Palbociclib in combination with endocrine therapy versus capecitabine in hormonal receptor-positive, human epidermal growth factor 2-negative, aromatase inhibitor-resistant metastatic breast cancer: a phase III randomised controlled trial-PEARL

BACKGROUND

Palbociclib plus endocrine therapy (ET) is the standard treatment of hormone receptor-positive and human epidermal growth factor receptor 2-negative, metastatic breast cancer (MBC). However, its efficacy has not been compared with that of chemotherapy in a phase III trial.

PATIENTS AND METHODS

PEARL is a multicentre, phase III randomised study in which patients with aromatase inhibitor (AI)-resistant MBC were included in two consecutive cohorts. In cohort 1, patients were randomised 1 : 1 to palbociclib plus exemestane or capecitabine. On discovering new evidence about estrogen receptor-1 (ESR1) mutations inducing resistance to AIs, the trial was amended to include cohort 2, in which patients were randomised 1 : 1 between palbociclib plus fulvestrant and capecitabine. The stratification criteria were disease site, prior sensitivity to ET, prior chemotherapy for MBC, and country of origin. Co-primary endpoints were progression-free survival (PFS) in cohort 2 and in wild-type ESR1 patients (cohort 1 + cohort 2). ESR1 hotspot mutations were analysed in baseline circulating tumour DNA.

RESULTS

From March 2014 to July 2018, 296 and 305 patients were included in cohort 1 and cohort 2, respectively. Palbociclib plus ET was not superior to capecitabine in both cohort 2 [median PFS: 7.5 versus 10.0 months; adjusted hazard ratio (aHR): 1.13; 95% confidence interval (CI): 0.85-1.50] and wild-type ESR1 patients (median PFS: 8.0 versus 10.6 months; aHR: 1.11; 95% CI: 0.87-1.41). The most frequent grade 3-4 toxicities with palbociclib plus exemestane, palbociclib plus fulvestrant and capecitabine, respectively, were neutropenia (57.4%, 55.7% and 5.5%), hand/foot syndrome (0%, 0% and 23.5%), and diarrhoea (1.3%, 1.3% and 7.6%). Palbociclib plus ET offered better quality of life (aHR for time to deterioration of global health status: 0.67; 95% CI: 0.53-0.85).

CONCLUSIONS

There was no statistical superiority of palbociclib plus ET over capecitabine with respect to PFS in MBC patients resistant to AIs. Palbociclib plus ET showed a better safety profile and improved quality of life.

SEOM clinical guidelines in early-stage breast cancer 2015

Breast cancer is a major public health problem. Despite remarkable advances in early diagnosis and treatment, one in three women may have metastases since diagnosis. Better understanding of prognostic and predictive factors allows us to select the most appropriate adjuvant therapy in each patient. In these guidelines, we summarize current evidence for the medical management of early-stage breast cancer.

P5-14-22: Prospective Observational Study To Describe the Clinicopathological and Biological Characteristics and the Management of Metastatic Breast Cancer Patients Who Experienced Complete or Partial Remission or Disease Stabilization during at Least 3 Years

Background

Trastuzumab has shown an improvement in survival outcomes among patients with HER2+ metastatic breast cancer (MBC). Identification of pathological, clinical factors and tumor genetic profile that may predict long-term remission has become a key-issue. We aimed to describe the clinicopathological and biological characteristics of MBC patients who experienced complete response (CR), partial response (PR), or stable disease (SD) during at least 3 years and their management in routine clinical practice.

Methods: Multicenter, observational, cross-sectional study. Data were collected from women with HER2+ MBC treated with a trastuzumab-based regimen who maintained a partial or complete remission or disease stabilization beyond 3 years. The interim results from the first 65 patients evaluated are presented.

Results: Median age: 59 (52-70) years. Metastatic disease was diagnosed after a median of 23.5 (1.6−48.8) months since primary tumor diagnosis. The predominant tumor type was ductal carcinoma (89.2%) and 47% showed histological grade III. Mean tumor size: 3.6±2.2cm (anatomical pathology), 5.1±2.8cm (imaging studies). Hormonal status: Progesterone receptor positive 46% and estrogen receptor positive 43%. Most common metastatic sites: lung (23%), liver (17%) and bone (14%). Overexpression of HER2 was assessed by IHC in 97% of patients, of whom 94% were HER2+ (3+) and 17% had FISH+ HER2 status. Tumor was positive for p53 and Ki67 in 23% and 41.5%, respectively. Surgery was performed on 83% of patients, of which 73% underwent radical mastectomy; 96% had their axillary nodes removed. Surgery of metastases was performed on 7.8%. First line chemotherapy was received by 91% with the most frequent schemes being paclitaxel (24%), vinorelbine (15%) and paclitaxel/carboplatine (14%). First line hormonal therapy and radiotherapy was used in 45% and 12%, respectively. All patients received first line trastuzumab, administered on a weekly schedule in 51%. Trastuzumab was used in combination in most of patients (89.2%) with a median number of cycles of 18 (7.0−41.5) and during a median of 53.3±25 months. 66% of patients achieved a CR, 21% PR and 13% had SD. Median time since trastuzumab was initiated to CR, PR or SD was 5 (4-7) months. Median duration of CR, PR or SD was 56 (44.5−78.0) months. Trastuzumab was maintained beyond CR, PR or SD in 99% during a median of 46.5 (35-67) months. 75% of patients continue on treatment with trastuzumab. Only 2 patients discontinued trastuzumab due to toxicity. At the time of the analysis, 19% had progressed, 57% were alive and free of disease and among patients on treatment (93%), 54% were on trastuzumab. Cardiac toxicity was the most common toxicity (36%) among those suffering at least one (22%).

Conclusions: The preliminary findings support that trastuzumab provides a substantial long-term survival benefit with a manageable safety profile in HER2+ MBC patients. This study adds to the evidence that there may be benefit in continuing trastuzumab after achieving remission or disease stabilization. Final results will be presented in the forthcoming congress.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-14-22.

Pegylated liposomal doxorubicin in combination with cyclophosphamide and trastuzumab in HER2-positive metastatic breast cancer patients: efficacy and cardiac safety from the GEICAM/2004-05 study

BACKGROUND

In order to determine the feasibility of substituting pegylated liposomal doxorubicin (PLD) for doxorubicin in combination with cyclophosphamide and trastuzumab as adjuvant therapy, we conducted a phase II study of the combination as first-line therapy in human epidermal growth factor receptor 2 (HER2) overexpressing metastatic breast cancer (MBC).

METHODS

PLD 50 mg/m(2) and cyclophosphamide 600 mg/m(2) were administered every 4 weeks for six cycles; trastuzumab (4 mg/kg loading dose, then 2 mg/kg) was administered weekly for 24 weeks. The primary end point was objective response rate (ORR), and the secondary end points included time to progression (TTP), overall survival (OS), and safety.

RESULTS

Among the 48 evaluable patients, ORR was 68.8% [95% confidence interval (CI) 55.69% to 81.91%], with 6 patients (12.5%) achieving a complete response and 27 (56.2%) a partial response. The median TTP was 12 months (95% CI 9-15.1 months), and the median OS was 34.2 months (95% CI 27.2-41.2 months). Febrile neutropenia was seen in three patients, grade 3 hand-foot syndrome in 29.2% of patients, and grade 3-4 mucositis in 22.9% of patients. Symptomatic congestive heart failure was not observed, and 16.7% of patients experienced grade 2 asymptomatic left ventricular systolic dysfunction.

CONCLUSION

The combination of PLD-cyclophosphamide-concurrent trastuzumab is a feasible, safe, and effective first-line regimen for HER2-overexpressing MBC.

PIK3CA mutations in breast cancer: A potential predictive marker

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Background: Somatic mutations in phosphoinositide-3-kinase catalytic alpha (PIK3CA) activates Akt, attenuates apoptosis and promotes tumor invasion. The common mutations E545K and H1047R confer resistance to paclitaxel in immortalized breast cancer cell lines. We screened primary breast cancers for PIK3CA mutations in the helical and catalytic domains. Methods: Tumor samples from 61 stage I-III breast cancer patients treated with adjuvant chemo- and/or hormone therapy were examined for PIK3CA mutations E542K, E545K and H1047R by the 5-nuclease assay (TaqMan) using the ABI Prism 7900HT Sequence Detection System. Results: Mutations were found in 17 patients (27.9%): 6 E542K; 5 E545K; 6 H1047R. PIK3CA mutations were not associated with expression of estrogen or progesterone receptors, lymph node metastases, or ERBB2 overexpression. (See table ) Conclusions: PIK3CA mutations occur frequently in breast cancer and could be a novel predictive marker of chemoresistance and an appealing target for therapeutic inhibition, independent of hormone receptors and ERBB2 status.

[Table: see text]

No significant financial relationships to disclose.

Phase I study of weekly CPT-11 (irinotecan)/docetaxel in patients with advanced solid tumors

Based on the synergistic cytotoxicity demonstrated in vitro by topoisomerase I inhibitors followed by docetaxel and the feasibility of giving both drugs on a weekly schedule avoiding overlapping toxicities, we designed a phase I trial of weekly CPT-11 (irinotecan)/docetaxel to determine the dose-limiting toxicities (DLT) and the maximum-tolerated dose (MTD) of this combination. Eighteen patients with advanced solid tumors treated with at least one prior chemotherapy regimen were included in this trial. CPT-11 was administered as a 90-min (intravenous) IV infusion followed immediately by docetaxel as a 30-min IV infusion. Both drugs were given on days 1, 8 and 15 in 4-week cycles. Four escalating dose levels of CPT-11/docetaxel (level I: 60/20 mg/m(2), level II: 60/25 mg/m(2), level III: 70/25 mg/m(2), and level IV: 70/30 mg/m(2)) were studied. Forty-seven cycles were administered (range, 1-5 courses) with a median number of 2.6 cycles per patient. Grade 4 leukopenia was the DLT reached at dose-level IV (CPT-11/docetaxel 70/30 mg/m(2)). Four patients had grade 3 anemia at dose levels III (two patients) and IV (two patients), while grade 3/4 thrombocytopenia was not seen. Grade 3/4 non-hematologic toxicities included grade 3 diarrhea in two patients (dose levels II and IV), grade 3 asthenia in one patient (dose level II) and grade 3 stomatitis in one patient (dose level I). The recommended dose of this weekly schedule is CPT-11 70 mg/m(2) and docetaxel 25 mg/m(2). DLT of this regimen is leukopenia, although toxicity is manageable at the recommended dose level. The activity of this regimen is being evaluated in a phase II study in previously treated patients with advanced non-small cell lung cancer.