PD-L1 blockade in combination with carboplatin as immune induction in metastatic lobular breast cancer: the GELATO trial.

Invasive lobular breast cancer (ILC) is the second most common histological breast cancer subtype, but ILC-specific trials are lacking. Translational research revealed an immune-related ILC subset, and in mouse ILC models, synergy between immune checkpoint blockade and platinum was observed. In the phase II GELATO trial ( NCT03147040 ), patients with metastatic ILC were treated with weekly carboplatin (area under the curve 1.5 mg ml-1 min-1) as immune induction for 12 weeks and atezolizumab (PD-L1 blockade; triweekly) from the third week until progression. Four of 23 evaluable patients had a partial response (17%), and 2 had stable disease, resulting in a clinical benefit rate of 26%. From these six patients, four had triple-negative ILC (TN-ILC). We observed higher CD8+ T cell infiltration, immune checkpoint expression and exhausted T cells after treatment. With this GELATO trial, we show that ILC-specific clinical trials are feasible and demonstrate promising antitumor activity of atezolizumab with carboplatin, particularly for TN-ILC, and provide insights for the design of highly needed ILC-specific trials.

Differential Survival and Therapy Benefit of Patients with Breast Cancer Are Characterized by Distinct Epithelial and Immune Cell Microenvironments.

PURPOSE: Extensive work in preclinical models has shown that microenvironmental cells influence many aspects of cancer cell behavior, including metastatic potential and their sensitivity to therapeutics. In the human setting, this behavior is mainly correlated with the presence of immune cells. Here, in addition to T cells, B cells, macrophages, and mast cells, we identified the relevance of nonimmune cell types for breast cancer survival and therapy benefit, including fibroblasts, myoepithelial cells, muscle cells, endothelial cells, and seven distinct epithelial cell types. EXPERIMENTAL DESIGN: Using single-cell sequencing data, we generated reference profiles for all these cell types. We used these reference profiles in deconvolution algorithms to optimally detangle the cellular composition of more than 3,500 primary breast tumors of patients that were enrolled in the SCAN-B and MATADOR clinical trials, and for which bulk mRNA sequencing data were available. RESULTS: This large data set enables us to identify and subsequently validate the cellular composition of microenvironments that distinguish differential survival and treatment benefit for different treatment regimens in patients with primary breast cancer. In addition to immune cells, we have identified that survival and therapy benefit are characterized by various contributions of distinct epithelial cell types. CONCLUSIONS: From our study, we conclude that differential survival and therapy benefit of patients with breast cancer are characterized by distinct microenvironments that include specific populations of immune and epithelial cells.

IHC-based Ki67 as response biomarker to tamoxifen in breast cancer window trials enrolling premenopausal women.

Window studies are gaining traction to assess (molecular) changes in short timeframes. Decreased tumor cell positivity for the proliferation marker Ki67 is often used as a proxy for treatment response. Immunohistochemistry (IHC)-based Ki67 on tissue from neo-adjuvant trials was previously reported to be predictive for long-term response to endocrine therapy for breast cancer in postmenopausal women, but none of these trials enrolled premenopausal women. Nonetheless, the marker is being used on this subpopulation. We compared pathologist assessed IHC-based Ki67 in samples from pre- and postmenopausal women in a neo-adjuvant, endocrine therapy focused trial (NCT00738777), randomized between tamoxifen, anastrozole, or fulvestrant. These results were compared with (1) IHC-based Ki67 scoring by AI, (2) mitotic figures, (3) mRNA-based Ki67, (4) five independent gene expression signatures capturing proliferation, and (5) blood levels for tamoxifen and its metabolites as well as estradiol. Upon tamoxifen, IHC-based Ki67 levels were decreased in both pre- and postmenopausal breast cancer patients, which was confirmed using mRNA-based cell proliferation markers. The magnitude of decrease of Ki67 IHC was smaller in pre- versus postmenopausal women. We found a direct relationship between post-treatment estradiol levels and the magnitude of the Ki67 decrease in tumors. These data suggest IHC-based Ki67 may be an appropriate biomarker for tamoxifen response in premenopausal breast cancer patients, but anti-proliferative effect size depends on estradiol levels.

Carboplatin-Cyclophosphamide or Paclitaxel without or with Bevacizumab as First-Line Treatment for Metastatic Triple-Negative Breast Cancer (BOOG 2013-01).

BACKGROUND: The addition of bevacizumab to chemotherapy conferred a modest progression-free survival (PFS) benefit in metastatic triple-negative breast cancer (mTNBC). However, no overall survival (OS) benefit has been reported. Also, its combination with carboplatin-cyclophosphamide (CC) has never been investigated. METHODS: The Triple-B study is a multicenter, randomized phase IIb trial that aims to prospectively validate predictive biomarkers, including baseline plasma vascular endothelial growth factor receptor-2 (pVEGFR-2), for bevacizumab benefit. mTNBC patients were randomized between CC and paclitaxel (P) without or with bevacizumab (CC ± B or P ± B). Here we report on a preplanned safety and preliminary efficacy analysis after the first 12 patients had been treated with CC+B and on the predictive value of pVEGFR-2. RESULTS: In 58 patients, the median follow-up was 22.1 months. Toxicity was manageable and consistent with what was known for each agent separately. There was a trend toward a prolonged PFS with bevacizumab compared to chemotherapy only (7.0 vs. 5.2 months; adjusted HR = 0.60; 95% CI 0.33-1.08; p = 0.09), but there was no effect on OS. In this small study, pVEGFR-2 concentration did not predict a bevacizumab PFS benefit. Both the intention-to-treat analysis and the per-protocol analysis did not yield a significant treatment-by-biomarker test for interaction (pinteraction = 0.69). CONCLUSIONS: CC and CC+B are safe first-line regimens for mTNBC and the side effects are consistent with those known for each individual agent. pVEGFR-2 concentration did not predict a bevacizumab PFS benefit.

POSEIDON Trial Phase 1b Results: Safety, Efficacy and Circulating Tumor DNA Response of the Beta Isoform-Sparing PI3K Inhibitor Taselisib (GDC-0032) Combined with Tamoxifen in Hormone Receptor Positive Metastatic Breast Cancer Patients.

PURPOSE: The strategy of combining endocrine therapy with PI3K-mTOR inhibition has shown promise in estrogen receptor (ER)-positive breast cancer, but new agents and combinations with a better therapeutic index are urgently needed. Taselisib is a potent, selective, beta-isoform-sparing PI3 kinase inhibitor. PATIENTS AND METHODS: 30 patients with ER-positive, metastatic breast cancer who had failed prior endocrine therapy were treated with escalating doses of taselisib (2 or 4 mg in an intermittent or continuous schedule) combined with tamoxifen 20 mg once daily in this phase 1b study using a "rolling six" design. RESULTS: Taselisib combined with tamoxifen was generally well tolerated, with treatment-emergent adverse events as expected for this class of drugs, including diarrhea (13 patients, 43%), mucositis (10 patients, 33%), and hyperglycemia (8 patients, 27%). No dose-limiting toxicities were observed. Objective responses were seen in 6 of 25 patients with RECIST-measurable disease (ORR 24%). Median time to disease progression was 3.7 months. Twelve of 30 patients (40%) had disease control for 6 months or more. Circulating tumor (ct)DNA studies using next-generation tagged amplicon sequencing identified early indications of treatment response and mechanistically relevant correlates of clinical drug resistance (e.g., mutations in KRAS, ERBB2) in some patients. CONCLUSIONS: Taselisib can be safely combined with tamoxifen at the recommended phase 2 dose of 4 mg given once daily on a continuous schedule. Preliminary evidence of antitumor activity was seen in both PIK3CA mutant and wild-type cancers. The randomized phase 2 part of POSEIDON (testing tamoxifen plus taselisib or placebo) is currently recruiting.

Immune induction strategies in metastatic triple-negative breast cancer to enhance the sensitivity to PD-1 blockade: the TONIC trial.

The efficacy of programmed cell death protein 1 (PD-1) blockade in metastatic triple-negative breast cancer (TNBC) is low1-5, highlighting a need for strategies that render the tumor microenvironment more sensitive to PD-1 blockade. Preclinical research has suggested immunomodulatory properties for chemotherapy and irradiation6-13. In the first stage of this adaptive, non-comparative phase 2 trial, 67 patients with metastatic TNBC were randomized to nivolumab (1) without induction or with 2-week low-dose induction, or with (2) irradiation (3 × 8 Gy), (3) cyclophosphamide, (4) cisplatin or (5) doxorubicin, all followed by nivolumab. In the overall cohort, the objective response rate (ORR; iRECIST14) was 20%. The majority of responses were observed in the cisplatin (ORR 23%) and doxorubicin (ORR 35%) cohorts. After doxorubicin and cisplatin induction, we detected an upregulation of immune-related genes involved in PD-1-PD-L1 (programmed death ligand 1) and T cell cytotoxicity pathways. This was further supported by enrichment among upregulated genes related to inflammation, JAK-STAT and TNF-α signaling after doxorubicin. Together, the clinical and translational data of this study indicate that short-term doxorubicin and cisplatin may induce a more favorable tumor microenvironment and increase the likelihood of response to PD-1 blockade in TNBC. These data warrant confirmation in TNBC and exploration of induction treatments prior to PD-1 blockade in other cancer types.

Publisher Correction: Immune induction strategies in metastatic triple-negative breast cancer to enhance the sensitivity to PD-1 blockade: the TONIC trial.

In the version of this article originally published, there was an error in Fig. 3j. A label on the heatmap read "TGF-α signaling via NF-κB". It should have read "TNF-α signaling via NF-κB". The error has been corrected in the HTML and PDF versions of this article.

Independent replication of polymorphisms predicting toxicity in breast cancer patients randomized between dose-dense and docetaxel-containing adjuvant chemotherapy.

INTRODUCTION: Although pharmacogenomics has evolved substantially, a predictive test for chemotherapy toxicity is still lacking. We compared the toxicity of adjuvant dose-dense doxorubicin-cyclophosphamide (ddAC) and docetaxel-doxorubicin-cyclophosphamide (TAC) in a randomized multicenter phase III trial and replicated previously reported associations between genotypes and toxicity. RESULTS: 646 patients (97%) were evaluable for toxicity (grade 2 and higher). Whereas AN was more frequent after ddAC (P < 0.001), TAC treated patients more often had PNP (P < 0.001). We could replicate 2 previously reported associations: TECTA (rs1829; OR 4.18, 95% CI 1.84-9.51, P = 0.001) with PNP, and GSTP1 (rs1138272; OR 2.04, 95% CI 1.13-3.68, P = 0.018) with PNP. MATERIALS AND METHODS: Patients with pT1-3, pN0-3 breast cancer were randomized between six cycles A60C600 every 2 weeks or T75A50C500 every 3 weeks. Associations of 13 previously reported single nucleotide polymorphisms (SNPs) with the most frequent toxicities: anemia (AN), febrile neutropenia (FN) and peripheral neuropathy (PNP) were analyzed using logistic regression models. CONCLUSIONS: In this independent replication, we could replicate an association between 2 out of 13 SNPs and chemotherapy toxicities. These results warrant further validation in order to enable tailored treatment for breast cancer patients.

Trastuzumab in combination with weekly paclitaxel and carboplatin as neo-adjuvant treatment for HER2-positive breast cancer: The TRAIN-study.

AIM: To determine the efficacy and safety of an anthracycline-free neo-adjuvant regimen consisting of weekly paclitaxel, carboplatin and trastuzumab in HER2-positive breast cancer. PATIENTS AND METHODS: Patients with stage II or III HER2-positive breast cancer received weekly paclitaxel ([P], 70 mg/m2), trastuzumab ([T], 2 mg/kg, loading dose 4 mg/kg) and carboplatin ([C], AUC = 3 mg ml-1 min) for 24 weeks. In weeks 7, 8, 15, 16, 23 and 24, trastuzumab was administered without chemotherapy. The primary end-point was pathologic complete response in the surgical resection specimen, defined as the absence of invasive tumour cells in breast and axilla. RESULTS: One hundred and eleven patients were included in the study, and 108 were evaluable for the primary end-point. The pathologic complete response rate was 43% (95% confidence interval [CI]: 33-52). Median follow-up was 52 months, and the 3-year event-free survival was 88% (95% CI: 82-94), and the 3-year overall survival was 92% (95% CI: 88-98). The most common grade 3-4 adverse events were neutropenia (67%) and thrombocytopenia (43%). Less than five percent of patients experienced febrile neutropenia. No symptomatic left ventricular systolic dysfunction was observed during neo-adjuvant treatment. CONCLUSION: An anthracycline-free neo-adjuvant regimen of weekly paclitaxel, trastuzumab and carboplatin is highly effective in HER2-positive breast cancer with manageable toxicity.