Summary Background Phosphatidylinositol 3-kinase (PI3K) pathway activation is a hallmark of endocrine therapy-resistant, hormone receptor-positive breast cancer. This phase 3 study assessed the ...efficacy of the pan-PI3K inhibitor buparlisib plus fulvestrant in patients with advanced breast cancer, including an evaluation of the PI3K pathway activation status as a biomarker for clinical benefit. Methods The BELLE-2 trial was a randomised, double-blind, placebo-controlled, multicentre study. Postmenopausal women aged 18 years or older with histologically confirmed, hormone receptor-positive and human epidermal growth factor (HER2)-negative inoperable locally advanced or metastatic breast cancer whose disease had progressed on or after aromatase inhibitor treatment and had received up to one previous line of chemotherapy for advanced disease were included. Eligible patients were randomly assigned (1:1) using interactive voice response technology (block size of 6) on day 15 of cycle 1 to receive oral buparlisib (100 mg/day) or matching placebo, starting on day 15 of cycle 1, plus intramuscular fulvestrant (500 mg) on days 1 and 15 of cycle 1, and on day 1 of subsequent 28-day cycles. Patients were assigned randomisation numbers with a validated interactive response technology; these numbers were linked to different treatment groups which in turn were linked to treatment numbers. PI3K status in tumour tissue was determined via central laboratory during a 14-day run-in phase. Randomisation was stratified by PI3K pathway activation status (activated vs non-activated vs and unknown) and visceral disease status (present vs absent). Patients, investigators, local radiologists, study team, and anyone involved in the study were masked to the identity of the treatment until unblinding. The primary endpoints were progression-free survival by local investigator assessment per Response Evaluation Criteria In Solid Tumors (version 1.1) in the total population, in patients with known (activated or non-activated) PI3K pathway status, and in PI3K pathway-activated patients. Efficacy analyses were done in the intention-to-treat population. Safety was analysed in all patients who received at least one dose of study drug and had at least one post-baseline safety assessment according to the treatment they received. This trial is registered with ClinicalTrials.gov , number NCT01610284 , and is currently ongoing but not recruiting participants. Findings Between Sept 7, 2012, and Sept 10, 2014, 1147 patients from 267 centres in 29 countries were randomly assigned to receive buparlisib (n=576) or placebo plus fulvestrant (n=571). In the total patient population (n=1147), median progression-free survival was 6·9 months (95% CI 6·8–7·8) in the buparlisib group versus 5·0 months (4·0–5·2) in the placebo group (hazard ratio HR 0·78 95% CI 0·67–0·89; one-sided p=0·00021). In patients with known PI3K status (n=851), median progression-free survival was 6·8 months (95% CI 5·0–7·0) in the buparlisib group vs 4·5 months (3·3–5·0) in the placebo group (HR 0·80 95% CI 0·68–0·94; one-sided p=0·0033). In PI3K pathway-activated patients (n=372), median progression-free survival was 6·8 months (95% CI 4·9–7·1) in the buparlisib group versus 4·0 months (3·1–5·2) in the placebo group (HR 0·76 0·60–0·97, one-sided p=0·014). The most common grade 3–4 adverse events in the buparlisib group versus the placebo group were increased alanine aminotransferase (146 25% of 573 patients vs six 1% of 570), increased aspartate aminotransferase (103 18% vs 16 3%), hyperglycaemia (88 15% vs one <1%), and rash (45 8% vs none). Serious adverse events were reported in 134 (23%) of 573 patients in the buparlisib group compared with 90 16% of 570 patients in the placebo group; the most common serious adverse events (affecting ≥2% of patients) were increased alanine aminotransferase (17 3% of 573 vs one <1% of 570) and increased aspartate aminotransferase (14 2% vs one <1%). No treatment-related deaths occurred. Interpretation The results from this study show that PI3K inhibition combined with endocrine therapy is effective in postmenopausal women with endocrine-resistant, hormone receptor-positive and HER2-negative advanced breast cancer. Use of more selective PI3K inhibitors, such as α-specific PI3K inhibitor, is warranted to further improve safety and benefit in this setting. No further studies are being pursued because of the toxicity associated with this combination. Funding Novartis Pharmaceuticals Corporation.
Summary Background mTOR inhibition reverses trastuzumab resistance via the hyperactivated PIK/AKT/mTOR pathway due to PTEN loss, by sensitising PTEN-deficient tumours to trastuzumab. The BOLERO-1 ...study assessed the efficacy and safety of adding everolimus to trastuzumab and paclitaxel as first-line treatment for patients with HER2-positive advanced breast cancer. Methods In this phase 3, randomised, double-blind trial, patients were enrolled across 141 sites in 28 countries. Eligible patients were aged 18 years or older, with locally assessed HER2-positive advanced breast cancer, with Eastern Cooperative Oncology Group (ECOG) performance status of 0–1, who had not received previous trastuzumab or chemotherapy for advanced breast cancer within 12 months of randomisation, had measurable disease as per Response Evaluation Criteria in Solid Tumors (RECIST) or bone lesions in the absence of measurable disease, without previous systemic treatment for advanced disease except endocrine therapy. Patients were randomly assigned (2:1) with an interactive voice and web response system to receive either 10 mg everolimus once a day orally or placebo plus weekly trastuzumab intravenously at 4 mg/kg loading dose on day 1 with subsequent weekly doses of 2 mg/kg of each 4 week cycle plus paclitaxel intravenously at a dose of 80 mg/m2 on days 1, 8, and 15 of each 4 week cycle. Randomisation was stratified according to previous use of trastuzumab and visceral metastasis. Patients and investigators were masked to the assigned treatments. Identity of experimental treatments was concealed by use of everolimus and placebo that were identical in packaging, labelling, appearance, and administration schedule. The two primary objectives were investigator-assessed progression-free survival in the full study population and in the subset of patients with hormone receptor-negative breast cancer at baseline; the latter was added during the course of the study, before unmasking based on new clinical and biological findings from other studies. All efficacy analyses were based on the intention-to-treat population. Enrolment for this trial is closed and results of the final progression-free survival analyses are presented here. This trial is registered with ClinicalTrials.gov , number NCT00876395. Findings Between Sept 10, 2009, and Dec 16, 2012, 719 patients were randomly assigned to receive everolimus (n=480) or placebo (n=239). Median follow-up was 41·3 months (IQR 35·4–46·6). In the full population, median progression-free survival was 14·95 months (95% CI 14·55–17·91) with everolimus versus 14·49 months (12·29–17·08) with placebo (hazard ratio 0·89, 95% CI 0·73–1·08; p=0·1166). In the HR-negative subpopulation (n=311), median progression-free survival with everolimus was 20·27 months (95% CI 14·95–24·08) versus 13·08 months (10·05–16·56) with placebo (hazard ratio 0·66, 95% CI 0·48–0·91; p=0·0049); however, the protocol-specified significance threshold (p=0·0044) was not crossed. The most common adverse events with everolimus were stomatitis (314 67% of 472 patients in the everolimus group vs 77 32% of 238 patients in the placebo group), diarrhoea (267 57% vs 111 47% patients), and alopecia (221 47% vs 125 53%). The most frequently reported grade 3 or 4 adverse events in the everolimus group versus the placebo group were neutropenia (117 25% vs 35 15%), stomatitis (59 13% vs three 1%), anaemia (46 10% vs six 3%) and diarrhoea (43 9% vs 10 4%) On-treatment adverse event-related deaths were reported in 17 (4%) patients in the everolimus group and none in the placebo group. Interpretation Although progression-free survival was not significantly different between groups in the full analysis population, the 7·2 months prolongation we noted with the addition of everolimus in the HR-negative, HER2-positive population warrants further investigation, even if it did not meet prespecified criteria for significance. The safety profile was generally consistent with what was previously reported in BOLERO-3. Proactive monitoring and early management of adverse events in patients given everolimus and chemotherapy is crucial. Funding Novartis Pharmaceuticals.
Summary Background Utidelone, a genetically engineered epothilone analogue, has shown promise as a potential treatment for breast cancer in phase 1 and 2 trials. The aim of this phase 3 trial was to ...compare the efficacy and safety of utidelone plus capecitabine versus capecitabine alone in patients with metastatic breast cancer. Methods We did a multicentre, open-label, superiority, phase 3, randomised controlled trial in 26 hospitals in China. Eligible participants were female patients with metastatic breast cancer refractory to anthracycline and taxane chemotherapy regimens. We randomly assigned participants (2:1) using computer based randomisation and block sizes of 6 to a 21-day cycle of either utidelone (30 mg/m2 intravenously once per day on days 1–5) plus capecitabine (1000 mg/m2 orally twice per day on days 1–14), or capecitabine alone (1250 mg/m2 orally twice per day on days 1–14), until disease progression or unacceptable toxicity occurred. Patients, physicians, and assessors were not masked to treatment allocation; however, an independent radiology review committee used to additionally assess response was masked to allocation. The primary endpoint was centrally assessed (by an independent radiology review committee) progression-free survival, and analysed using the Kaplan-Meier product-limit method in the intention-to-treat population. Safety was assessed in all participants who received at least one dose of study drug. Follow-up is ongoing. This study is registered at ClinicalTrials.gov , number NCT02253459. Findings Between Aug 8, 2014, and Dec 14, 2015, we enrolled and randomly assigned 270 patients to treatment with utidelone plus capecitabine, and 135 to capecitabine alone. Median follow-up for progression-free survival was 6·77 months (IQR 3·81–10·32) for the utidelone plus capecitabine group and 4·55 months (2·55–9·39) for the capecitabine alone group. Median progression-free survival by central review in the utidelone plus capecitabine group was 8·44 months (95% CI 7·95–9·92) compared with 4·27 months (3·22–5·68) in the capecitabine alone group; hazard ratio 0·46, 95% CI 0·36–0·59; p<0·0001. Peripheral neuropathy was the most common grade 3 adverse event in the utidelone plus capecitabine group (58 22% of 267 patients vs 1 <1% of 130 patients in the capecitabine alone group). Palmar-plantar erythrodysaesthesia was the most prominent grade 3 adverse event in the capacitabine alone group (in 10 8% of 130 patients) and was the next most frequent grade 3 event in the utidelone plus capecitabine group (in 18 7% of 267 patients). 16 serious adverse events were reported in the combination therapy group (diarrhoea was the most common, in three 1% patients) and 14 serious adverse events were reported in the monotherapy group (the most common were diarrhoea, increased blood bilirubin, and anaemia, in two 2% patients for each event). 155 patients died (99 in the combination therapy arm, 56 in the monotherapy arm). All deaths were related to disease progression except for one in each group (attributed to pericardial effusion in the combination therapy group and dyspnoea in the monotherapy group) that were considered possibly or probably treatment-related. Interpretation Despite disease progression with previous chemotherapies, utidelone plus capecitabine was more efficacious compared with capecitabine alone for the outcome of progression-free survival, with mild toxicity except for peripheral sensory neuropathy, which was manageable. The findings from this study support the use of utidelone plus capecitabine as an effective option for patients with metastatic breast cancer. Funding Beijing Biostar Technologies, Beijing, China.
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