An Open-label Phase I Study of GDC-0927 in Postmenopausal Women with Locally Advanced or Metastatic Estrogen Receptor-Positive Breast Cancer.

PURPOSE: GDC-0927 is a novel, potent, nonsteroidal, orally bioavailable, selective estrogen receptor (ER) degrader that induces tumor regression in ER+ breast cancer xenograft models. PATIENTS AND METHODS: This phase I dose-escalation multicenter study enrolled postmenopausal women with ER+/HER2- metastatic breast cancer to determine the safety, pharmacokinetics, and recommended phase II dose of GDC-0927. Pharmacodynamics was assessed with [18F]-fluoroestradiol (FES) PET scans. RESULTS: Forty-two patients received GDC-0927 once daily. The MTD was not reached. The most common adverse events (AE) regardless of causality were nausea, constipation, diarrhea, arthralgia, fatigue, hot flush, back pain, and vomiting. There were no deaths, grade 4/5 AEs, or treatment-related serious AEs. Two patients experienced grade 2 AEs of special interest of deep vein thrombosis and jugular vein thrombosis, both considered unrelated to GDC-0927. Following dosing, approximately 1.6-fold accumulation was observed, consistent with the observed half-life and dosing frequency. There were no complete or partial responses. Pharmacodynamics was supported by >90% reduction in FES uptake and an approximately 40% reduction in ER expression, suggesting ER degradation is not the mechanistic driver of ER antagonism. Twelve patients (29%) achieved clinical benefit; 17 patients (41%) showed a confirmed best overall response of stable disease. Baseline levels of ER and progesterone receptor protein and mutant ESR1 circulating tumor DNA did not correlate with clinical benefit. CONCLUSIONS: GDC-0927 appeared to be well tolerated with pharmacokinetics supporting once-daily dosing. There was evidence of target engagement and preliminary evidence of antitumor activity in heavily pretreated patients with advanced/metastatic ER+/HER2- breast cancer with and without ESR1 mutations.

Genome-wide association studies of survival in 1520 cancer patients treated with bevacizumab-containing regimens.

Germline variants might predict cancer progression. Bevacizumab improves overall survival (OS) in patients with advanced cancers. No biomarkers are available to identify patients that benefit from bevacizumab. A meta-analysis of genome-wide association studies (GWAS) was conducted in 1,520 patients from Phase III trials (CALGB 80303, 40503, 80405 and ICON7), where bevacizumab was randomized to treatment without bevacizumab. We aimed to identify genes and single nucleotide polymorphisms (SNPs) associated with survival independently of bevacizumab treatment or through interaction with bevacizumab. A cause-specific Cox model was used to test the SNP-OS association in both arms combined (prognostic), and the effect of SNPs-bevacizumab interaction on OS (predictive) in each study. The SNP effects across studies were combined using inverse variance. Findings were tested for replication in advanced colorectal and ovarian cancer patients from The Cancer Genome Atlas (TGCA). In the GWAS meta-analysis, patients with rs680949 in PRUNE2 experienced shorter OS compared to patients without it (P = 1.02 × 10-7 , hazard ratio [HR] = 1.57, 95% confidence interval [CI] 1.33-1.86), as well as in TCGA (P = .0219, HR = 1.58, 95% CI 1.07-2.35). In the GWAS meta-analysis, patients with rs16852804 in BARD1 experienced shorter OS compared to patients without it (P = 1.40 × 10-5 , HR = 1.51, 95% CI 1.25-1.82) as well as in TCGA (P = 1.39 × 10-4 , HR = 3.09, 95% CI 1.73-5.51). Patients with rs3795897 in AGAP1 experienced shorter OS in the bevacizumab arm compared to the nonbevacizumab arm (P = 1.43 × 10-5 ). The largest GWAS meta-analysis of bevacizumab treated patients identified PRUNE2 and BARD1 (tumor suppressor genes) as prognostic genes of colorectal and ovarian cancer, respectively, and AGAP1 as a potentially predictive gene that interacts with bevacizumab with respect to patient survival.

A clinical calculator to predict disease outcomes in women with hormone receptor-positive advanced breast cancer treated with first-line endocrine therapy.

PURPOSE: Endocrine therapy (ET) is an effective strategy to treat hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced breast cancer (ABC) but nearly all patients eventually progress. Our goal was to develop and validate a web-based clinical calculator for predicting disease outcomes in women with HR+ABC who are candidates for receiving first-line single-agent ET. METHODS: The meta-database comprises 891 patient-level data from the control arms of five contemporary clinical trials where patients received first-line single-agent ET (either aromatase inhibitor or fulvestrant) for ABC. Risk models were constructed for predicting 24-months progression-free survival (PFS-24) and 24-months overall survival (OS-24). Final models were internally validated for calibration and discrimination using ten-fold cross-validation. RESULTS: Higher number of sites of metastases, measurable disease, younger age, lower body mass index, negative PR status, and prior endocrine therapy were associated with worse PFS. Final PFS and OS models were well-calibrated and associated with cross-validated time-dependent area under the curve (AUC) of 0.61 and 0.62, respectively. CONCLUSIONS: The proposed ABC calculator is internally valid and can accurately predict disease outcomes. It may be used to predict patient prognosis, aid planning of first-line treatment strategies, and facilitate risk stratification for future clinical trials in patients with HR+ABC. Future validation of the proposed models in independent patient cohorts is warranted.

A single-arm, prospective trial investigating the effectiveness of a non-hormonal vaginal moisturizer containing hyaluronic acid in postmenopausal cancer survivors.

PURPOSE: To assess the feasibility and efficacy of a non-hormonal hyaluronic acid (HLA) vaginal gel in improving vulvovaginal estrogen-deprivation symptoms in postmenopausal women with a history of hormone receptor-positive (HR+) cancer. METHODS: For this single-arm, prospective longitudinal trial, we identified disease-free patients with a history of HR+ breast cancer treated with aromatase inhibitors or HR+ endometrial cancer treated with surgery and postoperative radiation. Participants used HLA daily for the first 2 weeks, and then 3×/week until weeks 12-14; dosage was then increased to 5×/week for non-responders. Vulvovaginal symptoms and pH were assessed at 4 time points (baseline [T1], 4-6 weeks [T2], 12-14 weeks [T3], 22-24 weeks [T4]) with clinical evaluation, the Vaginal Assessment Scale (VAS), Vulvar Assessment Scale (VuAS), Female Sexual Function Index (FSFI), and Menopausal Symptom Checklist (MSCL). RESULTS: Of 101 patients, mean age was 55 years (range, 31-78), 68% (n = 69) were partnered, and 60% (n = 61) were sexually active. In linear mixed models, VAS/VuAS scores significantly improved at all assessment points (all p < 0.001). MSCL scores similarly improved (all p < 0.001). FSFI scores significantly improved from T1 to T2 (p < 0.03), T3 (p < 0.001), and T4 (p < 0.001). Severe vaginal pH (> 6.5) decreased from 26% at T1 to 19% at T4 (p = 0.18). CONCLUSIONS: HLA moisturization improved vulvovaginal health/sexual function of cancer survivors. While HLA administration 1-2×/week is recommended for women in natural menopause, a 3-5×/week schedule appears to be more effective for symptom relief in cancer survivors.

Impact of adjuvant chemotherapy or tamoxifen-alone on the ovarian reserve of young women with breast cancer.

PURPOSE: To determine the longitudinal impact of adjuvant chemotherapy and tamoxifen-only treatments on the reproductive potential of women with breast cancer by using a sensitive ovarian reserve marker anti-Mullerian hormone (AMH) as a surrogate. METHODS: One-hundred-and-forty-two women with a primary diagnosis of breast cancer were prospectively followed with serum AMH assessments before the initiation, and 12, 18 and 24 months after the completion of adjuvant chemotherapy or the start of tamoxifen-only treatment. The chemotherapy regimens were classified into Anthracycline-Cyclophosphamide-based (AC-based) and Cyclophosphamide-Methotrexate + 5-Fluorouracil (CMF). Longitudinal data were analyzed by mixed effects model for treatment effects over time, adjusting for baseline age and BMI. RESULTS: Both chemotherapy regimens resulted in significant decline in ovarian reserve compared to the tamoxifen-only treatment (p < 0.0001 either regimen vs. tamoxifen for overall trend). AMH levels sharply declined at 12 months but did not show a significant recovery from 12 to 18 and 18 to 24 months after the completion of AC-based or CMF regimens. The degree of decline did not differ between the two chemotherapy groups (p = 0.53). In contrast, tamoxifen-only treatment did not significantly alter the age-adjusted serum AMH levels over the 24-month follow up. Likewise, the use of adjuvant tamoxifen following AC-based regimens did not affect AMH recovery. CONCLUSIONS: Both AC-based regimens and CMF significantly compromise ovarian reserve, without a recovery beyond 12 months post-chemotherapy. In contrast, tamoxifen-only treatment does not seem to alter ovarian reserve. These data indicate that the commonly used chemotherapy regimens but not the hormonal therapy compromise future reproductive potential.

Alterations in PTEN and ESR1 promote clinical resistance to alpelisib plus aromatase inhibitors.

Alpelisib is a selective inhibitor of PI3Kα, shown to improve outcomes for PIK3CA mutant, hormone receptor positive (HR+) metastatic breast cancers (MBC) when combined with antiestrogen therapy. To uncover mechanisms of resistance, we conducted a detailed, longitudinal analysis of tumor and plasma circulating tumor DNA among such patients from a phase I/II trial combining alpelisib with an aromatase inhibitor (AI) (NCT01870505). The trial's primary objective was to establish safety with maculopapular rash emerging as the most common grade 3 adverse event (33%). Among 44 evaluable patients, the observed clinical benefit rate was 52%. Correlating genetic alterations with outcome, we identified loss-of-function PTEN mutations in 25% of patients with resistance. ESR1 activating mutations also expanded in number and allele fraction during treatment and were associated with resistance. These data indicate that genomic alterations that mediate resistance to alpelisib or antiestrogen may promote disease progression and highlight PTEN loss as a recurrent mechanism of resistance to PI3Kα inhibition.

Real-world survival outcomes of heavily pretreated patients with refractory HR+, HER2-metastatic breast cancer receiving single-agent chemotherapy-a comparison with MONARCH 1.

PURPOSE: In MONARCH 1 (NCT02102490), single-agent abemaciclib demonstrated promising efficacy activity and tolerability in a population of heavily pretreated women with refractory HR+, HER2- metastatic breast cancer (MBC). To help interpret these results and put in clinical context, we compared overall survival (OS) and duration of therapy (DoT) between MONARCH 1 and a real-world single-agent chemotherapy cohort. METHODS: The real-world chemotherapy cohort was created from a Flatiron Health electronic health records-derived database based on key eligibility criteria from MONARCH 1. The chemotherapies included in the cohort were single-agent capecitabine, gemcitabine, eribulin, or vinorelbine. Results were adjusted for baseline demographics and clinical differences using Mahalanobis distance matching (primary analysis) and entropy balancing (sensitivity analysis). OS and DoT were analyzed using the Kaplan-Meier method and Cox proportional hazards regression. RESULTS: A real-world single-agent chemotherapy cohort (n = 281) with eligibility criteria similar to the MONARCH 1 population (n = 132) was identified. The MONARCH 1 (n = 108) cohort was matched to the real-world chemotherapy cohort (n = 108). Median OS was 22.3 months in the abemaciclib arm versus 13.6 months in the matched real-world chemotherapy cohort with an estimated hazard ratio (HR) of 0.54. The median DoT was 4.1 months in MONARCH 1 compared to 2.9 months in the real-world chemotherapy cohort with HR of 0.76. CONCLUSIONS: This study demonstrates an approach to create a real-world chemotherapy cohort suitable to serve as a comparator for trial data. These exploratory results suggest a survival advantage and place the benefit of abemaciclib monotherapy in clinical context.

Clinical Significance of Circulating Tumor Cells in Hormone Receptor-positive Metastatic Breast Cancer Patients who Received Letrozole with or Without Bevacizumab.

PURPOSE: We evaluated the prognostic and predictive value of circulating tumor cells (CTCs) hormone receptor-positive (HR+) metastatic breast cancer (MBC) patients randomized to letrozole alone or letrozole plus bevacizumab in the first-line setting (CALGB 40503). EXPERIMENTAL DESIGN: Blood samples were collected at pretreatment and three additional time points during therapy. The presence of ≥5 CTCs per 7.5 mL of blood was considered CTC positive. Association of CTCs with progression-free survival (PFS) and overall survival (OS) was assessed using Cox regression models. RESULTS: Of 343 patients treated, 294 had CTC data and were included in this analysis. Median follow-up was 39 months. In multivariable analysis, CTC-positive patients at baseline (31%) had significantly reduced PFS [HR, 1.49; 95% confidence interval (CI), 1.12-1.97] and OS (HR, 2.08; 95% CI, 1.49-2.93) compared with CTC negative. Failure to clear CTCs during treatment was associated with significantly increased risk of progression (HR, 2.2; 95% CI, 1.58-3.07) and death (HR, 3.4; 95% CI, 2.36-4.88). CTC-positive patients who received only letrozole had the worse PFS (HR, 2.3; 95% CI, 1.54-3.47) and OS (HR, 2.6; 95% CI, 1.59-4.40). Median PFS in CTC-positive patients was significantly longer (18.0 vs. 7.0 months) in letrozole plus bevacizumab versus letrozole arm (P = 0.0009). Restricted mean survival time analysis further revealed that addition of bevacizumab was associated with PFS benefit in both CTC-positive and CTC-negative patients, but OS benefit was only observed in CTC-positive patients. CONCLUSIONS: CTCs were highly prognostic for the addition of bevacizumab to first-line letrozole in patients with HR+ MBC in CALGB 40503. Further research to determine the potential predictive value of CTCs in this setting is warranted.

Increased chemotherapy-induced ovarian reserve loss in women with germline BRCA mutations due to oocyte deoxyribonucleic acid double strand break repair deficiency.

OBJECTIVE: To assess whether woman who have BRCA mutations (WBM) experience more declines in ovarian reserve after chemotherapy treatment, as it induces oocyte death by deoxyribonucleic acid (DNA) damage, and BRCA mutations result in DNA damage repair deficiency. DESIGN: Longitudinal cohort study. SETTING: Academic centers. PATIENT(S): The 108 evaluable women with breast cancer were stratified into those never tested (negative family history; n = 35) and those negative (n = 59) or positive (n = 14) for a pathogenic BRCA mutation. INTERVENTION(S): Sera were longitudinally obtained before and 12-24 months after chemotherapy treatment, assayed for antimüllerian hormone (AMH), and adjusted for age at sample collection. MAIN OUTCOME MEASURE(S): Ovarian recovery, defined as the geometric mean of the after chemotherapy age-adjusted AMH levels compared with baseline levels. RESULT(S): Compared with the controls, the before chemotherapy treatment AMH levels were 24% and 34% lower in those negative or positive for BRCA mutations, consistent with accelerated ovarian aging in WBM. The WBM had a threefold difference in AMH recovery after chemotherapy treatment (1.6%), when compared with BRCA negative (3.7%) and untested/low risk controls (5.2%). Limiting the analysis to the most common regimen, doxorubicin and cyclophosphamide followed by paclitaxel, showed similar results. These findings were mechanistically confirmed in an in vitro mouse oocyte BRCA knockdown bioassay, which showed that BRCA deficiency results in increased oocyte susceptibility to doxorubicin. CONCLUSION(S): Women who have pathogenic BRCA mutations are more likely to lose ovarian reserve after chemotherapy treatment, suggesting an emphasis on fertility preservation. Furthermore, our findings generate the hypothesis that DNA repair deficiency is a shared mechanism between aging, infertility, and cancer. CLINICAL TRIAL REGISTRATION NUMBER: NCT00823654.

Toward Improving Practices for Submission of Diagnostic Tissue Blocks for National Cancer Institute Clinical Trials.

OBJECTIVES: The National Cancer Institute (NCI) National Clinical Trials Network performs phase II and III clinical trials, which increasingly rely on the submission of diagnostic formalin-fixed, paraffin-embedded tissue blocks for biomarker assessment. Simultaneously, advances in precision oncology require that clinical centers maintain diagnostic specimens for ancillary, standard-of-care diagnostics. This has caused tissue blocks to become a limited resource for advancing the NCI clinical trial enterprise and the practice of modern molecular pathology. METHODS: The NCI convened a 1-day workshop of multidisciplined experts to discuss barriers and strategic solutions to facilitate diagnostic block submission for clinical trial science, from the perspective of patient advocates, legal experts, pathologists, and clinical oncologists. RESULTS: The expert views and opinions were carefully noted and reported. CONCLUSIONS: Recommendations were proposed to reduce institutional barriers and to assist organizations in developing clear policies regarding diagnostic block submission for clinical trials.

Double PIK3CA mutations in cis increase oncogenicity and sensitivity to PI3Kα inhibitors.

Activating mutations in PIK3CA are frequent in human breast cancer, and phosphoinositide 3-kinase alpha (PI3Kα) inhibitors have been approved for therapy. To characterize determinants of sensitivity to these agents, we analyzed PIK3CA-mutant cancer genomes and observed the presence of multiple PIK3CA mutations in 12 to 15% of breast cancers and other tumor types, most of which (95%) are double mutations. Double PIK3CA mutations are in cis on the same allele and result in increased PI3K activity, enhanced downstream signaling, increased cell proliferation, and tumor growth. The biochemical mechanisms of dual mutations include increased disruption of p110α binding to the inhibitory subunit p85α, which relieves its catalytic inhibition, and increased p110α membrane lipid binding. Double PIK3CA mutations predict increased sensitivity to PI3Kα inhibitors compared with single-hotspot mutations.

Multifocal/Multicentric Ipsilateral Invasive Breast Carcinomas with Similar Histology: Is Multigene Testing of All Individual Foci Necessary?

BACKGROUND: Multiple synchronous ipsilateral invasive breast carcinomas (BCs) with similar histology usually have concordant receptor status. It is unknown whether individual foci with similar histology also share molecular and biological similarities or are heterogenous. This study examined the concordance of the 21-gene recurrence score (RS) in multiple synchronous morphologically similar ipsilateral BCs. PATIENTS AND METHODS: We identified patients with multiple ipsilateral BCs and available RS treated at our institution from 1/2014 to 6/2018. BCs were divided into three groups based on RS: (1) RS in same risk category, (2) RS in different risk categories but within 2-unit difference (e.g., RS 17 and RS 19), and (3) RS in different risk categories and a change of > 2 units. BCs in groups 1 and 2 were considered as concordant (no significant clinical impact) and BCs in group 3 as discordant (variation affects management). RESULTS: A total of 53 patients met the study criteria. RS was concordant in 46 (87%) cases. Seven (13%) cases were discordant (group 3). Of these, three (43%, 3/7) had biopsy cavity changes (BXC) adjacent to the BC with highest RS. In two cases the focus with higher RS had a lower percentage of progesterone receptor-positive tumor cells. In two cases, extensive ductal carcinoma in situ was associated with the BC focus with lower RS. CONCLUSIONS: Morphologically similar multifocal ipsilateral BCs have concordant RS in 87% (46/53) of cases. Our results suggest that, in cases of morphologically similar multifocal BCs, testing of a single focus provides accurate prognostic and predictive information.

The Genomic Landscape of Endocrine-Resistant Advanced Breast Cancers.

We integrated the genomic sequencing of 1,918 breast cancers, including 1,501 hormone receptor-positive tumors, with detailed clinical information and treatment outcomes. In 692 tumors previously exposed to hormonal therapy, we identified an increased number of alterations in genes involved in the mitogen-activated protein kinase (MAPK) pathway and in the estrogen receptor transcriptional machinery. Activating ERBB2 mutations and NF1 loss-of-function mutations were more than twice as common in endocrine resistant tumors. Alterations in other MAPK pathway genes (EGFR, KRAS, among others) and estrogen receptor transcriptional regulators (MYC, CTCF, FOXA1, and TBX3) were also enriched. Altogether, these alterations were present in 22% of tumors, mutually exclusive with ESR1 mutations, and associated with a shorter duration of response to subsequent hormonal therapies.

A phase IIA trial of acupuncture to reduce chemotherapy-induced peripheral neuropathy severity during neoadjuvant or adjuvant weekly paclitaxel chemotherapy in breast cancer patients.

PURPOSE: Chemotherapy-induced peripheral neuropathy (CIPN) is a common and potentially dose-limiting side-effect of neurotoxic chemotherapy for cancer patients. We evaluated the preliminary efficacy of acupuncture in preventing worsening CIPN in patients receiving paclitaxel. METHODS: In this phase IIA single-arm clinical trial, we screened stage I-III breast cancer patients receiving neoadjuvant/adjuvant weekly paclitaxel for development of CIPN. The primary objective was to assess acupuncture's efficacy in preventing the escalation of National Cancer Institute-Common Toxicity Criteria for Adverse Events (NCI-CTCAE), version 4.0, grade II CIPN to higher grades. Acupuncture was deemed worthy of further study if 23 or more of the 27 enrolled patients did not develop grade III CIPN. Outcome measures (NCI-CTCAE CIPN grade, Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity [FACT/GOG-Ntx], Neuropathic Pain Scale [NPS]) were obtained weekly during the intervention. RESULTS: Of 104 patients screened, 37 developed grade II CIPN (36%), and 28 (27%) enrolled into the intervention phase; one was removed due to protocol violation. Of the 27 patients receiving acupuncture, 26 completed paclitaxel treatment without developing grade III CIPN, meeting our prespecified success criteria for declaring acupuncture worthy of further study. FACT/GOG-Ntx and NPS scores remained stable during the intervention while continuing weekly paclitaxel. Acupuncture treatment was well tolerated; 4 of 27 (15%) patients reported grade I bruising. CONCLUSIONS: Acupuncture was safe and showed preliminary evidence of effectiveness in reducing the incidence of high grade CIPN during chemotherapy. A follow-up randomised controlled trial is needed to establish definitive efficacy in CIPN prevention for patients at risk.

A rigorous evaluation of an institutionally-based communication skills program for post-graduate oncology trainees.

OBJECTIVE: Integrating education about physician-patient communication into oncology specialists' education is important to improve quality of care. Our aim was to rigorously evaluate a 4-year institutionally-based patient communication skills program for oncology post-graduate trainees. METHODS: Trainees from 10 specialties in the U.S. participated in patient communication skills modules tailored to sub-specialties. The program was evaluated by comparing pre-post scores on hierarchical outcomes: course evaluation, self-confidence, skills uptake in standardized and real patient encounters, and patient evaluations of satisfaction with communication. We examined breadth of skill usage as key outcome. Generalized estimating equations were used in data analysis. RESULTS: Two hundred and sixty-two trainees' data were analyzed, resulting in 984 standardized and 753 real patient encounters. Participants reported high satisfaction and demonstrated significant skill growth with standardized patients, but transfer of these skills into real patient encounters was incomplete. Participants with lower baseline scores had larger improvements with both standardized and real patients. CONCLUSION: The program was well received and increased participant skills in the simulated setting without effective transfer to real patient encounters. PRACTICE IMPLICATIONS: Future work should allocate proportionally greater resources to trainees with lower baseline scores and measure breadth of participant skill usage as an outcome.

Checkpoint Inhibitors in the Treatment of Breast Cancer.

PURPOSE OF REVIEW: The treatment landscape for many cancers has dramatically changed with the development of checkpoint inhibitors. This article will review the literature concerning the use of checkpoint inhibitors in breast cancer. RECENT FINDINGS: The histological subtype of BC with the strongest signal of efficacy has been triple-negative breast cancer (TNBC). Early trials of single-agent checkpoint inhibitors did not demonstrate a uniformly positive signal. Clinical studies suggest response rates between 5 and 10% in pretreated patients and roughly 20-25% for untreated advanced TNBC. However, in the small subset of patients who do respond, the response is often durable. More encouraging results have been reported with their use in combination with chemotherapy in the neoadjuvant setting. Larger phase III studies are underway to confirm these earlier findings. An immune-directed therapeutic approach for the management of BC is underway, and it is likely that combination therapy will be required to achieve a level of efficacy worthy of use in the BC treatment paradigm. These agents are not without both economic and clinical toxicity; therefore, it is imperative that we identify patients most likely to benefit from these therapies through well-designed biologically plausible clinical studies and by evaluating novel combinatorial approaches with informative biomarker driven correlative studies.

Identification of risk factors for toxicity in patients with hormone receptor-positive advanced breast cancer treated with bevacizumab plus letrozole: a CALGB 40503 (alliance) correlative study.

BACKGROUND: In hormone receptor-positive advanced breast cancer, a progression-free survival benefit was reported with addition of bevacizumab to first-line letrozole. However, increased toxicity was observed. We hypothesized that functional age measures could be used to identify patients at risk for toxicity while receiving letrozole plus bevacizumab for hormone receptor-positive advanced breast cancer. METHODS: CALGB 40503 was a phase III trial that enrolled patients with hormone receptor-positive advanced breast cancer randomized to letrozole with or without bevacizumab. Patients randomized to bevacizumab were approached to complete a validated assessment tool evaluating physical function, comorbidity, cognition, psychological state, social support, and nutritional status. The relationship between pretreatment assessment measures and the incidence of grade ≥ 3 (National Cancer Institute Common Terminology Criteria for Adverse Events Version 3.0) adverse events was determined. RESULTS: One hundred thirteen (58%) of 195 patients treated with letrozole plus bevacizumab completed the pretreatment assessment questionnaire. One patient was excluded due to missing adverse event data. The median age of patients was 56. Frequently reported grade ≥ 3 adverse events were hypertension (26%), pain (20%), and proteinuria (7%). Two hemorrhagic events (one grade 5) and 1 thrombosis event occurred. Age ≥ 65 years (p < 0.01), decreased vision (p = 0.04), and poorer pretreatment physical function measures (p < 0.05) were found on univariate analysis to be significantly associated with increased incidence of grade ≥ 3 adverse events. Upon multivariate analysis, age ≥ 65 years (p = 0.01) and decreased vision (p = 0.04) remained significant. Univariable and multivariable logistic regression models demonstrated associations between age, vision, the ability to walk up flights of stairs, and grade ≥ 3 adverse events. CONCLUSIONS: Age (≥ 65 years), decreased vision, and impairments in physical function correlated with increased incidence of toxicity in patients receiving first-line letrozole plus bevacizumab. When evaluating therapy likely to increase toxicity, functional assessment measures can identify patients at increased risk for side effects who may benefit from closer monitoring.

Phase II Study of Taselisib (GDC-0032) in Combination with Fulvestrant in Patients with HER2-Negative, Hormone Receptor-Positive Advanced Breast Cancer.

Purpose: This single-arm, open-label phase II study evaluated the safety and efficacy of taselisib (GDC-0032) plus fulvestrant in postmenopausal women with locally advanced or metastatic HER2-negative, hormone receptor (HR)-positive breast cancer.Patients and Methods: Patients received 6-mg oral taselisib capsules daily plus intramuscular fulvestrant (500 mg) until disease progression or unacceptable toxicity. Tumor tissue (if available) was centrally evaluated for PIK3CA mutations. Adverse events (AE) were recorded using NCI-CTCAE v4.0. Tumor response was investigator-determined using RECIST v1.1.Results: Median treatment duration was 4.6 (range: 0.9-40.5) months. All patients experienced ≥1 AE, 30 (50.0%) had grade ≥3 AEs, and 19 (31.7%) experienced 35 serious AEs. Forty-seven of 60 patients had evaluable tissue for central PIK3CA mutation testing [20 had mutations, 27 had no mutation detected (MND)]. In patients with baseline measurable disease, clinical activity was observed in tumors with PIK3CA mutations [best confirmed response rate: 38.5% (5/13; 95% CI, 13.9-68.4); clinical benefit rate (CBR): 38.5% (5/13; 95% CI, 13.9-68.4)], PIK3CA-MND [best confirmed response rate: 14.3% (3/21; 95% CI, 3.0-36.3); CBR: 23.8% (5/21; 95% CI, 8.2-47.2)], and unknown PIK3CA mutation status [best confirmed response rate: 20.0% (2/10; 95% CI, 2.5-55.6); CBR: 30.0% (3/10; 95% CI, 6.7-65.2)].Conclusions: Taselisib plus fulvestrant had clinical activity irrespective of PIK3CA mutation status, with numerically higher objective response rate and CBR in patients with PIK3CA-mutated (vs. -MND) locally advanced or metastatic HER2-negative, HR-positive breast cancer. No new safety signals were reported. A confirmatory phase III trial is ongoing. Clin Cancer Res; 24(18); 4380-7. ©2018 AACR.