ET, were randomly allocated to receive either palbociclib plus fulvestrant or placebo plus fulvestrant. The primary endpoint was investigator-assessed PFS. Kaplan-Meier approach and Cox proportional hazards model were applied to estimate the association of treatment strategies with PFS among HER2-0 and HER2-low-positive populations. The two trials are registered with ClinicalTrials.gov, number NCT01740427 and NCT01942135. FINDINGS: Of the 666 patients with MBC from the PALOMA-2 study, there were 153 HER2-0 and 513 HER2-low-positive patients. In the HER2-0 population, no significant difference in PFS was observed between the palbociclib-letrozole and placebo-letrozole groups (hazard ratio = 0.79, 95% confidence interval [CI] 0.48-1.30, p = 0.34). In the HER2-low-positive population, palbociclib-letrozole demonstrated a significantly lower risk of PFS than placebo-letrozole group (hazard ratio = 0.52, 95% CI 0.41-0.66, p < 0.0001). The PALOMA-3 study analysed 520 patients with MBC. Within the 153 HER2-0 patients, the palbociclib-fulvestrant group showed a significantly longer PFS than the placebo-fulvestrant group (hazard ratio = 0.54, 95% CI 0.30-0.95, p = 0.034). Among the 367 HER2-low-positive patients, palbociclib-fulvestrant improved PFS (hazard ratio = 0.39, 95% CI 0.28-0.54, p < 0.0001). INTERPRETATION: The combination of a CDK4/6 inhibitor with ET significantly improved PFS in HER2-low-positive patients, while for HER2-0 patients, benefits were primarily observed in patients who had progressed on previous ET. Furthermore, HER2-0 patients may derive limited benefits from first-line CDK4/6 inhibitor treatment. Further work is needed to validate these findings and to delineate patient subsets that are most likely to benefit from the combination of CDK4/6 inhibitors and ET as first-line treatments. FUNDING: None.

Clinicogenomic characterization of inflammatory breast cancer.

Background: Inflammatory breast cancer (IBC) is a rare and poorly characterized type of breast cancer with an aggressive clinical presentation. The biological mechanisms driving the IBC phenotype are relatively undefined-partially due to a lack of comprehensive, large-scale genomic studies and limited clinical cohorts. Patients and Methods: A retrospective analysis of 2457 patients with metastatic breast cancer who underwent targeted tumor-only DNA-sequencing was performed at Dana-Farber Cancer Institute. Clinicopathologic, single nucleotide variant (SNV), copy number variant (CNV) and tumor mutational burden (TMB) comparisons were made between clinically confirmed IBC cases within a dedicated IBC center versus non-IBC cases. Results: Clinicopathologic differences between IBC and non-IBC cases were consistent with prior reports-including IBC being associated with younger age at diagnosis, higher grade, and enrichment with hormone receptor (HR)-negative and HER2-positive tumors. The most frequent somatic alterations in IBC involved TP53 (72%), ERBB2 (32%), PIK3CA (24%), CCND1 (12%), MYC (9%), FGFR1 (8%) and GATA3 (8%). A multivariate logistic regression analysis revealed a significant enrichment in TP53 SNVs in IBC; particularly in HER2-positive and HR-positive disease which was associated with worse outcomes. Tumor mutational burden (TMB) did not differ substantially between IBC and non-IBC cases and a pathway analysis revealed an enrichment in NOTCH pathway alterations in HER2-positive disease. Conclusion: Taken together, this study provides a comprehensive, clinically informed landscape of somatic alterations in a large cohort of patients with IBC. Our data support higher frequency of TP53 mutations and a potential enrichment in NOTCH pathway activation-but overall; a lack of major genomic differences. These results both reinforce the importance of TP53 alterations in IBC pathogenesis as well as their influence on clinical outcomes; but also suggest additional analyses beyond somatic DNA-level changes are warranted.

Antibody-Drug Conjugate Sacituzumab Govitecan Enables a Sequential TOP1/PARP Inhibitor Therapy Strategy in Patients with Breast Cancer.

PURPOSE: The antibody-drug conjugate (ADC) sacituzumab govitecan (SG) comprises the topoisomerase 1 (TOP1) inhibitor (TOP1i) SN-38, coupled to a monoclonal antibody targeting trophoblast cell surface antigen 2 (TROP-2). Poly(ADP-ribose) polymerase (PARP) inhibition may synergize with TOP1i and SG, but previous studies combining systemic PARP and TOP1 inhibitors failed due to dose-limiting myelosuppression. Here, we assess the proof-of-mechanism and clinical feasibility for SG and talazoparib (TZP) employing an innovative sequential dosing schedule. PATIENTS AND METHODS: In vitro models tested pharmacodynamic endpoints, and in a phase 1b clinical trial (NCT04039230), 30 patients with metastatic triple-negative breast cancer (mTNBC) received SG and TZP in a concurrent (N = 7) or sequential (N = 23) schedule. Outcome measures included safety, tolerability, preliminary efficacy, and establishment of a recommended phase 2 dose. RESULTS: We hypothesized that tumor-selective delivery of TOP1i via SG would reduce nontumor toxicity and create a temporal window, enabling sequential dosing of SG and PARP inhibition. In vitro, sequential SG followed by TZP delayed TOP1 cleavage complex clearance, increased DNA damage, and promoted apoptosis. In the clinical trial, sequential SG/TZP successfully met primary objectives and demonstrated median progression-free survival (PFS) of 7.6 months without dose-limiting toxicities (DLT), while concurrent dosing yielded 2.3 months PFS and multiple DLTs including severe myelosuppression. CONCLUSIONS: While SG dosed concurrently with TZP is not tolerated clinically due to an insufficient therapeutic window, sequential dosing of SG followed by TZP proved a viable strategy. These findings support further clinical development of the combination and suggest that ADC-based therapy may facilitate novel, mechanism-based dosing strategies.

Health-related quality of life with sacituzumab govitecan in HR+/HER2- metastatic breast cancer in the phase III TROPiCS-02 trial.

BACKGROUND: The TROPiCS-02 study (NCT03901339) demonstrated that sacituzumab govitecan (SG) has superior clinical outcomes over treatment of physician's choice (TPC) chemotherapy in patients with hormone receptor-positive, human epidermal growth factor 2 receptor-negative (HR+/HER2-) metastatic breast cancer (mBC). Here, we present health-related quality of life (HRQoL) patient-reported outcome (PRO) findings from this study. PATIENTS AND METHODS: Eligible adults with HR+/HER2- mBC who previously received a taxane, endocrine-based therapy, a CDK4/6 inhibitor, and 2-4 lines of chemotherapy were randomized 1:1 to receive SG or TPC until progression or unacceptable toxicity. PROs were assessed at baseline and on day 1 of each cycle, using the European Organization for Research and Treatment of Cancer Quality-of-Life Core 30 (EORTC QLQ-C30), EQ-5D-5L, and PRO Common Terminology Criteria for Adverse Events (PRO-CTCAE). RESULTS: Compared to TPC, overall least square mean change from baseline was significantly better for SG for physical functioning and dyspnea, but worse for diarrhea. Time to first clinically meaningful worsening or death was significantly longer for SG in global health status/quality of life, physical functioning, fatigue, emotional functioning, dyspnea, insomnia, and financial difficulties of the EORTC QLQ-C30 and the EQ-VAS, but longer for TPC in diarrhea. Few patients in both arms reported experiencing any worsening to level 3 or 4 treatment-related symptomatic events during treatment, as assessed by 16 PRO-CTCAE items, except for diarrhea frequency and amount of hair loss, which favored TPC. CONCLUSIONS: SG was associated with an HRQoL benefit in most symptoms and functioning, compared with TPC. This supports the favorable profile of SG as a treatment option for patients with pretreated HR+/HER2- mBC.

Subgroup analyses from the phase 3 ASCENT study of sacituzumab govitecan in metastatic triple-negative breast cancer.

In this post hoc analysis of the ASCENT study, we compared outcomes with sacituzumab govitecan (SG) vs single-agent chemotherapy in clinically important subgroups of patients with metastatic triple-negative breast cancer (mTNBC). Patients with mTNBC refractory to/relapsing after ≥2 prior chemotherapies (≥1 in the metastatic setting) were randomized 1:1 to receive SG or treatment of physician's choice (TPC) until unacceptable toxicity/progression. The primary endpoint was progression-free survival (PFS) per RECIST 1.1 by central review in patients without brain metastases. Patients with brain metastases were allowed if metastases were stable ≥4 weeks. In the intention-to-treat (ITT) population, 19% of patients were age ≥65 years; 12% were Black, and 12% had brain metastases. SG improved PFS and overall survival (OS), respectively, vs TPC in patients age ≥65 years (7.1 vs 2.4 months and 14.7 vs 8.9 months), or of Black race (5.4 vs 2.2 months and 13.8 vs 8.5 months), consistent with outcomes in the ITT population. Patients with brain metastases had numerically higher median PFS with SG vs TPC, but median OS was similar between treatment groups. SG was well tolerated and had a manageable safety profile consistent with the full safety population across all subgroups; neutropenia and diarrhea were the most common treatment-emergent adverse events. These findings confirm the meaningful clinical benefit of SG vs standard chemotherapy in patient subgroups with high unmet needs. SG should be considered an effective and safe treatment option for patients with mTNBC eligible for second-line or later therapy. ClinicalTrials.gov Number: NCT02574455.

Prognosis and treatment outcomes for patients with stage IA triple-negative breast cancer.

To evaluate the role of chemotherapy in stage IA triple-negative breast cancer, we conducted a retrospective population-based study including 8601 patients. The use of chemotherapy significantly increased from 2010 to 2019 in patients with T1b and T1c tumors (p = 0.001 and p < 0.001, respectively). Receipt of chemotherapy was associated with improved breast cancer-specific survival (BCSS, adjusted hazard ratio = 0.70; p = 0.006), particularly in patients with T1c tumors (5-year BCSS 94.5% vs. 91.2%).

Clinicopathological characteristics and eligibility for adjuvant olaparib of germline BRCA1/2 mutation carriers with HER2-negative early breast cancer.

Following the survival benefit demonstrated in the OlympiA trial, one year of adjuvant olaparib is now recommended for all patients with germline BRCA1/2 pathogenic/likely pathogenic variants (PV) and high-risk, HER2-negative early breast cancer after chemotherapy. However, optimal identification of high-risk patients who may derive benefit from this genomically-directed therapy is debated. In this study, we sought to characterize the real-world proportion of gBRCA1/2 PV carriers eligible for adjuvant olaparib according to the OlympiA criteria, and to compare clinicopathologic characteristics and outcomes between eligible and ineligible patients.

Impact of dose reductions on adjuvant abemaciclib efficacy for patients with high-risk early breast cancer: analyses from the monarchE study.

In monarchE, adjuvant abemaciclib significantly improved invasive disease-free survival (IDFS) and distant relapse-free survival (DRFS), with sustained benefit beyond the 2-year treatment period. Abemaciclib dose reductions were allowed to proactively manage adverse events. Exploratory analyses to investigate the impact of dose reductions on efficacy were conducted. Across the three patient subgroups as defined by relative dose intensity (≤66%, 66-93%, ≥93%), the estimated 4-year IDFS rates were generally consistent (87.1%, 86.4%, and 83.7%, respectively). In the time-dependent Cox proportional hazard model, the effect of abemaciclib was consistent at the full dose compared to being reduced to a lower dose (IDFS hazard ratio: 0.905; 95% confidence interval: 0.727, 1.125; DRFS hazard ratio: 0.942; 95% confidence interval: 0.742, 1.195). These analyses showed that the efficacy of adjuvant abemaciclib was not compromised by protocol mandated dose reductions for patients with node positive, hormone receptor positive, human epidermal growth factor 2-negative, high-risk early breast cancer.

Exemestane plus everolimus and palbociclib in metastatic breast cancer: clinical response and genomic/transcriptomic determinants of resistance in a phase I/II trial.

The landscape of cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) resistance is still being elucidated and the optimal subsequent therapy to overcome resistance remains uncertain. Here we present the final results of a phase Ib/IIa, open-label trial (NCT02871791) of exemestane plus everolimus and palbociclib for CDK4/6i-resistant metastatic breast cancer. The primary objective of phase Ib was to evaluate safety and tolerability and determine the maximum tolerated dose/recommended phase II dose (100 mg palbociclib, 5 mg everolimus, 25 mg exemestane). The primary objective of phase IIa was to determine the clinical benefit rate (18.8%, n = 6/32), which did not meet the predefined endpoint (65%). Secondary objectives included pharmacokinetic profiling (phase Ib), objective response rate, disease control rate, duration of response, and progression free survival (phase IIa), and correlative multi-omics analysis to investigate biomarkers of resistance to CDK4/6i. All participants were female. Multi-omics data from the phase IIa patients (n = 24 tumor/17 blood biopsy exomes; n = 27 tumor transcriptomes) showed potential mechanisms of resistance (convergent evolution of HER2 activation, BRAFV600E), identified joint genomic/transcriptomic resistance features (ESR1 mutations, high estrogen receptor pathway activity, and a Luminal A/B subtype; ERBB2/BRAF mutations, high RTK/MAPK pathway activity, and a HER2-E subtype), and provided hypothesis-generating results suggesting that mTOR pathway activation correlates with response to the trial's therapy. Our results illustrate how genome and transcriptome sequencing may help better identify patients likely to respond to CDK4/6i therapies.

Adjuvant nivolumab, capecitabine or the combination in patients with residual triple-negative breast cancer: the OXEL randomized phase II study.

Chemotherapy and immune checkpoint inhibitors have a role in the post-neoadjuvant setting in patients with triple-negative breast cancer (TNBC). However, the effects of nivolumab, a checkpoint inhibitor, capecitabine, or the combination in changing peripheral immunoscore (PIS) remains unclear. This open-label randomized phase II OXEL study (NCT03487666) aimed to assess the immunologic effects of nivolumab, capecitabine, or the combination in terms of the change in PIS (primary endpoint). Secondary endpoints included the presence of ctDNA, toxicity, clinical outcomes at 2-years and association of ctDNA and PIS with clinical outcomes. Forty-five women with TNBC and residual invasive disease after standard neoadjuvant chemotherapy were randomized to nivolumab, capecitabine, or the combination. Here we show that a combination of nivolumab plus capecitabine leads to a greater increase in PIS from baseline to week 6 (91%) compared with nivolumab (47%) or capecitabine (53%) alone (log-rank p = 0.08), meeting the pre-specified primary endpoint. In addition, the presence of circulating tumor DNA (ctDNA) is associated with disease recurrence, with no new safety signals in the combination arm. Our results provide efficacy and safety data on this combination in TNBC and support further development of PIS and ctDNA analyses to identify patients at high risk of recurrence.