Lasofoxifene versus fulvestrant for ER+/HER2- metastatic breast cancer with an ESR1 mutation: results from the randomized, phase II ELAINE 1 trial.

BACKGROUND: Acquired estrogen receptor alpha (ER/ESR1) mutations commonly cause endocrine resistance in ER+ metastatic breast cancer (mBC). Lasofoxifene, a novel selective ER modulator, stabilizes an antagonist conformation of wild-type and ESR1-mutated ER-ligand binding domains, and has antitumor activity in ESR1-mutated xenografts. PATIENTS AND METHODS: In this open-label, randomized, phase II, multicenter, ELAINE 1 study (NCT03781063), we randomized women with ESR1-mutated, ER+/human epidermal growth factor receptor 2 negative (HER2-) mBC that had progressed on an aromatase inhibitor (AI) plus a cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) to oral lasofoxifene 5 mg daily or IM fulvestrant 500 mg (days 1, 15, and 29, and then every 4 weeks) until disease progression/toxicity. The primary endpoint was progression-free survival (PFS); secondary endpoints were safety/tolerability. RESULTS: A total of 103 patients received lasofoxifene (n = 52) or fulvestrant (n = 51). The most current efficacy analysis showed that lasofoxifene did not significantly prolong median PFS compared with fulvestrant: 24.2 weeks (∼5.6 months) versus 16.2 weeks (∼3.7 months; P = 0.138); hazard ratio 0.699 (95% confidence interval 0.434-1.125). However, PFS and other clinical endpoints numerically favored lasofoxifene: clinical benefit rate (36.5% versus 21.6%; P = 0.117), objective response rate [13.2% (including a complete response in one lasofoxifene-treated patient) versus 2.9%; P = 0.124], and 6-month (53.4% versus 37.9%) and 12-month (30.7% versus 14.1%) PFS rates. Most common treatment-emergent adverse events with lasofoxifene were nausea, fatigue, arthralgia, and hot flushes. One death occurred in the fulvestrant arm. Circulating tumor DNA ESR1 mutant allele fraction (MAF) decreased from baseline to week 8 in 82.9% of evaluable lasofoxifene-treated versus 61.5% of fulvestrant-treated patients. CONCLUSIONS: Lasofoxifene demonstrated encouraging antitumor activity versus fulvestrant and was well tolerated in patients with ESR1-mutated, endocrine-resistant mBC following progression on AI plus CDK4/6i. Consistent with target engagement, lasofoxifene reduced ESR1 MAF, and to a greater extent than fulvestrant. Lasofoxifene may be a promising targeted treatment for patients with ESR1-mutated mBC and warrants further investigation.

High-dimensional immune cell profiling of cerebrospinal fluid from patients with metastatic breast cancer and leptomeningeal disease.

Leptomeningeal disease (LMD) is a devastating complication of metastatic breast cancer (MBC). In this non-therapeutic study, we enrolled 12 patients with MBC and known or suspected LMD who were undergoing a lumbar puncture as part of clinical care and collected extra cerebrospinal fluid (CSF) and a paired blood sample from each patient at a single time point. Of the 12 patients, 7 patients are confirmed to have LMD based on positive cytology and/or convincing MRI imaging (LMDpos), and 5 patients are deemed not to have LMD based on similar criteria (LMDneg). Using high-dimensional, multiplexed flow cytometry, we profile and compare the CSF and peripheral blood mononuclear cell (PBMCs) immune populations between patients with LMD and those without. Patients with LMD observe a lower overall frequency of CD45+ cells (29.51% vs. 51.12%, p < 0.05), lower frequencies of CD8+ T cells (12.03% vs. 30.40%, p < 0.01), and higher frequency of Tregs than patients without LMD. Interestingly, the frequency of partially exhausted CD8+ T cells (CD38hiTIM3lo) is ~6.5-fold higher among patients with LMD vs. those without (2.99% vs. 0.44%, p < 0.05). Taken together, these data suggest that patients with LMD may have lower overall immune infiltrates than patients without LMD, suggesting a more permissive CSF immune microenvironment but a higher frequency of partially exhausted CD8+ T cells, which may offer an important therapeutic target.

Optimizing treatment management of trastuzumab deruxtecan in clinical practice of breast cancer.

INTRODUCTION: The antibody-drug conjugate trastuzumab deruxtecan (T-DXd) targets human epidermal growth factor receptor 2 (HER2) and has been evaluated in patients with HER2-positive unresectable/metastatic breast cancer in the phase II DESTINY-Breast01 trial (NCT03248492; DS8201-A-U201) and the randomized phase III DESTINY-Breast03 trial (NCT03529110; DS8201-A-U302). Approximately 20 additional studies are ongoing in breast cancer, including HER2-low breast cancer, and other solid tumor types within the DESTINY trial program. T-DXd has demonstrated a generally manageable safety profile, with low-grade hematologic and gastrointestinal adverse events (AEs) among the most common; interstitial lung disease (ILD)/pneumonitis has been observed in patients receiving T-DXd and can be severe. This review discusses the management of common AEs and AEs of special interest in patients with HER2-positive unresectable/metastatic breast cancer, including nausea and vomiting, neutropenia, infusion-related reactions, alopecia, fatigue, ILD/pneumonitis, and left ventricular dysfunction. METHODS: Expert opinions, institutional protocols, and strategies to help optimize AE management and maximize the potential benefits of T-DXd in patients with breast cancer from five oncologists treating patients with T-DXd in North America and Europe are discussed. RESULTS: Prophylaxis for nausea and vomiting and proactive management of ILD/pneumonitis are especially important in treating patients with T-DXd. Management strategies for other T-DXd-related AEs of interest (e.g. neutropenia, infusion-related reactions, alopecia, fatigue, and left ventricular dysfunction) are also discussed. CONCLUSIONS: This review provides context for understanding the usage, monitoring, and management practices of other health care providers and institutions with experience using T-DXd to help with safe and effective management of T-DXd-related AEs, particularly since the duration of T-DXd treatment may be quite long. Proper management of T-DXd-related AEs will allow optimal exposure and benefit from T-DXd and will help avoid premature discontinuation or improper dose reductions.

Treatment Efficacy Score-continuous residual cancer burden-based metric to compare neoadjuvant chemotherapy efficacy between randomized trial arms in breast cancer trials.

BACKGROUND: Difference in pathologic complete response (pCR) rate after neoadjuvant chemotherapy does not capture the impact of treatment on downstaging of residual cancer in the experimental arm. We developed a method to compare the entire distribution of residual cancer burden (RCB) values between clinical trial arms to better quantify the differences in cytotoxic efficacy of treatments. PATIENTS AND METHODS: The Treatment Efficacy Score (TES) reflects the area between the weighted cumulative distribution functions of RCB values from two trial arms. TES is based on a modified Kolmogorov-Smirnov test with added weight function to capture the importance of high RCB values and uses the area under the difference between two distribution functions as a statistical metric. The higher the TES the greater the shift to lower RCB values in the experimental arm. We developed TES from the durvalumab + olaparib arm (n = 72) and corresponding controls (n = 282) of the I-SPY2 trial. The 11 other experimental arms and control cohorts (n = 947) were used as validation sets to assess the performance of TES. We compared TES to Kolmogorov-Smirnov, Mann-Whitney, and Fisher's exact tests to identify trial arms with higher cytotoxic efficacy and assessed associations with trial arm level survival differences. Significance was assessed with a permutation test. RESULTS: In the validation set, TES identified arms with a higher pCR rate but was more accurate to identify regimens as less effective if treatment did not reduce the frequency of high RCB values, even if the pCR rate improved. The correlation between TES and survival was higher than the correlation between the pCR rate difference and survival. CONCLUSIONS: TES quantifies the difference between the entire distribution of pathologic responses observed in trial arms and could serve as a better early surrogate to predict trial arm level survival differences than pCR rate difference alone.

Adjuvant abemaciclib combined with endocrine therapy for high-risk early breast cancer: safety and patient-reported outcomes from the monarchE study.

BACKGROUND: In monarchE, abemaciclib plus endocrine therapy (ET) as adjuvant treatment of hormone receptor-positive, human epidermal growth factor 2-negative, high-risk, early breast cancer (EBC) demonstrated a clinically meaningful improvement in invasive disease-free survival versus ET alone. Detailed safety analyses conducted at a median follow-up of 27 months and key patient-reported outcomes (PROs) are presented. PATIENTS AND METHODS: The safety population included all patients who received at least one dose of study treatment (n = 5591). Safety analyses included incidence, management, and outcomes of common and clinically relevant adverse events (AEs). Patient-reported health-related quality of life, ET symptoms, fatigue, and side-effect burden were assessed. RESULTS: The addition of abemaciclib to ET resulted in higher incidence of grade ≥3 AEs (49.7% versus 16.3% with ET alone), predominantly laboratory cytopenias [e.g. neutropenia (19.6%)] without clinical complications. Abemaciclib-treated patients experienced more serious AEs (15.2% versus 8.8%). Discontinuation of abemaciclib and/or ET due to AEs occurred in 18.5% of patients, mainly due to grade 1/2 AEs (66.8%). AEs were managed with comedications (e.g. antidiarrheals), abemaciclib dose holds (61.7%), and/or dose reductions (43.4%). Diarrhea was generally low grade (grade 1/2: 76%); grade 2/3 events were highest in the first month (20.5%), most were short-lived (≤7 days) and did not recur. Venous thromboembolic events (VTEs) were higher with abemaciclib + ET (2.5%) versus ET (0.6%); in the abemaciclib arm, increased VTE risk was observed with tamoxifen versus aromatase inhibitors (4.3% versus 1.8%). PROs were similar between arms, including being 'bothered by side-effects of treatment', except for diarrhea. At ≥3 months, most patients reporting diarrhea reported 'a little bit' or 'somewhat'. CONCLUSIONS: In patients with high-risk EBC, adjuvant abemaciclib + ET has an acceptable safety profile and tolerability is supported by PRO findings. Most AEs were reversible and manageable with comedications and/or dose modifications, consistent with the known abemaciclib toxicity profile.

Immunotherapy toxicity: identification and management.

The widespread adoption of immunotherapy has revolutionized the treatment of various cancer types, including metastatic triple-negative breast cancer (TNBC), which has long been associated with poor prognostic outcomes. In particular, immune checkpoint inhibitors (ICIs) that target and inhibit programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1), have shown promising results in the treatment of patients with metastatic TNBC. However, while manipulating the immune system to induce antitumor response, ICIs can also lead to a unique set of immune-related adverse events (IRAEs), which differ from standard chemotherapy toxicities due to their immune-based origin. These toxicities require highly specific management, including guidance from multidisciplinary specialists. The primary treatment strategy against IRAEs is systemic corticosteroid use, but additional treatment approaches may also involve supportive care, additional immunosuppression, and concurrent treatment delay or discontinuation. Given the rising prevalence of ICI therapy, it is essential to educate clinicians on the presentation and management of these potentially life-threatening events so that they are identified early and treated appropriately. Using data from recent clinical trials, this review will focus on known IRAEs, particularly those seen in patients with breast cancer, and will summarize their prevalence, severity, and outcomes. We will discuss optimal strategies for early recognition and management, as well as approaches toward cautious retreatment following resolution of IRAEs.

Long-term efficacy and safety of addition of carboplatin with or without veliparib to standard neoadjuvant chemotherapy in triple-negative breast cancer: 4-year follow-up data from BrighTNess, a randomized phase III trial.

BACKGROUND: Primary analyses of the phase III BrighTNess trial showed addition of carboplatin with/without veliparib to neoadjuvant chemotherapy significantly improved pathological complete response (pCR) rates with manageable acute toxicity in patients with triple-negative breast cancer (TNBC). Here, we report 4.5-year follow-up data from the trial. PATIENTS AND METHODS: Women with untreated stage II-III TNBC were randomized (2 : 1 : 1) to paclitaxel (weekly for 12 doses) plus: (i) carboplatin (every 3 weeks for four cycles) plus veliparib (twice daily); (ii) carboplatin plus veliparib placebo; or (iii) carboplatin placebo plus veliparib placebo. All patients then received doxorubicin and cyclophosphamide every 2-3 weeks for four cycles. The primary endpoint was pCR. Secondary endpoints included event-free survival (EFS), overall survival (OS), and safety. Since the co-primary endpoint of increased pCR with carboplatin plus veliparib with paclitaxel versus carboplatin with paclitaxel was not met, secondary analyses are descriptive. RESULTS: Of 634 patients, 316 were randomized to carboplatin plus veliparib with paclitaxel, 160 to carboplatin with paclitaxel, and 158 to paclitaxel. With median follow-up of 4.5 years, the hazard ratio for EFS for carboplatin plus veliparib with paclitaxel versus paclitaxel was 0.63 [95% confidence interval (CI) 0.43-0.92, P = 0.02], but 1.12 (95% CI 0.72-1.72, P = 0.62) for carboplatin plus veliparib with paclitaxel versus carboplatin with paclitaxel. In post hoc analysis, the hazard ratio for EFS was 0.57 (95% CI 0.36-0.91, P = 0.02) for carboplatin with paclitaxel versus paclitaxel. OS did not differ significantly between treatment arms, nor did rates of myelodysplastic syndromes, acute myeloid leukemia, or other secondary malignancies. CONCLUSIONS: Improvement in pCR with the addition of carboplatin was associated with long-term EFS benefit with a manageable safety profile, and without increasing the risk of second malignancies, whereas adding veliparib did not impact EFS. These findings support the addition of carboplatin to weekly paclitaxel followed by doxorubicin and cyclophosphamide neoadjuvant chemotherapy for early-stage TNBC.

Adjuvant abemaciclib combined with endocrine therapy for high-risk early breast cancer: updated efficacy and Ki-67 analysis from the monarchE study.

BACKGROUND: Adjuvant abemaciclib combined with endocrine therapy (ET) previously demonstrated clinically meaningful improvement in invasive disease-free survival (IDFS) and distant relapse-free survival (DRFS) in hormone receptor-positive, human epidermal growth factor receptor 2-negative, node-positive, high-risk early breast cancer at the second interim analysis, however follow-up was limited. Here, we present results of the prespecified primary outcome analysis and an additional follow-up analysis. PATIENTS AND METHODS: This global, phase III, open-label trial randomized (1 : 1) 5637 patients to adjuvant ET for ≥5 years ± abemaciclib for 2 years. Cohort 1 enrolled patients with ≥4 positive axillary lymph nodes (ALNs), or 1-3 positive ALNs and either grade 3 disease or tumor ≥5 cm. Cohort 2 enrolled patients with 1-3 positive ALNs and centrally determined high Ki-67 index (≥20%). The primary endpoint was IDFS in the intent-to-treat population (cohorts 1 and 2). Secondary endpoints were IDFS in patients with high Ki-67, DRFS, overall survival, and safety. RESULTS: At the primary outcome analysis, with 19 months median follow-up time, abemaciclib + ET resulted in a 29% reduction in the risk of developing an IDFS event [hazard ratio (HR) = 0.71, 95% confidence interval (CI) 0.58-0.87; nominal P = 0.0009]. At the additional follow-up analysis, with 27 months median follow-up and 90% of patients off treatment, IDFS (HR = 0.70, 95% CI 0.59-0.82; nominal P < 0.0001) and DRFS (HR = 0.69, 95% CI 0.57-0.83; nominal P < 0.0001) benefit was maintained. The absolute improvements in 3-year IDFS and DRFS rates were 5.4% and 4.2%, respectively. Whereas Ki-67 index was prognostic, abemaciclib benefit was consistent regardless of Ki-67 index. Safety data were consistent with the known abemaciclib risk profile. CONCLUSION: Abemaciclib + ET significantly improved IDFS in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative, node-positive, high-risk early breast cancer, with an acceptable safety profile. Ki-67 index was prognostic, but abemaciclib benefit was observed regardless of Ki-67 index. Overall, the robust treatment benefit of abemaciclib extended beyond the 2-year treatment period.

The efficacy, challenges, and facilitators of telemedicine in post-treatment cancer survivorship care: an overview of systematic reviews.

BACKGROUND: Telemedicine services have been increasingly used to facilitate post-treatment cancer survivorship care, including improving access; monitoring health status, health behaviors, and symptom management; enhancing information exchange; and mitigating the costs of care delivery, especially since the COVID-19 pandemic. To inform guidance for the use of telemedicine in the post-COVID era, the aim of this overview of systematic reviews (SRs) was to evaluate the efficacy of, and survivor engagement in, telemedicine interventions in the post-treatment survivorship phase, and to consider implementation barriers and facilitators. METHODS: PubMed, Cochrane CENTRAL, CINAHL, Embase, and Web of Science databases were searched. SRs that examined the use of telemedicine in the post-treatment phase of cancer survivorship, published between January 2010 and April 2021, were included. Efficacy data were synthesized narratively. Implementation barriers and facilitators were synthesized using the Consolidated Framework for Implementation Research. RESULTS: Twenty-nine SRs were included. A substantive body of evidence found telemedicine to benefit the management of psychosocial and physical effects, particularly for improving fatigue and cognitive function. There was a lack of evidence on the use of telemedicine in the prevention and surveillance for recurrences and new cancers as well as management of chronic medical conditions. This overview highlights a range of diverse barriers and facilitators at the patient, health service, and system levels. CONCLUSIONS: This review highlights the benefits of telemedicine in addressing psychosocial and physical effects, but not in other areas of post-treatment cancer survivorship care. This large review provides practical guidance for use of telemedicine in post-treatment survivorship care.

First-line atezolizumab plus nab-paclitaxel for unresectable, locally advanced, or metastatic triple-negative breast cancer: IMpassion130 final overall survival analysis.

BACKGROUND: Guidelines recommend atezolizumab plus nab-paclitaxel (A + nP) for first-line treatment of unresectable, locally advanced, or metastatic triple-negative breast cancer expressing programmed death-ligand 1 (PD-L1) on tumor-infiltrating immune cells (IC), based on IMpassion130. We report the final overall survival (OS) and safety of that study as per the prespecified analysis plan. PATIENTS AND METHODS: Patients were randomized to nP 100 mg/m2 (days 1, 8, and 15 of a 28-day cycle) with atezolizumab 840 mg (A + nP) or placebo (P + nP; days 1 and 15), until progression or unacceptable toxicity. Coprimary endpoints were progression-free survival [intention-to-treat (ITT) and PD-L1 IC-positive populations] and OS (tested hierarchically in the ITT population and, if significant, in the PD-L1 IC-positive population). RESULTS: Each arm comprised 451 patients; 666 (73.8%) had died by the final OS analysis cut-off (median follow-up, 18.8 months; interquartile range, 8.9-34.7 months). Median OS in the ITT population was 21.0 months [95% confidence interval (CI), 19.0-23.4 months] with A + nP, and 18.7 months (95% CI, 16.9-20.8 months) with P + nP [stratified hazard ratio (HR), 0.87; 95% CI, 0.75-1.02; P = 0.077]. Exploratory analysis in the PD-L1 IC-positive population showed a median OS of 25.4 months (95% CI, 19.6-30.7 months) with A + nP (n = 185) and 17.9 months (95% CI, 13.6-20.3 months) with P + nP (n = 184; stratified HR, 0.67; 95% CI, 0.53-0.86). Safety outcomes were consistent with previous analyses and the known toxicity profiles of each agent. Immune-mediated adverse events of special interest were reported in 58.7% and 41.6% of patients treated with A + nP and P + nP, respectively. CONCLUSION: Although the OS benefit in the ITT population was not statistically significant, precluding formal testing, clinically meaningful OS benefit was observed with A + nP in PD-L1 IC-positive patients, consistent with prior interim analyses. This combination remained safe and tolerable with longer follow-up.

Biomarker analyses in the phase III ASCENT study of sacituzumab govitecan versus chemotherapy in patients with metastatic triple-negative breast cancer.

BACKGROUND: The pivotal phase III ASCENT trial demonstrated improved survival outcomes associated with sacituzumab govitecan (SG), an anti-trophoblast cell-surface antigen 2 (anti-Trop-2) antibody-drug conjugate linked with the topoisomerase-inhibitor SN-38, over single-agent chemotherapy treatment of physician's choice (TPC) in previously treated metastatic triple-negative breast cancer (mTNBC). This prespecified, exploratory biomarker analysis from the ASCENT trial evaluates the association between tumor Trop-2 expression and germline BRCA1/2 mutation status with clinical outcomes. PATIENTS AND METHODS: Patients with mTNBC refractory to or progressing after two or more prior chemotherapies, with one or more in the metastatic setting, were randomized to receive SG (10 mg/kg intravenously days 1 and 8, every 21 days) or TPC (capecitabine, eribulin, vinorelbine, or gemcitabine) until disease progression/unacceptable toxicity. Biopsy or surgical specimens were collected at study entry to determine Trop-2 expression level using a validated immunohistochemistry assay and histochemical scoring. Germline BRCA1/2 mutation status was collected at baseline. RESULTS: Of 468 assessable patients, 290 had Trop-2 expression data [64% (n = 151 SG) versus 60% (n = 139 TPC)] and 292 had known BRCA1/2 mutation status [63% (n = 149 SG) versus 61% (n = 143 TPC)]. Median progression-free survival in SG- versus TPC-treated patients was 6.9, 5.6, and 2.7 months versus 2.5, 2.2, and 1.6 months for high, medium, and low Trop-2 expression, respectively. Median overall survival (14.2, 14.9, and 9.3 months versus 6.9, 6.9, and 7.6 months) and objective response rates (44%, 38%, and 22% versus 1%, 11%, and 6%) were numerically higher with SG versus TPC in patients with high, medium, and low Trop-2 expression, respectively. Efficacy outcomes were numerically higher with SG versus TPC in patients with and without germline BRCA1/2 mutations. CONCLUSIONS: SG benefits patients with previously treated mTNBC expressing high/medium Trop-2 compared with standard-of-care chemotherapy and regardless of germline BRCA1/2 mutation status. The small number of patients with low Trop-2 expression precludes definitive conclusions on the benefit of SG in this subgroup.

Alpelisib plus fulvestrant for PIK3CA-mutated, hormone receptor-positive, human epidermal growth factor receptor-2-negative advanced breast cancer: final overall survival results from SOLAR-1.

BACKGROUND: Activation of the phosphatidylinositol-3-kinase (PI3K) pathway via PIK3CA mutations occurs in 28%-46% of hormone receptor-positive (HR+), human epidermal growth factor receptor-2-negative (HER2-) advanced breast cancers (ABCs) and is associated with poor prognosis. The SOLAR-1 trial showed that the addition of alpelisib to fulvestrant treatment provided statistically significant and clinically meaningful progression-free survival (PFS) benefit in PIK3CA-mutated, HR+, HER2- ABC. PATIENTS AND METHODS: Men and postmenopausal women with HR+, HER2- ABC whose disease progressed on or after aromatase inhibitor (AI) were randomized 1 : 1 to receive alpelisib (300 mg/day) plus fulvestrant (500 mg every 28 days and once on day 15) or placebo plus fulvestrant. Overall survival (OS) in the PIK3CA-mutant cohort was evaluated by Kaplan-Meier methodology and a one-sided stratified log-rank test was carried out with an O'Brien-Fleming efficacy boundary of P ≤ 0.0161. RESULTS: In the PIK3CA-mutated cohort (n = 341), median OS [95% confidence interval (CI)] was 39.3 months (34.1-44.9) for alpelisib-fulvestrant and 31.4 months (26.8-41.3) for placebo-fulvestrant [hazard ratio (HR) = 0.86 (95% CI, 0.64-1.15; P = 0.15)]. OS results did not cross the prespecified efficacy boundary. Median OS (95% CI) in patients with lung and/or liver metastases was 37.2 months (28.7-43.6) and 22.8 months (19.0-26.8) in the alpelisib-fulvestrant and placebo-fulvestrant arms, respectively [HR = 0.68 (0.46-1.00)]. Median times to chemotherapy (95% CI) for the alpelisib-fulvestrant and placebo-fulvestrant arms were 23.3 months (15.2-28.4) and 14.8 months (10.5-22.6), respectively [HR = 0.72 (0.54-0.95)]. No new safety signals were observed with longer follow-up. CONCLUSIONS: Although the analysis did not cross the prespecified boundary for statistical significance, there was a 7.9-month numeric improvement in median OS when alpelisib was added to fulvestrant treatment of patients with PIK3CA-mutated, HR+, HER2- ABC. Overall, these results further support the statistically significant prolongation of PFS observed with alpelisib plus fulvestrant in this population, which has a poor prognosis due to a PIK3CA mutation. CLINICALTRIALS. GOV ID: NCT02437318.

Talazoparib versus chemotherapy in patients with germline BRCA1/2-mutated HER2-negative advanced breast cancer: final overall survival results from the EMBRACA trial.

BACKGROUND: In EMBRACA, talazoparib prolonged progression-free survival versus chemotherapy (hazard ratio [HR] 0.542 [95% confidence interval (CI) 0.413-0.711]; P < 0.0001) and improved patient-reported outcomes (PRO) in germline BRCA1/2 (gBRCA1/2)-mutated advanced breast cancer (ABC). We report final overall survival (OS). PATIENTS AND METHODS: This randomized phase III trial enrolled patients with gBRCA1/2-mutated HER2-negative ABC. Patients received talazoparib or physician's choice of chemotherapy. OS was analyzed using stratified HR and log-rank test and prespecified rank-preserving structural failure time model to account for subsequent treatments. RESULTS: A total of 431 patients were entered in a randomized study (287 talazoparib/144 chemotherapy) with 412 patients treated (286 talazoparib/126 chemotherapy). By 30 September 2019, 216 deaths (75.3%) occurred for talazoparib and 108 (75.0%) chemotherapy; median follow-up was 44.9 and 36.8 months, respectively. HR for OS with talazoparib versus chemotherapy was 0.848 (95% CI 0.670-1.073; P = 0.17); median (95% CI) 19.3 months (16.6-22.5 months) versus 19.5 months (17.4-22.4 months). Kaplan-Meier survival percentages (95% CI) for talazoparib versus chemotherapy: month 12, 71% (66% to 76%)/74% (66% to 81%); month 24, 42% (36% to 47%)/38% (30% to 47%); month 36, 27% (22% to 33%)/21% (14% to 29%). Most patients received subsequent treatments: for talazoparib and chemotherapy, 46.3%/41.7% received platinum and 4.5%/32.6% received a poly(ADP-ribose) polymerase (PARP) inhibitor, respectively. Adjusting for subsequent PARP and/or platinum use, HR for OS was 0.756 (95% bootstrap CI 0.503-1.029). Grade 3-4 adverse events occurred in 69.6% (talazoparib) and 64.3% (chemotherapy) patients, consistent with previous reports. Extended follow-up showed significant overall improvement and delay in time to definitive clinically meaningful deterioration in global health status/quality of life and breast symptoms favoring talazoparib versus chemotherapy (P < 0.01 for all), consistent with initial analyses. CONCLUSIONS: In gBRCA1/2-mutated HER2-negative ABC, talazoparib did not significantly improve OS over chemotherapy; subsequent treatments may have impacted analysis. Safety was consistent with previous observations. PRO continued to favor talazoparib.

Improved tolerability of neratinib in patients with HER2-positive early-stage breast cancer: the CONTROL trial.

BACKGROUND: Neratinib is an irreversible pan-HER tyrosine kinase inhibitor approved for extended adjuvant treatment in early-stage HER2-positive breast cancer based on the phase III ExteNET study. In that trial, in which no antidiarrheal prophylaxis was mandated, grade 3 diarrhea was observed in 40% of patients and 17% discontinued due to diarrhea. The international, open-label, sequential-cohort, phase II CONTROL study is investigating several strategies to improve tolerability. PATIENTS AND METHODS: Patients who completed trastuzumab-based adjuvant therapy received neratinib 240 mg/day for 1 year plus loperamide prophylaxis (days 1-28 or 1-56). Sequential cohorts evaluated additional budesonide or colestipol prophylaxis (days 1-28) and neratinib dose escalation (DE; ongoing). The primary end point was the incidence of grade ≥3 diarrhea. RESULTS: Final data for loperamide (L; n = 137), budesonide + loperamide (BL; n = 64), colestipol + loperamide (CL; n = 136), and colestipol + as-needed loperamide (CL-PRN; n = 104) cohorts, and interim data for DE (n = 60; completed ≥six cycles or discontinued; median duration 11 months) are available. No grade 4 diarrhea was observed. Grade 3 diarrhea rates were lower than ExteNET in all cohorts and lowest in DE (L 31%, BL 28%, CL 21%, CL-PRN 32%, DE 15%). Median number of grade 3 diarrhea episodes was one; median duration per grade 3 episode was 1.0-2.0 days across cohorts. Most grade 3 diarrhea and diarrhea-related discontinuations occurred in month 1. Diarrhea-related discontinuations were lowest in DE (L 20%, BL 8%, CL 4%, CL-PRN 8%, DE 3%). Decreases in health-related quality of life did not cross the clinically important threshold. CONCLUSIONS: Neratinib tolerability was improved with preemptive prophylaxis or DE, which reduced the rate, severity, and duration of neratinib-associated grade ≥3 diarrhea compared with ExteNET. Lower diarrhea-related treatment discontinuations in multiple cohorts indicate that proactive management can allow patients to stay on neratinib for the recommended time period. CLINICALTRIALS.GOV: NCT02400476.

Time course and management of key adverse events during the randomized phase III SOLAR-1 study of PI3K inhibitor alpelisib plus fulvestrant in patients with HR-positive advanced breast cancer.

BACKGROUND: Alpelisib (α-selective phosphatidylinositol 3-kinase inhibitor) plus fulvestrant is approved in multiple countries for men and postmenopausal women with PIK3CA-mutated, hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer following progression on or after endocrine therapy. A detailed understanding of alpelisib's safety profile should inform adverse event (AE) management and enhance patient care. PATIENTS AND METHODS: AEs in the phase III SOLAR-1 trial were assessed in patients with and without PIK3CA mutations. The impact of protocol-specified AE-management recommendations was evaluated, including an amendment to optimize hyperglycemia and rash management. RESULTS: Patients were randomly assigned to receive fulvestrant plus alpelisib (n = 284) or placebo (n = 287). The most common grade 3/4 AEs with alpelisib were hyperglycemia (grade 3, 32.7%; grade 4, 3.9%), rash (grade 3, 9.9%), and diarrhea (grade 3, 6.7%). Median time to onset of grade ≥3 toxicity was 15 days (hyperglycemia, based on fasting plasma glucose), 13 days (rash), and 139 days (diarrhea). Metformin alone or in combination with other antidiabetic agents was used by most patients (87.1%) with hyperglycemia. Preventive anti-rash medication resulted in lower incidence (any grade, 26.7% versus 64.1%) and severity of rash (grade 3, 11.6% versus 22.7%) versus no preventative medication. Discontinuations due to grade ≥3 AEs were lower following more-detailed AE management guidelines (7.9% versus 18.1% previously). Patients with PIK3CA mutations had a median alpelisib dose intensity of 248 mg/day. Median progression-free survival with alpelisib was 12.5 and 9.6 months for alpelisib dose intensities of ≥248 mg/day and <248 mg/day, respectively, compared with 5.8 months with placebo. CONCLUSIONS: Hyperglycemia and rash occurred early during alpelisib treatment, while diarrhea occurred at a later time point. Early identification, prevention, and intervention, including concomitant medications and alpelisib dose modifications, resulted in less severe toxicities. Reductions in treatment discontinuations and improved progression-free survival at higher alpelisib dose intensities support the need for optimal AE management. CLINICALTRIALS. GOV ID: NCT02437318.