Systemic Treatment of Patients With Metastatic Breast Cancer: ASCO Resource-Stratified Guideline

PURPOSE

To guide clinicians and policymakers in three global resource-constrained settings on treating patients with metastatic breast cancer (MBC) when Maximal setting-guideline recommended treatment is unavailable.

METHODS

A multidisciplinary, multinational panel reviewed existing ASCO guidelines and conducted modified ADAPTE and formal consensus processes.

RESULTS

Four published resource-agnostic guidelines were adapted for resource-constrained settings; informing two rounds of formal consensus; recommendations received ≥75% agreement.

RECOMMENDATIONS

Clinicians should recommend treatment according to menopausal status, pathological and biomarker features when quality results are available. In first-line, for hormone receptor (HR)-positive MBC, when a non-steroidal aromatase inhibitor and CDK 4/6 inhibitor combination is unavailable, use hormonal therapy alone. For life-threatening disease, use single-agent chemotherapy or surgery for local control. For premenopausal patients, use ovarian suppression or ablation plus hormone therapy in Basic settings. For human epidermal growth factor receptor 2 (HER2)-positive MBC, if trastuzumab, pertuzumab, and chemotherapy are unavailable, use trastuzumab and chemotherapy; if unavailable, use chemotherapy. For HER2-positive, HR-positive MBC, use standard first-line therapy, or endocrine therapy if contraindications. For triple-negative MBC with unknown PD-L1 status, or if PD-L1-positive and immunotherapy unavailable, use single-agent chemotherapy. For germline BRCA1/2 mutation-positive MBC, if poly(ADP-ribose) polymerase inhibitor is unavailable, use hormonal therapy (HR-positive MBC) and chemotherapy (HR-negative MBC). In second-line, for HR-positive MBC, Enhanced setting recommendations depend on prior treatment; for Limited, use tamoxifen or chemotherapy. For HER2-positive MBC, if trastuzumab deruxtecan is unavailable, use trastuzumab emtansine; if unavailable, capecitabine and lapatinib; if unavailable, trastuzumab and/or chemotherapy (hormonal therapy alone for HR-positive MBC).Additional information is available at www.asco.org/resource-stratified-guidelines. It is ASCO's view that healthcare providers and system decision-makers should be guided by the recommendations for the highest stratum of resources available. The guideline is intended to complement but not replace local guidelines.

Trilaciclib Prior to Chemotherapy in Patients with Metastatic Triple-Negative Breast Cancer: Final Efficacy and Subgroup Analysis from a Randomized Phase II Study

PURPOSE

We report final antitumor efficacy results from a phase II study of trilaciclib, an intravenous cyclin-dependent kinase 4/6 (CDK4/6) inhibitor, administered prior to gemcitabine plus carboplatin (GCb) in patients with metastatic triple-negative breast cancer (NCT02978716).

PATIENTS AND METHODS

Patients were randomized (1:1:1) to group 1 [GCb (days 1, 8); n = 34], group 2 [trilaciclib prior to GCb (days 1, 8); n = 33], or group 3 [trilaciclib (days 1, 8) and trilaciclib prior to GCb (days 2, 9); n = 35]. Subgroup analyses were performed according to CDK4/6 dependence, level of programmed death-ligand 1 (PD-L1) expression, and RNA-based immune signatures using proportional hazards regression. T-cell receptor (TCR) β CDR3 regions were amplified and sequenced to identify, quantify, and compare the abundance of each unique TCRβ CDR3 at baseline and on treatment.

RESULTS

Median overall survival (OS) was 12.6 months in group 1, not reached in group 2 (HR = 0.31; P = 0.0016), 17.8 months in group 3 (HR = 0.40; P = 0.0004), and 19.8 months in groups 2 and 3 combined (HR = 0.37; P < 0.0001). Efficacy outcomes were comparable regardless of cancer CDK4/6 dependence status and immune signatures. Administering trilaciclib prior to GCb prolonged OS irrespective of PD-L1 status but had greater benefit in the PD-L1-positive population. T-cell activation was enhanced in patients receiving trilaciclib.

CONCLUSIONS

Administering trilaciclib prior to GCb enhanced antitumor efficacy, with significant improvements in OS. Efficacy outcomes in immunologic subgroups and enhancements in T-cell activation suggest these improvements may be mediated via immunologic mechanisms.

Chemotherapy and Targeted Therapy for Patients With Human Epidermal Growth Factor Receptor 2-Negative Metastatic Breast Cancer That is Either Endocrine-Pretreated or Hormone Receptor-Negative: ASCO Guideline Update

PURPOSE

This guideline updates recommendations of the ASCO guideline on chemotherapy and targeted therapy for patients with human epidermal growth factor receptor 2-negative metastatic breast cancer (MBC) that is either endocrine-pretreated or hormone receptor (HR)-negative.

METHODS

An Expert Panel conducted a targeted systematic literature review guided by a signals approach to identify new, potentially practice-changing data that might translate into revised guideline recommendations.

RESULTS

The Expert Panel reviewed abstracts from the literature review and retained 14 articles.

RECOMMENDATIONS

Patients with triple-negative, programmed cell death ligand-1-positive MBC may be offered the addition of immune checkpoint inhibitor to chemotherapy as first-line therapy. Patients with triple-negative, programmed cell death ligand-1-negative MBC should be offered single-agent chemotherapy rather than combination chemotherapy as first-line treatment, although combination regimens may be offered for life-threatening disease. Patients with triple-negative MBC who have received at least two prior therapies for MBC should be offered treatment with sacituzumab govitecan. Patients with triple-negative MBC with germline BRCA mutations previously treated with chemotherapy may be offered a poly (ADP-ribose) polymerase inhibitor rather than chemotherapy. Patients with HR-positive human epidermal growth factor receptor 2-negative MBC for whom chemotherapy is being considered should be offered single-agent chemotherapy rather than combination chemotherapy, although combination regimens may be offered for highly symptomatic or life-threatening disease. Patients with HR-positive MBC with disease progression on an endocrine agent may be offered treatment with either endocrine therapy with or without targeted therapy or single-agent chemotherapy. Patients with HR-positive MBC with germline BRCA mutations no longer benefiting from endocrine therapy may be offered a poly (ADP-ribose) polymerase inhibitor rather than chemotherapy. No recommendation regarding when a patient's care should be transitioned to hospice or best supportive care alone is possible.Additional information is available at www.asco.org/breast-cancer-guidelines.

Neoadjuvant talazoparib in patients with germline BRCA1/2 (gBRCA1/2) mutation-positive, early HER2-negative breast cancer (BC): Results of a phase 2 study

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Background: Talazoparib (TALA) is a poly(ADP-ribose) polymerase inhibitor approved as monotherapy for treating adult patients (pts) with g BRCA1/2-mutated HER2-negative locally advanced or metastatic BC. Methods: This phase 2, non-randomized, single-arm, open-label study (NCT03499353) evaluated the efficacy and safety of TALA in the neoadjuvant setting for pts with early g BRCA1/2-mutated HER2− BC. Primary endpoint was evaluation of pathologic complete response (pCR) as assessed by Independent Central Review (ICR) after completing 24 weeks of neoadjuvant TALA monotherapy 1 mg QD (0.75 mg for moderate renal impairment) followed by surgery. Secondary endpoints included pCR by investigator (INV) and residual cancer burden (RCB) by ICR (RCB: 0 [pCR], I [minimal], II [moderate], III [extensive]). The evaluable population included pts who received at least 80% of the TALA dose prescribed at treatment start and underwent breast surgery and pCR assessment, plus those who progressed before pCR could be assessed. The intent-to-treat (ITT) population included all pts who received at least 1 dose of TALA. Results: Of 61 pts treated with TALA (ITT and safety populations), 48 comprised the evaluable population. All pts had triple-negative BC. 60 pts had adenocarcinoma and 1 had squamous cell histology, with the following staging: I=20, II=27, III=14. Mean age was 44.6 years, mean duration of 4.5 wks since disease onset, mean duration of treatment of 23.3 wks, and mean overall relative dose intensity of 84.5% (ITT population). pCR (assessed by ICR and INV) and RCB (by ICR) for the evaluable and ITT populations are shown in the table below. Ten (16.4%) patients discontinued treatment due to progressive disease. One pt had a disruption of treatment as a result of COVID-19 restrictions, 2 pts for other reasons: to undergo surgery early and consent withdrawal; 9 patients received <80% dose. Treatment-emergent adverse events (AEs) were reported in 98.4% of pts (27.9% grade [G] 1, 23.0% G2, 45.9% G3, 1.6% G4); the most common were fatigue (78.7%; G1 54.1%; G2 21.3%; G3 3.3%), nausea (68.9%; G1 54.1%; G2 13.1%; G3 1.6%), and alopecia (57.4%; G1 54.1%; G2 3.3%). Three (4.9%) pts discontinued treatment due to AEs (G3 anemia [n=2] and G3 vertigo [n=1]) and continued on study. Conclusions: TALA monotherapy in the neoadjuvant setting was active and showed pCR rates comparable to those observed with combination anthracycline and taxane-based chemotherapy regimens and was generally well tolerated. Clinical trial information: NCT03499353. [Table: see text]

Assessment of sacituzumab govitecan (SG) versus treatment of physician’s choice (TPC) cohort by agent in the phase 3 ASCENT study of patients (pts) with metastatic triple-negative breast cancer (mTNBC)

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Background: In pts with pretreated mTNBC, standard-of-care chemotherapy is associated with low objective response rates (ORRs) and short median progression-free survival (PFS). SG is an antibody-drug conjugate composed of an anti–Trop-2 antibody coupled to the cytotoxic SN-38 payload via a proprietary, hydrolyzable linker. SG received accelerated FDA approval for treatment of pts with mTNBC who have received ≥2 prior therapies for metastatic disease. The confirmatory phase 3 ASCENT study (NCT02574455) in pts with relapsed/refractory mTNBC demonstrated a significant survival benefit of SG over TPC (median PFS: 5.6 vs 1.7 mo, HR 0.41, P< 0.0001; median overall survival [OS]: 12.1 vs 6.7 mo, HR 0.48, P< 0.0001) with a tolerable safety profile. Here we summarize efficacy results for SG vs each TPC agent in ASCENT to examine how each TPC agent performed individually. Methods: Pts had mTNBC refractory to or progressing after ≥2 prior standard chemotherapy regimens. Pts were randomized 1:1 to receive SG (10 mg/kg intravenously on days 1 and 8, every 21 days) or single-agent TPC (eribulin, vinorelbine, capecitabine, or gemcitabine). Primary endpoint was PFS per RECIST 1.1 by independent review in brain metastases-negative (BMNeg) pts. Secondary endpoints were ORR per RECIST 1.1, duration of response, OS, and safety. Outcomes for each of the agents in the TPC arm were analyzed and compared with SG. Results: Of 529 pts enrolled, 468 were BMNeg. Among pts in the TPC cohort (n = 233), eribulin was the most commonly chosen chemotherapy (n = 126), followed by vinorelbine (n = 47), capecitabine (n = 31), and gemcitabine (n = 29). Treatment with eribulin, vinorelbine, capecitabine, and gemcitabine resulted in shorter median PFS vs SG (2.1, 1.6, 1.6, and 2.7 vs 5.6 mo, respectively); similar results were observed for median OS (6.9, 5.9, 5.2, and 8.4 vs 12.1 mo), ORR (5%, 4%, 6%, and 3% vs 35%), and clinical benefit rate (CBR; 8%, 6%, 10%, and 14% vs 45%). Key grade ≥3 treatment-related adverse events (TRAEs) with TPC overall vs SG included neutropenia (33% vs 51%), leukopenia (5% vs 10%), fatigue (5% vs 3%), and anemia (5% vs 8%). Key grade ≥3 TRAEs with eribulin vs SG included neutropenia (30% vs 51%), leukopenia (5% vs 10%), fatigue (5% vs 3%), anemia (2% vs 8%), and peripheral neuropathy (2% vs none), respectively. The safety profiles of vinorelbine, capecitabine, and gemcitabine combined were consistent with that of TPC overall and with eribulin. One treatment-related death was reported for the TPC arm (eribulin) and none with SG. Conclusions: The efficacy benefit observed with SG vs TPC in pts with mTNBC was retained when evaluating each TPC chemotherapy agent individually. These results confirm that SG should be considered as a new standard of care in pts with pretreated mTNBC. Clinical trial information: NCT02574455 .

Neoadjuvant talazoparib (TALA) in patients (pts) with germline BRCA1/2 (gBRCA1/2) mutation-positive, early HER2-negative breast cancer (BC): Exploration of tumor BRCA mutational status and zygosity and overall mutational landscape in a phase 2 study

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Background: TALA is a poly(ADP-ribose) polymerase inhibitor approved as monotherapy for adult pts with g BRCA1/2-mutated HER2-negative locally advanced/metastatic BC. We report biomarker analyses from a phase 2, nonrandomized, single-arm, open-label study (NEOTALA; NCT03499353) evaluating the efficacy and safety of TALA in the neoadjuvant setting for pts with early g BRCA1/2-mutated HER2− BC. Efficacy and safety results are presented separately. Methods: The biomarker analysis population was all pts treated with TALA for whom biomarker results are available. To support molecular eligibility, blood was tested using BRCAnalysis CDx (Myriad Genetics). Baseline tumor tissue was retrospectively tested using FoundationOne CDx, with BRCA1/2 zygosity assessed using somatic-germline-zygosity (SGZ; Sun et al. JCO PO, 2018). Germline mutational status of 14 non- BRCA DNA damage response (DDR) genes was retrospectively assessed in baseline saliva samples using Ambry CustomNext-Cancer. Mutations were defined as known/likely pathogenic/deleterious variants, including copy number alterations (CNAs). Association between mutational status of MYC or RAD21 and primary endpoint pathological complete response (pCR) as per Independent Central Review was investigated with logistic regression. Results: Of 52 evaluable tumor samples from 61 treated pts, 39 (75%) and 13 (25%) pts exhibited BRCA1 and BRCA2 mutations, respectively; 1 (2%) pt exhibited mutations in both genes, and 1 (2%) pt had mutations in neither. BRCA loss of heterozygosity (LOH) was seen in 42/43 (98%) evaluable BRCA-mutant tumors. Of 45 pts evaluable centrally for both germline and tumor, 44/45 (98%) pts exhibited the same BRCA mutation in tumor as originally detected in germline, with the remaining pt exhibiting a g BRCA1 mutation, but lacking a tumor BRCA mutation. None of 49 saliva-evaluable pts exhibited non- BRCA germline DDR mutations. TP53 (51 [98%] pts) was the most frequently mutated gene in tumors. MYC and RAD21 (each 14 [27%] pts) were the most frequent CNAs. No evidence of association between mutational status of MYC or RAD21 and pCR was found (odds ratio=0.39, 95% CI 0.12-2.30). Based on a cutoff of ≥16%, genomic LOH was elevated in 24/27 (89%) tumors evaluable for both gLOH and pCR, precluding assessment of the potential association of gLOH high/low status with pCR. Conclusions: Tumor BRCA mutations were evident in nearly all pts in the biomarker analysis population, with BRCA LOH evident in all but 1 BRCA-mutated tumor. No pts had non- BRCA germline DDR gene mutations; tumor TP53 mutations were near-universal. MYC and RAD21 each exhibited CNAs in 27% of tumors, with no association with pCR. These results support the central role of BRCA mutations in tumor pathobiology in this indication. Clinical trial information: NCT03499353.

Cisplatin +/- rucaparib after preoperative chemotherapy in patients with triple-negative or BRCA mutated breast cancer

Patients with triple-negative breast cancer (TNBC) who have residual disease after neoadjuvant therapy have a high risk of recurrence. We tested the impact of DNA-damaging chemotherapy alone or with PARP inhibition in this high-risk population. Patients with TNBC or deleterious BRCA mutation (TNBC/BRCAmut) who had >2 cm of invasive disease in the breast or persistent lymph node (LN) involvement after neoadjuvant therapy were assigned 1:1 to cisplatin alone or with rucaparib. Germline mutations were identified with BROCA analysis. The primary endpoint was 2-year disease-free survival (DFS) with 80% power to detect an HR 0.5. From Feb 2010 to May 2013, 128 patients were enrolled. Median tumor size at surgery was 1.9 cm (0-11.5 cm) with 1 (0-38) involved LN; median Residual Cancer Burden (RCB) score was 2.6. Six patients had known deleterious BRCA1 or BRCA2 mutations at study entry, but BROCA identified deleterious mutations in 22% of patients with available samples. Toxicity was similar in both arms. Despite frequent dose reductions (21% of patients) and delays (43.8% of patients), 73% of patients completed planned cisplatin. Rucaparib exposure was limited with median concentration 275 (82-4694) ng/mL post-infusion on day 3. The addition of rucaparib to cisplatin did not increase 2-year DFS (54.2% cisplatin vs. 64.1% cisplatin + rucaparib; P = 0.29). In the high-risk post preoperative TNBC/BRCAmut setting, the addition of low-dose rucaparib did not improve 2-year DFS or increase the toxicity of cisplatin. Genetic testing was underutilized in this high-risk population.

Abstract PD1-06: Trilaciclib improves overall survival when given with gemcitabine/carboplatin in patients with metastatic triple-negative breast cancer: Final analysis of a randomized phase 2 trial

Background

Trilaciclib is an intravenous (IV) cyclin-dependent kinase 4/6 (CDK4/6) inhibitor. Preliminary data showed that adding trilaciclib prior to gemcitabine plus carboplatin (GCb) significantly increased overall survival (OS) compared with GCb alone among patients with metastatic triple-negative breast cancer (mTNBC) (Tan et al., Lancet Oncol. 2019;20:1587-1601). Here, final antitumor efficacy results (objective response rate [ORR], progression-free survival [PFS], and OS) are reported for the whole study population, and in cohorts according to CDK4/6 dependence and level of programmed death ligand-1 (PD-L1) expression.

Methods

This was a randomized, open-label, phase 2 study of patients with mTNBC who had received ≤2 previous lines of chemotherapy in the recurrent/metastatic setting (NCT02978716). Patients were randomized (1:1:1) to receive GCb on days 1 and 8 (group 1, n=34), trilaciclib prior to GCb on days 1 and 8 (group 2, n=33), or trilaciclib alone on days 1 and 8 and prior to GCb on days 2 and 9 (group 3, n=35), in 21-day cycles. PFS and OS (prespecified secondary endpoints) were assessed in the intention-to-treat (ITT) population, and ORR in response-evaluable patients.

Patient tumors were characterized as CDK4/6 independent (basal-like) or indeterminate (HER2-enriched, normal-like, luminal A/B) according to the established PAM50 signature, or CDK4/6 dependent (luminal androgen receptor) or indeterminate (basal-like 1/2, mesenchymal) according to the established Lehmann signature. PD-L1 expression was scored as negative or positive if &lt;1% or ≥1% of the total tumor area contained PD-L1-labelled immune cells, respectively, using the Ventana SP142 assay. Association of CDK4/6 dependence and PD-L1 expression with antitumor efficacy was assessed using proportional hazards regression.

Results

Median follow-up was 8.4 months (range: 0.1-25.7) for group 1, 14.0 months (1.3-33.6) for group 2, and 15.3 months (3.5-33.7) for group 3. The ORR among response-evaluable patients was 7/24 (29.2%) in group 1, 15/30 (50.0%) in group 2, and 12/31 (38.7%) in group 3. Median PFS (95% confidence interval [CI]) in the ITT population was 5.7 (3.3, 9.9) months in group 1, 9.4 (6.1, 11.9) months in group 2, and 7.3 (6.2, 13.9) months in group 3, with hazard ratios (HRs) of 0.62 (P = 0.2099) and 0.63 (P = 0.1816), for groups 2 and 3 versus group 1, respectively. Overall, 73.5%, 39.4%, and 57.1% of patients in groups 1, 2, and 3 had died. Median OS (95% CI) was 12.6 (6.3, 15.6) months in group 1, not reached (NR) (10.2, NR) in group 2 (HR = 0.31, P = 0.0016), and 17.8 (12.9, 32.7) months in group 3 (HR = 0.40, P = 0.0004). For groups 2 and 3 combined, median OS was 19.8 (14.0, NR) months (HR = 0.37, P &lt;0.0001 vs group 1). ORR, PFS, and OS were comparable in tumors categorized as CDK4/6 dependent, independent, or indeterminate. Antitumor efficacy by PD-L1 status is provided in the Table.

Conclusions

Mature data from this study confirm that administering trilaciclib prior to GCb enhances antitumor efficacy compared with GCb alone, with statistically significant improvements in OS. Subgroup analyses suggest that adding trilaciclib prior to GCb benefits patients regardless of CDK4/6 dependence status and PD-L1 expression. Additional immune subtyping analyses are ongoing and will be presented.

Group 1Group 2Group 3PD-L1 +vePD-L1 –vePD-L1 +vePD-L1 –vePD-L1 +vePD-L1 –vePatients, n171016101616ORR, n (%)4 (23.5)3 (30.0)8 (50.0)4 (40.0)7 (43.8)4 (25.0)Median PFS, months (95% CI)3.5 (2.2, NR)9.5 (5.2, NR)7.9 (4.3, NR)11.9 (8.8, NR)9.0 (6.2, NR)6.9 (6.4, NR)P value (Wald Test)––0.3470.6040.0690.766HR (95% CI)––0.70 (0.3, 1.5)0.76 (0.3, 2.2)0.46 (0.2, 1.1)1.16 (0.4, 3.1)Median OS, months (95% CI)10.5 (6.3, 18.8)13.9 (12.6, NR)20.1 (10.2, NR)NR (9.4, NR)32.7 (15.3, NR)17.8 (12.9, NR)P value (Wald Test)––0.0280.0830.020.239HR (95% CI)––0.35 (0.1, 0.9)0.34 (0.1, 1.2)0.33 (0.1, 0.8)0.57 (0.2, 1.5)HR and P values are for comparisons between group 2 versus group 1, and group 3 versus group 1.+ve, positive; –ve, negative; CI, confidence interval; HR, hazard ratio; NR, not reached; ORR, objective response rate; OS, overall survival; PD-L1, programmed death ligand-1; PFS, progression-free survival.

Citation Format: Joyce O'Shaughnessy, Gail S Wright, Anu R Thummala, Michael A Danso, Lazar Popovic, Timothy J Pluard, Hyo S Han, Željko Vojnović, Nikola Vasev, Ling Ma, Donald A Richards, Sharon T Wilks, Dušan Milenković, Jie Xiao, Jessica A Sorrentino, Janet Horton, Antoinette R Tan. Trilaciclib improves overall survival when given with gemcitabine/carboplatin in patients with metastatic triple-negative breast cancer: Final analysis of a randomized phase 2 trial [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD1-06.

Abstract GS4-01: Results from CONTESSA: A phase 3 study of tesetaxel plus a reduced dose of capecitabine versus capecitabine alone in patients with HER2-, hormone receptor + (HR+) metastatic breast cancer (MBC) who have previously received a taxane

Objectives: The key objectives of CONTESSA are to evaluate the efficacy and safety of tesetaxel plus a reduced dose of capecitabine as an all-oral regimen versus capecitabine alone in patients with HER2-, HR+ MBC previously treated with a taxane.

Rationale: Tesetaxel is a novel, oral taxane with several properties that make it unique, including: oral administration with a low pill burden; a long (8-day) terminal plasma half-life in humans, enabling infrequent, once-every-3 weeks (Q3W) dosing; no observed hypersensitivity reactions; and significant activity against chemotherapy-resistant breast cancer cell lines. More than 1,000 patients have been treated with tesetaxel in clinical studies. Tesetaxel had encouraging monotherapy activity in a Phase 2 study in 38 patients with HER2-, HR+ MBC, with a confirmed objective response rate (ORR) per RECIST 1.1 of 45% and median progression-free survival (PFS) of 5.4 months (Seidman et al, 2018 ASCO Annual Meeting).

Methodology: CONTESSA is a multinational, multicenter, randomized (1:1), Phase 3 registration study comparing tesetaxel (27 mg/m2 on Day 1 of a 21-day cycle) plus a reduced dose of capecitabine (1,650 mg/m2/day on Days 1-14 of a 21-day cycle) to the approved dose of capecitabine alone (2,500 mg/m2/day on Days 1-14 of a 21-day cycle) in patients with HER2-, HR+ MBC who have received no more than one chemotherapy regimen for advanced disease and have received a taxane in the (neo)adjuvant setting. There was no restriction on the disease-free interval following taxane therapy. The primary endpoint is PFS assessed by an Independent Radiologic Review Committee (IRC). CONTESSA was designed with 90% power to detect a 2.5-month improvement in median PFS (HR=0.71). Secondary endpoints are overall survival (OS), ORR and disease control rate.

Results: CONTESSA, which enrolled 685 patients, met the primary endpoint of improved PFS as assessed by the IRC. Median PFS was 9.8 months for tesetaxel plus a reduced dose of capecitabine versus 6.9 months for capecitabine alone, an improvement of 2.9 months [HR=0.716 (95% CI: 0.573-0.895); p=0.003]. ORR was 57% for tesetaxel plus a reduced dose of capecitabine versus 41% for capecitabine alone (p=0.0002). OS data are immature. Tesetaxel plus capecitabine was associated with a manageable side effect profile consistent with previous clinical studies. Grade ≥3 treatment-emergent adverse events (TEAEs) that occurred in ≥5% of patients (tesetaxel plus capecitabine vs. capecitabine alone) were: neutropenia (71.2% vs. 8.3%); diarrhea (13.4% vs. 8.9%); hand-foot syndrome (6.8% vs. 12.2%); febrile neutropenia (12.8% vs. 1.2%); fatigue (8.6% vs. 4.5%); hypokalemia (8.6% vs. 2.7%); leukopenia (10.1% vs. 0.9%); and anemia (8.0% vs. 2.1%). TEAEs resulting in treatment discontinuation in ≥1% of patients (tesetaxel plus capecitabine vs. capecitabine alone) were: neutropenia or febrile neutropenia (4.2% vs. 1.5%); neuropathy (3.6% vs. 0.3%); diarrhea (0.9% vs. 1.5%); and hand-foot syndrome (0.6% vs. 2.1%). Treatment discontinuation due to any adverse event occurred in 23.1% of patients treated with tesetaxel plus capecitabine versus 11.9% of patients treated with capecitabine alone. Grade 2 alopecia occurred in 8.0% of patients treated with tesetaxel plus capecitabine versus 0.3% of patients treated with capecitabine alone. Grade ≥3 neuropathy occurred in 5.9% of patients treated with tesetaxel plus capecitabine versus 0.9% of patients treated with capecitabine alone.

Conclusion: An all-oral regimen of tesetaxel plus a reduced dose of capecitabine significantly improved PFS versus capecitabine alone. Neutropenia was the most frequent Grade ≥3 TEAE. Rates of clinically significant alopecia and neuropathy were low.

Citation Format: Joyce O'Shaughnessy, Lee Schwartzberg, Martine Piccart, Hope S. Rugo, Denise A Yardley, Javier Cortes, Michael Untch, Nadia Harbeck, Gail S. Wright, Igor Bondarenko, John Glaspy, Zbigniew Nowecki, Fadi Kayali, Arlene Chan, Christelle Levy, Mei-Ching Liu, Sung-Bae Kim, Julie Lemieux, Alexey Manikhas, Sara Tolaney, Elaine Lim, Andrea Gombos, Agostina Stradella, Mark Pegram, Peter Fasching, Laszlo Mangel, Vladimir Semiglazov, Veronique Dieras, Luca Gianni, Michael A Danso, Jeff Vacirca, Stew Kroll, Joseph O'Connell, Kevin Tang, Thomas Wei, Andrew Seidman. Results from CONTESSA: A phase 3 study of tesetaxel plus a reduced dose of capecitabine versus capecitabine alone in patients with HER2-, hormone receptor + (HR+) metastatic breast cancer (MBC) who have previously received a taxane [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr GS4-01.

Antiemetics: ASCO Guideline Update

PURPOSE

To update the guideline to include new anticancer agents, antiemetics, and antiemetic regimens and to provide recommendations on the use of dexamethasone as a prophylactic antiemetic in patients receiving checkpoint inhibitors (CPIs).

METHODS

ASCO convened an Expert Panel and updated the systematic review to include randomized controlled trials (RCTs) and meta-analyses of RCTs published between June 1, 2016, and January 24, 2020. To address the dexamethasone and CPI question, we conducted a systematic review of RCTs that evaluated the addition of a CPI to chemotherapy.

RESULTS

The systematic reviews included 3 publications from the updated search and 10 publications on CPIs. Two phase III trials in adult patients with non–small-cell lung cancers evaluating a platinum-based doublet with or without the programmed death 1 (PD-1) inhibitor pembrolizumab recommended that all patients receive dexamethasone as a component of the prophylactic antiemetic regimen. In both studies, superior outcomes were noted in the PD-1 inhibitor–containing arms. Other important findings address olanzapine in adults and fosaprepitant in pediatric patients.

RECOMMENDATIONS

Recommendations for adults are unchanged with the exception of the option of adding olanzapine in the setting of hematopoietic stem cell transplantation. Dosing information now includes the option of a 5-mg dose of olanzapine in adults and intravenous formulations of aprepitant and netupitant-palonosetron. The option of fosaprepitant is added to pediatric recommendations. There is no clinical evidence to warrant omission of dexamethasone from guideline-compliant prophylactic antiemetic regimens when CPIs are administered to adults in combination with chemotherapy. CPIs administered alone or in combination with another CPI do not require the routine use of a prophylactic antiemetic. Additional information is available at www.asco.org/supportive-care-guidelines .

Trilaciclib plus chemotherapy versus chemotherapy alone in patients with metastatic triple-negative breast cancer: a multicentre, randomised, open-label, phase 2 trial

BACKGROUND

Trilaciclib is an intravenous cell-cycle inhibitor that transiently maintains immune cells and haemopoietic stem and progenitor cells in G1 arrest. By protecting the immune cells and bone marrow from chemotherapy-induced damage, trilaciclib has the potential to optimise antitumour activity while minimising myelotoxicity. We report safety and activity data for trilaciclib plus gemcitabine and carboplatin chemotherapy in patients with metastatic triple-negative breast cancer.

METHODS

In this randomised, open-label, multicentre, phase 2 study, adult patients (aged ≥18 years) with evaluable, biopsy-confirmed, locally recurrent or metastatic triple-negative breast cancer who had no more than two previous lines of chemotherapy were recruited from 26 sites in the USA, three in Serbia, two in North Macedonia, one in Croatia, and one in Bulgaria; sites were academic and community hospitals. Availability of diagnostic samples of tumour tissue confirming triple-negative breast cancer was a prerequisite for enrolment. Eligible patients were randomly assigned (1:1:1) by an interactive web-response system, stratified by number of previous lines of systemic therapy and the presence of liver metastases, to receive intravenous gemcitabine 1000 mg/m² and intravenous carboplatin (area under the concentration-time curve 2 μg × h/mL) on days 1 and 8 (group 1), gemcitabine and carboplatin plus intravenous trilaciclib 240 mg/m² on days 1 and 8 (group 2), or gemcitabine and carboplatin on days 2 and 9 plus trilaciclib on days 1, 2, 8, and 9 (group 3) of 21-day cycles. Patients continued treatment until disease progression, unacceptable toxicity, withdrawal of consent, or discontinuation by the investigator. The primary objective was to assess the safety and tolerability of combining trilaciclib with gemcitabine and carboplatin chemotherapy. The primary endpoints were duration of severe neutropenia during cycle 1 and the occurrence of severe neutropenia during the treatment period. Overall survival was included as a key secondary endpoint. Analyses were in the intention-to-treat population. Safety was assessed in all patients who received at least one dose of study treatment. This study is registered with EudraCT, 2016-004466-26, and ClinicalTrials.gov, NCT02978716, and is ongoing but closed to accrual.

FINDINGS

Between Feb 7, 2017, and May 15, 2018, 142 patients were assessed for eligibility and 102 were randomly assigned to group 1 (n=34), group 2 (n=33), or group 3 (n=35). Of all patients, 38 (37%) had received one or two lines of previous chemotherapy in the metastatic setting. Median follow-up was 8·4 months (IQR 3·8-13·6) for group 1, 12·7 months (5·5-17·4) for group 2, and 12·9 months (6·7-16·8) for group 3. Data cutoff for myelosuppression endpoints was July 30, 2018, and for antitumour activity endpoints was May 17, 2019. During cycle 1, mean duration of severe neutropenia was 0·8 day (SD 2·4) in group 1, 1·5 days (3·5) in group 2, and 1·0 day (2·6) in group 3 (group 3 vs group 1 one-sided adjusted p=0·70). Severe neutropenia occurred in nine (26%) of 34 patients in group 1, 12 (36%) of 33 patients in group 2, and eight (23%) of 35 patients in group 3 (p=0·70). Overall survival was 12·6 months (IQR 5·8-15·6) in group 1, 20·1 months (9·4-not reached) in group 2, and 17·8 months (8·8-not reached) in group 3 (group 3 vs group 1 two-sided p=0·0023). The most common treatment-emergent adverse events were anaemia (22 [73%] of 34), neutropenia (21 [70%]), and thrombocytopenia (18 [60%]) in group 1; neutropenia (27 [82%] of 33), thrombocytopenia (18 [55%]) and anaemia (17 [52%]) in group 2; and neutropenia (23 [66%] of 35), thrombocytopenia (22 [63%]), and nausea (17 [49%]) in group 3. There were no treatment-related deaths.

INTERPRETATION

No significant differences were observed in myelosuppression endpoints with trilaciclib plus gemcitabine and carboplatin in patients with metastatic triple-negative breast cancer; however, the regimen was generally well tolerated and overall survival results were encouraging. Further studies of trilaciclib in this setting are warranted.

FUNDING

G1 Therapeutics.

Abstract PD1-01: Trilaciclib (T), a CDK4/6 inhibitor, dosed with gemcitabine (G), carboplatin (C) in metastatic triple negative breast cancer (mTNBC) patients: Preliminary phase 2 results

Background: Cytotoxic chemotherapy-induced damage of hematopoietic stem and progenitor cells (HSPCs) results in acute toxicities consisting of multi-lineage myelosuppression, and late onset toxicities consisting of progressive bone marrow suppression with increased incidence of therapy-related myeloid neoplasms. T is an IV CDK4/6 inhibitor in development to preserve HSPC and immune system function during cytotoxic chemotherapy (myelopreservation). Proof of concept for myelopreservation with T was observed in a randomized, placebo-controlled Phase 2 trial in small-cell lung cancer patients receiving 1st-line chemotherapy. This trial in mTNBC patients (NCT02978716) was designed to explore the utility of T in combination with GC.

Methods: This Phase 2, randomized, open-label study enrolled patients in the US and EU with mTNBC who had received 0-2 prior systemic cytotoxic therapies in the locally recurrent or metastatic setting and had no symptomatic brain metastases. Patients were randomized (1:1:1) to GC alone (Group 1) or T plus GC (Group 2) using a standard schedule (D1, 8 every 21 days) or to an alternative schedule (T on D1, 2, 8 and 9 with GC on D2 and 9 every 21 days; Group 3). On those days when both T and GC were scheduled, T was administered iv prior to GC infusion. Prophylactic growth factors were not administered in cycle 1; otherwise supportive care was allowed as needed. Primary objectives were safety and tolerability; tumor response was evaluated using RECIST v1.1 and PFS and OS were assessed. Myelopreservation endpoints reflecting the potential effects of T on multiple cellular lineages include occurrence of Grade 4 neutropenia (primary), RBC and platelet transfusions (primary), and lymphocyte counts with immune profiling (secondary and exploratory). A signature of CDK4/6 independence developed from preclinical data will be used to evaluate archival tumor tissue samples and data analysis is ongoing.

Results: 95 patients were dosed; median age 57 years (range 32,86), ECOG PS 0 (53%) or 1 (47%), 25% had liver metastases at baseline, and approximately 50% had received no systemic therapy in the recurrent/metastatic setting. Fifty-five patients remain on treatment. Disease progression was the most common reason for drug discontinuation (22/40; 55%). Overall the most common (≥ 25%) TEAEs were anemia (47%), nausea (35%), fatigue (34%), neutropenia (32%), platelet count decreased (25%), and vomiting (25%). The most frequent (≥ 15%) Grade 3 or 4 TEAEs were hematologic toxicities, i.e. neutropenia (28%), anemia (21%), neutrophil count decreased (21%) and thrombocytopenia (16%). These were also the most frequent drug-related TEAEs observed. Tumor efficacy data are being evaluated.

Conclusions: This trial, assessing the myelopreservation effects of T when combined with GC in patients with mTNBC, has completed enrollment. Myelopreservation data, immune profiling, as well as ORR and preliminary PFS results will be presented by study arm at the meeting.

Citation Format: O'Shaughnessy J, Wright GS, Thummala AR, Danso MA, Popovic L, Pluard TJ, Cheung E, Han HS, Daniel BR, Vojnovic Z, Vasev N, Ling M, Richards DA, Wilks ST, Milenkovic D, Sorrentino JA, Roberts PJ, Bomar M, Yang Z, Antal JM, Malik RK, Morris SR, Tan A. Trilaciclib (T), a CDK4/6 inhibitor, dosed with gemcitabine (G), carboplatin (C) in metastatic triple negative breast cancer (mTNBC) patients: Preliminary phase 2 results [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD1-01.

Antiemetics: American Society of Clinical Oncology Clinical Practice Guideline Update

Purpose

To update the ASCO guideline for antiemetics in oncology.

Methods

ASCO convened an Expert Panel and conducted a systematic review of the medical literature for the period of November 2009 to June 2016.

Results

Forty-one publications were included in this systematic review. A phase III randomized controlled trial demonstrated that adding olanzapine to antiemetic prophylaxis reduces the likelihood of nausea among adult patients who are treated with high emetic risk antineoplastic agents. Randomized controlled trials also support an expanded role for neurokinin 1 receptor antagonists in patients who are treated with chemotherapy.

Recommendation

Key updates include the addition of olanzapine to antiemetic regimens for adults who receive high-emetic-risk antineoplastic agents or who experience breakthrough nausea and vomiting; a recommendation to administer dexamethasone on day 1 only for adults who receive anthracycline and cyclophosphamide chemotherapy; and the addition of a neurokinin 1 receptor antagonist for adults who receive carboplatin area under the curve ≥ 4 mg/mL per minute or high-dose chemotherapy, and for pediatric patients who receive high-emetic-risk antineoplastic agents. For radiation-induced nausea and vomiting, adjustments were made to anatomic regions, risk levels, and antiemetic administration schedules. Rescue therapy alone is now recommended for low-emetic-risk radiation therapy. The Expert Panel reiterated the importance of using the most effective antiemetic regimens that are appropriate for antineoplastic agents or radiotherapy being administered. Such regimens should be used with initial treatment, rather than first assessing the patient’s emetic response with less-effective treatment. Additional information is available at www.asco.org/supportive-care-guidelines and www.asco.org/guidelineswiki .

Phase (Ph) 2 stage 1 clinical activity of seviteronel, a selective CYP17-lyase and androgen receptor (AR) inhibitor, in women with advanced AR+ triple-negative breast cancer (TNBC) or estrogen receptor (ER)+ BC: CLARITY-01

1102

Background: Seviteronel (Sevi), an oral selective CYP17-lyase and AR inhibitor that blocks testosterone and estradiol production and competitively antagonizes the AR, is in Ph 2 clinical development for BC and prostate cancer. The primary objective of this ongoing Ph 2 study (NCT02580448) is to estimate the activity of once daily Sevi in women with AR+ TNBC and ER+ BC as measured by clinical benefit rate (CBR) at 16 and 24 weeks (wk), respectively. Methods: Patients (pts) with ER+/HER2-normal metastatic BC following progression of ≥1 prior line of endocrine therapy or TNBC were enrolled with no limit of prior therapies in either cohort. Evaluable pts had AR ≥10% via central IHC staining (TNBC only) and 1 post-baseline scan. Sevi was administered at 450 mg oral daily. Scans were performed every 8 wk. Circulating tumor cell (CTC) enumeration was performed by EPIC CTC analysis. A Simon’s 2-stage design was employed to determine activity (≥2 of 13 CBR16 in TNBC and ≥2 of 12 CBR24 in ER+ BC allow for accrual to Stage 2). Results: As of 4 Oct, 2016, 16 pts with AR+ TNBC (6 evaluable) and 14 pts with ER+ BC (11 evaluable) were enrolled. 67% had visceral metastases; 10% had stable brain metastases. 60% had ≥2 lines of prior therapy for advanced disease. 13 of 14 (93%) TNBC pts who underwent central AR testing had AR ≥10%. Four pts in the TNBC cohort and 8 pts in the ER+ cohort remain on therapy. CBR16 (TNBC) and CBR24 (ER+) was 2 of 6 (33%) and 2 of 11 (18%) allowing Stage 2 accrual in both cohorts. 7 of 10 evaluable pts with CTCs present at baseline had a CTC decline at C2D1, including all that met CBR (-94.3% [-27.5, -100] median [range]). The most common adverse events (≥ 25%) were fatigue (50%), nausea (43%) and decreased appetite (33%); all Grade 1/2. Updated CBR data will be presented at the time of presentation. Conclusions: Sevi Stage 1 activity is suggested by CBRs, along with associated CTC declines in heavily pre-treated pts with high disease burden. The observed safety profile is consistent with on-target pharmacology. Stage 2 enrollment is ongoing. Sevi may provide a novel treatment option for women with AR+ TNBC or ER+ BC. Clinical trial information: NCT02580448.

Antiemetics: American Society of Clinical Oncology Focused Guideline Update

PURPOSE

To update a key recommendation of the American Society of Clinical Oncology antiemetic guideline. This update addresses the use of the oral combination of netupitant (a neurokinin 1 [NK1] receptor antagonist) and palonosetron (a 5-hydroxytryptamine-3 [5-HT3] receptor antagonist) for the prevention of acute and delayed nausea and vomiting in patients receiving chemotherapy.

METHODS

An update committee conducted a targeted systematic literature review and identified two phase III clinical trials and a randomized phase II dose-ranging study.

RESULTS

In one phase III trial, the oral combination of netupitant and palonosetron was associated with higher complete response rates (no emesis and no rescue medications) compared with palonosetron alone in patients treated with anthracycline plus cyclophosphamide chemotherapy (74% v 67% overall; P = .001). In another phase III trial, the oral combination of netupitant and palonosetron was safe and effective across multiple cycles of moderately or highly emetogenic chemotherapies. In the phase II dose-ranging study, each dose of netupitant (coadministered with palonosetron 0.50 mg) produced higher complete response rates than palonosetron alone among patients receiving cisplatin-based chemotherapy. The highest dose of netupitant (ie, 300 mg) was most effective.

RECOMMENDATIONS

All patients who receive highly emetogenic chemotherapy regimens (including anthracycline plus cyclophosphamide) should be offered a three-drug combination of an NK1 receptor antagonist, a 5-HT3 receptor antagonist, and dexamethasone. The oral combination of netupitant and palonosetron plus dexamethasone is an additional treatment option in this setting. The remaining recommendations from the 2011 ASCO guideline are unchanged pending a full update. Additional information is available at www.asco.org/guidelines/antiemetics and www.asco.org/guidelineswiki.

The prevalence and pattern of chemotherapy-induced peripheral neuropathy (CIPN) among women with breast cancer receiving care in a large community oncology practice

80

Background: CIPN is a common side effect of taxane-based chemotherapy agents. This study examined the prevalence, severity, and risk factors of CIPN and its impact on quality of life (QOL) among women treated for breast cancer in a large U.S. community oncology practice. Methods: In this cross-sectional survey study, women previously treated with taxane-based chemotherapy for early stage breast cancer completed the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ-C30), breast cancer module (QLQ-BR23) and CIPN module (QLQ-CIPN20). Each subscale is scored 0-100 where higher scores indicate better function or greater symptom severity. Clinical data were abstracted from the medical record. Bivariate analyses were conducted to test pre- specified hypotheses. Results: 126 women with mean age 56.7 years (SD = 11.8) were stage I-II (79.4%) or stage III (20.6%) at the time of the survey; 65.1% were White and 27.8% were Black or African American. 73.0% of women reported they had CIPN. The mean time since last taxane chemotherapy cycle was 144.9 weeks (SD = 112.9). The mean (SD) score of QLQ-C30 global health status/QOL was 77.0 (20.3) and physical function was 85.7 (17.1). QLQ-CIPN20 mean scores for the sensory, motor, and autonomic subscales were 18.9 (23.1), 18.6 (18.7), and 17.1 (21.8), respectively. Presence of CIPN was associated with patient referral and visitation to a neurologist or pain specialist (p < 0.05). CIPN symptom severity was negatively correlated with global health status/QOL and physical and role functioning (range of r= -0.46 to -0.72). Further, it was not associated with age, body mass index, diabetes, or cumulative taxane dosage, but was greater for Black or African American patients versus White patients (e.g., sensory: 28.6 vs 14.5, p < 0.002). CIPN sensory impairment was marginally greater for patients treated with paclitaxel compared to docetaxel (23.3 vs 15.6, p < 0.06). Conclusions: CIPN was prevalent in this community oncology practice and significantly impacts function and QOL. These data highlight the importance of developing methods to mitigate CIPN.

Phase III study of iniparib plus gemcitabine and carboplatin versus gemcitabine and carboplatin in patients with metastatic triple-negative breast cancer

PURPOSE

There is a lack of treatments providing survival benefit for patients with metastatic triple-negative breast cancer (mTNBC), with no standard of care. A randomized phase II trial showed significant benefit for gemcitabine, carboplatin, and iniparib (GCI) over gemcitabine and carboplatin (GC) in clinical benefit rate, response rate, progression-free survival (PFS), and overall survival (OS). Here, we formally compare the efficacy of these regimens in a phase III trial.

PATIENTS AND METHODS

Patients with stage IV/locally recurrent TNBC who had received no more than two previous chemotherapy regimens for mTNBC were randomly allocated to gemcitabine 1,000 mg/m(2) and carboplatin area under the curve 2 (days 1 and 8) alone or GC plus iniparib 5.6 mg/kg (days 1, 4, 8, and 11) every 3 weeks. Random assignment was stratified by the number of prior chemotherapies. The coprimary end points were OS and PFS. Patients receiving GC could cross over to iniparib on progression.

RESULTS

Five hundred nineteen patients were randomly assigned (261 GCI; 258 GC). In the primary analysis, no statistically significant difference was observed for OS (hazard ratio [HR] = 0.88; 95% CI, 0.69 to 1.12; P = .28) nor PFS (HR = 0.79; 95% CI, 0.65 to 0.98; P = .027). An exploratory analysis showed that patients in the second-/third-line had improved OS (HR = 0.65; 95% CI, 0.46 to 0.91) and PFS (HR = 0.68; 95% CI, 0.50 to 0.92) with GCI. The safety profile for GCI was similar to GC.

CONCLUSION

The trial did not meet the prespecified criteria for the coprimary end points of PFS and OS in the ITT population. The potential benefit with iniparib observed in second-/third-line subgroup warrants further evaluation.

Chemotherapy and targeted therapy for women with human epidermal growth factor receptor 2-negative (or unknown) advanced breast cancer: American Society of Clinical Oncology Clinical Practice Guideline

PURPOSE

To identify optimal chemo- and targeted therapy for women with human epidermal growth factor 2 (HER2)- negative (or unknown) advanced breast cancer.

METHODS

A systematic review of randomized evidence (including systematic reviews and meta-analyses) from 1993 through to current was completed. Outcomes of interest included survival, progression-free survival, response, quality of life, and adverse effects. Guideline recommendations were evidence based and were agreed on by the Expert Panel via consensus.

RESULTS

Seventy-nine studies met the inclusion criteria, comprising 20 systematic reviews and/or meta-analyses, 30 trials on first-line treatment, and 29 trials on second-line and subsequent treatment. These trials form the evidence base for the guideline recommendations.

RECOMMENDATIONS

Endocrine therapy is preferable to chemotherapy as first-line treatment for patients with estrogen receptor-positive metastatic breast cancer unless improvement is medically necessary (eg, immediately life-threatening disease). Single agent is preferable to combination chemotherapy, and longer planned duration improves outcome but must be balanced against toxicity. There is no single optimal first-line or subsequent line chemotherapy, and choice of treatment will be determined by multiple factors including prior therapy, toxicity, performance status, comorbid conditions, and patient preference. The role of bevacizumab remains controversial. Other targeted therapies have not so far been shown to enhance chemotherapy outcome in HER2-negative breast cancer.

Human epidermal growth factor receptor 2 (HER2) suppression with the addition of lapatinib to trastuzumab in HER2-positive metastatic breast cancer (HALT: LPT112515)

TPS664

Background: Evidence supports the concept of dual HER2 blockade as a treatment strategy for HER2+ breast cancer (BC). In patients with prior trastuzumab (T)-treated HER2+ metastatic BC (MBC), treatment with T plus lapatinib (L) was associated with longer progression-free survival (PFS) and overall survival (OS) compared with L alone, and had an acceptable safety and tolerability profile. In patients with stage II/III BC, preoperative treatment with T plus L plus paclitaxel (P) resulted in significantly higher pathologic complete response rates compared with P combined with either agent alone. This study is designed to evaluate whether the addition of L improves PFS among women with HER2+ MBC receiving T as maintenance therapy. Methods: In this open-label, Phase III study, 280 patients will be stratified by line of treatment (first/second) and hormone receptor status (positive/negative), then randomized 1:1 to receive maintenance treatment with either L (1000 mg qd, continuously) in combination with T (6 mg/kg once every 3 weeks [q3w]), or T (6 mg/kg q3w) alone until disease progression, death, discontinuation due to adverse events, or other reasons. The primary endpoint is PFS; secondary endpoints are OS, clinical benefit rate, and safety. Eligible patients are females, aged ≥18 years with HER2+ MBC who have completed 12-24 weeks of first-/second-line treatment with T plus chemotherapy with an objective response or stable disease at chemotherapy discontinuation. Patients with stable brain metastases are eligible if entering the study on second-line treatment. Efficacy endpoints will be analyzed in the intent-to-treat population. A total of 193 PFS events is required to detect a 50% increase in median PFS from 18 weeks (T alone) to 27 weeks (L+T) with an associated hazard ratio of 0.667, an 80% power and a 1-sided type I error of 0.025. One interim analysis is planned for futility when ~97 PFS events (50% of required events) have been observed. Safety endpoints will be analyzed in all randomized patients who receive ≥1 dose of study medication. The trial is currently open for accrual in the United States and Canada. Clinical trial information: NCT00968968.

Interim safety results of eribulin (E) combined with ramucirumab (RAM) in patients (pts) with advanced metastatic breast cancer (MBC)

110

Background: VEGF-mediated angiogenesis contributes to breast cancer (BC) pathogenesis. RAM (IMC-1121B), a fully human IgG1 monoclonal antibody (MAb), targets VEGFR-2, blocking the interaction of VEGF ligands and VEGFR‑2. DC101 (murine anti-VEGFR-2 MAb) impairs vascular function and increases tumor hypoxia in xenograft BC models and inhibits tumor growth in cytotoxic-resistant models. E is a novel non-taxane microtubule inhibitor indicated in MBC pts who have received ≥2 prior chemotherapy regimens, including an anthracycline and a taxane. It is hypothesized that addition of RAM to E as 3rd-5th line therapy in MBC will result in an improvement of median PFS in this ongoing, multicenter, US study. A planned safety analysis of an initial cohort is reported. Methods: Pts with locally recurrent or MBC (HER2+ or HER2-) and 2-4 prior chemotherapy regimens are randomized 1:1 to receive RAM+E or E (E 1.4 mg/m2 Days 1, 8; RAM 10 mg/kg Day 1; q21 days). Pts are stratified by TNBC and prior antiangiogenic therapy status and must have ECOG PS 0-1 and normal LVEF. Planned accrual: 134 pts. Results: Evaluable pts (n=13, 8 RAM+E) received ≥1 dose of RAM+E or E and completed 2 cycles of therapy (or discontinued prior to completing the initial 2 cycles). Median age is 55 yrs. Assessment of adverse events (all cause) revealed nausea, fatigue, headache, and neutropenia were more frequent for RAM+E; anemia was more frequent for E. G1 sensory neuropathy was reported for 1 pt in each arm. One RAM+E pt experienced G3 febrile neutropenia and odynophagia, recovered within a week, and subsequently received reduced dosage (E = 1.1 mg/m2; RAM = 8 mg/kg). No deaths are reported. The safety assessment committee recommended to continue the trial unmodified. Conclusions: Based on preliminary data, the combination of RAM+E demonstrates an acceptable toxicity profile. Accrual continues, with planned updated safety and dose intensity data to be presented at the meeting. [Table: see text]

HALT MBC: HER2 suppression with the addition of lapatinib to trastuzumab in HER2-positive metastatic breast cancer (LPT112515)

TPS658

Background: Dual blockade of HER2 with the combination of trastuzumab (T) and lapatinib (L) enhances antitumor activity in HER2-positive breast cancer (BC) preclinical models due to the complementary mechanisms of action of the 2 agents. In patients (pts) with T-treated HER2-positive metastatic BC (MBC), treatment with the combination was associated with longer progression-free (PFS) and overall survival (OS) compared with L alone. In pts with stage II/III BC, preoperative treatment with the combination plus paclitaxel (P) resulted in significantly higher pathologic complete response rates compared with P combined with either agent alone. This evidence supports the concept of dual HER2 blockade as a treatment strategy for HER2-positive MBC. The present study is designed to evaluate whether the addition of L improves PFS among women with HER2-positive MBC receiving T as maintenance therapy. Methods: In this open-label, Phase III study, 280 pts will be stratified by line of treatment (first/second) and hormone receptor status (positive/negative), then randomized 1:1 to receive maintenance treatment with either L (1000 mg qd, continuously) in combination with T (6 mg/kg once every 3 weeks [q3w]) or T (6 mg/kg q3w) alone. Pts will receive study treatment until disease progression, death, discontinuation due to adverse events, or other reasons. The primary endpoint is PFS; secondary endpoints are OS, clinical benefit rate, and safety. Key eligibility criteria include pts with HER2-positive MBC who have completed 12 to 24 weeks of first- or second-line treatment with T plus chemotherapy with an objective response or stable disease at time of chemotherapy discontinuation. Pts with stable brain metastases are eligible if entering the study on second-line treatment. Efficacy endpoints will be analyzed in the ITT population. A total of 193 PFS events is required to detect a 50% increase in median PFS (hazard ratio=0.67) for L plus T compared with T alone (median PFS 27 vs 18 weeks, respectively). The hypothesis will be tested using a 1-sided test with 80% power and a type I error of 0.025. The trial is currently open for accrual in the United States and Canada.