Abiraterone acetate, exemestane or the combination in postmenopausal patients with estrogen receptor-positive metastatic breast cancer

Resistance to nonsteroidal aromatase inhibitors is a major obstacle in the management of estrogen receptor-positive postmenopausal metastatic breast cancer. The addition of abiraterone acetate to exemestane did not improve clinical outcomes compared with exemestane alone in an androgen receptor-enriched population, potentially due to induced serum progesterone as a resistance mechanism.

Background

Androgen receptor (AR) signaling and incomplete inhibition of estrogen signaling may contribute to metastatic breast cancer (MBC) resistance to a nonsteroidal aromatase inhibitor (NSAI; letrozole or anastrozole). We assessed whether combined inhibition of androgen biosynthesis with abiraterone acetate plus prednisone and estradiol synthesis with exemestane (E) may be of clinical benefit to postmenopausal patients with NSAI-pretreated estrogen receptor-positive (ER+) MBC.

Patients and methods

Patients (N = 297) were stratified by the number of prior therapies for metastatic disease (0–1 versus 2) and by prior NSAI use (adjuvant versus metastatic), and randomized (1 : 1 : 1) to receive oral once daily 1000 mg abiraterone acetate plus 5 mg prednisone (AA) versus AA with 25 mg E (AAE) versus 25 mg E alone (E). Each treatment arm was well balanced with regard to the proportion of patients with AR-positive breast cancer. The primary end point was progression-free survival (PFS). Secondary end points included overall survival, clinical benefit rate, duration of response, and overall response rate.

Results

There was no significant difference in PFS with AA versus E (3.7 versus 3.7 months; hazard ratio [HR] = 1.1; 95% confidence interval [CI] 0.82–1.60; P = 0.437) or AAE versus E (4.5 versus 3.7 months; HR = 0.96; 95% CI 0.70–1.32; P = 0.794). Increased serum progesterone concentrations were observed in both arms receiving AA, but not with E. Grade 3 or 4 treatment-emergent adverse events associated with AA, including hypokalemia and hypertension, were less common in patients in the E (2.0% and 2.9%, respectively) and AA arms (3.4% and 1.1%, respectively) than in the AAE arm (5.8% for both).

Conclusions

Adding AA to E in NSAI-pretreated ER+ MBC patients did not improve PFS compared with treatment with E. An AA-induced progesterone increase may have contributed to this lack of clinical activity.

ClinicalTrials.gov

NCT01381874.

Randomized, phase II, placebo-controlled trial of onartuzumab and/or bevacizumab in combination with weekly paclitaxel in patients with metastatic triple-negative breast cancer

BACKGROUND

Increased hepatocyte growth factor/MET signaling is associated with an aggressive phenotype and poor prognosis in triple-negative breast cancer (TNBC). We evaluated the benefit of adding onartuzumab, a monoclonal anti-MET antibody, to paclitaxel with/without bevacizumab in patients with TNBC.

PATIENTS AND METHODS

Women with metastatic TNBC were randomized to receive onartuzumab plus placebo plus weekly paclitaxel (OP; n = 60) or onartuzumab plus bevacizumab plus paclitaxel (OBP; n = 63) or placebo plus bevacizumab plus paclitaxel (BP; n = 62). The primary end point was progression-free survival (PFS); additional end points included overall survival (OS), objective response rate (ORR), and safety. This trial was hypothesis generating and did not have power to detect minimum clinically meaningful differences between treatment arms.

RESULTS

There was no improvement in PFS with the addition of onartuzumab to BP [hazard ratio (HR), 1.08; 95% confidence interval (CI) 0.69-1.70]; the risk of a PFS event was higher with OP than with BP (HR, 1.74; 95% CI 1.13-2.68). Most patients had MET-negative tumors (88%); PAM50 subtype analysis showed basal-like tumors in 68% of samples. ORR was higher in the bevacizumab arms (OBP: 42.2%; 95% CI 28.6-57.1; BP: 54.7%; 95% CI 41.0-68.4) compared with OP (27.5%; 95% CI 15.9-40.6). Median OS was shorter with OBP (HR, 1.36; 95% CI 0.75-2.46) and OP (HR, 1.92; 95% CI 1.03-3.59), than with BP. Peripheral edema was more frequent in the onartuzumab arms (OBP, 51.8%; OP, 58.6%) versus BP (17.7%).

CONCLUSION

This study did not show a clinical benefit of the addition of onartuzumab to paclitaxel with/without bevacizumab in patients with predominantly MET-negative TNBC.

CLINICALTRIALSGOV

NCT01186991.

Everolimus plus exemestane for hormone-receptor-positive, human epidermal growth factor receptor-2-negative advanced breast cancer: overall survival results from BOLERO-2†

BACKGROUND

The BOLERO-2 study previously demonstrated that adding everolimus (EVE) to exemestane (EXE) significantly improved progression-free survival (PFS) by more than twofold in patients with hormone-receptor-positive (HR(+)), HER2-negative advanced breast cancer that recurred or progressed during/after treatment with nonsteroidal aromatase inhibitors (NSAIs). The overall survival (OS) analysis is presented here.

PATIENTS AND METHODS

BOLERO-2 is a phase III, double-blind, randomized international trial comparing EVE 10 mg/day plus EXE 25 mg/day versus placebo (PBO) + EXE 25 mg/day in postmenopausal women with HR(+) advanced breast cancer with prior exposure to NSAIs. The primary end point was PFS by local investigator assessment; OS was a key secondary end point.

RESULTS

At the time of data cutoff (3 October 2013), 410 deaths had occurred and 13 patients remained on treatment. Median OS in patients receiving EVE + EXE was 31.0 months [95% confidence interval (CI) 28.0-34.6 months] compared with 26.6 months (95% CI 22.6-33.1 months) in patients receiving PBO + EXE (hazard ratio = 0.89; 95% CI 0.73-1.10; log-rank P = 0.14). Poststudy treatments were received by 84% of patients in the EVE + EXE arm versus 90% of patients in the PBO + EXE arm. Types of poststudy therapies were balanced across arms, except for chemotherapy (53% EVE + EXE versus 63% PBO + EXE). No new safety concerns were identified.

CONCLUSIONS

In BOLERO-2, adding EVE to EXE did not confer a statistically significant improvement in the secondary end point OS despite producing a clinically meaningful and statistically significant improvement in the primary end point, PFS (4.6-months prolongation in median PFS; P < 0.0001). Ongoing translational research should further refine the benefit of mTOR inhibition and related pathways in this treatment setting.

TRIAL REGISTRATION NUMBER

NCT00863655.

Bosutinib plus capecitabine for selected advanced solid tumours: results of a phase 1 dose-escalation study

Background:

This phase 1 study evaluated the maximum tolerated dose (MTD), safety, and efficacy of bosutinib (competitive Src/Abl tyrosine kinase inhibitor) plus capecitabine.

Methods:

Patients with locally advanced/metastatic breast, pancreatic, or colorectal cancers; cholangiocarcinoma; or glioblastoma received bosutinib plus capecitabine at eight of nine possible dose combinations using an ‘up-down' design to determine the toxicity contour of the combination.

Results:

Among 32 enrolled patients, none of the 9 patients receiving MTD (bosutinib 300 mg once daily plus capecitabine 1000 mg m⁻² twice daily) experienced dose-limiting toxicities (DLTs). Overall, 2 out of 31 (6%) evaluable patients experienced DLTs (grade 3 neurologic pain (n=1); grade 3 pruritus/rash and increased alanine aminotransferase (n=1)). Most common treatment-related adverse events (AEs) were diarrhoea, nausea, vomiting, palmar-plantar erythrodysesthesia (PPE), fatigue; most frequent grade 3/4 AEs: PPE, fatigue, and increased alanine/aspartate aminotransferase. Although diarrhoea was common, 91% of affected patients experienced maximum grade 1/2 events that resolved. Best overall confirmed partial response or stable disease >24 weeks (all tumour types) was observed in 6 and 13% of patients.

Conclusions:

In this population of patients with advanced solid tumours, bosutinib plus capecitabine demonstrated a safety profile similar to that previously reported for bosutinib or capecitabine monotherapy; limited efficacy was observed.

REBECA: a phase I study of bevacizumab and whole-brain radiation therapy for the treatment of brain metastasis from solid tumours

BACKGROUND

Brain metastases (BMs) are associated with a poor prognosis. Standard treatment comprises whole-brain radiation therapy (WBRT). As neo-angiogenesis is crucial in BM growth, combining angiogenesis inhibitors such as bevacizumab with radiotherapy is of interest. We aimed to identify the optimal regimen of bevacizumab combined with WBRT for BM for phase II evaluation and provide preliminary efficacy data.

PATIENTS AND METHODS

In this multicentre single-arm phase I study with a 3 + 3 dose-escalation design, patients with unresectable BM from solid tumours received three cycles of bevacizumab at escalating doses [5, 10 and 15 mg/kg every 2 weeks at dose levels (DL) 0, 1 and 2, respectively] and WBRT (30 Gy/15 fractions/3 weeks) administered from day 15. DL3 consisted of bevacizumab 15 mg/kg with WBRT from day 15 in 30 Gy/10 fractions/2 weeks. Safety was evaluated using NCI-CTCAE version 3. BM response (RECIST 1.1) was assessed by magnetic resonance imaging at 6 weeks and 3 months after WBRT.

RESULTS

Nineteen patients were treated, of whom 13 had breast cancer. There were no DLTs. Grade 1-2 in-field and out-field toxicities occurred for five and nine patients across all DLs, respectively, including three and six patients (including one patient with both, so eight patients overall) of nine patients in DL3. One patient experienced BM progression during treatment (DL0). At the 3-month post-treatment assessment, 10 patients showed a BM response: one of three treated at DL0, one of three at DL1, two of three at DL2 and six of seven at DL3, including one complete response. BM progression occurred in five patients, resulting in two deaths. The remaining patient died from extracranial disease progression.

CONCLUSION

Bevacizumab combined with WBRT appears to be a tolerable treatment of BM. DL3 warrants further efficacy evaluation based on the favourable safety/efficacy balance. ClinicalTrials.gov Identifier: NCT01332929.

Randomised proof-of-concept phase II trial comparing targeted therapy based on tumour molecular profiling vs conventional therapy in patients with refractory cancer: results of the feasibility part of the SHIVA trial

Background:

The SHIVA trial is a multicentric randomised proof-of-concept phase II trial comparing molecularly targeted therapy based on tumour molecular profiling vs conventional therapy in patients with any type of refractory cancer. Results of the feasibility study on the first 100 enrolled patients are presented.

Methods:

Adult patients with any type of metastatic cancer who failed standard therapy were eligible for the study. The molecular profile was performed on a mandatory biopsy, and included mutations and gene copy number alteration analyses using high-throughput technologies, as well as the determination of oestrogen, progesterone, and androgen receptors by immunohistochemistry (IHC).

Results:

Biopsy was safely performed in 95 of the first 100 included patients. Median time between the biopsy and the therapeutic decision taken during a weekly molecular biology board was 26 days. Mutations, gene copy number alterations, and IHC analyses were successful in 63 (66%), 65 (68%), and 87 (92%) patients, respectively. A druggable molecular abnormality was present in 38 patients (40%).

Conclusions:

The establishment of a comprehensive tumour molecular profile was safe, feasible, and compatible with clinical practice in refractory cancer patients.

Activity of trabectedin in germline BRCA1/2-mutated metastatic breast cancer: results of an international first-in-class phase II study

BACKGROUND

Breast cancer is a heterogeneous disease defined by both germline and somatic abnormalities. In preclinical models, tumors carrying homologous recombination defects are highly sensitive to trabectedin. This phase II trial evaluated the efficacy and safety of trabectedin in BRCA1/2 germline mutation carriers with pretreated metastatic breast cancer (MBC).

PATIENTS AND METHODS

Trabectedin 1.3 mg/m(2) as a 3-h i.v. infusion was administered every 3 weeks until progression or intolerance. The primary efficacy end point was the objective response rate (ORR) as per RECIST. Secondary efficacy end points comprised time-to-event end points, and changes in tumor volume and expression of tumor marker CA15.3. Safety was evaluated using the NCI-CTCAE.

RESULTS

Forty BRCA1/2 germline mutation carriers with MBC were included. Confirmed partial response (PR) occurred in 6 of 35 assessable patients [ORR = 17%; 95% confidence interval (CI) 7% to 34%] and lasted 1.4-6.8 months. Median PFS was 3.9 months (95% CI 1.6-5.5 months). Eight patients (21%) showed changes in tumor volume, and 14 (40%) a clinical benefit. Trabectedin-related adverse events were generally mild/moderate, the most common being fatigue, nausea, constipation and anorexia. Severe laboratory abnormalities (neutropenia, transaminase increases) were mostly transient and noncumulative, and were managed by dose adjustments.

CONCLUSIONS

With the caveat of the limited patient number, trabectedin monotherapy showed activity and was well tolerated in heavily pretreated MBC patients selected for germline BRCA mutation. These results prompt further evaluation of trabectedin alone or combined with other specific drugs in this indication.

CLINICALTRIALSGOV

NCT00580112.

Pathological complete response after neoadjuvant chemotherapy is an independent predictive factor irrespective of simplified breast cancer intrinsic subtypes: a landmark and two-step approach analyses from the EORTC 10994/BIG 1-00 phase III trial

BACKGROUND

Pathological complete response (pCR) following chemotherapy is strongly associated with both breast cancer subtype and long-term survival. Within a phase III neoadjuvant chemotherapy trial, we sought to determine whether the prognostic implications of pCR, TP53 status and treatment arm (taxane versus non-taxane) differed between intrinsic subtypes.

PATIENTS AND METHODS

Patients were randomized to receive either six cycles of anthracycline-based chemotherapy or three cycles of docetaxel then three cycles of eprirubicin/docetaxel (T-ET). pCR was defined as no evidence of residual invasive cancer (or very few scattered tumour cells) in primary tumour and lymph nodes. We used a simplified intrinsic subtypes classification, as suggested by the 2011 St Gallen consensus. Interactions between pCR, TP53 status, treatment arm and intrinsic subtype on event-free survival (EFS), distant metastasis-free survival (DMFS) and overall survival (OS) were studied using a landmark and a two-step approach multivariate analyses.

RESULTS

Sufficient data for pCR analyses were available in 1212 (65%) of 1856 patients randomized. pCR occurred in 222 of 1212 (18%) patients: 37 of 496 (7.5%) luminal A, 22 of 147 (15%) luminal B/HER2 negative, 51 of 230 (22%) luminal B/HER2 positive, 43 of 118 (36%) HER2 positive/non-luminal, 69 of 221(31%) triple negative (TN). The prognostic effect of pCR on EFS did not differ between subtypes and was an independent predictor for better EFS [hazard ratio (HR) = 0.40, P < 0.001 in favour of pCR], DMFS (HR = 0.32, P < 0.001) and OS (HR = 0.32, P < 0.001). Chemotherapy arm was an independent predictor only for EFS (HR = 0.73, P = 0.004 in favour of T-ET). The interaction between TP53, intrinsic subtypes and survival outcomes only approached statistical significance for EFS (P = 0.1).

CONCLUSIONS

pCR is an independent predictor of favourable clinical outcomes in all molecular subtypes in a two-step multivariate analysis.

CLINICALTRIALSGOV

EORTC 10994/BIG 1-00 Trial registration number NCT00017095.

Abstract P6-12-08: Serum biomarkers identification using quantitative proteomics in patients with HER2-positive inflammatory breast cancer receiving trastuzumab plus bevacizumab-based chemotherapy (BEVERLY 2 trial)

Background

Inflammatory breast cancer (IBC) is a rare but aggressive form of locally advanced breast cancer, the optimal systemic treatment of which is still discussed. Beverly 2 trial was a phase II study evaluating the efficacy and safety of a preoperative regimen associating bevacizumab, trastuzumab, and chemotherapy in 52 patients with non-metastatic HER2-positive IBC, reporting a promising rate of pathological complete response (pCR, 63.5%, 95% CI 49.4–77.5; Pierga et al, Lancet Oncol, 2012). During the study, serum samples were collected at baseline and subjected to proteomic-based approaches to identify circulating biomarkers predictive of treatment response.

Methods

Baseline serum samples from responsive (pCR, according to Sataloff classification, n = 12) and non-responsive (no pCR, n = 11) patients were subjected to isobaric Tag for Relative and Absolute Quantification (iTRAQ)-based proteomics. Samples were pooled according to pCR and hormone receptor (HR) status, to constitute 4 independent mixes (pCR/HR-positive, pCR/HR-negative, nopCR/HR-positive, nopCR/HR-negative). Each of them underwent immuno-depletion of highly abundant proteins, concentration, reduction, alkylation and tryptic digestion. Then, each mix was fractionated and subjected to iTRAQ identification and quantitation using nano-liquid chromatography (LC) and electrospray ionisation (ESI)-orbitrap tandem mass spectrometry (MS/MS) (LTQ-orbitrap, Thermofisher). Differentially expressed proteins were analysed using IPA (IngenuitySystems) to highlight biological functions and signalling pathways that were most significantly enriched.

Results

iTRAQ-based measurements identified and quantified a total of 302 serum proteins. Among them, 48 proteins displayed a significant (fold-change &gt; 1.5 and p-value &lt; 0.05) differential expression between pCR and noPCR pts (18 proteins down-regultated and 30 proteins up-regulated in pCR patients), some of them previously described to be involved in breast cancer biology and/or angiogenesis, including : Alpha-1-acid glycoprotein 1, von Willebrand factor, Galectin-3-binding protein, serum amyloid A-1, Apolipoprotein E, Pigment epithelium-derived factor, Corticosteroid-binding globulin (down-regulated proteins in pCR patients); serum amyloid P-component, angiotensinogen, plasma serine protease inhibitor, carbonic anhydrase 1, mannose-binding protein C, hyaluronan-binding protein 2, peroxiredoxin-2, properdin, ADAMTS13, tetranectin, biotinidase, lumican (up-regulated proteins in pCR patients). Proteins with differential expression during treatment were involved in various biological processes, including cell-to-cell signaling and interaction, lipid metabolism, small molecule biochemistry, molecular transport, cellular function and maintenance as well as various canonical pathways such as acute phase response signalling, LXR/RXR activation and coagulation system.

Conclusion

iTRAQ-based quantitative proteomics identify serum proteins that could predict the therapeutic response to pre-operative trastuzumab plus bevacizumab-based chemotherapy in HER2-positive IBC.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-12-08.

Abstract P4-01-05: 3’-deoxy-3’-[18F]fluoro-thymidine (18F-FLT) positron emission tomography (PET): An accurate and effective tool for assessing tumor response in breast cancer

Objectives : A French multicenter study was promoted by the national French cancer federation (Unicancer R&D) to assess the potential of [18F]FLT (positron emission tomography (PET) biomarker of proliferation)to manage breast cancer neoadjuvant chemotherapy (NAC). The main objective was to compare changes in tumor [18F]FLT uptake to histopathological changes induced by NAC, assuming an arrest of tumor growth related to the effectiveness of NAC.

Methods : 97 patients (age 48.6 +/- 10.2 y.) were included in 13 nuclear medicine centers. All patients were eligible to anthracycline-based NAC for a de novo unifocal breast cancer (ductal n = 84, lobular = 11, other type = 2; stage II n = 75, stage III n = 21 et stage IV n = 1). 90 patients underwent a baseline PET before the onset of NAC (PET1) and a final PET after the end of NAC and before surgery (PET3). PET acquisitions were performed 60±7min after FLT injection. SUVmax (maximum standardized uptake value), SUVpeak (1 cm3 ROI including pixel max) and SUV41 (isocontour 41% of pixel max) were computed. Changes in SUV on PET3 vs PET1 were analyzed in relation to histopathological findings at the end of NAC (Sataloff criteria).

Results : Tumor FLT uptake decreased markedly between TEP1 and TEP3 (SUVmax = 6.2±4.8 vs 1.3±1.2 respectively; SUVpeak = 4.6±3.2 vs 0.9±0.9; SUV41 = 3.6±2.8 vs 0.8±0.7). Total or near-total therapeutic effect (grade A) were obtained in 20 patients, more than 50% therapeutic effect but less than total or near-total effect (grade B) in 37 patients, less than 50% therapeutic effect but visible effect (grade C) in 22 patients, or no therapeutic effect (grade D) in 11 patients. SUVmax decreased dramatically (87.5%) to background levels in all patients with a complete response (grade A). Overall, changes in SUV differed depending on the type of histological response (p&lt;0.01) i.e. SUVmax changes were more pronounced as pathological responses were good: 61% for grade D; 65.7% grade C and 69.8% grade B. The same results were obtained with the two other SUV types.

Conclusions : Pathologic response to NAC in breast cancer can be assessed accurately by FLT.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-01-05.