Izquierdo, Miguel

Abstract Background: The erythropoietin (EPO) receptor activation can stimulate tumor proliferation and may be implicated in resistance to anti-HER2 therapies. EPO administration can be used for the management of chemotherapy-induced anemia. We aim to assess if EPO intake during the adjuvant anti-HER2 treatment impacts the outcomes of HER2-positive early breast cancer (EBC) patients. Methods: For this post hoc analysis of the ALTTO trial (NCT00490139), we categorized two cohorts according to the use of EPO during adjuvant anti-HER2 treatment: i) at least one EPO dose (EPO-cohort) vs ii) no EPO (non-EPO-cohort). We compared their baseline characteristics to identify potential confounders. The primary endpoint disease-free-survival (DFS), and the secondary endpoint overall survival (OS) were compared between these two cohorts, with subgroup analysis according to menopausal status, tumor characteristics, and anti-HER2 treatment. Kaplan Meier method, log-rank test, and Cox regression model adjusted for confounders were performed for DFS and OS (removal criterion p<0.10). The frequency of cardiovascular and thromboembolic adverse events (AEs) of EPO interest was compared between both cohorts. Results: Out of the 8,381 patients recruited in the ALTTO trial, 123 (1.5%) received EPO concomitantly with adjuvant treatment, 59 in the single HER2 blockade (Lapatinib (L)-alone or Trastuzumab (T)-alone) and 64 in dual blockade (T→L or T+L) arms. The median age of EPO-cohort patients was 54 (range: 27-74) years, and 39% were premenopausal, while most had pathologic tumor size >2 cm (56.9%), positive nodal status (58.5%), positive hormone receptor (HR) status (61.8%), and poorly differentiated or undifferentiated histologic grade (64.2%). Baseline characteristics were similar in both cohorts, except for the timing of chemotherapy, for which 93.5% of patients from the EPO-cohort were enrolled in the concurrent designs (2/2B) vs 44.2% in the non-EPO-cohort (p<0.001). Median FU was 6.9 years, with 6,409 (76.5%) patients still on follow-up. For the entire ALTTO cohort, the estimated 3- and 7-year DFS were 88.3% (95% CI: 87.6% - 89.0%) and 80.1% (95% CI: 79.1% - 81.0%), respectively. No difference in DFS by EPO administration (Yes/No) was observed (log-rank p=0.70). The effect of EPO remained non-significant when controlled for the four stratification factors and all other characteristics (p=0.91). The effect of EPO administration on DFS was significant for the subgroup of premenopausal women (p=0.041), favoring the EPO-cohort, noting that this result is based on small event numbers. The interaction was found significant in Cox analysis (p=0.024), remaining significant after adjustment for important prognostic variables (p=0.032). For the entire ALTTO cohort, 758 (9.0%) deaths occurred, with 3-year OS estimate 95.7% (95% CI: 95.2% - 96.1%) and 7-year OS estimate 89.9% (89.2% - 90.6%). The OS results are consistent with those for DFS regarding the lack of a significant association with EPO and the significance (p<0.10) of menopausal status and EPO interaction. In the EPO-cohort (n=123), eight (6.5%) AEs of EPO interest were recorded, while from the non-EPO-cohort (n=8,147), 417 (5.1%) reported similar AEs. Three fatal and 25 life-threatening AEs of EPO interest were recorded in the non-EPO-cohort, and none in the EPO-cohort. Conclusion: EPO administration to patients receiving adjuvant anti-HER2 treatment for HER2-positive EBC was safe and not associated with a harmful impact on survival outcomes, however the sample size of patients who received EPO is rather small. These findings contrast with data suggesting poorer outcomes with EPO, therefore further investigation of tumour microenvironment is needed to better understand these results, particularly in the premenopausal subgroup. Citation Format: Diogo Martins-Branco, Marie Kassapian, Véronique Debien, Rafael Caparica, Daniel Eiger, Urania Dafni, Charitini Andriakopoulou, Sarra El-Abed, Miguel Izquierdo, Malou Vicente, Saranya Chumsri, Martine Piccart-Gebhart, Alvaro Moreno-Aspitia, Ann Søegaard Knop, Janine Lombard, Evandro de Azambuja. The impact of erythropoietin administration concomitantly with adjuvant anti-HER2 treatment on the patients’ outcome: Sub-analysis of the ALTTO study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-14-05.

AbstractThe JAK/STAT3 signaling pathway may be aberrantly activated and have various and conflicting roles in breast cancer. The current study explored prognostic implications of activated STAT3 in human epidermal growth factor receptor 2 (HER2)‐positive primary breast cancers in the context of a large prospective study (ALTTO). Activated STAT3 was determined by immunohistochemical analysis of STAT3 phosphorylation (Y705) performed on the primary tumors. This analysis evaluated whether patients with activated STAT3 had disease‐free survival (DFS) and overall survival (OS) different from patients without activated STAT3. A total of 5694 patients out of the 8381 patients enrolled in ALTTO were included in this analysis (67.9%), and 2634 of them (46%) had evidence of STAT3 activation (minimum tumor Allred score ≥2). The median follow‐up was 6.93 years (6.85‐6.97 years), at the end of which 1035 (18.18%) and 520 (9.13%) patients experienced DFS and OS events, respectively. Patients with STAT3 activation experienced improved DFS compared to those without it (multivariable hazard ratio [HR], 0.84; 95% confidence interval [CI] 0.74‐0.95; P = .006). There were no group differences in OS (multivariable HR, 0.92; 95% CI 0.78‐1.10; P = .37). This effect was limited to ER‐positive tumors. In conclusion, these findings support the role of STAT3 activation as a marker of favorable outcome in ER‐positive/HER2‐positive breast cancer patients.

Abstract Background: Disease relapse is observed in a significant proportion of HER2-positive breast cancer (BC) patients with residual disease (RD) after neoadjuvant treatment, as well as in a subgroup of those achieving pathological complete response (pCR). As the host immune response plays a key role in modulating the activity of anti-HER2 agents, we investigated the association of T- and B-cell receptor (TCR and BCR) repertoires with pCR and event-free survival (EFS) in the NeoALTTO phase 3 trial. Methods: RNA sequencing (RNAseq) data from baseline tumor biopsies were available for 254 patients out of the 455 enrolled in the study. Among those, 166 did not achieve a pCR defined as ypT0/is. Matched RNAseq data from RD samples were available for 43 cases. TCR/BCR repertoires were extracted from RNAseq data using the MiXCR software. TCR and BCR read counts, number of clones, evenness, Shannon entropy, Gini index, length of the complementarity determining region 3, top and second top clone proportion were evaluated. Survival analysis was performed using univariate and multivariate (adjusted for tumor size, nodal status, grade, estrogen receptor [ER] status, age and treatment arm) Cox proportional hazard models, while logistic regressions were used for pCR. False discovery rate (FDR) was obtained using Benjamini & Hochberg method. Results: Baseline TCR top (odds ratio [OR]=0.63 [95% CI 0.46-0.87], FDR=0.021) and second top (OR=0.57 [0.41-0.79], FDR=0.004) clone proportion were significantly associated with a lower probability of achieving pCR in the multivariate analysis. BCR evenness (hazard ratio [HR]=1.5 [1.2-2], FDR=0.015) and Gini index (HR=0.66 [0.52-0.85], FDR=0.015) were significantly associated with EFS in the multivariate analysis. In residual disease, BCR evenness and Gini index showed a similar trend in the EFS univariate analysis, while TCR read counts, number of clones, and entropy were associated with lower HR (P<0.05), although FDR were borderline significant (0.05<FDR<0.1). A model to predict EFS including baseline BCR evenness, ER status, stromal tumor-infiltrating lymphocyte level, and pCR was able to identify 3 groups with good, intermediate and poor prognosis (Kaplan-Meier 5-year EFS rates of 95%, 80% and 58%, respectively). Of note, about 63%, 45% and 12% of the patients achieved a pCR in the three prognostic groups, respectively. Conclusions: In the NeoALTTO trial, the presence of an evenly distributed BCR repertoire was associated with worse EFS. A model integrating baseline immune-related and clinical features was able to identify patients with excellent prognosis despite RD or, conversely, with poor prognosis after pCR. We envision that our model has the potential to allow the personalization of post-operative treatment strategies after both pCR and RD in HER2-positive BC. Further validation of our findings is warranted. Citation Format: Mattia Rediti, David Venet, Françoise Rothé, Tao Qing, Marion Maetens, Ian Bradbury, Miguel A. Izquierdo, Serena Di Cosimo, Florentine Hilbers, Mohammed Bajji, Nadia Harbeck, Michael Untch, David L. Rimm, Stephen Chia, Minetta C. Liu, Cristina Saura, Jens Huober, Paolo Nuciforo, Roberto Salgado, Sherene Loi, Lajos Pusztai, Christos Sotiriou. Predictive and prognostic role of T- and B-cell receptor repertoire in HER2-positive breast cancer: An analysis of the NeoALTTO clinical trial [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1998.

511 Background: Clinicopathological and molecular features, including estrogen receptor (ER) status and PAM50 subtypes, have shown an association with immunogenicity and tumor-infiltrating lymphocyte (TIL) levels in breast cancer (BC). To investigate the complexity of the immune response in HER2+ BC, we explored the association of T- and B-cell receptor (TCR and BCR) repertoires with clinicopathological characteristics, PAM50 subtypes and outcome in the NeoALTTO phase III trial. Methods: RNA sequencing (RNAseq) data from baseline tumor biopsies were available for 254 out of the 455 patients enrolled. TCR and BCR repertoires were extracted from RNAseq data using the MiXCR software. Repertoire and diversity measures (read counts, number of clones, evenness, Gini index, Shannon entropy, length of the complementarity-determining region 3 [CDR3], top and second top clone proportions) were estimated. PAM50 subtypes were computed from RNAseq data. Univariate and multivariate (adjusted for clinicopathological characteristics, TIL levels dichotomized using the median value of 12.5% and treatment arm) Cox proportional hazard models were used for survival analysis, while logistic regressions were used for pathological complete response (pCR), defined as ypT0/is. All results reported had a false discovery rate (FDR) <0.05. Results: Higher BCR read counts, number of clones and Gini index were significantly associated with ER-negative as well as grade 3 tumors. Among the PAM50 subtypes, HER2-enriched (HER2-E) showed significantly higher BCR read counts, number of clones and Gini index along with lower evenness compared to luminal A and B, as well as higher length of CDR3 than luminal A. Of note, basal-like showed similar BCR diversity measures to HER2-E. No significant differences were noted for TCR diversity measures. In multivariate analyses, neither TCR nor BCR features were associated with pCR, while BCR evenness (HR 1.5; 95%CI 1.1-2.1) and Gini index (HR 0.66; 95%CI 0.5-0.88) were associated with event-free survival. Conclusions: BCR repertoire measures suggest a clonal expansion in HER2-E and basal-like PAM50 subtypes. Furthermore, the implementation of BCR-derived biomarkers can help to identify patients with an improved clinical outcome after neoadjuvant anti-HER2 treatment. Our findings highlight the heterogeneity of the immune response within HER2+ BC and provide support for biomarker-driven treatment strategies including immunotherapy in this BC subtype. Further validation is required. Clinical trial information: NCT00553358 .

502 Background: Pre-specified 5-year analyses of the phase III Adjuvant Lapatinib and/or Trastuzumab Treatment Optimisation (ALTTO) Trial defined in Amendments 11&12. Methods: From June 2007 to July 2011, 8381 patients (pts) were randomised from 946 sites in 44 countries to receive either L+T, T→L, L, or T. In 2011, due to futility the L arm was closed and is not included in this analysis. The primary end point is disease-free survival (DFS). Secondary objectives include treatment comparisons with respect to overall survival (OS), time to recurrence (TTR), time to distant recurrence (TDR), cardiac and overall safety and tolerability. Primary analysis results of the study were published in JCO 2015 34:1034-1042. This updated analysis occurs at a 6.9 yrs median follow up (MFU). Results: All patients have reached 5-years of follow-up. 705 DFS events for L+T vs T have been observed. HR for DFS was 0.86 (95% CI, 0.74-1.00; 6-yr DFS%=85% vs 82%) for L+T vs T and 0.93 (95% CI, 0.81-1.08; 6-yr DFS%=84% vs 82%) for T→L vs. T. The 6-year OS was 93%, 92%, and 91% for L+T, T→L, and T, respectively. HR for OS was 0.86 (95% CI, 0.70-1.06) for L+T vs. T and 0.88 (95% CI, 0.71-1.08) for T→L vs. T. DFS differences for L+T vs. T were slightly higher for the hormone-receptor(ER)-negative [HR 0.80 (95% CI, 0.64-1.00; 6-yr DFS%=84% vs. 80%)] and the sequential chemotherapy [HR 0.83 (95% CI, 0.69-1.00; 6-yr DFS%=83% vs.79%)] subgroups. There were no differences in sites of first DFS events according to treatment arm for CNS, loco-regional, or distant recurrences. There were more AEs related to study treatment (L+T 93% vs T 64%). The incidence of primary cardiac end points was low: 1% for L+T, 0.5% for T→L and 0.9% for T. Conclusions: The HRs for this updated analysis are similar to those from the Primary Analysis and the event rate remains lower than anticipated (705 vs 850 planned). Cardiac toxicity remains low. This analysis suggests that HER2+/ER- tumors may have a different biology than HER2+/ER+ and may benefit more from dual HER2 blockade. Long-term follow up continues. Clinical trial information: NCT00490139.