Citations

Objective To examine the influence of solar cycle and geomagnetic effects on the incidence of giant cell arteritis (GCA) and rheumatoid arthritis (RA). Methods We used data from patients with GCA (1950–2004) and RA (1955–2007) obtained from population-based cohorts. Yearly trends in age-adjusted and sex-adjusted incidence were correlated with the F10.7 index (solar radiation at 10.7 cm wavelength, a proxy for the solar extreme ultraviolet radiation) and AL index (a proxy for the westward auroral electrojet and a measure of geomagnetic activity). Fourier analysis was performed on AL, F10.7, and GCA and RA incidence rates. Results The correlation of GCA incidence with AL is highly significant: GCA incidence peaks 0–1 year after the AL reaches its minimum (ie, auroral electrojet reaches a maximum). The correlation of RA incidence with AL is also highly significant. RA incidence rates are lowest 5–7 years after AL reaches maximum. AL, GCA and RA incidence power spectra are similar: they have a main peak (periodicity) at about 10 years and a minor peak at 4–5 years. However, the RA incidence power spectrum main peak is broader (8–11 years), which partly explains the lower correlation between RA onset and AL. The auroral electrojets may be linked to the decline of RA incidence more strongly than the onset of RA. The incidences of RA and GCA are aligned in geomagnetic latitude. Conclusions AL and the incidences of GCA and RA all have a major periodicity of about 10 years and a secondary periodicity at 4–5 years. Geomagnetic activity may explain the temporal and spatial variations, including east-west skewness in geographic coordinates, in GCA and RA incidence, although the mechanism is unknown. The link with solar, geospace and atmospheric parameters need to be investigated. These novel findings warrant examination in other populations and with other autoimmune diseases.

Abstract Metastatic epidural spinal cord compression (MESCC) is an oncologic emergency and if left untreated, permanent paralysis will ensue. The treatment of MESCC is governed by disease, patient, and treatment factors. Patient's preferences and goals of care are to be weighed into the treatment plan. Ideally, a patient with MESCC is evaluated by an interdisciplinary team promptly to determine the urgency of the clinical scenario. Treatment recommendations must take into consideration the risk-benefit profiles of surgical intervention and radiotherapy for the particular individual's circumstance, including neurologic status, performance status, extent of epidural disease, stability of the spine, extra-spinal disease status, and life expectancy. In patients with high spinal instability neoplastic score (SINS) or retropulsion of bone fragments in the spinal canal, surgical intervention should be strongly considered. The rate of development of motor deficits from spinal cord compression may be a prognostic factor for ultimate functional outcome, and should be taken into account when a treatment recommendation is made. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

A small number of common susceptibility loci have been identified for pancreatic cancer, one of which is marked by rs401681 in the TERT–CLPTM1L gene region on chromosome 5p15.33. Because this region is characterized by low linkage disequilibrium, we sought to identify whether additional single nucleotide polymorphisms (SNPs) could be related to pancreatic cancer risk, independently of rs401681. We performed an in‐depth analysis of genetic variability of the telomerase reverse transcriptase (TERT) and the telomerase RNA component (TERC) genes, in 5,550 subjects with pancreatic cancer and 7,585 controls from the PANcreatic Disease ReseArch (PANDoRA) and the PanScan consortia. We identified a significant association between a variant in TERT and pancreatic cancer risk (rs2853677, odds ratio = 0.85; 95% confidence interval = 0.80–0.90, p = 8.3 × 10−8). Additional analysis adjusting rs2853677 for rs401681 indicated that the two SNPs are independently associated with pancreatic cancer risk, as suggested by the low linkage disequilibrium between them (r2 = 0.07, D′ = 0.28). Three additional SNPs in TERT reached statistical significance after correction for multiple testing: rs2736100 (p = 3.0 × 10−5), rs4583925 (p = 4.0 × 10−5) and rs2735948 (p = 5.0 × 10−5). In conclusion, we confirmed that the TERT locus is associated with pancreatic cancer risk, possibly through several independent variants.

Abstract Introduction: Triple negative breast cancers (TNBC) are characterized as lacking estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) expression and TNBC patients have higher rates of recurrence and death compared with other breast cancer subtypes. For TNBC patients who fail standard chemotherapy, there are a lack of novel drug therapies, given the absence of well-defined molecular targets. Recently, a microarray meta-analysis identified 7 triple negative subtypes, including the validation of the luminal androgen receptor (LAR) positive subtype [Lehmann, 2011]. However, microarray technology is dependent on probe-target specificity and the 7 subtypes have yet to be validated using RNA sequencing data, and the presences of recurrent genomic alterations in the 7 subtypes are unknown. METHODS: We obtained 1106 breast cancer RNA-Seq bam files from The Cancer Genome Atlas (TCGA) and aligned with Tophat v1.3. The PAM50 intrinsic gene signature was used to extract a cohort of 128 TNBC samples. Consensus clustering of genes, greater than 75th percentile of variance, was performed using Kmeans clustering in Spearman's correlation space. A nearest centroid prediction model was developed from genes differentially expressed among the clusters. Eighty independent TNBC RNA sequencing samples were obtained (British Colombia; BC) [Shah, 2012] which were calibrated to our TNBC conditional quantile normalized cohort and sub-typed by our model. RESULTS: Using RNA-Seq gene expression count data, we identified 5 clusters, all of which were stable, including the LAR cluster. Signaling pathway impact analysis (SPIA) implicated cytokine-cytokine receptor interaction, leukocyte transendothelial migration, and regulation of actin cytoskeleton pathways commonly altered in the non-LAR TNBC subtypes. In contrast, cell cycle, ECM-receptor interaction, endocrine regulated calcium reabsorption, and insulin signaling pathways were altered in the LAR versus non-LAR subtypes. Neuroactive ligand-receptor interactions were observed to be altered commonly between all sub-types. We then applied our model to the Shah, et al cohort. In this cohort, the LAR subtype was consistent with Shah's classification of ‘other’ TNBC and contained no basal samples by PAM50 intrinsic modeling. Analysis of sub-type specific mutation data from the BC cohort demonstrates an increased mutational load in ECM-related proteins, particularly the myosins, along with increased TP53 clonality in the non-LAR subtypes. CONCLUSIONS: Using TCGA RNASeq data, we have confirmed the presence of 5 major TNBC subtypes, including the LAR; which was negligible in basal composition by PAM50 intrinsic modeling. SPIA pathway analysis indicates a core set of pathways demonstrating altered expression across the TNBC sub-types and the identification of molecular targets within each subtype is ongoing. Citation Format: Kevin J. Thompson, Xiaojia Tang, Zhifu Sun, Jason P. Sinnwell, Hugues Sicotte, Douglas W. Mahoney, Steven Hart, Peter T. Vedell, Poulami Barman, Jeanette E. Eckel Passow, Eric D. Wieben, James N. Ingle, Judy C. Boughey, Liewei Wang, Richard Weinshilboum, Krishna R. Kalari, Matthew P. Goetz. Molecular classification of triple negative breast cancer via RNA-sequencing data. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5592. doi:10.1158/1538-7445.AM2014-5592

Abstract Background: Genome wide association studies (GWAS) have recently identified 8 loci identified with multiple myeloma (MM) susceptibility. We hypothesized that germ line genetic variants may also affect MM progression. We performed the first GWAS of MM survival, by conducting a meta-analysis of two existing studies at University of California San Francisco (UCSF) and the Mayo Clinic, and replicating findings in the International Multiple Myeloma rESEarch (IMMEnSE) consortium. Methods: The UCSF study included 353 MM patients genotyped on an Illumina Omni5 and Illumina 660 array. The Mayo clinic study included 239 MM patients genotyped on an Affymetrix 6.0 array. We imputed missing genotypes using the 1000 Genomes dataset and performed a GWAS for survival using proportional hazards models adjusting for age and gender and genetic ancestry using principal components analysis. We conducted a meta-analysis of the results from the two GWAS. We replicated the top SNPs in the IMMEnSE cohort which included 772 patients with survival data from 7 European countries and one North American site. We used the dataset from Grundberg et al (Nat Genetics 2012) to test for an association between SNPs associated with survival and gene expression in immortalized lymphocytes. We used gene expression data from Zhan et al (Blood 2006) to analyze the association between expression and survival. Results: In meta-analysis, we found a genome wide significant association between SNPs on a region at 16p13 and survival (rs72773978; p=2.9x10e-10). Patients with the minor allele were at increased risk for mortality (HR 2.73; 95% CI: 1.99 - 3.73). The top associated SNPs were all in strong linkage disequilibrium and were centered over the gene FOPNL. We replicated the association in the IMMEnSE cohort and found a significant association between the top SNP from the discovery dataset (rs72773978 p=0.037). We used previously published data to determine the association between gene expression and the top associated SNPs from the GWAS. The top SNP (rs72773978) was not in previously published eQTL databases, so we used rs7201759 which was also associated with survival in our data (p=3.8x10e-10) as a proxy. The minor allele for this SNP was associated with increased levels of expression of FOPNL (p=9x10e-5), but not with expression of any other genes within a 1 megabase region. Finally, we also observed an association between increased expression of FOPNL and shorter survival (HR: 2.62 per standard deviation.; 95% CI: 1.08 - 6.32). Conclusion: Germ line variants at 16p13 near the FOPNL gene are associated with survival among MM patients. FOPNL is thought to be involved in centrosomal function, and centrosomal activity has previously been associated with survival in MM patients. Our results support this previous observation. Furthermore, they suggest that germ line variants could also be useful in assessing prognosis for patients with MM. Citation Format: Elad Ziv, Eric Dean, Donglei Hu, Alessandro Martino, Daniel Serie, Daniele Campa, Blake Aftab, Paige Bracci, Gabriele Buda, Jennifer Caswell, Charles Dumontet, Marek Dudziński, Laura Fejerman, Alexandra Greenberg, Scott Hunstman, Artur Jurczyszyn, Krzysztof Jamroziak, Shaji Kumar, Herlander Marques, Thomas Martin, Joaquin Martinez-Lopez, Vincent Rajkumar, Juan Sainz, Annette Juul Vangsted, Marzena Watek, Jeffrey Wolf, Susan Slager, Federico Canzian, Celine Vachon. Genome wide association study identifies variants at 16p13 associated with survival in multiple myeloma patients. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5078. doi:10.1158/1538-7445.AM2014-5078

Abstract INTRODUCTION Next generation sequencing (NGS) of patients has significantly changed our ways to study cancer genomics as it provides precise estimates of gene expression, fusion transcripts, expressed single nucleotide variants (eSNVs), splice variants and copy number variants. The Breast Cancer Genome Guided Therapy (BEAUTY) is an ongoing clinical study in which RNA sequencing (RNAseq) and whole exome sequencing (WES) are performed prior to, during and after neoadjuvant chemotherapy. Here we report the use of these sequencing technologies to investigate gene expression levels and mutational profiles in a triple negative breast cancer (TNBC) patient enrolled in BEAUTY whose disease did not respond to neoadjuvant paclitaxel and anthracycline/cycphosphamide. METHODS Computational approaches were used to integrate WES and RNAseq data obtained before therapy (V1T), after 12 weekly paclitaxel treatments (V2T) and after anthracycline-based regimen at surgical resection (V3T) to study a single patient with persistent TNBC disease after neoadjuvant chemotherapy. RESULTS Using RNA-Seq data, we identified an inter-chromosomal fusion transcript between chromosome 20 and 22 (GNAS-TTC38) that was highly expressed at V1T, V2T and V3T. We also identified intra-chromosomal fusion transcripts that were expressed at two time points, such as fusion transcript (KANSL1-ARL17A) on chromosome 17 for V1T and V2T and fusion transcript (RBM12B-LINC00535) on chromosome 8 for V2T and V3T time points. Several gene expression changes were also observed. Gene expression analysis of V1T, V2T and V3T tumors was performed. Differential temporal gene expression profiles of 9884 genes that were significant and varying at different time points were obtained for pathway analysis. Pathway analysis of 9884 genes identified up regulation and down regulation of several transcription factors with a fold change of 2x or more. When compared to blood, DNA tumor and RNA-Seq data, we identified 81 common somatic eSNVs that were expressed in both V1T and V2T time points and we are in the process of investigating V3T data. We found alterations of key transporter domains (CD225, Coatamer_beta_C, DUF2435, Dynamitin, EI24, GLTP, LMF1, Porin_3, V-ATPase_C) in our V1T and V2T SNV data. Similar to gene expression analysis, we are in the process of obtaining the list of mutations at various time points to identify driver and passenger mutation candidate genes for this specific TNBC patient. CONCLUSIONS Our initial time-series analysis of eSNV, fusion transcripts and gene expression data demonstrate that intensive analysis for individual patients is feasible. Further investigation of drug transporters and transcription regulators may help develop personalized treatment strategies for patients with disease resistant to current regimens. Citation Format: Krishna R. Kalari, Xiaojia Tang, Kevin J. Thompson, Douglas W. Mahoney, Poulami Barman, Jason P. Sinnwell, Hugues Sicotte, Peter Vedell, Steven N. Hart, Travis J. Dockter, Katie N. Jones, Amy L. Conners, Ann M. Moyer, Daniel W. Visscher, Jia Yu, Bowen Gao, Sarah A. McLaughlin, John A. Copland, Alvaro Moreno-Aspitia, Donald W. Northfelt, Richard J. Gray, Vera J. Suman, Jeanette E. Eckel Passow, Jean-Pierre A. Kocher, Eric D. Wieben, Gianrico Farrugia, Cloann G. Schultz, James N. Ingle, Richard Weinshilboum, Matthew P. Goetz, Liewei Wang, Judy C. Boughey. Analysis of sequencing data to identify potential drug targets for an individual newly diagnosed with basal breast cancer who failed to respond to current standard neoadjuvant chemotherapy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4185. doi:10.1158/1538-7445.AM2014-4185

Abstract Treatment of glioblastoma multiforme (GBM) continues to be a challenge due to its infiltrative nature, tumor heterogeneity, and lack of therapeutic agents that penetrate the blood-brain barrier (BBB). While the primary tumor is permeable to some degree, the ability of GBM cells to invade areas of parenchyma with an intact BBB indicates development of BBB-penetrable compounds is a necessity. The multifunctional protein MDM2 holds promise as a therapeutic target in a variety of cancers and plays a critical role in controlling cell survival, invasion, and DNA repair. MDM2 antagonists such as nutlin3a and RG7112 are being used to interrogate the impact of modulating MDM2 function in combination with front-line therapy. Our objective was to investigate whether MDM2 antagonists, alone or in combination with temozolomide (TMZ), can augment cell death in orthotopic GBM xenograft models. In vitro data indicate that TMZ and nutlin3a are synergistic in decreasing cell viability in wild type (wt) p53 U87-MG, primary human wt p53 GBM10 and mutant (mt) p53 GBM43 cells. Pharmacodynamic studies demonstrated that the mechanism of action for promoting cell death following exposure to TMZ/nutlin3a was multifactorial. Comet assays indicated that repair of TMZ-mediated DNA damage was significantly delayed in wt and mt p53 GBM cells treated with TMZ/nutlin3a compared to TMZ alone and the base excision repair protein Ape1 was downregulated in cells treated with TMZ/nutlin3a. Pharmacokinetic studies guided development of rational dosing regimens in which 2-3 five-day cycles of TMZ followed by nutlin3a 4 hours later were investigated. In ectopic U87-MG xenografts, nutlin3a sensitized xenografts to TMZ-mediated cell death. Orthotopic studies employing U87-MG, GBM10, and GBM43 tumors are being utilized to determine if nutlin3a levels detectable in the brain via HPLC-MS/MS(API 4000) are sufficient to modulate MDM2 function in the context of TMZ and increase survival. In the TMZ-resistant GBM10 (wtp53, MGMTpos, and PTENnull) orthotopic model, there was a modest increase in median survival from 63 days with TMZ to 73 days with TMZ/nutlin3a. Higher and more sustained brain levels of MDM2 antagonists will likely be necessary to improve survival. The MDM2 antagonist RG7112 has an improved PK profile and structural analysis of RG7112 and nutlin3a via QikProp 3.0 (www.schrodinger.com) indicates that RG7112 also has an improved predicted brain/blood partition coefficient (plog BB) compared to nutlin3a (RG7112 = -0.17; nutlin3a = -0.415). Studies are in progress to assess the brain penetration of RG7112 and its effect on GBM growth in vivo. Taken together, our data suggest that modulation of MDM2 function in the context of cytotoxic therapy has the potential to alter mechanisms involved in DNA repair that can promote cell death and improve survival. Citation Format: Haiyan Wang, Shanbao Cai, Barbara J. Bailey, Lawrence M. Gelbert, M. Reza Saadatzadeh, Aaron A. Cohen-Gadol, Jann N. Sarkaria, Paul Territo, Taxiarchis M. Georgiadis, T. Zachary Gunter, Samy Meroueh, Eric C. Long, David R. Jones, Lindsey D. Mayo, Shannon Harlan, Karen E. Pollok. Sensitization of temozolomide-mediated glioblastoma cell death by targeting MDM2: Assessment of PD biomarkers, brain penetration, and efficacy in humanized orthotopic xenograft models. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2741. doi:10.1158/1538-7445.AM2014-2741

Abstract Intro: Male BC is a rare disease (<1% male tumors); knowledge is limited and management extrapolated from female BC. An international consortium, coordinated by EORTC and TBCRC, was created to better characterize and manage this disease, with 3 parts: 1) retrospective joint analysis 2) prospective registry 3) clinical trial(s). We report 1st results of part 1. Methods: Joint analysis of male BC pts with available FU & FFPE samples, treated in 1990-2010, in 23 centers from 9 countries. Clinical data, long term outcomes, local pathology were centrally analyzed at EORTC. FFPE samples were analyzed at 3 central labs (UK, NL, US) for histology, grade, ER, PR, AR, HER-2, Ki67. Cut-off for positivity: Allred score ≥ 3 for ER/ AR/PR; 20% for Ki67; ASCO-CAP for HER2. Outcome data (OS & RFS) analyzed per Kaplan Meier, p-values correspond to logrank test, CI’s by Brookmeyer & Crowley. Reported % use number of non-missing values as denominator. Results: 1822 pts enrolled; 349 (19%) ineligible (no valid central lab assessment); of 1473 eligible pts (1384 from EU, 89 from US) 63% diagnosed in 2001-2010. Median age at diagnosis (Dx) was 68.5 ys. Of pts with known M status at Dx, 56 (5.1%) were M1; of 1046 M0 cases, 60% were N0 and 51% had T1 tumors at Dx; 4% of pts had BCS and 18% had SLNB; half received adjuvant RT. (Neo)adjuvant CT was used in 30% of M0 pts, most (44%) anthracycline-only; 77% of M0 pts received adjuvant ET, most tamoxifen (88.4%). Central pathology: 697 cases with central histology & grade (full series ongoing): 87% ductal, 53% grade 2. In 1473 pts, at least 1 biomarker centrally assessed; 92% ER highly+ (Allred 7-8), PR had wider variation (35% highly+); 87% AR highly+; 25% Ki67 high; 5% HER2pos. Using IHC surrogates: 58% Luminal A-like, 35% LuminalB-like/HER2neg, 6% LuminalB-like/HER2pos; 0.1% HER2pos/non-Luminal; 1% TNBC (16% not classified). Outcome: For 1046 M0 pts, median FU was 5.7 yrs (0-19.2); 63% alive at analysis; in 88% cause of death was reported, mainly 33% non-cancer and 28% progression(PD)/toxicity. Significant OS improvement over time is seen. 75% (42/56) M1 pts died, mainly due PD. In M0 pts, median OS (yrs) was significantly correlated with ER+ p=0.001 [Allred 0-2: 3.9 (0.1, 6.0); 3-6: 7.1 (4.7, 11.7); 7-8: 8.8 (8.3, 10.0)] & with PR+ p=0.022 [Allred 0-2: 7.3 (6.1, 10.3), 3-6: 8.0 (7.0, 9.3), 7-8: 9.5 (8.4, 12.8)]; less correlation for AR; no major differences for HER2 or Ki67. Median OS & grade (394 cases; full series ongoing): Grade1: 12.8 yrs (6.1-15.6); Grade2: 7.9 (6.5-10.7); Grade3: 9.3 (4.9-21.1). Median OS for IHC surrogates: 8.7 (7.8-9.7) for Luminal A; 8.3 (6.9-9.4) for Luminal B/HER-2neg; 9.3 years (5.9-21.1) for Luminal B/HER-2+. Similar results were seen for RFS. ER/PR/AR using histoscores will be presented. Conclusions: a) 56% pts had T1 tumors at Dx but only 4% had BCS; b) ER was highly + in >90% but adjuvant ET given in only 77% pts; c) Male BC is usually ER+, PR+ & AR+ and of Luminal A-like subtype (5% HER2pos & 1% TNBC); d) Significant improvement in OS over time; e) ER and PR (Allred) are prognostic (high expression/better prognosis), less for AR, not for Ki67 nor IHC surrogates; f) In-depth characterization of samples is ongoing. Funding: BCRF, EBCC Council, Pink Ribbon NL, BRO. Citation Format: Fatima Cardoso, John Bartlett, Leen Slaets, Carolien van Deurzen, Elise van Leewen-Stok, Peggy Porter, Barbro Linderholm, Ingrid Hedenfalk, Carolien Schroder, John Martens, Jane Bayani, Christi van Asperen, Melissa Murray, Clifford Hudis, Lavinia Middleton, Joanna Vermeij, Stephanie Peeters, Judith Fraser, Monica Nowaczyk, Isabel Rubio, Stefan Aebi, Catherine Kelly, Kathryn Ruddy, Eric Winer, Cecilia Nilsson, Lissandra Dal Lago, Larissa Korde, Kim Benstead, Danielle Van Den Weyngaert, Oliver Bogler, Theodora Goulioti, Nicolas Dif, Carlo Messina, Konstantinos Tryfonidis, Jan Bogaerts, Sharon Giordano. Characterization of male breast cancer: First results of the EORTC10085/TBCRC/BIG/NABCG International Male BC Program [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr S6-05.

Abstract Background: Preclinical and clinical data indicate a key role for the PI3-kinase (PI3K) pathway in the pathogenesis of resistance to endocrine therapies in hormone receptor-positive (HR) breast cancer (BC) and suggest that combining PI3K inhibitors with endocrine therapy may partially overcome this resistance. FERGI is the first randomized Phase II study testing pictilisib (GDC-0941), a PI3K inhibitor, in combination with fulvestrant to evaluate this hypothesis in MBC patients with and without PIK3CA-mutant tumors. Methods: 168 post-menopausal pts with ER-positive, HER2-negative MBC were randomized (1:1) to receive fulvestrant with either pictilisib 340 mg QD (n=89, "combination" arm) or matching placebo (n=79, "control" arm). To be eligible, pts had to have relapsed during or within 6 mos of completing adjuvant AI treatment or have progressed on an AI for MBC. Pts were stratified based on tumor PIK3CA mutation status, resistance to prior AI therapy and presence of measurable disease. The primary endpoint was PFS by investigator assessment in the intent-to-treat (ITT) group and in pts with centrally confirmed PIK3CA-mutant tumors. The primary analysis was based on a 6 mo median duration follow up. Results: Baseline disease and prior treatment characteristics were similar between study arms. Observed treatment-emergent AEs were consistent with those previously described for single agent pictilisib and fulvestrant (primary toxicities were rash and GI disorders). In the ITT population (84 events) the median PFS (mPFS) was 6.2 mo in the combination arm vs 3.8 months for the control arm (HR, 0.77; 95% CI, 0.50-1.19). For pts with PIK3CA-mutant tumors (37 events), mPFS was 6.2 mo in the combination arm vs 5.1 mo in the control arm (HR, 0.92; 95% CI, 0.48-1.76). For pts without a detectable PIK3CA mutant tumor (43 events), mPFS was 5.8 months in the combination arm vs 3.6 months in the control arm (HR, 0.64; 95% CI, 0.35-1.17). Exploratory post-hoc subgroup analysis suggested improvement in PFS in pts with ER+ and PR+ tumors (centrally confirmed) treated with pictilisib plus fulvestrant. In the ER+/PR+ subgroup (57 events) mPFS was 7.2 mo in the combination arm vs 3.7 mo in the control arm (HR, 0.46; 95% CI, 0.27 to 0.78). This improvement was independent of tumor PIK3CA mutation status. Multivariate analysis suggests that this treatment effect in pts with ER+/PR+ tumors is maintained after adjusting for possible baseline imbalances. A similar analysis on pts with luminal A tumors (per PAM50 analysis) was also consistent with the findings in pts ER+/PR+ disease. Conclusions: This is the first report of a blinded, randomized clinical study evaluating a PI3K inhibitor in pts with MBC. In the ITT population, the addition of pictilisib to fulvestrant was associated with a mPFS improvement of 3.8 mo to 6.2 mo. Exploratory subgroup analyses suggested in pts with ER+/PR+ tumors are more likely to derive benefit from the addition of pictilisib to fulvestrant irrespective of PIK3CA mutation status, though the subgroup analyses are limited by the sample size. Additional biomarker analyses will be reported. Citation Format: Ian Krop, Stephen Johnston, Ingrid A Mayer, Maura Dickler, Vinod Ganju, Andres Forero-Torres, Bohuslav Melichar, Serafin Morales, Richard de Boer, Steven Gendreau, Mika Derynck, Mark Lackner, Jill Spoerke, Ru-Fang Yeh, Gallia Levy, Vivian Ng, Carol O'Brien, Heidi Savage, Yuanyuan Xiao, Timothy Wilson, Soo Chin Lee, Katarina Petrakova, Susanne Vallentin, Denise Yardley, Matthew Ellis, Martine Piccart, Edith A Perez, Eric Winer, Peter Schmid. The FERGI phase II study of the PI3K inhibitor pictilisib (GDC-0941) plus fulvestrant vs fulvestrant plus placebo in patients with ER+, aromatase inhibitor (AI)-resistant advanced or metastatic breast cancer – Part I results [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr S2-02.