Citations

Abstract We evaluated the joint associations between a new 313-variant PRS (PRS313) and questionnaire-based breast cancer risk factors for women of European ancestry, using 72 284 cases and 80 354 controls from the Breast Cancer Association Consortium. Interactions were evaluated using standard logistic regression and a newly developed case-only method for breast cancer risk overall and by estrogen receptor status. After accounting for multiple testing, we did not find evidence that per-standard deviation PRS313 odds ratio differed across strata defined by individual risk factors. Goodness-of-fit tests did not reject the assumption of a multiplicative model between PRS313 and each risk factor. Variation in projected absolute lifetime risk of breast cancer associated with classical risk factors was greater for women with higher genetic risk (PRS313 and family history) and, on average, 17.5% higher in the highest vs lowest deciles of genetic risk. These findings have implications for risk prevention for women at increased risk of breast cancer.

Abstract Radioimmunotherapy (RIT) is a therapeutic modality indicated for the treatment of patients with relapsed or refractory low-grade, follicular, or transformed non-Hodgkin’s lymphoma (NHL), where the mechanism of action involves the intrinsic activity of the monoclonal antibody and the cytotoxic effects of radiation. The primary toxicity is a late-occurring, transient, and reversible myelosuppression. Because of concerns regarding the long-term effects of radiation on the bone marrow, we investigated the incidence of treatment-related myelodysplastic syndrome (t-MDS) and treatment-related acute myelogenous leukemia (t-AML) after ibritumomab tiuxetan RIT. A total of 746 patients with NHL were treated with the ibritumomab tiuxetan regimen in registration and compassionate-use trials between 1996 and 2002. Patients had a median age of 61 years (range, 24–87) and had received a median of 3 prior therapies (range, 0–9+). The crude incidence of t-MDS or t-AML was 2.3% (17/746), with an incidence of 4.7% (10/211) in patients enrolled in registration trials and of only 1.3% (7/535) in patients included in the compassionate-use trial, with a median follow-up of 5.7 and 3.5 years, respectively. These malignancies were documented at a median of 5.6 years (range, 1.2–13.9) after the diagnosis of NHL and 1.5 years (range, 0.1–5.8) after RIT. The annualized rates were 0.3% (95% CI, 0.2%–0.4%) a year after the diagnosis of NHL and 0.7% (95% CI, 0.4%–1.0%) a year after RIT. Cox multivariate regression analysis found that previous treatment with a purine nucleoside analog was a significant risk factor for t-MDS or t-AML (hazard ratio, 3.9 [95% CI, 1.5–10.4]; P = .006). All patients in whom t-MDS or t-AML developed and in whom cytogenetic data were available (n = 15) had multiple cytogenetic aberrations, commonly of chromosomes 5 and 7, suggesting an association with previous exposure to chemotherapy. There were documented bone marrow cytogenetic abnormalities before treatment in 2 patients who developed t-MDS or t-AML. These data suggest that the annualized incidence of t-MDS or t-AML following ibritumomab tiuxetan RIT is consistent with that expected on the basis of the patients’ history of treatment for NHL. Cytogenetic testing before administration of RIT may identify existing chromosomal abnormalities in previously treated patients, particularly in those who have been treated with alkylating agents and/or purine nucleoside analogs and who are thereby at a higher risk for t-MDS or t-AML.

Abstract Background: As the first radiolabled monoclonal antibody approved for the treatment for the treatment of cancer, yttrium 90 (90Y) ibritumomab tiuxetan (Zevalin®) achieves both high response rates and durable remissions in patients with relapsed or refractory, low-grade, follicular, or transformed B-cell NHL. Because of the stability of 90Y ibritumomab tiuxetan and its favorable pharmacokinetic profile (ie, predictable urinary clearance and absence of dehalogenation), dosing is based on patient weight and platelet counts. Yttrium 90 ibritumomab tiuxetan is typically delivered at a dose of 0.4 mCi/kg (in patients with platelets >150,000/mm3) or 0.3 mCi/kg (in patients with platelets ≤150,000/mm3) to a maximum recommended dose (MRD) of 32 mCi. However, patients >80 kg with platelet counts exceeding 150,000/mm3 may receive a lower drug concentration (ie, <0.4 mCi/kg 90Y) as a result of dose capping. We evaluated whether the 32 mCi dose cap influences the safety or efficacy of ibritumomab tiuxetan therapy in patients >80 kg. Methods: Efficacy and safety data were collected for patients from 3 registrational trials that received either 0.4 mCi/kg 90Y (patients ≤80 kg) or 32 mCi 90Y (patients >80 kg). Results: Clinical responses in 170 patients were evaluated. Patients ≤80 kg (n = 103) had a median weight of 70 kg (range, 45–80 kg) versus a median weight of 95 kg (range, 81–159) for patients >80 kg (n = 67). Gender (41% M vs 73% M, respectively; P <.01) was the only significantly different baseline characteristic between the ≤80 kg and >80 kg groups. Similar efficacy and safety results were reported for both subsets of patients. Overall response rates of 79% and 70% were observed for patients ≤80 kg and >80 kg, respectively (P =.27); and no significant differences were seen in complete response rates (28% vs 34%, respectively; P =.40). Median TTP (8.9 months vs 9.5 months; P =.53) and median DR (8.5 months vs 11.5 months; P =.34) were equivalent between the 2 weight-based groups. In addition, there were no statistically significant differences in safety measures including grade 3/4 nonhematologic adverse events, neutropenia, thrombocytopenia, or anemia. Conclusions: As a consequence of dose capping at an MRD of 32 mCi, 39% of patients received a lower dose/kg of 90Y ibritumomab tiuxetan. However, despite the difference in dose administered on a unit of body weight basis, the efficacy and safety results were similar between patients ≤80 kg and >80 kg. We conclude that the 32 mCi dose cap does not influence the efficacy or safety profile of 90Y ibritumomab tiuxetan for patients >80 kg.

INTRODUCTION The cerebral cortex underlies our complex cognitive capabilities. Variations in human cortical surface area and thickness are associated with neurological, psychological, and behavioral traits and can be measured in vivo by magnetic resonance imaging (MRI). Studies in model organisms have identified genes that influence cortical structure, but little is known about common genetic variants that affect human cortical structure. RATIONALE To identify genetic variants associated with human cortical structure at both global and regional levels, we conducted a genome-wide association meta-analysis of brain MRI data from 51,665 individuals across 60 cohorts. We analyzed the surface area and average thickness of the whole cortex and 34 cortical regions with known functional specializations. RESULTS We identified 369 nominally genome-wide significant loci ( P < 5 × 10 −8 ) associated with cortical structure in a discovery sample of 33,992 participants of European ancestry. Of the 360 loci for which replication data were available, 241 loci influencing surface area and 66 influencing thickness remained significant after replication, with 237 loci passing multiple testing correction ( P < 8.3 × 10 −10 ; 187 influencing surface area and 50 influencing thickness). Common genetic variants explained 34% (SE = 3%) of the variation in total surface area and 26% (SE = 2%) in average thickness; surface area and thickness showed a negative genetic correlation ( r G = −0.32, SE = 0.05, P = 6.5 × 10 −12 ), which suggests that genetic influences have opposing effects on surface area and thickness. Bioinformatic analyses showed that total surface area is influenced by genetic variants that alter gene regulatory activity in neural progenitor cells during fetal development. By contrast, average thickness is influenced by active regulatory elements in adult brain samples, which may reflect processes that occur after mid-fetal development, such as myelination, branching, or pruning. When considered together, these results support the radial unit hypothesis that different developmental mechanisms promote surface area expansion and increases in thickness. To identify specific genetic influences on individual cortical regions, we controlled for global measures (total surface area or average thickness) in the regional analyses. After multiple testing correction, we identified 175 loci that influence regional surface area and 46 that influence regional thickness. Loci that affect regional surface area cluster near genes involved in the Wnt signaling pathway, which is known to influence areal identity. We observed significant positive genetic correlations and evidence of bidirectional causation of total surface area with both general cognitive functioning and educational attainment. We found additional positive genetic correlations between total surface area and Parkinson’s disease but did not find evidence of causation. Negative genetic correlations were evident between total surface area and insomnia, attention deficit hyperactivity disorder, depressive symptoms, major depressive disorder, and neuroticism. CONCLUSION This large-scale collaborative work enhances our understanding of the genetic architecture of the human cerebral cortex and its regional patterning. The highly polygenic architecture of the cortex suggests that distinct genes are involved in the development of specific cortical areas. Moreover, we find evidence that brain structure is a key phenotype along the causal pathway that leads from genetic variation to differences in general cognitive function. Identifying genetic influences on human cortical structure. ( A ) Measurement of cortical surface area and thickness from MRI. ( B ) Genomic locations of common genetic variants that influence global and regional cortical structure. ( C ) Our results support the radial unit hypothesis that the expansion of cortical surface area is driven by proliferating neural progenitor cells. ( D ) Cortical surface area shows genetic correlation with psychiatric and cognitive traits. Error bars indicate SE. IMAGE CREDITS: (A) K. COURTNEY; (C) M. R. GLASS

7509 Background: NTX-010 is a naturally occurring replication-competent picornavirus with potent and selective tropism for SCLC tumor cells expressing neuroendocrine markers. A phase I study of NTX-010 showed evidence of antitumor activity in patients with SCLC. Methods: ES-SCLC patients (pts) with SD, PR or CR after at least 4 cycles of platinum-based chemotherapy were pre-registered to confirm diagnosis of SCLC with > 1 neuroendocrine marker by a central pathology review. Eligible pts were.randomized 1:1 to placebo (B) or NTX-010 (A). NTX-010 or placebo was administered intravenously as a 1-hour infusion in 100 mL normal saline as a single dose of 1 x1011vp/kg. Viral studies to determine distribution, clearance of the virus and the presence of neutralizing antibodies were done. The primary goal of this trial was to compare the progression-free survival (PFS) of arm A to B based on a sample size of 45 patients per arm to detect an improvement in median PFS from 3 to 5 months (m). A pre-planned interim futility analysis was done after 40 PFS events, and reported here. Results: The trial is permanently closed to accrual. One-hundred and twenty pts were pre-registered, of whom 58 were randomized. Baseline age, gender, ECOG performance status, and histology were balanced between arms. Median age was 63 (range: 44 - 82). 31% of pts had a PS of 0 and 69% of 1. Grade 4 adverse events were seen in 3 (12.5%) patients in arm A and none in arm B. Based on the interim futility analysis, PFS was 1.7 m (95% CI: 1.3-3.1) for arm A and 1.7 m (95% CI: 1.4-4.3) for arm B. Pts with viral RNA at 7 (7 pts) and 14 (6 pts) days had worse PFS compared to those with no detectable levels within arm A (1.0 vs 1.6 m, p=0.02; 0.9 vs. 1.2 m, p=0.06). Median follow-up in pts is 6.1 m. The 3-month OS estimates are 83% (95% CI: 69%-100%) and 85% (70%-100%) for arms A and B respectively. Conclusions: This phase II study showed no benefit in PFS for ES-SCLC patients receiving NTX-010. Pts with detectable virus at 7 and 14 days had worse PFS. Clinical trial information: NCT01017601.

1087 Background: EP is a unique topoisomerase 1 inhibitor that provides continuous exposure to SN38. EP demonstrated a 29% overall response rate in patients with mBC, leading to a phase III global BEACON study in patients with mBC. CTCs in patient blood samples provide a minimally invasive approach to detect PD markers of drug activity. We developed quantitative multiplex immunofluorescent assays to measure target-specific PD biomarkers for EP in CTCs isolated pre- and post-treatment. Methods: Assays for Top1, Top2, g-H2Ax, Rad51, ABCG2, and Ki-67 were developed using control (0.1% DMSO) and drug-treated (SN38, 10 uM) tumor cell lines (HCT116, MCF7, A549, SKBr3) and PBMCs from healthy donors. The optimal antibody for each biomarker was then multiplexed in a panel with antibodies against cytokeratin, CD45 and DAPI for phenotypic identification of CTCs. For analysis of BEACON pts, serial 7.5 mL whole blood samples were drawn and shipped ambient to Apocell (Houston, TX) for further processing. PBMCs were separated and CTCs were isolated using ApoStream technology. CTCs were stained for PD markers and analyzed using an iCys laser scanning cytometer equipped with image analysis software. Results: Antibodies bound to tumor cells showed staining confined to the nucleus (Top1, Top2, g-H2AX, Ki-67) or membrane (ABCG2), exhibited defined peak separation from their isotype controls, and signal strength correlated with cellular expression of high and low levels of markers. To date, ~ 80% of BEACON pts consent to participate in the CTC sub-study. As of 30 Oct 2012, data from 167 pre-dose blood samples from BEACON pts were available. 99% of blood samples were successfully processed. 93% had detectable CTCs, yielding a median of 216 CTCs (range: 7.5-14816). Staining was positive for Top1, Top2, g-H2Ax, Rad51, ABCG2, and Ki-67 in 82%, 89%, 16%, 53%, 31%, 52% of samples, respectively. Conclusions: EP target-specific pharmacodynamic biomarkers can be reliably measured in CTCs isolated from patients participating in BEACON. Sample collection and analysis of pre- and post-treatment samples is ongoing. Clinical trial information: NCT01492101.

13013 Background: The glutathione metabolic pathway is directly involved in the inactivation of platinum compounds. Our earlier work indicated that genotypes corresponding to varied glutathione-related enzyme activities may predict survival in patients with advanced lung cancer. Herein, we evaluated the role of glutathione-related genotypes on clinical outcomes in stage IIIB/IV non-small cell lung cancer patients who were stable or responding from one prior platinum-based chemotherapy. Methods: DNA samples from patients who had tumor regression or stable disease after treatment with one platinum based chemotherapy regimen were analyzed using 6 polymorphic DNA markers that encode 5 important enzymes in the glutathione metabolic pathway. The contrasting genotypes used in the analysis were GCLC (homozygous repeat 77 vs. heterozygous 7*), GPX1 (CC vs. other), GSTP1-I105V (AA vs. other), GSTP1-A114V (CC vs. other), GSTM1 (null vs. present), and GSTT1 (null vs. present). Multivariable Cox proportional hazards models adjusted for age, gender, treatment arm, ECOG performance status, stage, and prior tumor response, were used to evaluate the prognostic significance of the genotypes at each locus. Results: Data from 112 patients with a median follow-up of 10.6 (range: 0.4–56.3) months was used. No significant difference in time to disease progression was observed for any of the genotypes. Among the 6 genomic DNA markers, the GCLC genotype was an important prognostic factor for overall survival after adjusting for other factors. In particular, patients carrying a 77 repeat genotype (homozygous) had a significantly worse survival (Hazard ratio = 1.67, 95% CI: 1.05–2.63). Conclusions: Genotypes of glutathione-related enzymes, especially GCLC, may be used as host factors in predicting patients’ prognosis after platinum-based chemotherapy. Further investigation to define and measure the effects of these genes in chemotherapeutic regimens is needed. (This work was partly supported by NIH research grants CA77118, CA80127, and CA84354.) No significant financial relationships to disclose.

19503 Background: This study was performed to assess the value of combined modality therapy in elderly patients by comparing the differences in outcome of those who received radiotherapy (RT) alone or RT plus chemotherapy for stage III NSCLC. Methods: North Central Cancer Treatment Group (NCCTG) performed 2 recent phase III trials for stage III NSCLC. The first trial, 90–24–51, included 3 arms: once-daily radiotherapy (QDRT) alone, twice daily RT (BIDRT) alone, and concurrent chemotherapy plus BIDRT. The second trial, 94–24- 52 included 2 arms and compared concurrent chemotherapy with either QDRT or BIDRT. The chemotherapy arms of both trials included etoposide and cisplatin administered concurrently with RT. Only the patients ≥65 years of age (elderly) who participated in these trials were included in this analysis. Results: Of the 166 elderly patients included in this analysis, 37 received RT alone and 129 received concurrent chemotherapy plus RT. The median and 5-year survival rates were 10.5 months and 5.4% for the RT alone group compared to 13.7 months and 14.7% for the RT plus chemotherapy group (log-rank p=0.05). Patients who received RT plus chemotherapy experienced significantly greater severe (grade ≥3) toxicity than those who received RT alone (89.9% versus 32.4%, p < 0.01). Conclusions: Elderly patients who participated in these trials appear to gain a survival advantage from RT and chemotherapy compared to RT alone. As is the case with younger patients, this benefit comes at the cost of additional toxicity. No significant financial relationships to disclose.