Efficacy of olaparib in advanced cancers with germline or somatic mutations in BRCA1, BRCA2, CHEK2 and ATM, a Belgian Precision tumor-agnostic phase II study

BACKGROUND

The Belgian Precision initiative aims to maximize the implementation of tumor-agnostic next-generation sequencing in patients with advanced cancer and enhance access to molecularly guided treatment options. Academic tumor-agnostic basket phase II studies are part of this initiative. The current investigator-driven trial aimed to investigate the efficacy of olaparib in advanced cancers with a (likely) pathogenic mutation (germline or somatic) in a gene that plays a role in homologous recombination (HR).

PATIENTS AND METHODS

This open-label, multi-cohort, phase II study examines the efficacy of olaparib in patients with an HR gene mutation in their tumor and disease progression on standard of care. Patients with a somatic or germline mutation in the same gene define a cohort. For each cohort, a Simon minimax two-stage design was used. If a response was observed in the first 13 patients, 14 additional patients were included. Here, we report the results on four completed cohorts: patients with a BRCA1, BRCA2, CHEK2 or ATM mutation.

RESULTS

The overall objective response rate across different tumor types was 11% in the BRCA1-mutated (n = 27) and 21% in the BRCA2-mutated (n = 27) cohorts. Partial responses were seen in pancreatic cancer, gallbladder cancer, endocrine carcinoma of the pancreas and parathyroid cancer. One patient with a BRCA2 germline-mutated colon cancer has an ongoing complete response with 19+ months on treatment. Median progression-free survival in responding patients was 14+ months (5-34+ months). The clinical benefit rate was 63% in the BRCA1-mutated and 46% in the BRCA2-mutated cohorts. No clinical activity was observed in the ATM (n = 13) and CHEK2 (n = 14) cohorts.

CONCLUSION

Olaparib showed efficacy in different cancer types harboring somatic or germline mutations in the BRCA1/2 genes but not in ATM and CHEK2. Patients with any cancer type harboring BRCA1/2 mutations should have access to olaparib.

Antitumor activity of lurbinectedin in combination with oral capecitabine in patients with metastatic breast cancer

BACKGROUND

Preclinical studies showed a synergistic effect for 5-fluorouracil and lurbinectedin against solid tumors. This phase I trial evaluated a combination of capecitabine plus lurbinectedin in patients with selected advanced solid tumors. Results in patients with relapsed metastatic breast cancer (MBC) are described.

PATIENTS AND METHODS

Patients received capecitabine daily on day (D)1-D14 combined with lurbinectedin on D1, D8 or D1 every 3 weeks (q3w) intravenously, following a standard 3 + 3 escalation design and expansion at the recommended dose (RD).

RESULTS

Of the 81 enrolled patients, 28 had relapsed MBC: 20 with hormone receptor (HR)-positive tumors and 8 with triple-negative tumors; 3 treated in the D1,D8 schedule and 25 in the D1 schedule. The RD was capecitabine 1650 mg/m² daily on D1-D14 plus lurbinectedin 2.2 mg/m² on D1 q3w. Sixteen confirmed responses and two prolonged disease stabilizations (≥6 months) were observed [overall response rate (ORR)/clinical benefit rate (CBR) = 57%/64% at all dose levels; 47%/60% at the RD]. Twelve responses and both prolonged stabilizations occurred in HR-positive tumors (ORR/CBR = 60%/70% at all dose levels, 56%/78% at the RD). Four responses were found in triple-negative tumors (ORR and CBR = 50% at all dose levels; 33% at the RD). Myelotoxicity was reversible and manageable at the RD; most non-hematological toxicities were mild/moderate. No episodes of febrile neutropenia or severe palmar-plantar erythrodysesthesia syndrome occurred. No major pharmacokinetic drug-drug interaction was found between lurbinectedin, capecitabine or capecitabine metabolites.

CONCLUSIONS

The capecitabine/lurbinectedin combination showed encouraging clinical activity in relapsed MBC, especially in HR-positive tumors. Toxicity was manageable at the RD. Further development is warranted in relapsed MBC.

PRECISION: the Belgian molecular profiling program of metastatic cancer for clinical decision and treatment assignment

PRECISION is an initiative from the Belgian Society of Medical Oncology (BSMO) in collaboration with several stakeholders, encompassing four programs that aim to boost genomic and clinical knowledge with the ultimate goal to offer patients with metastatic solid tumors molecularly guided treatments. The PRECISION 1 study has led to the creation of a clinico-genomic database. The Belgian Approach for Local Laboratory Extensive Tumor Testing (BALLETT) and GeNeo studies will increase the number of patients with advanced cancer that have comprehensive genotyping of their cancer. The PRECISION 2 project consists of investigator-initiated phase II studies aiming to provide access to a targeted drug for patients whose tumors harbor actionable mutations in case the matched drug is not available through reimbursement or clinical trials in Belgium.

Unravelling triple-negative breast cancer molecular heterogeneity using an integrative multiomic analysis

Background

Recent efforts of genome-wide gene expression profiling analyses have improved our understanding of the biological complexity and diversity of triple-negative breast cancers (TNBCs) reporting, at least six different molecular subtypes of TNBC namely Basal-like 1 (BL1), basal-like 2 (BL2), immunomodulatory (IM), mesenchymal (M), mesenchymal stem-like (MSL) and luminal androgen receptor (LAR). However, little is known regarding the potential driving molecular events within each subtype, their difference in survival and response to therapy. Further insight into the underlying genomic alterations is therefore needed.

Patients and methods

This study was carried out using copy-number aberrations, somatic mutations and gene expression data derived from the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) and The Cancer Genome Atlas. TNBC samples (n = 550) were classified according to Lehmann's molecular subtypes using the TNBCtype online subtyping tool (http://cbc.mc.vanderbilt.edu/tnbc/).

Results

Each subtype showed significant clinic-pathological characteristic differences. Using a multivariate model, IM subtype showed to be associated with a better prognosis (HR = 0.68; CI = 0.46-0.99; P = 0.043) whereas LAR subtype was associated with a worst prognosis (HR = 1.47; CI = 1.0-2.14; P = 0.046). BL1 subtype was found to be most genomically instable subtype with high TP53 mutation (92%) and copy-number deletion in genes involved in DNA repair mechanism (BRCA2, MDM2, PTEN, RB1 and TP53). LAR tumours were associated with higher mutational burden with significantly enriched mutations in PI3KCA (55%), AKT1 (13%) and CDH1 (13%) genes. M and MSL subtypes were associated with higher signature score for angiogenesis. Finally, IM showed high expression levels of immune signatures and check-point inhibitor genes such as PD1, PDL1 and CTLA4.

Conclusion

Our findings highlight for the first time the substantial genomic heterogeneity that characterize TNBC molecular subtypes, allowing for a better understanding of the disease biology as well as the identification of several candidate targets paving novel approaches for the development of anticancer therapeutics for TNBC.

Abstract P2-05-17: ARGX-111 depletes MET-expressing circulating tumor cells via enhanced ADCC, resulting in inhibition of metastasis

Several lines of experimental evidence suggest that Hepatocyte Growth Factor (HGF) and its receptor MET play an important role in breast cancer progression and drug resistance. To date, targeted MET inhibitors in clinical development have primarily shown cytostatic rather than cytotoxic effects. Development of a cytotoxic MET inhibitor would serve to complement standard breast cancer therapy, especially when administered in the adjuvant/neo-adjuvant setting.

We have developed ARGX-111, a human antibody antagonist of MET function. ARGX-111 blocks both HGF-dependent and -independent signaling, down-regulates tumor cell surface expression of MET and kills MET-overexpressing cells by enhanced antibody-dependent cellular cytotoxicity (ADCC).

ARGX-111 was shown to be more efficacious than an ADCC-inactive control antibody in both HGF-dependent and -independent tumor xenograft models. ADCC reporter assays confirmed the cytotoxic effects of ARGX-111 in patient-derived primary tumor specimens, including MET-expressing breast cancer stem-like cells. In an orthotopic mouse model of metastatic mammary carcinoma (MDA-MB-231), adjuvant or neo-adjuvant treatment with ARGX-111 was significantly more effective in depleting circulating tumor cells (CTCs) and suppressing the development of bone and lung metastases than the ADCC-inactive control.

Taken together, these results provide a rationale for clinical investigation of ARGX-111 in the early breast cancer setting. An ongoing Phase 1 study (NCT02055066) is examining the effects of ARGX-111 on CTCs, alongside the assessment of its safety and efficacy.

Citation Format: Morello V, Hultberg A, De Jonge N, Huyghe L, Hanssens V, Brouckaert P, Saunders M, Dreier T, Thibault A, Rolfo C, Aftimos P, Awada A, Michieli P, de Haard H. ARGX-111 depletes MET-expressing circulating tumor cells via enhanced ADCC, resulting in inhibition of metastasis. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-05-17.

Molecular imaging as a tool to investigate heterogeneity of advanced HER2-positive breast cancer and to predict patient outcome under trastuzumab emtansine (T-DM1): the ZEPHIR trial

BACKGROUND

Only human epidermal growth factor receptor (HER)2 status determined by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) has been validated to predict efficacy of HER2-targeting antibody-drug-conjugate trastuzumab emtansine (T-DM1). We propose molecular imaging to explore intra-/interpatient heterogeneity in HER2 mapping of metastatic disease and to identify patients unlikely to benefit from T-DM1.

PATIENTS AND METHODS

HER2-positive mBC patients with IHC3+ or FISH ≥ 2.2 scheduled for T-DM1 underwent a pretreatment HER2-positron emission tomography (PET)/computed tomography (CT) with (89)Zr-trastuzumab. [(18)F]2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT was performed at baseline and before T-DM1 cycle 2. Patients were grouped into four HER2-PET/CT patterns according to the proportion of FDG-avid tumor load showing relevant (89)Zr-trastuzumab uptake (>blood pool activity): patterns A and B were considered positive (>50% or all of the tumor load 'positive'); patterns C and D were considered negative (>50% or all of the tumor load 'negative'). Early FDG-PET/CT was defined as nonresponding when >50% of the tumor load showed no significant reduction of FDG uptake (<15%). Negative (NPV) and positive predictive values (PPV) of HER2-PET/CT, early FDG response and their combination were assessed to predict morphological response (RECIST 1.1) after three T-DM1 cycles and time-to-treatment failure (TTF).

RESULTS

In the 56 patients analyzed, 29% had negative HER2-PET/CT while intrapatient heterogeneity (patterns B and C) was found in 46% of patients. Compared with RECIST1.1, respective NPV/PPV for HER2-PET/CT were 88%/72% and 83%/96% for early FDG-PET/CT. Combining HER2-PET/CT and FDG-PET/CT accurately predicted morphological response (PPV and NPV: 100%) and discriminated patients with a median TTF of only 2.8 months [n = 12, 95% confidence interval (CI) 1.4-7.6] from those with a TTF of 15 months (n = 25, 95% CI 9.7-not calculable).

CONCLUSIONS

Pretreatment imaging of HER2 targeting, combined with early metabolic response assessment holds great promise for improving the understanding of tumor heterogeneity in mBC and for selecting patients who will/will not benefit from T-DM1.

CLINICALTRIALSGOV IDENTIFIER

NCT01565200.

The AURORA initiative for metastatic breast cancer

Metastatic breast cancer is one of the leading causes of cancer-related mortality among women in the Western world. To date most research efforts have focused on the molecular analysis of the primary tumour to dissect the genotypes of the disease. However, accumulating evidence supports a molecular evolution of breast cancer during its life cycle, with metastatic lesions acquiring new molecular aberrations. Recognising this critical gap of knowledge, the Breast International Group is launching AURORA, a large, multinational, collaborative metastatic breast cancer molecular screening programme. Approximately 1300 patients with metastatic breast cancer who have received no more than one line of systemic treatment for advanced disease will, after giving informed consent, donate archived primary tumour tissue, as well as will donate tissue collected prospectively from the biopsy of metastatic lesions and blood. Both tumour tissue types, together with a blood sample, will then be subjected to next generation sequencing for a panel of cancer-related genes. The patients will be treated at the discretion of their treating physicians per standard local practice, and they will be followed for clinical outcome for 10 years. Alternatively, depending on the molecular profiles found, patients will be directed to innovative clinical trials assessing molecularly targeted agents. Samples of outlier patients considered as 'exceptional responders' or as 'rapid progressors' based on the clinical follow-up will be subjected to deeper molecular characterisation in order to identify new prognostic and predictive biomarkers. AURORA, through its innovative design, will shed light onto some of the unknown areas of metastatic breast cancer, helping to improve the clinical outcome of breast cancer patients.

A phase II randomized study comparing navelbine and capecitabine (Navcap) followed either by Navcap or by weekly docetaxel in the first-line treatment of HER-2/neu negative metastatic breast cancer

Following the proven efficacy and tolerability of Navcap and Navcap followed by docetaxel in the treatment of MBC, a phase II randomized study was initiated to assess the ORR of both arms in the first-line setting of MBC. Patients with no prior chemotherapy for MBC and HER-2/neu negative were eligible. All patients received Navcap (V 25 mg/m2 on d1 and d8 and C 825 mg/m2 bid D1-14 q3w) for a total of 4 cycles. Patients progressing under Navcap were withdrawn and received docetaxel as second-line treatment. Patients responding or stable were randomized to 2 arms: 4 cycles of Navcap (A) or 12 weekly docetaxel (25 mg/m²/week) (B). From July 2004 to July 2008, a total of 106 patients were enrolled. Ninety-four patients were evaluable before randomization, with a clinical benefit of 58%. Twenty-one patients (22%) had disease progression and were therefore not randomized. Forty-one patients were randomized to arm A and 29 patients to arm B. ORRs were 56 and 71% in arms A and B, respectively. The median time to progression and overall survival were 10 and 35 months in arm A and 12 and 37 months in arm B. Adverse events were mild. Arm A: grade 3-4 neutropenia (10%), grade 3 anemia (5%). Arm B: grade 3 neutropenia (6%), grade 3 anemia (6.2%), and grade 2 alopecia (12%).

CONCLUSION

Both Navcap and Navcap followed by Docetaxel regimens were tolerated with manageable toxicity, offering consistent activities in terms of response rate for metastatic breast cancer patients.