Citations

Abstract Background LIV-1, a transmembrane protein and downstream target of STAT3, is highly expressed in breast cancer cells. It is associated with lymph node involvement and metastatic progression. SGN-LIV1A is an anti-LIV-1 antibody conjugated via a protease-cleavable linker to monomethyl auristatin E (MMAE). Upon binding to cell-surface LIV-1, SGN-LIV1A is internalized and releases MMAE, which binds to tubulin and induces G2/M arrest and apoptosis. Methods This is an ongoing, phase 1 dose-escalation study evaluating safety, tolerability, pharmacokinetics, and antitumor activity of SGN-LIV1A (q3 wks IV) in women with LIV-1-positive, unresectable, locally advanced or metastatic breast cancer (LA/MBC) (NCT01969643). Patients (pts) with measurable disease and ≥2 prior cytotoxic regimens for LA/MBC were eligible. Pts with ≥Grade 2 neuropathy were excluded. Response was assessed per RECIST v1.1; pts with stable disease (SD) or better could continue treatment until disease progression or intolerable toxicity. At completion of dose escalation in hormone receptor-positive/HER2-negative (HR+/HER2–) and triple-negative (TN) pts, expansion cohorts were opened to further evaluate safety and antitumor activity of monotherapy in TN pts and combination therapy with trastuzumab (Tz) in HER2-positive (HER2+) pts. Pre- and post-treatment tumor biopsies were done to evaluate LIV-1 expression and other correlative endpoints. Results To date, 39 pts (18 HR+/HER2–, 21 TN) have received a median of 3 cycles (range, 1–10) of SGN-LIV1A monotherapy at doses of 0.5–2.8 mg/kg. Median age was 57 yrs (range, 33–79). At baseline, pts had a median of 4 prior cytotoxic regimens for LA/MBC (range, 2–8); 36 had visceral disease and 25 had bone involvement. No dose-limiting toxicities (DLT) occurred in 19 DLT-evaluable pts; maximum tolerated dose was not exceeded at 2.8 mg/kg. Treatment-emergent adverse events (AEs) reported in ≥30% of pts were: fatigue (64%), nausea (54%), alopecia (46%), decreased appetite (41%), constipation (39%), neutropenia (33%), and vomiting (31%). Peripheral neuropathy was reported in 9 pts (23%). Most AEs were Grade 1/2, except neutropenia (all ≥Grade 3). Four pts discontinued treatment due to AEs (acute respiratory distress syndrome, nausea, pneumonia, tachycardia). In dose escalation, modest activity was observed in 17 efficacy evaluable (EE) HR+/HER2- pts, with a disease control rate (DCR) of 59% (10 SD), including 1 pt with SD≥24 wks. Among the 17 EE TN pts (dose escalation plus cohort expansion), the overall response rate (ORR) was 41% (7 PR), DCR was 82% (7 PR, 7 SD) and clinical benefit rate (CBR=OR+SD≥24 wks) was 53% (9 pts). For TN pts, median PFS was 17.1 wks (95% CI: 6.0, 18.4); 6 pts remain on treatment. Of 281 MBC tumor samples evaluated for LIV-1, 93% were positive; 81% had moderate-to-high expression (H-score ≥100). Conclusions LIV-1 is expressed in almost all MBC tumors. SGN-LIV1A monotherapy has been generally well tolerated and shown encouraging antitumor activity in heavily pretreated TN MBC, with a PR rate of 41% and a CBR at ≥24 wks of 53%. Response duration data continue to evolve. Enrollment continues in the TN monotherapy expansion cohort and the HER2+ combination cohort with Tz. Citation Format: Forero-Torres A, Modi S, Specht J, Miller K, Weise A, Burris III H, Liu M, Krop I, Pusztai L, Kostic A, Li M, Mita M. Phase 1 study of the antibody-drug conjugate (ADC) SGN-LIV1A in patients with heavily pretreated metastatic breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-12-04.

Abstract Introduction: Only half of hormone receptor positive (HR+) metastatic breast cancer (MBC) patients (pts) benefit from endocrine therapy (ET). Circulating tumor cells (CTC) are prognostic in pts with MBC using CellSearch® technology. The CTC-endocrine therapy index (CTC-ETI) provides semi-quantitative analyses of CTC-ER (estrogen receptor), BCL2, HER2, and Ki67 expression. We hypothesized that CTC-ETI high (elevated CTC number and/or low expression of ER and BCL2, and high expression of HER2 and Ki-67) might predict resistance to ET in a prospective, multi-institutional clinical trial: COMETI-P2-2012.0 (NCT01701050). Methods: 121 pts with ER+, HER2 negative (-), and progressive MBC after one or more lines of ET or within 12 months (mos) of completing adjuvant ET, who were initiating a new ET, were enrolled after informed consent. CTC and CTC-ETI were determined as previously reported (Paoletti C et al, CCR 2015) at baseline (BL), 1, 2, 3, and 12 mos, and/or at the time of progression. Imaging was performed every 3 mos. Association of CTC levels and CTC-ETI with patient outcomes (progression free survival (PFS); rapid progression (RP) defined as progression within 3 mos) was assessed using logrank and Fisher's exact tests. Trial design estimated 85 PFS and 51 RP events, providing >90% power (2-sided a=0.05); pts with unsuccessful BL CTC-ETI or ineligible were unevaluable. Only baseline (BL) data are reported in this abstract. Results: 32% of enrolled pts had progression within 12 mos of completing adjuvant ET, whereas 40%, 20%, and 8% had 1, 2, ≥3 lines of ET for MBC. CTC-ETI was successfully determined in 93% of pts (90% CI, 88% to 97%). CTC were ≥5 CTC/7.5 ml whole blood in 37/108 (34%) pts evaluable for clinical validity. Elevated CTC was associated with worse PFS (median (m) PFS: 3.3 vs. 5.9 mos; P<0.01). Low, intermediate, and high CTC-ETI were observed in 75 (69%), 6 (6%), and 27 (25%) pts, respectively. CTC-ETI was associated with PFS (logrank P<0.01): pts with low, intermediate, and high CTC-ETI had mPFS of 5.7, 8.5, and 2.8 mos, respectively. In the 96 pts eligible for determination, elevated CTC was associated with RP, (65.6% vs. 42.2%; P=0.05) as was CTC-ETI (P=0.003): 79.2% (95% CI, 57.8% to 92.9%) of pts with high CTC-ETI had RP versus 41.2% (95% CI, 29.4% to 53.8%) with low CTC-ETI; in the small group with intermediate CTC-ETI 1 of 4 pts (25%) had RP. Conclusions: In this multi-institutional, prospective study, CTC-ETI was accurately determined, confirming the previously established analytical validity of the assay, meeting the primary objective of the trial. Elevated CTC and CTC-ETI high compared to low were associated with poor outcomes to ET. CTC-ETI distribution resulted in a small number of patients assigned to the intermediate group, restricting our ability to associate this group with outcomes. These results suggest that CTC-biomarker phenotype and enumeration have clinical validity. CTC-ETI may identify ER+ HER2– MBC pts who are unlikely to benefit from ET and might be better treated with ET in combination with other therapies or proceed to chemotherapy. Further analyses including CTC-ETI at serial time points during ET are planned. Citation Format: Paoletti C, Regan MM, Liu MC, Marcom PK, Hart LL, Smith II JW, Tedesco KL, Amir E, Krop IE, DeMichele AM, Goodwin PJ, Block M, Aung K, Cannell EM, Darga EP, Baratta PJ, Brown ME, McCormack RT, Hayes DF. Circulating tumor cell number and CTC-endocrine therapy index predict clinical outcomes in ER positive metastatic breast cancer patients: Results of the COMETI Phase 2 trial [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-01-01.

PurposeTo evaluate if cardiac magnetic resonance elastography (MRE) can measure increased stiffness in patients with cardiac amyloidosis. Myocardial tissue stiffness plays an important role in cardiac function. A noninvasive quantitative imaging technique capable of measuring myocardial stiffness could aid in disease diagnosis, therapy monitoring, and disease prognostic strategies. We recently developed a high‐frequency cardiac MRE technique capable of making noninvasive stiffness measurements.Materials and MethodsIn all, 16 volunteers and 22 patients with cardiac amyloidosis were enrolled in this study after Institutional Review Board approval and obtaining formal written consent. All subjects were imaged head‐first in the supine position in a 1.5T closed‐bore MR imager. 3D MRE was performed using 5 mm isotropic resolution oblique short‐axis slices and a vibration frequency of 140 Hz to obtain global quantitativein vivoleft ventricular stiffness measurements. The median stiffness was compared between the two cohorts. An octahedral shear strain signal‐to‐noise ratio (OSS‐SNR) threshold of 1.17 was used to exclude exams with insufficient motion amplitude.ResultsFive volunteers and six patients had to be excluded from the study because they fell below the 1.17 OSS‐SNR threshold. The myocardial stiffness of cardiac amyloid patients (median: 11.4 kPa, min: 9.2, max: 15.7) was significantly higher (P = 0.0008) than normal controls (median: 8.2 kPa, min: 7.2, max: 11.8).ConclusionThis study demonstrates the feasibility of 3D high‐frequency cardiac MRE as a contrast‐agent‐free diagnostic imaging technique for cardiac amyloidosis.Level of Evidence:2Technical Efficacy:Stage 2J. Magn. Reson. Imaging 2017;46:1361–1367.

LBA4 Background: Lapatinib (L) is a HER1-HER2 tyrosine kinase inhibitor. The Adjuvant Lapatinib and/or Trastuzumab Treatment Optimisation (ALTTO) Trial is a randomised, phase III trial comparing 3 oral L-containing regimens with T, each given for 1 year. Methods: From June 2007 to July 2011, 8381 patients (pts) were randomised from 946 sites in 44 countries to receive either L+T, T→L, L, or T. Anti-HER2 therapy was initiated after completing all chemotherapy (N=4613), concurrently with a taxane following anthracycline (N=3337), or concurrently with a non-anthracycline, platinum-containing regimen (N=431). The L arm was closed in Aug 2011 for futility and is not presented. The primary endpoint is invasive disease-free survival (DFS). L+T vs. T is tested for superiority and T→L vs. T is tested for non-inferiority at 1.11 margin. P≤0.025 is required for statistical significance. 850 DFS events in the L+T vs. T comparison would provide 80% power to detect a true hazard ratio (HR) of 0.80 with experiment-wide alpha=0.05. The current analysis was planned to occur either after observing these 850 events or at 4.5 yrs median follow up (MFU). Results: Pt and disease characteristics were well balanced. 40% were node-negative and 57% were hormone receptor positive. Only 555 DFS events for the L+T vs. T comparison were observed at 4.5 years MFU. HR for DFS was 0.84 (97.5% CI, 0.70-1.02; P=0.048; 4-yr DFS%=88% vs. 86%) for L+T vs. T and 0.93 (97.5% CI, 0.76-1.13; non-inferiority P=0.044; 4-yr DFS%=87% vs. 86%) for T→L vs. T. Diarrhoea (75% vs. 20%), rash (55% vs. 20%) and hepatobiliary (23% vs. 16%) adverse events were more frequent in L+T vs. T. Primary cardiac endpoints were infrequent (<1%) in all arms. Conclusions: L+T has lower risk of a DFS event compared with T, and T→L appeared non-inferior to T, but neither finding was statistically significant. The first DFS results of dual HER2 blockade in the adjuvant ALTTO at 4.5 years MFU are unexpected considering the effect shown by doubling the pCR rate with L+T vs. T in the NeoALLTO trial. Follow up continues. Clinical trial information: NCT00490139.

166 Background: T-DM1 is an antibody-drug conjugate composed of trastuzumab, a stable linker, and the cytotoxic agent DM1. Few T-DM1 data are available in settings approximating clinical practice. We present safety and efficacy data from T-PAS, an expanded access study of T-DM1 in patients (pts) with previously treated HER2-positive MBC. Methods: T-PAS is a US multicenter study of T-DM1 (3.6 mg/kg q3w) in HER2-positive (IHC 3+ or FISH/CISH+) locally advanced or MBC. Key eligibility criteria: prior anthracycline and taxane; prior capecitabine or 5-FU and ≥2 HER2-directed agents (including trastuzumab and lapatinib) for MBC; LVEF ≥50%. Primary endpoint: safety; secondary endpoint: investigator-assessed objective response rate (ORR) in pts with measurable disease. Safety was assessed on day 1 of each cycle; ECHO/MUGA scans were every 12 weeks. Results: This analysis includes 215 pts enrolled in May 2010–Sep 2011 (data cutoff 7/31/2012). Pts received a median of 7 prior systemic MBC therapies (range 1–23) with a median cumulative anthracycline dose of 240 mg/m2(range 6–2645). At baseline, median LVEF was 60% and 50% of pts had investigator-reported cardiovascular disease. Median follow-up was 5.9 months (range 0.1–25.3); median T-DM1 duration was 5.0 months (range 0–23) with 15.8% receiving >18 cycles. ORR was 25.6% (42/164). Rate of grade ≥3 AEs was 43.7% and of SAEs of any grade was 18.1%. Most common all-grade AEs were fatigue (50.7%), nausea (36.3%), and headache (24.2%). Most common grade ≥3 AEs were thrombocytopenia (7.9%), fatigue (4.7%), and increased aspartate aminotransferase and anemia (each 3.7%). There were no grade ≥3 bleeding events. Cardiac dysfunction (primarily asymptomatic decreases in LVEF) was reported in 8 pts (3.7%); 4 were grade ≥3, 3 resulting in T-DM1 discontinuation. Conclusions: In this study that more closely reflects the real-world setting, the safety profile of T-DM1 was similar to that previously reported in conventional clinical trials, with no new safety signals. In this pretreated population (median of 7 prior therapies for HER2-positive MBC), significant activity was observed. Clinical trial information: NCT01120561.

1 Background: To determine whether the efficacy of a hypofractionated (H) schedule is no worse than a conventional (C) schedule in men with low-risk prostate cancer. Methods: From April 2006 to December 2009, one thousand one hundred fifteen men with low-risk prostate cancer (clinical stage T1-2a, Gleason ≤ 6, PSA < 10) were randomly assigned 1:1 to a conventional (C) schedule (73.8 Gy in 41 fractions over 8.2 weeks) or to a hypofractionated (H) schedule (70 Gy in 28 fractions over 5.6 weeks). The trial was designed to establish with 90% power and alpha = 0.05 that (H) results in 5-year disease-free survival (DFS) that is not lower than (C) by more than 7% (hazard ratio (HR) < 1.52). Secondary endpoints include freedom from biochemical recurrence (FFBR) and overall survival. At the third planned interim analysis (July 2015), the NRG Oncology Data Monitoring Committee recommended that the results of the trial be reported. Results: One thousand one hundred and one protocol eligible men were randomized: 547 to C and 554 to H. Median follow-up is 5.9 years. Baseline characteristics are not different according to treatment arm. At the time of analysis 185 DFS events have been observed; 99 in the C arm and 86 in the H arm. The estimated 7-year disease-free survival is 75.6% (95% CI 70.3, 80.1) in the C arm and 81.8% (77.5, 85.3) in the H arm. The DFS HR (C/H) is 0.85 (0.64, 1.14). Comparison of biochemical recurrence (HR = 0.77, (0.51, 1.17)) and overall survival (HR = 0.95, (0.65, 1.41)) also met protocol non-inferiority criteria. Grade ≥ 3 GI toxicity is 3.0% (C) vs. 4.6% (H), Relative risk (RR) for H vs. C 1.53, (95% CI 0.86, 2.83); grade ≥ 3 GU toxicity is 4.5% (C) vs. 6.4% (H), RR = 1.43 (0.86,2.37). Conclusions: In men with low-risk prostate cancer, 70 Gy in 28 fractions over 5.6 weeks is non-inferior to 73.8 Gy in 41 fractions over 8.2 weeks. Clinical trial information: NCT00331773.

The sequence of events that lead to inflammation and fibrosing nonalcoholic steatohepatitis (NASH) is incompletely understood. Hence, we investigated the chronology of whole body, tissue, and cellular events that occur during the evolution of diet-induced NASH. Male C57Bl/6 mice were assigned to a fast-food (FF; high calorie, high cholesterol, high fructose) or standard-chow (SC) diet over a period of 36 wk. Liver histology, body composition, mitochondrial respiration, metabolic rate, gene expression, and hepatic lipid content were analyzed. Insulin resistance [homeostasis model assessment-insulin resistance (HOMA-IR)] increased 10-fold after 4 wk. Fibrosing NASH was fully established by 16 wk. Total hepatic lipids increased by 4 wk and remained two- to threefold increased throughout. Hepatic triglycerides declined from sixfold increase at 8 wk to threefold increase by 36 wk. In contrast, hepatic cholesterol levels steadily increased from baseline at 8 wk to twofold by 36 wk. The hepatic immune cell population altered over time with macrophages persisting beyond 16 wk. Mitochondrial oxygen flux rates of FF mice diet were uniformly lower with all the tested substrates (13–276 pmol·s−1·ml−1 per unit citrate synthase) than SC mice (17–394 pmol·s−1·ml−1 per unit citrate synthase) and was accompanied by decreased mitochondrial:nuclear gene copy number ratios after 4 wk. Metabolic rate was lower in FF mice. Mitochondrial glutathione was significantly decreased at 24 wk in FF mice. Expression of dismutases and catalase was also decreased in FF mice. The evolution of NASH in the FF diet-induced model is multiphasic, particularly in terms of hepatic lipid composition. Insulin resistance precedes hepatic inflammation and fibrosis. Mitochondrial dysfunction and depletion occur after the histological features of NASH are apparent. Collectively, these observations provide a unique overview of the sequence of changes that coevolve with the histological evolution of NASH. NEW & NOTEWORTHY This study demonstrates in a first of kind longitudinal analysis, the evolution of nonalcoholic steatohepatitis (NASH) on a fast-food diet-induced model. Key findings include 1) hepatic lipid composition changes in a multiphasic fashion as NASH evolves; 2) insulin resistance precedes hepatic inflammation and fibrosis, answering a longstanding chicken-and-egg question regarding the relationship of insulin resistance to liver histology in NASH; and 3) mitochondrial dysfunction and depletion occur after the histological features of NASH are apparent.

249 Background: HA, a glycosaminoglycan in the tumor matrix, accumulates in 20-30% of solid tumors and ≥28%, ≥42% and ≥87% of colon, gastric and pancreatic ductal adenocarcinoma (PDA) tumors, respectively. Tumors that accumulate HA can develop high interstitial fluid pressure (IFP) and are resistant to chemotherapy. HA in human PDA is associated with disease progression and poor prognosis. In animal models, PEGPH20 reduced tumor-associated HA, tumor IFP and tumor growth, and increased efficacy of chemotherapy. Pharmacodynamic (PD) activity of PEGPH20 is being evaluated in Phase 1 (Ph1) trials. Methods: Two Ph1 studies in pts with advanced solid tumors refractory to prior therapy examined the safety, tolerability, PK, PD and MTD of single-agent IV PEGPH20. Dosing in Study 1 was 2x/wk and then reduced to q21d and in Study 2 is 1-2x/wk x 4wks and 1x/wk thereafter with dexamethasone pre-medication regimen. Biomarkers evaluated: Histochemistry to detect depletion of tumor HA, serum HA catabolites, Dynamic Contrast Enhanced (DCE)-MRI and FDG-PET. Results: In Study 1, the first 3 pts demonstrated musculoskeletal events (MSE; 2 pts dosed with 50 µg/kg 2x/wk, severe; 1 pt dosed with 0.5µg/kg 2x/wk, moderate) not predicted from GLP safety studies. The frequency of drug administration was reduced to q21d and the next 10 pts tolerated ≤1.5 µg/kg. In Study 2, dexamethasone pre-medication regimen was evaluated while dosing at 1-2x/wk. Nine pts were dosed ≤5.0 µg/kg. Doses ≤3.0 µg/kg administered 2x/wk were tolerated with intermittent Grade 1-2 MSE. Activity of PEGPH20 was reflected by increased HA serum catabolites. Pre- and post-dose biopsies from 2 colon pts demonstrated a 23-60% reduction in tumor HA after 4 wks of PEGPH20 dosing. DCE-MRI of PDA and FDG-PET of lung metastases increased tumor perfusion (Ktrans) and decreased metabolic activity 8 and 24hrs post-PEGPH20 dose and was still apparent after 4 wks of treatment with PEGPH20. Conclusions: Ongoing Ph1 studies have shown in vivo activity of PEGPH20 through HA plasma catabolites, tumor HA depletion, DCE-MRI and FDG-PET.

LBA7005 Background: In meta-analyses, platinum-based adjuvant (adj) chemotherapy (CT) in completely resected NSCLC increased cure rate by ∼5%. At BR.19 initiation, adj study results with third-generation agents were unavailable. Gefitinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, showed activity in monotherapy trials. We report a trial of adj gefitinib versus placebo after complete resection of NSCLC. Methods: Patients (pts) with stage IB-IIIA NSCLC were stratified by sex, stage, histology, post-op radiation, and after Jan 2003, adj CT. Pts were randomized to gefitinib 250 mg or placebo daily x 2 years. Study endpoints included overall survival (OS), disease free survival (DFS), toxicity, preplanned correlative studies. Study closed prematurely in Apr. 2005. Trial committee and NCIC CTG staff remained blinded to study drug. Results: 503 pts randomized (Sep 2002-Apr 2005); median age 67, males 54%, PS 0 54%; stage IB 49%, II 38%, III 13%; adenocarcinoma 59%, squamous 28%; ever smokers 89%; adj CT 17%; lobectomy 82%. Commonest grade 3/4 toxicities = fatigue 5%, rash 4% and diarrhea 5%. grade 3+ pneumonitis in 7 (1.4%) pts and led to death in 1. Median follow-up is 4.7 yrs; median treatment time is 4.8 mos. For gefitinib versus placebo, median DFS is 4.2 yrs versus not yet reached (NYR) HR1.22 (95% C.I. 0.93-1.61), p=0.15 and median OS 5.1 yrs versus NYR HR 1.24 (95% C.I. 0.94-1.64), p=0.14. In multivariate analysis, tumor size >4cm was predictive of poor DFS (p<0.0001) and never smoking for better OS with gefitinib (p=0.02). Results for KRAS and EGFR copy are available on 350 and 348 pts respectively. KRAS mutations were neither prognostic HR 1.12 (95% C.I. 0.67-1.86), p=0.66 nor predictive of gefitinib benefit (p = 0.16) on OS. EGFRcopy whether low/high polysomy or amplification was neither prognostic (p=0.77) nor predictive of OS benefit from gefitinib. Conclusions: Adjuvant gefitinib after complete resection of early stage NSCLC did not confer DFS or OS advantage in overall population. KRAS and EGFR copy were neither prognostic nor predictive of benefit from gefitinib. EGFR mutational analysis will be presented. [Table: see text]