Efficacy and Safety of Ribociclib With Letrozole in US Patients Enrolled in the MONALEESA-2 Study

BackgroundIn the Mammary Oncology Assessment of LEE011’s (Ribociclib's) Efficacy and Safety (MONALEESA-2) study, combination treatment with the selective inhibitor of cyclin-dependent kinases 4/6 ribociclib with letrozole significantly improved progression-free survival (PFS) versus letrozole alone in postmenopausal women with hormone receptor-positive HR⁺/HER2^? advanced breast cancer (ABC). Herein we present results from the subset of US patients enrolled in MONALEESA-2.Patients and MethodsPostmenopausal women with HR⁺/HER2^? ABC without previous treatment for advanced disease were randomized (1:1) to ribociclib 600 mg/d (3 weeks on/1 week off) with letrozole 2.5 mg/d (continuous) or placebo with letrozole. The primary end point was locally assessed PFS.ResultsOverall, 213 US patients were enrolled in MONALEESA-2 (ribociclib, n = 100; placebo, n = 113). Baseline characteristics were similar between treatment groups and consistent with the global population. With a median follow-up of 27 months, 38 (38%) and 29 (26%) patients in the ribociclib and placebo groups, respectively, had continued to receive treatment. Median PFS was 27.6 months with ribociclib and 15.0 months with placebo (hazard ratio, 0.53). The most common all-cause adverse events were neutropenia (ribociclib, 72.0% [n = 72]; placebo, 4.6% [n = 5]), nausea (ribociclib, 69.0% [n = 69]; placebo, 44.0% [n = 48]), and fatigue (ribociclib, 60.0% [n = 60]; placebo, 50.5% [n = 55]). Two patients (ribociclib, 2.0%; placebo, 0%) experienced febrile neutropenia.ConclusionIn the US subset of MONALEESA-2, ribociclib with letrozole showed superior efficacy versus letrozole alone. These findings are consistent with the global population and support first-line use of ribociclib with letrozole in patients with HR⁺/HER2^? ABC.     

Clinical considerations of the role of palbociclib in the management of advanced breast cancer patients with and without visceral metastases

BackgroundThis report assesses the efficacy and safety of palbociclib plus endocrine therapy (ET) in women with hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer (ABC) with or without visceral metastases.Patients and methodsPre- and postmenopausal women with disease progression following prior ET (PALOMA-3; N = 521) and postmenopausal women untreated for ABC (PALOMA-2; N = 666) were randomized 2 : 1 to ET (fulvestrant or letrozole, respectively) plus palbociclib or placebo. Progression-free survival (PFS), safety, and patient-reported quality of life (QoL) were evaluated by prior treatment and visceral involvement.ResultsVisceral metastases incidence was higher in patients with prior resistance to ET (58.3%, PALOMA-3) than in patients naive to ET in the ABC setting (48.6%, PALOMA-2). In patients with prior resistance to ET and visceral metastases, median PFS (mPFS) was 9.2 months with palbociclib plus fulvestrant versus 3.4 months with placebo plus fulvestrant [hazard ratio (HR), 0.47; 95% confidence interval (CI), 0.35–0.61], and objective response rate (ORR) was 28.0% versus 6.7%, respectively. In patients with nonvisceral metastases, mPFS was 16.6 versus 7.3 months, HR 0.53; 95% CI 0.36–0.77. In patients with visceral disease and naive to ET in the advanced disease setting, mPFS was 19.3 months with palbociclib plus letrozole versus 12.9 months with placebo plus letrozole (HR 0.63; 95% CI 0.47–0.85); ORR was 55.1% versus 40.0%; in patients with nonvisceral disease, mPFS was not reached with palbociclib plus letrozole versus 16.8 months with placebo plus letrozole (HR 0.50; 95% CI 0.36–0.70). In patients with prior resistance to ET with visceral metastases, palbociclib plus fulvestrant significantly delayed deterioration of QoL versus placebo plus fulvestrant, whereas patient-reported QoL was maintained with palbociclib plus letrozole in patients naive to endocrine-based therapy for ABC.ConclusionsPalbociclib plus ET prolonged mPFS in patients with visceral metastases, increased ORRs, and in patients previously treated for ABC, delayed QoL deterioration, presenting a standard treatment option among patients with visceral metastases amenable to endocrine-based therapy.Clinical trial registrationNCT01942135, NCT01740427     

Palbociclib Plus Fulvestrant in Korean Patients from PALOMA-3 With Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor 2–Negative Advanced Breast Cancer

In the PALOMA-3 trial, the median progression-free survival (PFS) was longer among patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2−) advanced breast cancer (ABC) treated with palbociclib plus fulvestrant than those treated with placebo plus fulvestrant. This subgroup analysis examined the efficacy and safety of palbociclib among Korean patients enrolled in PALOMA-3 (n = 43 [palbociclib group, n = 24; placebo group, n = 19]). In both groups, > 40% of patients were pre/perimenopausal at enrollment. The median PFS was significantly prolonged with palbociclib vs. placebo (12.3 [95% confidence interval (CI), 9.1–not estimable] vs. 5.4 months [95% CI, 1.9–9.2]; hazard ratio, 0.40 [95% CI, 0.19–0.83]; one-sided p = 0.005), and the confirmed objective response was 21.1% and 11.8%, respectively (odds ratio, 2.0 [95% CI, 0.24–24.8]). Neutropenia was the most common adverse event associated with palbociclib. Overall, palbociclib plus fulvestrant was effective and generally safe among Korean patients with HR+/HER2− ABC, regardless of menopausal status.     

The Impact of Real-World Alternative Dosing Strategies of Palbociclib on Progression-Free Survival in Patients with Metastatic Breast Cancer

Background: Palbociclib, a cyclin-dependent kinase 4 and 6 (CDK 4/6) inhibitor, in combination with letrozole or fulvestrant has been demonstrated to prolong the progression-free survival (PFS) in patients with hormone receptor-positive (HR+), human epidermal growth factor 2-negative (HER2-) metastatic breast cancer. In efforts to mitigate neutropenic toxicities, oncologists in real-world practice have prescribed alternative dosing strategies with palbociclib, yet the implication on PFS is unknown. Methods: We conducted a retrospective, observational chart review of all female patients at our clinics with HR+, HER2- metastatic breast cancer receiving palbociclib in combination with either letrozole or fulvestrant with a first dose initiated between June 2016 and December 2018 and followed their disease course until 30 April 2020. Results: The median PFS for all clinic patients receiving palbociclib and letrozole (n = 63) was 40.8 months (95% confidence interval (CI) 25.6–not estimable) and 16.97 months (95% CI 8.57–not estimable) for patients receiving palbociclib and fulvestrant (n = 11). We identified seven alternative dosing strategies prescribed by oncologists, the most prevalent being prescribing palbociclib for three weeks on and two weeks off (n = 8). The Kaplan–Meier curves for PFS in patients receiving letrozole and palbociclib prescribed alternative dosing strategies appear to diverge from monograph dosing early in the treatment. Many patients prescribed palbociclib using alternative dosing strategies continued to be observed even by the 18-month timepoint. The prevalence of grade 4 neutropenia was lower for patients on palbociclib with letrozole, suggesting a possible mitigation of severe neutropenia with alternative dosing strategies. Conclusions: We conclude that alternative dosing strategies used by oncologists such as prescribing palbociclib for three weeks on, two weeks off may achieve comparable disease control while mitigating neutropenic toxicities when compared to standard monograph dosing recommendations, prolonging treatment tolerability and adherence. Further large-scale studies are needed to confirm these results for future clinical adoption.     

Phase II Multicenter Study of Docetaxel and Bevacizumab With or Without Trastuzumab as First-Line Treatment for Patients With Metastatic Breast Cancer

BackgroundAdding bevacizumab to docetaxel or paclitaxel in the first-line improves the progression-free survival (PFS) of metastatic breast cancer (MBC) patients. Docetaxel has been studied with bevacizumab at the maximally tolerated dose of 100 mg/m². We investigated the effects of combining bevacizumab with docetaxel (75 mg/m²) with or without trastuzumab for human epidermal growth factor receptor 2–positive (HER2⁺) and HER2–negative (HER2⁻) patients, respectively.Patients and MethodsWe conducted a phase II study, stratified by HER2 status, of patients with locally advanced breast cancer or MBC who had received no prior chemotherapy for metastatic disease and showed no evidence or history of central nervous system metastases. Stratum 1 (HER2⁻) treatment consisted of bevacizumab (15 mg/kg) followed by docetaxel (75 mg/m²) administered every 3 weeks; stratum 2 (HER2⁺) treatment was the same as that of stratum 1 with the addition of trastuzumab (8 mg/kg loading dose on day 2 of cycle 1, and 6 mg/kg on day 1 of all subsequent cycles).ResultsThe trial accrued 73 patients (stratum 1, 52 patients; stratum 2, 21 patients). The most common grade 3 or 4 adverse event (all strata) was fatigue (stratum 1, 11.5%; stratum 2, 10%). The incidence of grade 3 hypertension was 6% for stratum 1 and 5% for stratum 2. The median PFS was 8.4 months (95% CI, 5.2-10.4 months) in stratum 1; the median PFS in stratum 2 was 13.3 months (95% CI, 11.9-35.4 months). The overall response rate for stratum 1was 58% and for stratum 2 was 81%, and the clinical benefit rates were 67% and 81%, respectively.ConclusionIn first-line treatment of MBC, adding docetaxel (75 mg/m²) to bevacizumab administered every 3 weeks in HER2⁻ patients, and docetaxel plus trastuzumab plus bevacizumab treatment in HER2⁺ patients are feasible and safe, with high response rates and promising PFS compared with those of bevacizumab-naive historic controls.     

Palbociclib as single agent or in combination with the endocrine therapy received before disease progression for estrogen receptor-positive,HER2-negative metastatic breast cancer: TREnd trial

BackgroundThe activity of palbociclib as a single agent in advanced breast cancer has not been extensively studied, with the only available clinical data limited to heavily pretreated patients. Preclinical data suggests palbociclib may partially reverse endocrine resistance, though this hypothesis has not been evaluated in previous clinical studies. This phase II, open-label, multicenter study examined the activity of palbociclib monotherapy, as well as palbociclib given in combination with the same endocrine therapy (ET) that was received prior to disease progression, in postmenopausal women with moderately pretreated, estrogen receptor-positive, HER2 negative advanced breast cancer.Patients and methodsEligible women with advanced disease which had progressed on one or two prior ETs were randomized 1 : 1 to receive either palbociclib alone, or palbociclib in combination with the ET as previously received. Primary end point was clinical benefit rate (CBR); secondary end points included progression-free survival (PFS).ResultsBetween October 2012 and July 2016, a total of 115 patients were randomized. The CBR was 54% [95% confidence interval (CI): 41.5–63.7] for combination therapy, and 60% (95% CI: 47.8–72.9) for monotherapy. Median PFS was 10.8 months (95% CI: 5.6–12.7) for combination therapy, and 6.5 months (95% CI: 5.4–8.5) for monotherapy [hazard ratio (HR) 0.69; 95% CI: 0.4–1.1, exploratory P-value = 0.12]. Exploratory analyses revealed the PFS advantage for combination therapy was seen in the subgroup of patients who received prior ET for >6 months (HR 0.53; 95% CI: 0.3–0.9, exploratory P-value = 0.02), but not in those who received prior ET for ≤6 months.ConclusionPalbociclib has clinical activity as a single agent in women with moderately pretreated, oestrogen receptor-positive, HER2-negative advanced breast cancer. Palbociclib may have potential to reverse endocrine resistance in patients with a history of previous durable response to ET.Clinical trial informationNCT02549430     

Fulvestrant 500 mg Versus Exemestane in Postmenopausal Women With Metastatic Breast Cancer Resistant to Adjuvant Nonsteroidal Aromatase Inhibitors in Clinical Practice: A Multicenter Retrospective Study

BackgroundFulvestrant 500 mg and exemestane are widely used agents in first-line therapy for metastatic breast cancer (MBC) of estrogen receptor (ER)-positive (ER⁺) postmenopausal MBC after failure of adjuvant nonsteroidal aromatase inhibitor (NSAI) treatment. Although fulvestrant 250 mg had similar efficacy compared with exemestane (Evaluation of Faslodex versus Exemestane Clinical Trial study) and fulvestrant 500 mg was superior to fulvestrant 250 mg (Comparison of FASLODEX In Recurrent or Metastatic Breast Cancer study), no direct comparison between fulvestrant 500 mg and exemestane has been conducted. The aim of this study was to compare the efficacy and safety of fulvestrant 500 mg and exemestane in daily practice.Patients and MethodsWe retrospectively evaluated the medical records of all patients with ER⁺ HER2⁻ MBC who received fulvestrant 500 mg or exemestane 25 mg as first-line therapy for MBC from 2015 to 2017 in 4 institutions. A total of 120 patients were available for analysis. Both agents accounted for 50% (60) patients.ResultsThe median progression-free survival (PFS) of the fulvestrant group was significantly longer than that in the exemestane group (6.2 months [95% confidence interval (CI), 5.0-7.4] versus 4.8 months [95% CI, 3.0-6.7], P = .024). In subgroup analysis, for patients with visceral metastasis or primary endocrine resistance, no significant difference considering PFS was observed in the 2 groups (P = .563 and .769). No significant difference of Grade 3/4 adverse events was observed in the 2 groups (3 patients, 5% versus 2 patients, 3.3%; P = .648).ConclusionFulvestrant 500 mg showed better efficacy than exemestane in first-line therapy for MBC of ER⁺ postmenopausal women after failure of adjuvant NSAI treatment. For patients with visceral metastasis or primary endocrine resistance, both treatments showed poor outcomes, indicating a need for further alternatives (targeted therapy or chemotherapy). Both agents were well tolerated in terms of toxicities.     

Clinical Characteristics and Outcomes of Single Versus Double Hormone Receptor–Positive Breast Cancer in 2 Large Databases

PurposeTo identify biologic and outcome differences between double hormone receptor (HR)-positive (dHR⁺, estrogen receptor (ER)⁺/progesterone receptor [PgR⁺]) and single HR-positive (sHR⁺, either ER⁺/PgR⁻ or ER⁻/PgR⁺) breast cancer; and to explore whether hormone therapy (HT) response in HER2-negative breast cancer correlates with HR status.Patients and MethodsThis retrospective study was conducted by using 2 large breast cancer databases: the Surveillance, Epidemiology, and End Results (SEER) database and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) clinical data set. Cox regression analysis was used to estimate overall survival (OS) and breast cancer–specific survival (BCSS) among sHR⁺ and dHR⁺ patients.ResultsIn the SEER database, dHR⁺ patients had significantly longer OS and BCSS than ER⁺/PgR⁻ patients in short-term follow-up (OS: hazard ratio = 0.620; 95% confidence interval [CI], 0.590, 0.652; P < .001; BCSS: hazard ratio = 0.493; 95% CI, 0.462, 0.526; P < .001). Meanwhile, ER⁻/PgR⁺ patients had younger age, larger tumor size, and higher disease grade than dHR⁺ and ER⁺/PgR⁻ patients. In patients who received HT, dHR⁺ patients had a more favorable OS than ER⁺/PgR⁻ patients (hazard ratio = 0.789; 95% CI, 0.635, 0.982; P = .034), and ER⁻/PgR⁺ patients had a worse OS than ER⁺/PgR⁻ patients at 10 years’ follow-up (hazard ratio = 7.991; 95% CI, 1.053, 60.644; P = .044). However, these groups had similar outcomes over longer periods.ConclusionIn HER2-negative breast cancer, sHR⁺ patients are associated with relatively worse characteristics and worse short-term outcomes than dHR⁺ patients. Additionally, the outcome of patients receiving HT may differ according to the HR status. However, further studies are needed to confirm these conclusions.     

Updated results from MONALEESA-2, a phase III trial of first-line ribociclib plus letrozole versus placebo plus letrozole in hormone receptor-positive,HER2-negative advanced breast cancer

BackgroundThe phase III MONALEESA-2 study demonstrated significantly prolonged progression-free survival (PFS) and a manageable toxicity profile for first-line ribociclib plus letrozole versus placebo plus letrozole in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–) advanced breast cancer. Here, we report updated efficacy and safety data, together with exploratory biomarker analyses, from the MONALEESA-2 study.Patients and methodsA total of 668 postmenopausal women with HR+, HER2– recurrent/metastatic breast cancer were randomized (1 : 1; stratified by presence/absence of liver and/or lung metastases) to ribociclib (600 mg/day; 3-weeks-on/1-week-off; 28-day treatment cycles) plus letrozole (2.5 mg/day; continuous) or placebo plus letrozole. The primary end point was locally assessed PFS. The key secondary end point was overall survival (OS). Other secondary end points included overall response rate (ORR) and safety. Biomarker analysis was an exploratory end point.ResultsAt the time of the second interim analysis, the median duration of follow-up was 26.4 months. Median PFS was 25.3 months [95% confidence interval (CI) 23.0–30.3] for ribociclib plus letrozole and 16.0 months (95% CI 13.4–18.2) for placebo plus letrozole (hazard ratio 0.568; 95% CI 0.457–0.704; log-rank P = 9.63 × 10⁻⁸). Ribociclib treatment benefit was maintained irrespective of PIK3CA or TP53 mutation status, total Rb, Ki67, or p16 protein expression, and CDKN2A, CCND1, or ESR1 mRNA levels. Ribociclib benefit was more pronounced in patients with wild-type versus altered receptor tyrosine kinase genes. OS data remain immature, with 116 deaths observed; 50 in the ribociclib arm and 66 in the placebo arm (hazard ratio 0.746; 95% CI 0.517–1.078). The ORR was 42.5% versus 28.7% for all patients treated with ribociclib plus letrozole versus placebo plus letrozole, respectively, and 54.5% versus 38.8%, respectively, for patients with measurable disease. Safety results, after a further 11.1 months of follow-up, were comparable with those reported at the first analysis, with no new or unexpected toxicities observed, and no evidence of cumulative toxicity.ConclusionsThe improved efficacy outcomes and manageable tolerability observed with first-line ribociclib plus letrozole are maintained with longer follow-up, relative to letrozole monotherapy.Clinical trials numberNCT01958021     

Lapatinib plus Letrozole as First‐Line Therapy for HER‐2+ Hormone Receptor–Positive Metastatic Breast Cancer

Objective.

To evaluate the efficacy and tolerability of letrozole plus lapatinib versus letrozole plus placebo in women with hormone receptor (HR)⁺ human epidermal growth factor receptor (HER)-2⁺ tumors receiving first-line therapy for metastatic breast cancer (MBC).

Patients and Methods.

Postmenopausal women (n = 1,286) with HR⁺ MBC were randomized to daily oral treatment with letrozole (2.5 mg) plus lapatinib (1,500 mg) versus letrozole (2.5 mg) plus placebo. Of the 1,286 patients enrolled in the phase III study, 219 had HER-2⁺ tumors. The primary endpoint was progression-free survival (PFS) in HER-2⁺ patients.

Results.

Results in the HR⁺ HER-2⁺ population (n = 219) are presented. The addition of lapatinib to letrozole resulted in a significantly lower risk for disease progression than with letrozole alone (hazard ratio, 0.71; 95% confidence interval, 0.53–0.96). The PFS time was 8.2 months, versus 3.0 months. The objective response rate (ORR) (28% versus 15%) and clinical benefit rate (CBR) (48% versus 29%) were also significantly greater in lapatinib-treated women. The most common adverse events in the lapatinib group were diarrhea (68%) and rash (46%), primarily grade 1 and 2.

Conclusions.

The addition of lapatinib to letrozole is well tolerated and leads to a significantly greater PFS time, ORR, and CBR than with letrozole alone in women with MBC who coexpress HR and HER-2.     

Clinical Significance of HER2-Positive and Triple-Negative Status in Small (≤ 1 cm) Node-Negative Breast Cancer

BackgroundData regarding the clinical significance of HER2⁺ and TN status in patients with small node-negative tumors are limited and conflicting. It remains unclear who, among those with small lesions, might benefit from more aggressive adjuvant therapy.Patients and MethodsWe identified all node-negative breast cancer patients with tumor size ≤ 1 cm diagnosed between January 1, 1995 and December 31, 2008 using our institutional breast service database. Patients were classified according to their receptor status into 3 groups: (1) hormone receptor (HR)-positive (estrogen receptor [ER]- or progesterone receptor [PR]-positive, HER2⁻); (2) HER2⁺ (immunohistochemistry 3⁺ or fluorescence in situ hybridization amplification ≥ 2); and (3) TN (ER⁻, PR⁻, and HER2⁻). RFS was calculated using Kaplan-Meier methods.ResultsAmong 656 patients with tumors ≤ 1 cm, 494 (75%) of the patients were HR⁺, 107 (16%) were HER2⁺, and 55 (9%) were TN. Median age was 59 years (range, 27-92 years). Median follow-up was 3.5 years. The 5-year RFS rates were 98.2%, 97.1%, and 83.5% in patients with HR⁺, HER2⁺, and TN tumors, respectively (P < .001). In multivariate analysis, TN status was associated with worse RFS (hazard ratio, 6.70; 95% confidence interval [CI], 3.02-14.86), and HER2⁺ was not (hazard ratio, 1.64; 95% CI, 0.73-3.69).ConclusionTN, but not HER2⁺ status, was associated with worse RFS in patients with T1abN0 tumors, and adjuvant chemotherapy might be considered in patients with TN breast cancer.     

Real-world Outcomes of Cyclin-dependent Kinase Inhibitors Continued Beyond First Disease Progression in Hormone Receptor-positive Metastatic Breast Cancer

BackgroundCDK4/6 inhibitors (CDK4/6i), in combination with aromatase inhibitors, are United States Food and Drug Administration-approved for the treatment of hormone receptor-positive (HR⁺)/human epidermal growth factor receptor 2-negative (HER2^?) metastatic breast cancer (MBC). The effectiveness of continuing them beyond first disease progression (PD) is currently unknown. This retrospective study evaluated the impact of the continuation of CDK4/6i beyond first PD in HR⁺/HER2^? MBC using real-world experience.Patients and MethodsA single-institution retrospective review of patients with HR⁺ MBC who received CDK4/6is from 2015 to 2018 and where CDK4/6is were continued beyond first PD. The primary outcome was progression-free survival (PFS) after initial PD on CDK4/6i therapy.ResultsThirty women with HR⁺/HER2^? MBC met eligibility criteria. Patients were identified from a prospective database of patients at the Cleveland Clinic Foundation who were prescribed CDK4/6is. The median age and follow-up duration were 47.5 years and 27 months, respectively. Most patients received palbociclib (PA)/letrozole as initial therapy (67%), followed by PA/fulvestrant (23%), and PA/other aromatase inhibitor (20%), and abemaciclib with either fulvestrant or letrozole (6%). As of January 31, 2019, 25 (83.3%) patients were still alive, and 19 (63%) patients had progressed. The estimated median PFS for continued CDK4/6i use beyond the first PD was 11.8 months (95% confidence interval, 5.34-13.13 months).ConclusionsAmong a small cohort of patients with HR⁺ MBC in a non-clinical trial setting, continuation of CDK4/6i-endocrine treatment post initial PD was associated with a median PFS of about 12 months. Formal randomized clinical trials evaluating the continuation of CDK4/6is beyond the first PD are currently ongoing and will provide more answers to this important clinical question.     

Does Tumor Size Predict Response to Neoadjuvant Chemotherapy in the Modern Era of Biologically Driven Treatment? A Nationwide Study of US Breast Cancer Patients

BackgroundTumor size has historically been used to stage breast cancer and guide treatment recommendations. The importance of tumor biology in long-term outcomes is increasingly being acknowledged. No large studies have examined the relative roles of tumor size and receptor status on response to neoadjuvant chemotherapy (NAC) in breast cancer.Patients and MethodsThe National Cancer Database was queried for women who underwent NAC and surgery for unilateral clinical stage I to III (cT1-3) invasive breast cancer from 2010 to 2013. Multivariable logistic regression models were used to assess the relation between receptor status, tumor size, and pathologic complete response (pCR) while controlling for other biologic, sociodemographic, diagnosis, and treatment factors.ResultsWe included 38,864 women in this study, most presented with cT2 disease (55%). Patients predominantly had estrogen receptor (ER)/progesterone receptor (PR)-positive (ER/PR⁺) HER2⁻ (45%) or ER/PR⁻ HER2⁻ (28%) disease. Nineteen percent (7432 patients) had a pCR. cT3 (odds ratio [OR], 0.64; 95% confidence interval [CI], 0.59-0.70) but not cT2 cancers (OR, 0.95; 95% CI, 0.89-1.02) were associated with lower pCR rates compared with cT1 disease. HER2⁺ (ER/PR⁺ HER2⁺: OR, 2.94; 95% CI, 2.72-3.18; ER/PR⁻ HER2⁺: OR, 6.45; 95% CI, 5.92-7.02) and ER/PR⁻ HER2⁻ cancers (OR, 3.94; 95% CI, 3.68-4.22) were more likely to experience pCR than those with ER/PR⁺ HER2⁻ cancers. Receptor status was more strongly associated with pCR than tumor size.ConclusionTumor size is independently associated with pCR after NAC after controlling for receptor status, although the effect of receptor status is stronger. These data reinforce the importance of receptor status as well as tumor size, each of which might act as surrogates for tumor biology, in setting expectations for outcomes in patients who undergo NAC.     

Everolimus Plus Letrozole for Treatment of Patients With HR+, HER2– Advanced Breast Cancer Progressing on Endocrine Therapy: An Open-label,Phase II Trial

Purpose

In the Breast cancer trials of OraL EveROlimus-2 (BOLERO-2) trial, everolimus plus exemestane improved progression-free survival (PFS) in patients with hormone receptor-positive (HR⁺), human epidermal growth factor receptor 2-negative (HER2^?) advanced breast cancer (ABC) recurring or progressing on/after prior endocrine therapy (ET), suggesting that dual blockade using targeted therapy and ET was an effective treatment option. Here, we investigated the clinical benefit of combining everolimus with different endocrine partner, letrozole, in a similar patient population.

Associations of Hormone-Related Factors With Breast Cancer Risk According to Hormone Receptor Status Among White and African American Women

BackgroundCauses of racial disparities in breast cancer incidence and mortality between white and African American women remain unclear. This study evaluated associations of menstrual and reproductive factors with breast cancer risk by race and cancer subtypes.Patients and MethodsIncluded in the study were 1866 breast cancer cases and 2306 controls recruited in the Nashville Breast Health Study, a population-based case-control study. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).ResultsAfrican American women were more likely to have estrogen receptor-negative (ER⁻), progesterone receptor-negative (PR⁻), and triple-negative (ER⁻PR⁻HER2⁻) breast cancer than white women. Age at menarche (≥ 14 years) and multiparity (≥ 3 live births) were inversely associated with ER⁺ tumors only, whereas late age at first live birth (> 30 years) and nulliparity were associated with elevated risk; such associations were predominantly seen in white women (OR = 0.70, 95% CI = 0.55-0.88; OR = 0.72, 95% CI = 0.56-0.92; OR = 1.42, 95% CI = 1.13-1.79; OR = 1.32, 95% CI = 1.06-1.63, respectively). Age at menopause between 47 and 51 years was associated with elevated risk of ER⁻ tumors in both white and African American women. Among women who had natural menopause, positive association between ever-use of hormone replacement therapy and breast cancer risk was seen in white women only (OR = 1.39, 95% CI = 1.03-1.87).ConclusionThis study suggests that certain hormone-related factors are differentially associated with risk of breast cancer subtypes, and these associations also differ by race.     

T-DM1 Efficacy in Patients With HER2-positive Metastatic Breast Cancer Progressing After a Taxane Plus Pertuzumab and Trastuzumab: An Italian Multicenter Observational Study

BackgroundT-DM1 improves progression-free survival (PFS) and overall survival (OS) in patients with metastatic human epidermal growth factor receptor 2-positive (HER2⁺) breast cancer progressing on prior trastuzumab plus a taxane. A paucity of data is available on T-DM1 efficacy after dual anti-HER2 blockade with pertuzumab and trastuzumab plus a taxane, which represents the current first-line standard of care. The present study is a retrospective/prospective evaluation of the efficacy and activity of second-line T-DM1 after front-line pertuzumab-based therapy.Patients and MethodsEligible patients were identified within the Gruppo Italiano Mammella (GIM) 14/BIOMETA study, a retrospective/prospective multicenter study on treatment patterns and outcomes of patients with metastatic breast cancer (ClinicalTrials.gov Identifier: NCT02284581). We searched for patients who received second-line T-DM1 after taxane plus trastuzumab and pertuzumab between November 15, 2013 and May 31, 2018. We calculated median PFS, median time to treatment failure (TTF), prolonged duration of therapy (PDT), objective response rate (ORR), and 1-year OS.ResultsOf 445 patients with HER2⁺ metastatic breast cancer, 77 were eligible for the analysis. At a median follow-up of 7 months, median PFS was 6.3 months (95% confidence intervals [CI], 4.8-7.7 months), and median TTF was 6.2 months (95% CI, 4-8.6 months). More than one-third of patients (37.6%; n = 29) experienced PDT with an ORR of 27.1%. At data cutoff, the median OS was not reached, and the 1-year OS was 82%.ConclusionsOur results show meaningful activity of T-DM1 after front-line pertuzumab plus trastuzumab and a taxane, with about 27% of patients having an objective response and 40% of patients achieving durable disease control.     

Progression-free survival as surrogate end point for overall survival in clinical trials of HER2-targeted agents in HER2-positive metastatic breast cancer

BackgroundThe gold standard end point in randomized clinical trials in metastatic breast cancer (MBC) is overall survival (OS). Although therapeutics have been approved based on progression-free survival (PFS), its use as a primary end point is controversial. We aimed to assess to what extent PFS may be used as a surrogate for OS in randomized trials of anti-HER2 agents in HER2+ MBC.MethodsEligible trials accrued HER2+ MBC patients in 1992–2008. A correlation approach was used: at the individual level, to estimate the association between investigator-assessed PFS and OS using a bivariate model and at the trial level, to estimate the association between treatment effects on PFS and OS. Correlation values close to 1.0 would indicate strong surrogacy.ResultsWe identified 2545 eligible patients in 13 randomized trials testing trastuzumab or lapatinib. We collected individual patient data from 1963 patients and retained 1839 patients from 9 trials for analysis (7 first-line trials). During follow-up, 1072 deaths and 1462 progression or deaths occurred. The median survival time was 22 months [95% confidence interval (CI) 21–23 months] and the median PFS was 5.7 months (95% CI 5.5–6.1 months). At the individual level, the Spearman correlation was equal to ρ = 0.67 (95% CI 0.66–0.67) corresponding to a squared correlation value of 0.45. At the trial level, the squared correlation between treatment effects (log hazard ratios) on PFS and OS was provided by R² = 0.51 (95% CI 0.22–0.81).ConclusionsIn trials of HER2-targeted agents in HER2+ MBC, PFS moderately correlates with OS at the individual level and treatment effects on PFS correlate moderately with those on overall mortality, providing only modest support for considering PFS as a surrogate. PFS does not completely substitute for OS in this setting.     

Progression-Free Survival for Real-World Use of Palbociclib in Hormone Receptor-Positive Metastatic Breast Cancer

BackgroundAdditional use of cyclin-dependent kinase 4/6 inhibitors with endocrine therapy improves progression-free survival (PFS) in advanced hormone receptor (HR)-positive HER2-negative breast cancer. However, neutropenia is a common reason for dose reductions, leading to concerns about palbociclib efficacy at lower doses. A safety analysis confirmed no PFS differences between palbociclib doses in the second-line setting, but to our knowledge, this has not been evaluated for first-line treatment.Patients and MethodsIn this retrospective, single-center cohort study we evaluated real-world use of first-line palbociclib with aromatase inhibitor (AI) treatment in HR-positive, HER2-negative metastatic breast cancer patients who received treatment between February 2015 and July 2017. The primary objective was to determine PFS of treatment with palbociclib and an AI in a real-world first-line setting. Secondary objectives included determining the PFS for patients treated with palbociclib on the basis of final doses, time to first dose reduction, time to treatment failure (TTF), and safety.ResultsSeventy patients were included in the final analysis. Median PFS was 26.4 months. No significant differences in PFS were observed on the basis of final doses of palbociclib (P = .77). Time to first dose reduction was 2.3 months. Median TTF was 26.1 months. Dose delays, reductions, and Grade 3/4 neutropenia were common (63%, n = 44; 57%, n = 40; and 62%, n = 43, respectively).ConclusionReal-world first-line palbociclib treatment produced outcomes similar to those in PALOMA-2 (Palbociclib and Letrozole in Advanced Breast Cancer) (median PFS 26.4 months vs. 24.8 months) despite more dose reductions (57%, n = 40 vs. 36%, n = 160) and shorter time to first dose reduction (2.3 vs. 3.0 months). No significant differences in PFS were observed for the varying palbociclib doses. Palbociclib dose reductions might not significantly affect PFS in the first-line setting.     

Efficacy and Safety of Anti–PD-1 Immunotherapy in Patients With Advanced NSCLC With BRAF,HER2, or MET Mutations or RET Translocation: GFPC 01-2018

IntroductionImmune-checkpoint inhibitor (ICI) efficacy in patients with NSCLC harboring molecular alterations remains poorly elucidated. This study was undertaken to determine ICI efficacy against BRAF-, HER2-, MET-, and RET-NSCLC in a real-world setting.MethodsIn this retrospective, multicenter study in ICI-treated BRAF-, HER2-, MET- or RET-NSCLCs, we analyzed clinical characteristics and outcomes: ICI-treatment duration, progression-free survival (PFS), objective response rate, duration of response, and overall survival (OS).ResultsThere were 107 patients with NSCLC (mean age, 65.5 y) included from 21 centers: 37% were never-smokers, 54% were men, and 93% had adenocarcinoma. Among them, 44 had BRAF mutation (V600: 26), 23 had HER2 mutation, 30 had MET mutation, and nine had RET translocation. Programmed cell death ligand 1 (PD-L1) status was known for 70 patients and was greater than or equal to 1% in 34 patients. Before ICI, patients had received a median of one treatment line. Median duration of response, PFS, and OS were 15.4 (95% confidence interval [CI]: 12.6–not reached [NR]) months, 4.7 (95% CI: 2.3–7.4) months, and 16.2 (95% CI: 12.0–24.0) months, respectively, for the entire cohort. The response rates for BRAF-V600, BRAF–non-V600, HER2, MET, and RET-altered NSCLC were 26%, 35%, 27%, 36%, and 38%, respectively. For patients who were PD-L1 negative and those who were PD-L1 positive, PFS was 3.0 (95% CI: 1.2–NR) and 4.3 (95% CI: 2.1–8.5) months, respectively, and OS was 11.7 (95% CI: 4.1–NR) and 35.8 (95% CI: 9.0–35.2) months, respectively. Toxicities were reported in 28 patients (26%), including 11 patients (10%) with a grade greater than or equal to three.ConclusionsIn this real-world setting, ICI efficacy against patients with BRAF-, HER2-, MET-, or RET-NSCLC seemed close to that observed in unselected patients with NSCLC. Large prospective studies on these subsets of patients are needed.     

nextMONARCH: Abemaciclib Monotherapy or Combined With Tamoxifen for Metastatic Breast Cancer

BackgroundAbemaciclib is a selective cyclin-dependent kinase 4 and 6 inhibitor administered continuously for hormone receptor-positive (HR⁺), human epidermal growth factor receptor 2-negative (HER2^?) advanced breast cancer. Abemaciclib is associated with dose-dependent early-onset diarrhea. nextMONARCH evaluated abemaciclib monotherapy (with or without prophylactic loperamide) and combined with tamoxifen for endocrine refractory metastatic breast cancer (MBC) after chemotherapy.Patients and MethodsnextMONARCH is an open-label, controlled, randomized, phase II study of women with endocrine-refractory HR⁺, HER2^? MBC previously treated with chemotherapy. Patients received abemaciclib 150 mg plus tamoxifen 20 mg (A+T), abemaciclib 150 mg every 12 hours (A-150), or abemaciclib 200 mg plus prophylactic loperamide (A-200). The primary objective was progression-free survival (PFS). PFS analyses tested superiority of A+T to A-200 and informal noninferiority of A-150 to A-200. The secondary objectives included the objective response rate (ORR), safety, and pharmacokinetics.ResultsThe median PFS was 9.1 months for A+T versus 7.4 months for A-200 (hazard ratio, 0.815; 95% confidence interval, 0.556-1.193; P = .293). The A-200 PFS was comparable to that with A-150 at 6.5 months (hazard ratio, 1.045; 95% confidence interval, 0.711-1.535; P = .811). The ORR was 34.6%, 24.1%, and 32.5% for A+T, A-150, and A-200, respectively. No new safety signals were identified. The incidence and severity of diarrhea (62.3%; grade 3, 7.8%) with A-200 was similar to that with A-150 (67.1%; grade 3, 3.8%). The pharmacokinetics were comparable to previous observations.ConclusionsThe addition of tamoxifen to abemaciclib did not significantly improve PFS or ORR compared with abemaciclib monotherapy but confirmed the single-agent activity of abemaciclib in heavily pretreated HR⁺, HER2^? MBC. Dose reductions and antidiarrheal medication generally managed diarrhea while maintaining efficacy.