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Background: Trastuzumab and pertuzumab have been shown to work by inhibiting the intracellular signaling linked to HER2 receptor activation, and cytotoxic immune mechanisms, including Fc-dependent immune cell activation. ER+ and ER-/HER2+ breast cancers (BC) are considered molecularly distinct entities (Bianchini G, ASCO 2011; Iwamoto T, ESMO 2012). Regardless of the ER status, immune gene signatures are prognostic and predictive of chemotherapy response (Iwamoto T, ESMO 2012). The gene expression profiles of pre-treatment tumor samples from patients of the NeoSphere trial of neoadjuvant pertuzumab+trastuzumab ± docetaxel (T) (Gianni L, Lancet Oncol 2012) were characterized. We assessed the association of pre-selected adaptive immune functions and key immune regulatory genes with the likelihood of achieving a pathological complete response (pCR) in NeoSphere. Methods: Baseline core biopsies were collected from 387/417 patients. Gene expression profiles (Affymetrix U133 Plus 2.0) were obtained for 367 samples (88% of all patients) that were evenly distributed among arms A (TH, n=90), B (THP, n=95), C (HP, n=98), and D (TP, n=84). ER status was defined by IHC. The primary endpoint was pCR in breast. We assessed metagenes (average expression of the associated genes) corresponding to: immunoglobulins (IgG), CD8A, MHC type I and type II (MHC1, MHC2), interferon inducible genes (I-IG) and STAT1-related genes. We also assessed the individual genes PD1, PD-L1, PD-L2, CTLA4, IFNG. Results: ER+ and ER-- tumors had differential mRNA expression for: CD8A, IgG, PD-L2, PD1, IFNG (overexpressed in ER--), and I-IG (overexpressed in ER+). Positive correlations were observed between most of these biomarkers. Only PD1 was inversely correlated with STAT1, interferon and MHC2. In logistic univariate regression analyses some biomarkers showed moderate association with pCR or residual disease without consistent patterns between treatment arms. However, a multivariate logistic regression model constructed for all the selected biomarkers revealed that high expression of PD-L1 was consistently associated with lower pCR rate in all chemotherapy containing arms (A, B and D). A similar trend was present also in Arm C, the arm with antibody treatment alone. In all arms, high expression of IFNG and/or STAT1 were associated with higher pCR rate. In multivariate analysis PD-L1, PD1 and STAT1 were associated with pCR irrespective of the ER status in combined arms A, C and D. In arm B, both CTLA4 and PD-L1 were independently associated with lower pCR in ER-- tumors. Conclusions: The association between pCR and selected immune biomarkers in patients treated with pertuzumab, trastuzumab, or both, with or without chemotherapy, supports our understanding of the key role of the immune system in contributing to HER2-targeted antibody therapy on top of signaling inhibition. High PD-L1 expression emerged for its consistent association with lower pCR. These results provide a rationale for combining HER2-targeted treatments with immune-modulating agents and may allow the prediction of treatment benefit. Validation of these results with different assays is ongoing. [ABSTRACT FROM AUTHOR]

Background: Pathologic complete response (pCR) is a proposed surrogate endpoint for predicting long-term clinical benefit on endpoints such as disease-free survival (DFS), event-free survival (EFS), or overall survival (OS). A meta-analysis is needed to establish the magnitude of pCR improvement on a trial level that results in improved DFS, EFS, or OS. Methods: We identified 12 neoadjuvant randomized trials (N = 13,125) with pCR clearly defined and long-term follow-up available for EFS and OS. Trials included AGO 1 (n = 668), ECTO (n = 1355), EORTC 10994/BIG 1-00 (n = 1856), GeparDuo (n = 907), GeparQuattro (n = 1495), GeparTrio (n = 2072), GeparTrio-Pilot (n = 285), NOAH (n = 234), NSABP B18 (n = 760), and NSABP B27 (n = 2411), PREPARE (n = 733), and TECHNO (n = 217). Key objectives of the meta-analysis were to determine: (1) the relationship of pCR to EFS and OS, (2) the definition of pCR that correlates best with long-term outcome, (3) the breast cancer subtypes in which pCR is best correlated with long-term outcome and (4) the magnitude of pCR effect needed to improve EFS and OS. We compared three pCR definitions: absence of invasive cancer and in situ cancer in the breast and axillary nodes (ypT0ypN0), absence of invasive cancer in the breast and axillary nodes with DCIS allowed (ypT0/isypN0), and absence of invasive cancer in the breast with DCIS allowed irrespective of nodal involvement (ypT0/is). Results: Overall 13%, 18% and 22% of patients achieved a pCR defined as ypT0ypN0, ypT0/isypN0, and ypT0/is, respectively. Eradication of tumor from both the breast and lymph nodes (ypT0ypN0 or ypT0/isypN0) was better associated with improved EFS and OS compared to eradication of tumor from the breast alone (ypT0/is). Patients who achieved a pCR (ypT0/isypN0) had an improved EFS (HR = 0.48) and OS (HR = 0.36) compared to those who did not. pCR was uncommon in patients with low-grade hormone receptor-positive (HR+) tumors (7%) and more common in the following tumor subtypes: high-grade HR+ (16%), triple negative (34%), HR+/HER2+ (30%), and hormone receptor-negative (HR-)/HER2+ (50%). Patients with more aggressive tumor subtypes who achieved pCR had greater EFS compared to patients who did not achieve pCR as follows: HR+ high grade (HR = 0.27), HR+/HER2+ (HR = 0.58), HR-/HER2+ (HR = 0.25), and triple negative (HR = 0.24). A trial level analysis on the relationship between pCR effect size and EFS did not show a correlation. Conclusions: Individual patients who attain a pCR, defined as either ypT0ypN0 or ypT0/isypN0, have a more favorable long-term outcome. The data show comparable EFS or OS regardless of the presence or absence of DCIS. For consistency, a standard pCR definition (ypT0ypN0 or ypT0/isypN0) should be used in future trials. Impact of pCR effect is limited to patients with HR+/grade 3, HR-/HER2-, and HER2+ tumors. This meta-analysis did not establish the magnitude of increase in pCR rate needed to predict the superiority of one regimen over another in terms of EFS or OS. This may be due to low pCR rates and the heterogeneity of the patient population included in this meta-analysis. The absolute magnitude of improvement in pCR rate needed to impact long-term outcome may be greater than the observed difference in these trials and may vary according to breast cancer subtype. [ABSTRACT FROM AUTHOR]

BACKGROUND: Disease-free survival (DFS) is often a primary endpoint of randomized trials of adjuvant therapies for breast cancer, but long-term follow-up of DFS and especially overall survival (OS) remain important. When the primary DFS results favor the experimental arm, patients (pts) assigned to the control group may select the option to crossover to receive the experimental treatment via protocol amendment. Such "selective crossover" disturbs the integrity of the randomized comparison for any efficacy endpoints that rely on further follow-up. Selective crossover, which is motivated by positive results having been observed in the current trial, is distinct from so-called "unplanned crossover," which refers to non-adherence to protocol. In this abstract, we discuss the consequences of selective crossover for trials evaluating adjuvant trastuzumab, using the HERA (HERceptin Adjuvant) trial as an example, and present a variety of alternative analysis approaches. METHODS: HERA enrolled 5102 women with HER2-positive early breast cancer who had completed all surgery and (neo)adjuvant chemotherapy to compare 1 or 2 years of trastuzumab treatment vs observation. After a positive first interim analysis at 1y median follow-up (MFU) showed that 1 year of trastuzumab significantly improved DFS vs observation [MJ Piccart-Gebhart et al; NEJM 2005], event-free patients in the observation group were offered crossover to receive trastuzumab. 885 (52%) of the 1698 pts in the observation group selectively crossed over to trastuzumab. RESULTS: Previously reported intention-to-treat (ITT) analysis of HERA at 4y MFU showed a decreasing effectiveness of trastuzumab with respect to DFS compared with those at 2y MFU [L Gianni et al, Lancet Oncol 2011; I Smith et al, Lancet 2007]. In addition, the ITT analysis of OS at 4y MFU showed little effect of trastuzumab, while the analysis artificially censoring follow-up in the observation group at the time of selective crossover showed a substantial OS advantage for trastuzumab. The dependent censored analysis of OS is clearly biased in favor of trastuzumab because data for pts who remain event-free can be censored at the time of crossover, while data for the sicker pts in the observation group (those who relapsed) cannot be censored due to crossover. The issues related to the ITT and dependent censored analyses will be reviewed and discussed. Alternative analytic approaches designed to estimate the treatment effect that would have been observed had there been no selective crossover will be presented. The methods include the inverse probability of censoring weighted (IPCW) approach, and randomization-based estimators under the accelerated failure time model. HERA data to about 8y MFU (available fall 2012) will be used to illustrate approaches. CONCLUSION: Alternative methods addressing selective crossover are required to estimate the trastuzumab effect for updated analyses of DFS and OS for HERA, and for any other large randomized trial with positive interim results. [ABSTRACT FROM AUTHOR]

BACKGROUND Lymphedema (LE) is a common complication of breast cancer (BC) treatments conditioning disability that affects quality of life. Decongestive therapy is the most popular treatment but it determines only a transient advantage, while pharmacologic therapy didn't impact on LE. On the basis of clinical observations of LE regression in patients treated with sorafenib with antitumoral intent, we hypothesized that sorafenib could have an anti-LE activity through inhibition of vascular permeability by suppressing VEGFRs. METHODS We conducted a single-arm, monoistitutional phase II study in BC patients with treatment-acquired LE of the arm. Major or uncontrolled cardiological disease, brain metastasis, history of thromboembolism were exclusion criteria. Concomitant chemo or hormonal therapy was allowed. Pts received sorafenib 200 mg daily for a maximum of 8 weeks. The primary end-point was to evaluate the efficacy of sorafenib as reduction of LE, defined by the percentage reduction (PR) of the difference between the total arm circumference (measured as the sum of the circumference at 12 points) of the affected and the controlateral arm (Starritt, Peterk JA Cancer 2001-10): [(Initial Difference - Final Difference)/Initial Difference] x 100. Secondary end-points were safety and duration of response (DOR). The study was designed to test the null hypothesis that the PR of edema observed with this therapy was at most 20% versus the alternative hypothesis that the PR obtained by this regimen was ≥ 40%. RESULTS From May 2009 to April 2011, 36 BC pts were enrolled. All pts underwent axillary dissection and 29 pts had received adjuvant radiotherapy, but none on the axilla. Median time from primary breast surgery and from occurrence of edema to study enrollement was 65 and 49 months, respectively. All pts are evaluable for efficacy and toxicity. Most common toxicities included grade 1-2 gastralgia (17%), hypertension (17%) and rash (43%); one patient experienced grade 3 hand-foot syndrome. Twenty-five pts completed the planned 8 weeks of therapy, 11 (31%) had early treatment discontinuation after 2 (n = 6), 4 (n = 4) and 6 (n = 1) weeks of treatment due to recurrent grade 2 toxicity or to relapse of disease (n = 1). The median PR of the difference between the two arms was 34% (range, 2-100), 14 pts (39%) experienced a LE reduction ≥ 40%. Among 25 pts who completed therapy, 12 (48%) achieved a PR ≥ 40%. The median difference of total circumferences between the LE and controlateral arm was significantly reduced after treatment: 37 cm (range 8-88) vs 25 cm (range 1-62) (p = 0.006). Best response was achieved after a median of 5 weeks of therapy (range 1- 6) and the median DOR was 8 weeks (range 4-15). Reduction of LE was associated with improvement of related symptoms. After discontinuation of study drug 84% pts presented a progressive increase of total circumference of LE arm and returned to values similar to baseline after a median of 7 weeks (range 2-11). CONCLUSIONS: Low dose of sorafenib has a good toxicity profile and exerts a significant anti-LE activity in BC patients. The early but transient effect observed in this study suggests exploring different schedule of administration. Further studies are warranted in order to obtain a durable benefit in term of reduction of LE and quality of life. [ABSTRACT FROM AUTHOR]

Objectives: Different clinical behaviors are observed in tamoxifen-treated and untreated ERpositive, HER2-negative highly-proliferative breast cancer (BC) that demonstrate either high (highERS) or low (lowERS) expression of estrogen-related genes (Bianchini SABCS 2011). LowERS tumors are intrinsically endocrine resistant and at significant risk of relapse in the first 5 yrs after diagnosis. We studied lowERS and highERS BC in pts treated with neoadjuvant chemotherapy (NAC) and examined prognostic and predictive markers in the highest risk group of lowERS BC. Methods: We examined affymetrix gene expression data from 193 ER+/HER2-, high proliferation BC from pts treated with taxane-anthracycline-based NAC followed by endrocrine therapy. Previously defined cut-offs for markers of proliferation (MKS), and estrogen-related genes were applied (Bianchini SABCS 2011). Within the lowERS group, we examined pts treated with no systemic adjuvant therapy (n = 137; 50 events); adjuvant tamoxifen-only (n = 141; 36 events); and NAC (n = 127, 27 RCB0/I). We performed gene enrichment analysis for 2617 gene sets with known biological function (by 5000 random permutations). Primary endpoints were distant event free survival (DEFS) with follow-up censored at 5-yrs and pathological response (pathR) using the residual cancer burden (RCB) (Symmans JCO 2007). Results: The median follow-up of the NAC series was 3.1yrs. The DEFS at 4yrs was 0.94 [0.87-1.00] and 0.70 [0.60-0.81] in the high and low ERS groups, respectively (p = 0.004) (despite the higher rate of pathR (RCB0/I) to NAC in the low ERS group (9.5% and 21.9%; p = 0.04)). The pathR was prognostic in the lowERS group [HR 9.1 (CI 1.23-67.4); p = 0.009] but not in highERS (p = 0.485). In contrast, a different outcome was observed in BC with RCBII-III, were the 4-yrs DEFS was 0.93 [0.86-1.00] and 0.61 [0.49-0.76] in high and low ERS group, respectively (p = 0.0007). In the lowERS group there was substantial overlap in biological functions associated with prognosis in both tamoxifen-treated and untreated pts. At a conservative threshold of p < 0.0005, 38 gene sets were significant (31 good-prognosis involved in adaptive immune function, inflammation and chemotaxis and 7 poor prognosis gene sets involved in regulation of nuclear division and cell polarity). Only proliferation-related gene sets were predictive of RCB0/I. MKS as a continuous variable was predictive of pathR beyond clinical variables [OR 5.43 (2.04-16.1); p = 0.001]. Conclusions: Among ER+/HER2-, high proliferation BC the highERS group showed a low pathR rate with excellent prognosis even if there was residual disease. The lowERS group showed a higher rate of pathR which was significantly prognostic for good outcome. Lack of pathR in this group predicted for very poor prognosis despite subsequent adjuvant endocrine treatment. The clinical behaviour and aggressiveness of this subgroup is similar to triple negative tumors. The prognostic relevance of immune function provides a rationale for testing immunotherapeutic strategies in this subgroup. [ABSTRACT FROM AUTHOR]

Background: One year (yr) of trastuzumab (T) significantly improves disease-free (DFS) and overall survival (OS) in patients with HER2-positive early breast cancer (EBC) and is considered the standard of care. HERA is the only randomized trial investigating whether longer duration of T can further improve efficacy outcome. Materials and Methods: HERA (BIG 01-01) is an international, multicenter, phase III randomized trial involving 5102 women with HER2-positive EBC. Pts were randomized, after completion of primary therapy [surgery, chemotherapy and radiotherapy as indicated], to T every 3 weeks for 1 yr , 2 years (yrs), or observation. This landmark efficacy analysis compares the outcome of pts randomized to either 2 yrs or 1 yr of T who were disease-free at 1 yr after randomization (N = 1553 for 2 yrs, and N=1552 for 1 yr). The primary endpoint is DFS and secondary endpoints are OS and time to distant recurrence (TTDR). Updated efficacy analyses of the T arms vs. observation at 8-yrs of median follow-up (FU) are also presented. Results: On 12 April 2012 HERA reached the target number of 725 DFS events needed for 80% power to detect a true hazard ratio (HR) of 0.80 for the comparison of 2 yrs vs. 1 yr of T. The unadjusted HR for an event in the 2-yr vs. 1-yr T arms was 0.99 (95% CI 0.85-1.14; p = 0.86). OS in the two arms was comparable [HR=1.05 (95% CI 0.86-1.28; p = 0.63)]. TTDR results were similar . The primary cardiac endpoint* was comparable (1.0% vs. 0.8% for 2-yr and 1-yr arms, respectively), but the secondary cardiac endpoint** was higher in the 2-yr arm (7.2% vs. 4.1%). Importantly , the durable benefit in DFS and OS for both 1 yr and 2 yrs of T compared with observation remains stable at 8 yrs of median FU. Subgroup analyses including by hormone receptor status will be available for the meeting. Conclusions: These results confirm that 1 yr of adjuvant T remains the standard of care for HER2-positive EBC pts. It is also reassuring that the significant improvement in DFS and OS persists over time and that the incidence of cardiac endpoints remains low at a median FU of 8 yrs. * NYHA class III or IV, confirmed by a cardiologist, and LVEF < 50% and 10% below baseline, OR cardiac death. ** LVEF < 50% and ≥10% below baseline confirmed by repeat assessment, excluding patients with a primary cardiac endpoint. [ABSTRACT FROM AUTHOR]

Purpose: We assessed the 27-gene RT-qPCR-based DetermaIO assay and the same score calculated from RNA sequencing (RNA-seq) data as predictors of sensitivity to immune checkpoint therapy in the neoTRIPaPDL1 randomized trial that compared neoadjuvant carboplatin/nab-paclitaxel chemotherapy (CT) plus atezolizumab with CT alone in stage II/III triple-negative breast cancer. We also assessed the predictive function of the immuno-oncology (IO) score in expression data of patients treated with pembrolizumab plus paclitaxel (N = 29) or CT alone (N = 56) in the I-SPY2 trial., Experimental Design: RNA-seq data were obtained from pretreatment core biopsies from 242 (93.8%) of the 258 patients in the per-protocol-population. The DetermaIO RT-qPCR test, performed in the CAP/CLIA-accredited laboratory of Oncocyte Corp., was available for 220 patients (85.3%). A previously established threshold was used to assign DetermaIO-positive versus DetermaIO-negative status. Publicly available microarray data were used from I-SPY2., Results: IO scores calculated from RNA-seq and RT-qPCR data were highly concordant. In neoTRIPaPDL1, DetermaIO-positive cancers (N = 92, 41.8%) had pathologic complete response (pCR) rates of 69.8% and 46.9% in the CT + atezolizumab and CT arms, respectively. In DetermaIO-negative cases, pCR rates were similar in both arms (44.6% vs. 49.2%; interaction test P = 0.04). PDL1 protein expression and stromal tumor-infiltrating lymphocyte count were not predictive of differential benefit from atezolizumab. In I-SPY2, IO-positive cancers (45.9%) had pCR rates of 85.7% and 16%, with and without immunotherapy, respectively. In IO-negative cancers, pCR rates were 46.7% versus 16.1%., Conclusions: DetermaIO identified patients who benefited from neoadjuvant immunotherapy resulting in improved pCR rate, independently of PDL1., (©2024 The Authors; Published by the American Association for Cancer Research.)

Purpose: To explore whether specific triple-negative breast cancer (TNBC) molecular subtypes are predictive for a benefit from maintenance low-dose cyclophosphamide and methotrexate (CM) in the adjuvant IBCSG 22-00 phase III clinical trial., Experimental Design: RNA sequencing was performed on a selection of 347 TNBC formalin-fixed paraffin-embedded (FFPE) tumor samples following a case-cohort-like sampling. TNBC subtypes were computed on gene expression data. The association between TNBC subtypes and treatment outcome was assessed using a Cox proportional-hazards interaction test., Results: Immunomodulatory (IM) and basal-like/immune activated (BLIA) molecular subtypes showed a significant survival benefit when treated with low-dose CM [disease-free survival (DFS): HR, 0.5; 95% confidence interval (CI), 0.28-0.89; Pinteraction = 0.018 and HR, 0.49; 95% CI, 0.27-0.9; Pinteraction = 0.021]. Moreover, a high expression of regulatory T-cell immune signature was associated with a better prognosis in the CM arm, in line with a potential immunomodulating role of cyclophosphamide. In contrast, a worse outcome was observed in tumors with a mesenchymal (M) subtype treated with low-dose CM (DFS: HR, 1.9; 95% CI, 1.2-3; Pinteraction = 0.0044)., Conclusions: Our results show a differential benefit of low-dose CM therapy across different TNBC subtypes. Low-dose CM therapy could be considered as a potential strategy for TNBC tumors with IM subtype in the early-disease setting., (©2023 American Association for Cancer Research.)

DESTINY-Breast01 (NCT03248492) evaluated trastuzumab deruxtecan (T-DXd; DS-8201) in patients with heavily pretreated HER2-positive metastatic breast cancer (mBC). We present a subgroup of 24 patients with a history of treated brain metastases (BM), a population with limited treatment options. In patients with BMs, the confirmed objective response rate (cORR) was 58.3% [95% confidence interval (CI), 36.6%-77.9%], and the median progression-free survival (mPFS) was 18.1 months (95% CI, 6.7-18.1 months). In patients without BMs (n = 160), cORR was 61.3% and mPFS was 16.4 months. Eight patients (47.1%) experienced a best overall intracranial response of partial response or complete response. Seven patients (41.2%) had a best percentage change in brain lesion diameter from baseline consistent with stable disease. Two patients (8.3%) with BMs and two (1.3%) without BMs experienced progression in the brain. The safety profile of T-DXd was consistent with previous studies. The durable clinical activity of T-DXd in this population warrants further investigation., Significance: Advances in treating HER2-positive metastatic breast cancer have greatly improved patient outcomes, but intracranial progression remains an important risk for which few therapeutic options are currently available. T-DXd demonstrated durable efficacy in patients with stable, treated BMs. This article is highlighted in the In This Issue feature, p. 2711., (©2022 The Authors; Published by the American Association for Cancer Research.)

Purpose: The interplay between estrogen receptor (ER) and erbB tyrosine-kinase receptors (RTK) impacts growth and progression of ER-positive (ER+)/HER2-positive (HER2+) breast cancer and generates mitogenic signals converging onto the Cyclin-D1/CDK4/6 complex. We probed this cross-talk combining endocrine-therapy (fulvestrant), dual HER2-blockade (trastuzumab and pertuzumab), and CDK4/6-inhibition (palbociclib; PFHPert)., Experimental Design: Cytotoxic drug effects, interactions, and pharmacodynamics were studied after 72 hours of treatment and over 6 more days of culture after drug wash-out in three ER+/HER2+, two HER2low, and two ER-negative (ER-)/HER2+ breast cancer cell lines. We assessed gene-expression dynamic and association with Ki67 downregulation in 28 patients with ER+/HER2+ breast cancer treated with neoadjuvant PFHPert in NA-PHER2 trial (NCT02530424)., Results: In vitro, palbociclib and/or fulvestrant induced a functional activation of RTKs signalling. PFHPert had additive or synergistic antiproliferative activity, interfered with resistance mechanisms linked to the RTKs/Akt/MTORC1 axis and induced sustained senescence. Unexpected synergism was found in HER2low cells. In patients, Ki67 downregulation at week 2 and surgery were significantly associated to upregulation of senescence-related genes (P = 7.7E-4 and P = 1.8E-4, respectively). Activation of MTORC1 pathway was associated with high Ki67 at surgery (P = 0.019)., Conclusions: Resistance associated with the combination of drugs targeting ER and HER2 can be bypassed by cotargeting Rb, enhancing transition from quiescence to sustained senescence. MTORC1 pathway activation is a potential mechanism of escape and RTKs functional activation may be an alternative pathway for survival also in ER+/HER2low tumor. PFHPert combination is an effective chemotherapy-free regimen for ER+/HER2+ breast cancer, and the mechanistic elucidation of sensitivity/resistance patterns may provide insights for further treatment refinement., (©2022 American Association for Cancer Research.)

Purpose: To characterize expression of neuregulin-1 (NRG1), an HER3 ligand, in HER2-positive breast cancer and its relation with the efficacy of trastuzumab with or without pertuzumab., Experimental Design: Characterization of NRG1 expression in tumor cell lines, in tumor specimens, and in cancer-associated fibroblasts (CAFs). Patient-derived CAFs were used to investigate NRG1 impact on the activity of trastuzumab with or without pertuzumab in HER2-positive breast cancer cells. The relationship between NRG1 expression and pathologic response to anti-HER2-based neoadjuvant therapy was assessed in a retrospective patient cohort and in the NeoSphere trial., Results: NRG1 was expressed in HER2-positive breast cancer-derived fibroblasts at significantly higher levels than in cancer cells. NRG1 and the conditioned media (CM) from CAFs phosphorylated HER3 and AKT in cancer cells and mediated trastuzumab resistance. Stable genetic depletion of NRG1 from CAFs overcame trastuzumab resistance. Pertuzumab effectively suppressed trastuzumab resistance mediated by either NRG1 or CAF's CM. NRG1 engaged an epithelial-to-mesenchymal transition that was prevented by trastuzumab and pertuzumab. In clinical samples, stromal and/or tumor cell expression of NRG1 determined by immunohistochemistry was uncommon (13.2%) yet significantly linked with residual disease following trastuzumab-based neoadjuvant therapy. In the NeoSphere trial, the magnitude of the difference of pathologic complete response rates favoring the pertuzumab arm was higher in the NRG1- high group., Conclusions: CAF-derived NRG1 mediates trastuzumab resistance through HER3/AKT, which might be reverted by pertuzumab. In patients with HER2-positive breast cancer, high expression of NRG1 was associated to poor response to trastuzumab, but not in combination with pertuzumab., (©2021 American Association for Cancer Research.)

PIK3CA mutations are associated with resistance to HER2-targeted therapies. We previously showed that HER2 + /PIK3CA H1047R transgenic mammary tumors are resistant to the HER2 antibodies trastuzumab and pertuzumab but respond to PI3K inhibitor buparlisib (TPB). In this study, we identified mechanisms of resistance to combined inhibition of HER2 and PI3K. TPB-resistant tumors were generated by treating HER2 + /PIK3CA H1047R tumor-bearing mice long term with the drug combination. RNA sequencing of TPB-resistant tumors revealed that extracellular matrix and cell adhesion genes, including collagen II ( Col2a1 ), were markedly upregulated, accompanied by activation of integrin β1/Src. Cells derived from drug-resistant tumors were sensitive to TBP when grown in vitro , but exhibited resistance when plated on collagen or when reintroduced into mice. Drug resistance was partially reversed by the collagen synthesis inhibitor ethyl-3,4-dihydroxybenzoate. Inhibition of integrin β1/Src blocked collagen-induced resistance to TPB and inhibited growth of drug-resistant tumors. High collagen II expression was associated with significantly lower clinical response to neoadjuvant anti-HER2 therapy in HER2 + breast cancer patients. Overall, these data suggest that upregulation of collagen/integrin/Src signaling contributes to resistance to combinatorial HER2 and PI3K inhibition. Cancer Res; 77(12); 3280-92. ©2017 AACR ., (©2017 American Association for Cancer Research.)

Purpose: In spite of improvements of average benefit from adjuvant/neoadjuvant treatments, there are still individual patients with early breast cancer at high risk of relapse. We explored the association with outcome of robust gene cluster-based metagenes linked to proliferation, ER-related genes, and immune response to identify those high-risk patients., Experimental Design: A total of 3,847 publicly available gene-expression profiles were analyzed (untreated, N = 826; tamoxifen-treated, N = 685; chemotherapy-treated, N = 1,150). Genes poorly performing in formalin-fixed samples were removed. Outcomes of interest were pathologic-complete response (pCR) and distant metastasis-free survival (DMFS). In ER(+)HER2(-), the proliferation and ER-related metagenes were combined to define three risk groups. In HER2(+) and ER(-)HER2(-) risk groups were defined by tertiles of an immune-related metagene., Results: The high-proliferation/low-ER group of ER(+)HER2(-) breast cancer had significantly higher pCR rate [OR, 5.01 (1.76-17.99), P = 0.005], but poorer outcome [HR = 3.73 (1.63-8.51), P = 0.0018] than the low-proliferation/high-ER. A similar association with outcome applied to patients with residual disease (RD) after neoadjuvant chemotherapy (P = 0.01). In ER(-)HER2(-) and HER2(+) breast cancer, immune metagene in the high tertile was linked to higher pCR [33.7% vs. 11.6% in high and low tertile, respectively; OR, 3.87 (1.79-8.95); P = 0.0009]. In ER(-)HER2(-), after adjuvant/neoadjuvant chemotherapy, 5-year DMFS was 85.4% for high-tertile immune metagene, and 43.9% for low tertile. The outcome association was similar in patients with RD (P = 0.0055). In HER2(+) breast cancer treated with chemotherapy the association with risk of relapse was not significant., Conclusions: We developed metagene-based predictors able to define low and high risk of relapse after adjuvant/neoadjuvant therapy. High-risk patients so defined should be preferably considered for trials with investigational agents., (©2015 American Association for Cancer Research.)

Purpose: We report a retrospective exploratory analysis of the association of the research-based prediction analysis of microarray 50 (PAM50) subtype predictor with pathologic complete response (pCR) and event-free survival (EFS) in women enrolled in the NeOAdjuvant Herceptin (NOAH) trial., Experimental Design: Gene expression profiling was performed using RNA from formalin-fixed paraffin-embedded core biopsies from 114 pretreated patients with HER2-positive (HER2(+)) tumors randomized to receive neoadjuvant doxorubicin/paclitaxel (AT) followed by cyclophosphamide/methotrexate/fluorouracil (CMF), or the same regimen in combination with trastuzumab for one year. A control cohort of 42 patients with HER2-negative tumors treated with AT-CMF was also included. The PAM50 subtypes, the PAM50 proliferation score, and the PAM50 risk of relapse score based on subtype (RORS) and subtype and proliferation (RORP) were evaluated., Results: HER2-enriched (HER2-E) tumors predominated within HER2(+) disease, although all PAM50 intrinsic subtypes were identified across the three cohorts. The OR for achieving pCR with trastuzumab-based chemotherapy for HER2(+)/HER2-E and HER2(+)/RORP-high were 5.117 (P = 0.009) and 8.469 (P = 0.025), respectively, compared with chemotherapy only. The pCR rates of HER2(+)/HER2-E and HER2(+)/RORP-high after trastuzumab-based chemotherapy were 52.9% and 75.0%, respectively. A statistically nonsignificant trend was observed for more pronounced survival benefit with trastuzumab in patients with HER2(+)/HER2-E and HER2(+)/RORP-high tumors compared with patients with HER2(+)/non-HER2-E and HER2(+)/non-RORP-high tumors, respectively., Conclusions: As determined by EFS and pCR, patients with HER2(+)/HER2-E tumors, or HER2(+)/RORP-high tumors, benefit substantially from trastuzumab-based chemotherapy. The clinical value of this genomic test within HER2(+) disease warrants further investigation., (©2014 AACR.)

Different kinases are expressed in different clinical subsets of breast cancer. In this study, we assessed kinase expression patterns in different clinical subtypes of breast cancer, evaluated the prognostic and predictive values of kinase metagenes, and investigated their functions in vitro. Four hundred twenty-eight protein kinases in gene expression data were examined from 684 cases of breast cancer and 51 breast cancer cell lines to identify kinase expression patterns. We tested the prognostic value of kinase metagenes in 684 node-negative patients who received no adjuvant therapy and the predictive value in 233 patients who received uniform neoadjuvant chemotherapy. Twelve kinases were overexpressed in estrogen receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative, 7 in HER2(+), and 28 in ER(-)/HER2(-) cancers, respectively. We examined the functional role of 22 kinases overexpressed in ER(-)/HER2(-) cancers using siRNA. Downregulation of these kinases caused significant subtype-specific inhibition of cell growth in vitro. Two robust kinase clusters, including an immune kinase cluster and a mitosis kinase cluster, were present in all clinical subgroups. High mitosis kinase score was associated with worse prognosis but higher pathologic complete response (pCR) in ER(+)/HER2(-) cancers, but not in ER(-)/HER2(-) or HER2(+) cancers, in univariate and multivariate analyses including other genomic predictors (MammaPrint, genomic grade index, and the 76-gene signature). Conversely, higher immune kinase score was associated with better survival in ER(+)/HER2(-) and HER2(+) tumors and also predicted higher probability of pCR in HER2(+) cancers. Taken together, our results indicate that kinases regulating mitosis and immune functions convey distinct prognostic information that varies by clinical subtype., (©2010 AACR.)

Based on preclinical studies demonstrating that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) exerts a potent and cancer cell-specific proapoptotic activity, recombinant TRAIL as well as agonistic anti-TRAIL-R1 and anti-TRAIL-R2 antibodies recently entered clinical trials. Additionally, gene therapy approaches using TRAIL-encoding adenovirus (Ad-TRAIL) are currently being developed to overcome the limitations inherent to TRAIL receptor targeting, i.e., pharmacokinetic of soluble TRAIL, pattern of receptor expression, and tumor cell resistance. To optimize gene therapy approaches, CD34+ cells transduced with Ad-TRAIL (CD34-TRAIL+) have been investigated as cellular vehicles for TRAIL delivery. Transduced cells exhibit a potent tumor killing activity on a variety of tumor cell types both in vitro and in vivo and are also cytotoxic against tumor cells resistant to soluble TRAIL. Studies in tumor-bearing nonobese diabetic/severe combined immunodeficient mice suggest that the antitumor effect of CD34-TRAIL+ cells is mediated by both direct tumor cell killing due to apoptosis and indirect tumor cell killing due to vascular-disrupting mechanisms. The clinical translation of cell and gene therapy approaches represent a challenging strategy that might achieve systemic tumor targeting and increased intratumor delivery of the therapeutic agent.

Purpose: The European Cooperative Trial in Operable breast cancer (ECTO) randomly tested whether efficacy of adjuvant doxorubicin followed by i.v. cyclophosphamide, methotrexate, and fluorouracil (CMF; doxorubicin-->CMF, arm A) could be improved by adding paclitaxel (doxorubicin/paclitaxel-->CMF) as adjuvant (arm B) or primary systemic therapy (PST, arm C). We report here feasibility, tolerability, locoregional antitumor activity, and breast conservation rate., Methods: A total of 1,355 women entered the study. Feasibility and safety were compared in arm A versus arms B plus C. Surgical findings were compared in arms A plus B versus arm C., Results: Grade 3 or 4 National Cancer Institute toxicities were low (<5%) in all arms. Neuropathy was more frequent in the paclitaxel-containing arms (grade 2, 20.5% versus 5.0%; grade 3, 1.3% versus 0.2%). At 31 months of follow-up, asymptomatic drop of left ventricular ejection fraction was similar in all arms, whereas symptomatic cardiotoxicity was recorded in three patients (0.5%) in A and in three patients (0.3%) in B plus C. PST induced clinical complete plus partial remission in 78%, with an in-breast pathologic complete response rate of 23% and an in-breast plus axilla pathologic complete response rate of 20%. In the multivariate analysis, only estrogen receptor (ER) status was significantly associated with pathologic complete response (odds ratio for ER negative, 5.77; 95% confidence interval, 3.49-9.52; P<0.0001). PTS induced a significant axillary downstaging (P<0.001), and breast sparing surgery was feasible in 65% versus 34% (P<0.001)., Conclusions: Doxorubicin/paclitaxel-->CMF is feasible, safe, and well tolerated. Given as PST, it is markedly active, allowing for breast-sparing surgery in a large fraction of patients.

Purpose: Combining trastuzumab with doxorubicin and paclitaxel (AT) is attractive because of the activity of AT and survival improvements observed when trastuzumab is added to either agent in HER2-positive metastatic breast cancer. This pilot study evaluates the efficacy and cardiac tolerability of AT followed by paclitaxel with trastuzumab started with AT or paclitaxel alone and investigates pharmacokinetic interactions., Experimental Design: Two cohorts of 16 patients were enrolled. Cohort 1 received three cycles of AT (60/150 mg/m2) plus trastuzumab (4 mg/kg initial dose followed by 2 mg/kg), initiated concomitantly with doxorubicin, followed by nine cycles of paclitaxel (80 mg/m2) plus trastuzumab and then trastuzumab alone. Cohort 2 was treated with the same regimen, but trastuzumab was initiated with paclitaxel after AT. Cardiac function, pharmacokinetic interactions, and efficacy were evaluated., Results: Median baseline left ventricular ejection fraction (LVEF) was 62% (range, 57-74%) and 66% (range, 57-77%) in cohorts 1 and 2, respectively. Most patients had an absolute decrease in LVEF. Congestive heart failure was not observed. LVEF in three patients decreased to <50% but recovered despite continued treatment. Response rates were 87.5% in both cohorts (cohort 1:2 complete response, 12 partial response; cohort 2:3 complete response, 11 partial response). No unexpected side effects were observed. Pharmacokinetics of paclitaxel and its metabolites and of doxorubicin were similar without and with trastuzumab., Conclusions: Trastuzumab administered with AT followed by weekly paclitaxel alone is highly active whether trastuzumab is initiated with AT or paclitaxel. Congestive heart failure was not observed, and LVEF decreases were reversible. Further studies of this regimen are warranted.

Purpose: The feasibility and utility of assessing quality of life (QoL) and disease-related symptoms in patients with advanced cancer have been evaluated in two Phase I clinical trials of p.o. administered ZD1839 ('Iressa'), an epidermal growth factor receptor tyrosine kinase inhibitor, in patients with advanced cancer., Experimental Design: Functional Assessment of Cancer Therapy (FACT) questionnaires, including disease-specific subscales for lung, head and neck, colorectal, prostate, and ovarian cancer, were completed by patients in two open-label, Phase I, escalating multiple-dose safety and tolerability trials., Results: In 157 patients, 92% of whom had received prior therapy, compliance in returning FACT questionnaires was 87% (European/Australian trial) and 57% (United States trial). This did not appear to be influenced by dose level or tumor type. For patients with colorectal, prostate, or ovarian cancer, median QoL [FACT and Trial Outcome Index (TOI)] scores deteriorated over time. In contrast, for patients with non-small cell lung cancer (NSCLC) or head and neck cancer, median FACT and TOI scores did not deteriorate significantly, and in the United States trial, head and neck cancer scores improved significantly over time. In patients with NSCLC, symptom-related scores measured by the Lung Cancer Subscale of FACT-L appeared sensitive to clinical change., Conclusions: QoL (FACT-L) questionnaires were used successfully in the Phase I clinical trials of ZD1839. They appeared to be a sensitive tool to monitor clinical changes for the five tumor types in these trials and showed that ZD1839 has the potential to improve patients' QoL.

Doxorubicin cardiotoxicity is a multifactorial process in which the alcohol metabolite doxorubicinol mediates the transition from reversible to irreversible damage. We investigated whether the tubulin-active taxane paclitaxel increases conversion of doxorubicin to doxorubicinol, thus explaining the high incidence of congestive heart failure when doxorubicin is used with paclitaxel. Specimens of human myocardium from patients undergoing bypass surgery were processed to obtain cytosolic fractions in which doxorubicin was converted to doxorubicinol by NADPH-dependent aldo/keto or carbonyl reductases. In this model, clinically relevant concentrations of paclitaxel (1-2.5 microM) increased doxorubicinol formation by mechanisms consistent with allosteric modulation of the reductases. Stimulation was observed over a broad range of basal enzymatic activity, and was accompanied by a similar pattern of enhanced formation of doxorubicinol aglycone, a metabolite potentially involved in the reversible phase of cardiotoxicity. The closely related analogue docetaxel had effects similar to paclitaxel, but increased doxorubicinol formation over a narrower range of enzymatic activity. The unrelated tubulin-active alkaloid vinorelbine had no effect. These results demonstrate that taxanes have a unique potential for enhancing doxorubicin metabolism to toxic species in human myocardium. The effects on doxorubicinol formation provide clues to explain the clinical pattern of doxorubicin-paclitaxel cardiotoxicity and also caution against the potential toxicity of combining docetaxel with high cumulative doses of doxorubicin.

The purpose of the present study was to characterize the distribution and elimination kinetics of the paclitaxel vehicle Cremophor EL (CrEL), a polyoxyethylated castor oil that can modulate P-glycoprotein-mediated multidrug resistance in vitro. The pharmacokinetics of CrEL were studied using noncompartmental models in 23 patients with histological proof of malignant solid tumors, receiving paclitaxel as a 3-h i.v. infusion at dose levels ranging from 100-225 mg/m2 (corresponding to CrEL doses of 8.33-18.8 ml/m2). Serial plasma samples were obtained before and up to 72 h after drug administration, and were analyzed for the presence of CrEL by a novel colorimetric dye-binding microassay. The area under the plasma concentration versus time curves and the peak plasma levels of CrEL increased from 253+/-36.8 (mean+/-SD) to 680+/- 180 microl.h/ml, and from 3.40+/-0.10 to 6.58+/-0.52 microl/ml, respectively, consistent with linear pharmacokinetics. Disappearance of CrEL from the central plasma compartment was characterized by a terminal elimination half-life of 84.1+/-20.4 h, resulting in extended persistence of substantial levels even at 1 week after paclitaxel treatment. The observed volume of distribution was extremely low and averaged 3.70+/-0.49 liters/m2, implying that the tumor delivery of CrEL is insignificant. Our results indicate that CrEL is a relatively slow clearance compound and that its distribution is limited to the central plasma compartment. Hence, CrEL is not likely to play a role in reversing P-glycoprotein-mediated multidrug resistance to paclitaxel in vivo.

The hypoxic radiosensitizers misonidazole or demethylmisonidazole were administered i.p. in a 2-liter volume to 6 patients affected by advanced ovarian carcinoma, and the pharmacokinetic course of the two drugs was studied. The clearance of misonidazole and demethylmisonidazole from the peritoneal fluid was 19.1 and 12.4 ml/min, respectively. At 3 hr after drug administration, both radiosensitizers had peritoneal fluid concentrations more than 8 times larger than in the plasma. The concentration x time exposure in the peritoneal fluid was 3.2 times larger than in plasma for misonidazole and 7.6 times for demethylmisonidazole. The advantage of i.p. delivery compared with systemic delivery decreases with distance from the peritoneal surface, but the advantage may be maintained for up to 1 mm or 100 cell layers. These differences between the two routes of administration provide a rational basis for the expectation that a substantial increase of the therapeutic benefits of misonidazole and demethylmisonidazole in potentiating radiation therapy or chemotherapy can be expected in treating tumors confined to the i.p. space.

Previously, 5-bromodeoxyuridine (BrdUrd) has been shown to be an effective radiosensitizing agent in rapidly dividing cells. As part of a Phase I/II study to evaluate BrdUrd as a radiosensitizer in gliomas, the pharmacology was studied in eight patients. BrdUrd was infused using an i.v. route as a 12-hr constant infusion each day for as long as 14 days. BrdUrd steady-state arterial levels are described for three different infusional rates: 1.6 mumol/sq m/min (350 mg/sq m/12 hr) produced a steady-state arterial level of 0.7 microM; 3.2 mumol/sq m/min (700 mg/sq m/12 hr) resulted in 2.1 microM; 5.9 mumol/sq m/min (650 mg/sq m/6 hr) showed a level of 3.9 microM. Because of myelosuppression, the highest tolerable dose for this intermittent long-term infusional therapy with BrdUrd appears to be 700 mg/sq m/12 hr. Contrary to the nonlinear pharmacokinetics of thymidine, 5-fluorouracil, and 5-fluorodeoxyuridine described previously, BrdUrd shows linear behavior in the range studied. BrdUrd still has promise as a radiosensitizer for gliomas in humans, but an alternative means of safe delivery into the carotid artery is needed. Because of an estimated 11- to 16-fold-higher local concentration, use of the intraarterial route could deliver optimum levels of BrdUrd to the tumor with minimal systemic toxicity.