Mutant Pts Research Articles

Evaluation of clinical outcomes by analysis of mutations in tumor tissue and circulating plasma DNA using next-generation sequencing (NGS) from STEAM, a prospective, randomized, multicenter study in metastatic colorectal cancer (mCRC).

11510 Background: STEAM (NCT01765582) assessed the efficacy and safety of concurrent (c) and sequential (s) FOLFOXIRI-bevacizumab (BEV) vs FOLFOX-BEV for first-line treatment of mCRC. Methods: The AVENIO ctDNA Expanded Kit (Research Use Only) was used to assess somatic mutations in 77 cancer-related genes by NGS in tissue, and both pre- and post-induction plasma samples (n = 182, 150 and 118 respectively) from STEAM. Four mutation classes including single-nucleotide variants (SNVs), indels, copy number amplifications (CNAs) and fusions were identified. SNVs and indels were called in tissue and plasma at allele frequencies of 5% and 0.25% respectively. Results: Overall concordance of mutations in pre-induction plasma with tissue was 83%. Concordance for the seven most mutated genes ranged from 91.5%-100%. In pts with matched samples (n = 118), RAS WT pts showed significantly longer progression-free survival (PFS) in both cFOLFOXIRI-BEV (A) and sFOLFOXIRI-BEV (B) arms versus FOLFOX-BEV (C), using genotyping of either tissue or plasma. This was not seen in RAS MUT pts. In contrast, TP53 WT showed no significant treatment differences while TP53 MUT showed longer PFS for cFOLFOXIRI-BEV versus FOLFOX-BEV. A list of mutation frequencies for all samples, as well as hierarchical clustering analysis of tissue mutations will be presented. Conclusions: The AVENIO ctDNA Expanded Kit identified mutations in 77 cancer-related genes, in both plasma and tissue, with high overall concordance. Compared to FOLFOX-BEV, longer PFS was observed for c- or s- FOLFOXIRI-BEV in RAS WT pts and for cFOLFOXIRI-BEV in TP53 MUT pts, irrespective of sample type. These results are hypothesis generating and require further clinical validation. Clinical trial information: NCT01765582. [Table: see text]

Impact of genomic heterogeneity on PI3K/AKT/mTOR inhibitors (PAMi) efficacy in gynecologic cancer (GYN) patients (pts).

5569 Background: Aberrant PI3K/AKT/mTOR activation is common in GYN. Predictive biomarkers to PAMi in GYN have yet to be identified. Methods: Advanced GYN pts with available genomic data, treated with PAMi in phase I/II clinical trials were selected. Mutation (mut) allele fractions (MAFs) were corrected for tumor purity and defined as clonal (cl) (≥ 0.4) or subclonal (scl) ( < 0.4). PAMi efficacy: (i) time to progression (TTP); (ii) clinical benefit rate (CBR: complete/partial response or stable disease > 4 months [m]); and (iii) ratio TTP on PAMi/ TTP on non-standard chemotherapy pre- or post-PAMi (PAMi/nsChemo TTP). Results: From 2010 to 2016, 264 GYN pts (152 ovarian(OC); 75 endometrial(EC); 37 cervical(CC)) had genomic analysis; 50 pts (24 OC [11 PIK3CA mut, 5 KRAS mut], 15 EC [6 PIK3CA mut, 5 PTEN mut, 4 KRAS mut], and 11 CC [9 PIK3CA mut, 3 KRAS mut]) received PAMi (17 pan-PI3K/mTOR or AKT inh, 17 α-PI3K inh, 16 PAMi targeted combos). PAMi therapy was matched (MA) to PIK3CA/PTEN mut in 30 pts (60%). Median age was 57 years (30-70); median number of prior lines was 2 (1-6) and 34 pts (68%) received nsChemo. Efficacy of PAMi: (i) median TTP (3.27 m [95% CI 2.1-4.4] with trend for longer TTP in OC compared to others [3.93 vs. 2.1 m, HR 0.57; p = 0.08], without differences according to MA status [p = 0.26] or regimen [p = 0.5]); (ii) CBR (42% [95% CI 27-58%], without differences according to tumor type [p = 0.47], MA status [p = 1] or regimen [p = 0.86]); and (iii) TTP PAMi/nsChemo ≥ 1.3 (42% [95% CI 24-63%], without differences according to tumor type [p = 0.53], MA status [p = 0.23] or regimen [p = 0.41]). Partial responses were seen in 5 pts (4 PIK3CA mut on single agent PAMi; 1 KRAS mut on PI3K + MEK inh). Of 4 KRAS mut pts, none had CBR with single agent PAMi. PIK3CA mut were cl in 63% of OC, 17% of EC and 40% of CC. Clonal exon 20 PIK3CA mut were more frequent in OC (p = 0.03). We found longer TTP for cl PIK3CA events (4.0 vs. 1.5 m in scl, HR 5.1, p = 0.006) and a trend for exon 20 events (4.4 vs. 1.4 m in exon 9, HR 1.7, p = 0.25). Conclusions: Regardless of PIK3CA/PTEN mut status, PAMi confer CBR in almost 40% of GYN pts. Functionality and clonality of PIK3CA mut impact on TTP and interact with tumor type. Coexisting KRAS mut may drive resistance to single agent PAMi.

Updated efficacy, safety, and biomarker analyses of STEAM, a randomized, open-label, phase II trial of sequential (s) and concurrent (c) FOLFOXIRI-bevacizumab (BV) vs FOLFOX-BV for first-line (1L) treatment (tx) of patients with metastatic colorectal cancer (mCRC).

657 Background: STEAM (NCT01765582) assessed efficacy and safety of 1L cFOLFOXIRI-BV and sFOLFOXIRI-BV vs FOLFOX-BV. Updated efficacy, safety, and exploratory biomarker data are reported. Methods: 280 tx-naive pts with mCRC were randomized 1:1:1 to BV-containing (5 mg/kg q2w) arms (cFOLFOXIRI, sFOLFOXIRI [alternating FOLFOX and FOLFIRI every 4 weeks {q4w}], or FOLFOX) in a 4–6 month (mo) induction phase, followed by maintenance. Primary objectives include progression-free survival (PFS). Secondary objectives include overall survival (OS). Tumor-relevant biomarker evaluations were exploratory. Results: Median PFS significantly improved and median OS showed a positive trend with cFOLFOXIRI-BV vs FOLFOX-BV. PFS significantly improved with cFOLFOXFIRI-BV vs FOLFOX-BV in BRAF wild type (WT); there was a positive trend in RAS WT and mutant (MUT) pts; no tx difference observed in BRAF MUT pts. In the safety pop., (n = 271), 88% had Grade ≥ 3 tx emergent AEs: 91% cFOLFOXIRI-BV; 87% sFOLFOXIRI-BV; 86% FOLFOX-BV. Conclusions: Improved PFS and a positive trend in OS were observed for cFOLFOXIRI-BV vs FOLFOX-BV. A positive PFS trend was seen in RAS WT and MUT pts, with significantly improved PFS in BRAF WT. The small number of BRAF MUT pts precluded estimation of tx effects. AEs for all 3 txs were consistent with previous reports. Clinical trial information: NCT01765582. [Table: see text]

D05 - FOLFOXIRI plus bevacizumab (bev) as upfront treatment for metastatic colorectal cancer (mCRC) patients (pts) with initially unresectable liver-limited disease (LLD)

Background: Surgical resection of colorectal liver metastases is a potentially curative option for a subgroup of initially unresectable mCRC pts. Active upfront regimens may increase the percentage of pts converted to resection and positively affect their survival. The aim of the present study was to assess the activity and efficacy of FOLFOXIRI plus bev in mCRC pts with LLD. Patients and Methods: Pts with unresectable LLD treated with FOLFOXIRI plus bev in FOIB, TRIBE and MOMA studies were selected. Baseline clinical and molecular characteristics and outcome parameters were collected. Results: 205 pts with LLD were identified. 184 (90%) pts presented with synchronous disease, 119 (61%) had = 4 metastases, liver metastases were bilobar in 140 (79%) cases, and primary tumor was unresected in 74 (36%). 137 (67%) pts responded, and 124 (60%) achieved early response. 91 (44%) pts underwent resection: R0, R1 and R2 resections were performed in 63 (69%), 11 (12%) and 17 (19%) cases, respectively. Having less than 6 involved segments (p = 0.014), achieving RECIST response (p < 0.001), early response (p = 0.002), and deeper response (p = 0.063) were associated with higher probability to undergo resection in the multivariable model. As compared to unresected pts, those achieving resection had longer PFS (median PFS: 18.1 vs 10.6 mos, HR: 0.47 [0.34-0.65], p < 0.001) and OS (median OS: 44.3 vs 22.5 mos, HR: 0.29 [0.20-0.44], p < 0.001). At a median follow up of 36.5 mos, the estimated 5ys-PFS and 5ys-OS in resected pts were 10% and 38%, respectively. Neither number and size of liver metastases, nor their distribution, nor number of involved segments, nodal status, CEA levels, Fong and Nordlinger score predicted RFS and OS of resected pts. Notably, BRAF mut pts resected after FOLFOXIRI plus bev achieved survival results comparable with RAS/BRAF wt and RAS mut. Radiological (p = 0.047) and pathological response (TRG 1-2 vs 3-4, p = 0.088) was associated with longer OS. Conclusion: FOLFOXIRI plus bev allowed to obtain high resection rate and remarkable survival results in a population of mCRC pts with extensive LLD, not selected for a conversion intent. Radiological and pathological response to FOLFOXIRI plus bev predict survival in resected pts, differently from traditional clinical risk scores and RAS/BRAF status.

Abstract P3-07-29: Role of germline BRCA status and tumor homologous recombination (HR) deficiency in response to neoadjuvant weekly paclitaxel followed by anthracycline-based chemotherapy

Abstract Background: Both HR deficiency and BRCA mutation status predict response to platinum-based therapy and BRCA mutation status predicts docetaxel resistance. However, the association of either biomarker with response to the individual elements of either AC or taxanes (T) is unknown since T is commonly given concomitantly with or after anthracyclines (A). We evaluated the association of HRD and BRCA mutation status with response to neoadjuvant weekly T followed by AC or (F)EC in high-risk breast cancer. Methods: We studied 140 high risk Stage I-III breast cancer patients (pts), enrolled in the breast cancer genome guided therapy study (BEAUTY), obtaining biopsies for DNA/RNA sequencing and MRI imaging to assess response to neoadjuvant weekly T (+trastuzumab+/-pertuzumab for HER2+ disease) followed by AC or (F)EC. Germline BRCA status and HR status of tumor samples (Myriad laboratories) were obtained. HR deficient tumor was defined as HRD score ≥42 or BRCA mutation. MRI response by changes in tumor size after 12 weeks of T was classified by WHO criteria. pCR was defined as ypT0/Tis ypN0. Both MRI response after T and pCR (after T and AC) were examined in terms of germline BRCA mutation (gBRCAmut vs. gBRCAwt) and tumor HR deficiency. Results: Of 140 pts enrolled, 8 withdrew consent and 2 carboplatin treated pts were excluded. Germline data were available for 124/130 pts. 12 patients had BRCA deleterious germline mutations (4 BRCA1, 8 BRCA2). MRI partial (PR)/complete response (CR) rate to T was 47.3% (95% CI: 37.8-57.0%) in the BRCAwt group and 66.7% (95% CI: 34.9-90.1%) in the BRCAmut group. No MRI CR's were observed in BRCA1 mut pts. In contrast, pCR rate was 50% in the 12 gBRCAmut pts (95% CI: 21.1-78.9%) and 31.3% in the 112 gBRCAwt pts (95% CI: 22.8-40.7%). HR deficiency status has thus far been determined for 74 pts: 26 pts have HD deficient tumors: 18 TNBC, 5 Luminal B, 2 ER-/HER2+; and 1 ER+/HER2+. Determination of HR deficiency is ongoing and will be reported for the full cohort in terms of 12 week MRI response to T and pCR to T+AC. HR deficientMolecular Subtypeyes (%)no (%)TBD (%)Luminal A0/112/11 (18.2)9/11 (81.8)Luminal B5/37 (13.5)13/37 (35.1)19/37 (51.3)Luminal NOS0/21/2 (50)1/2 (50)ER+/Her2+1/17 (5.8)14/17 (82.4)2/17 (11.8)ER-/Her2+2/20 (10)11/20 (55)7/20 (35)Triple Negative18/43 (41.9)6/43 (18.6)17/43 (39.5)germline BRCA statusMRI partial response after T (%)MRI complete response after T (%)pCR after T&amp;AC (%)BRCA11/4 (25)0/42/4 (50)BRCA25/8 (62.5)2/8 (25)4/8 (50)BRCAwt35/112 (31.3)18/112 (16.1)35/112 (31.3) Conclusion: In the setting of neoadjuvant weekly T followed by AC, pCR rates were non-significantly higher in pts with BRCA1 mutations. While we observed no overall association between BRCA mutation status and response rates to taxanes; nearly all MRI responses to taxanes (partial and complete) were observed in the BRCA2 group. Prospective studies are needed to validate these findings and to determine whether BRCA status can be used to select therapy. HR deficiency is uncommon in luminal A and HER2+, frequent in TNBC, and the association of HRD with both MRI response to taxanes and pCR will be reported at the meeting. Citation Format: Boughey JC, Kalari KR, Suman VJ, McLaughlin SA, Moreno Aspitia A, Moyer AM, Northfelt DW, Gray RJ, Vedell PT, Tang X, Dockter TJ, Jones KN, Felten SJ, Conners AL, Hart SN, Visscher DW, Wieben ED, Ingle JN, Hartman A-R, Timms K, Elkin E, Jones J, Wang L, Weinshilboum RW, Goetz MP. Role of germline BRCA status and tumor homologous recombination (HR) deficiency in response to neoadjuvant weekly paclitaxel followed by anthracycline-based chemotherapy. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-29.

Metastatic colorectal cancer (mCRC) treatment: A high-volume, single-center, real-life experience.

733 Background: Few data are available on outcome of clinical practice unselected patients (pts) with mCRC. Methods: We retrospectively collected data of pts with mCRC followed at our Institution from January 2010 to December 2013 evaluating the clinical characteristics, treatments and survival outcomes. Results: A total of 584 pts were evaluated, 461 were followed at our Center while 123 were seen for a second opinion. Median age was 66 ys (25-94), 59% were male, 63% had an ECOG PS = 0 while 11% ≥2. 33% had right colon primary, 68% synchronous metastatic (mts) disease and 70% a single mts site. 81% underwent surgery on primary and 41% on metastases. 51% were RAS mutated (mut) and 5% BRAF mut. 57 pts didn't receive any systemic treatment, 33 due to frail clinical conditions and 24 due to radical surgical approach (R0). Among 404 treated pts, 239 received all 3 available cytotoxic agents (oxaliplatin, irinotecan, 5FU), 324 bevacizumab and 98 anti-EGFR; 153 (38%) were enrolled in clinical trials. Median overall survival (OS) was 27.6 months (mo) for the entire mCRC population, 3.7 mo for untreated frail pts, 28.7 mo for treated pts while it is still not reached for untreated R0 pts. OS was significantly longer for pts receiving first line combination therapy (29 vs 17 mo, p &lt; 0.01) while a poor prognosis was confirmed for BRAF mut pts (p &lt; 0.001). In a multivariate analysis age &lt; 70, PS 0 and R0 surgery on mts disease showed a positive prognostic impact on OS while a right site of primary was a negative predictor of outcome. At logistic regression older age, low PS and peritoneal disease negatively affected the possibility to receive all 3 active drugs. Conclusions: Despite being an unselected population our outcomes are comparable with results of clinical trials in the corresponding period. We feel that such positive evidence derives from a personalization of treatment and a multidisciplinary approach to mts disease.

Response to Treatment Among SF3B1 Mutated Myelodysplastic Syndromes (MDS): A Case-Control Study from the MDS Clinical Research Consortium (MDS CRC)

IntroductionSomatic mutations in SF3B1 ,a gene encoding a core component of RNA splicing machinery, have been identified in patients (pts) with myelodysplastic syndrome (MDS). The SF3B1 mutation (MT) is more commonly detected in pts with ring sideroblasts (RS) morphology and is associated with favorable outcome. The pattern of response among SF3B1 mutated MDS pts to available treatment options, including erythropoiesis stimulating agents (ESA), hypomethylating agents (HMA) and lenalidomide is not known. The distinct underlying disease biology among such pts may alter response to treatment.MethodsPts treated at MDS CRC institutions with MT vs wild-type SF3B1 (WT) controls were matched 1:2. Matching criteria were age at diagnosis, year of diagnosis and International Prognostic Scoring System (IPSS) category at diagnosis. IPSS category was split into two groups (Low or Int-1 vs. Int-2 or High). Matching was performed using the R package by calculating a propensity score, which was then used to determine the two most similar WT SF3B1 patients for each SF3B1-mutated pt, without replacement. Additionally, to be included in the population, pts also had to have been treated with one of the following: ESAs, HMA, or lenalidomide. Response to treatment was evaluated by international Working Group criteria (IWG 2006) and classified as response if hematological improvement or better was achieved (HI+). Survival was calculated from date of treatment until date of death or last known follow-up, unless otherwise noted.Results:We identified 48 Pts with MT and 96 matched controls. Table 1 summarizes baseline characteristics comparing MT vs WT SF3B1 cohorts. SF3B1 MT was detected more often in association with RS, as expected. The majority of pts had lower-risk disease by IPSS and revised IPSS (IPSS-R). Pts with MT had higher platelets than controls. The most common concomitant somatic mutations observed were TET2 (30%), DNMT3A (21%), and ASXL1 (7%). Median follow-up time from diagnosis was 35 months (mo). Median overall survival (OS) from diagnosis was significantly longer for patients with SF3B1 MT (108.5 mo (68.8, NA)) than wild-type controls (28.3 mo (22.3, 36.4); p < 0.001). Patients with an SF3B1 MT had a decreased hazard of death (hazard ratio [HR]: 0.49 (95% confidence limits [95% CL]: 0.29, 0.84); p = 0.009)ESA was the first line therapy for 43 pts (88%) with MT and 55 WT Pts (56%). For ESA treated pts, 14 out 40 MT Pts responded (35%) compared to 9/56 among WT Pts (16%), p 0.032. Among those treated with HMA therapy, 5 out 21 (24%) MT pts responded compared to 11/46 (24%) WT Pts (p 0.99). Finally, for Pts treated with lenalidomide 4/16 (25%) and 4/21 (19%) responded among SF3B1 MT and WT Pts respectively, p 0.7.ConclusionsSF3B1 somatic mutation in MDS is commonly associated with RS, lower risk disease, and better OS. Pts with SF3B1 mutation had higher response to ESA compared WT SF3B1. No difference in response to HMA or lenalidomide was observed compared to WT patients. Response rates to lenalidomide and HMA were low in both MT patients and controls. Biologically rational therapies are needed that target this molecular disease subset.Table 1Baseline characteristicsSF3B1 MT (n=48)SF3B1 WT (n=96)P valueAgemedian65670.6Gendermale29 (60%)64(67%)0.5RaceWhite44/45 (98%)83/90 (92%)0.34WHO classificationRA RARS RCMD RARS-T Del5 q RAEB-I RAEB-II MDS-U MDS/MPN CMML3 24 8 4 1 3 3 2 0 06 9 17 2 6 10 9 3 11 9IPSSLow Int-1 Int-2 High29 (60%) 16 (33%) 3 (6%) 021 (22%) 69 (72%) 4 (4%) 2 (2%)< 0.001IPSS-RVery low Low Intermediate High Very High15 (31%) 26 (54%) 5 (10%) 2 (4%) 011 (11%) 37 (39%) 26 (27%) 18 (19%) 4 (4%)<0.001Lab values (mean)Hgb Platelets ANC myeloblasts9.7 274 2.63 19.6 108 1.92 20.46 <0.001 0.04 0.05 DisclosuresKomrokji:Novartis: Research Funding, Speakers Bureau; Celgene: Consultancy, Research Funding; Incyte: Consultancy; Pharmacylics: Speakers Bureau. Padron:Novartis: Speakers Bureau; Incyte: Research Funding. List:Celgene Corporation: Honoraria, Research Funding. Steensma:Incyte: Consultancy; Amgen: Consultancy; Celgene: Consultancy; Onconova: Consultancy. Sekeres:Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; TetraLogic: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees.

A Greater Mutational Complexity May Contribute to the Differential Prognostic Impact of Type 1/Type 1-like Versus Type 2/Type2-like Calreticulin Mutations in Primary Myelofibrosis

BACKGROUND. Calreticulin (CALR) mutations (mut) are associated with a IPSS/DIPSSplus and mutated ASXL1-independent favorable outcome in patients (pts) with primary myelofibrosis (PMF) compared to those harboring JAK2 V617F and MPL W515 mut and those lacking driver mutations ("triple negative", TN). Spliceosome mut were reported to be less represented in CALR - mut pts compared with other genotypes (Leukemia 2014;28:1472), but no other molecular or cytogenetic correlate is known. It is also debated whether there are prognostic differences between type 1/type 1 like (Ty1; a 52 bp deletion; p.L367fs*46) and type 2/type 2 like (Ty2; a 5 bp TTGTC insertion; p.K385fs*47) CALR mut. Tefferi et al (Blood 2014;124:2465) reported that only Ty1 was prognostically favorable, while either the opposite or no effect was found in other studies (Leukemia 2015; 29:249).AIMS and METHODS. To evaluate the prognostic relevance of different types of CALR mut in a series of 396 PMF pts (2008 WHO criteria) seen in our center. CALR mut were analyzed by high-resolution capillary electrophoresis and confirmed by Sanger sequencing. Deep sequencing based on Ion Torrent PGM platform was used to analyze mutations in 17 genes previously shown to recur at discrete frequencies in chronic phase and leukemic transformation (LT) of PMF. Comparisons of quantitative variables between groups were carried out by the nonparametric Wilcoxon rank-sum test.RESULTS. 251 pts (63.4%) harbored JAK2 V617F mut, 21 (5.3%) MPL W515 mut, 74 (18.7%) CALR mut, of which 53 (71.6%) Ty1 and 21 (28.4%) Ty2; 50 pts (12.6%) were TN. There was no statistically significant difference between Ty1 and Ty2 for common hematologic and clinical variables. Conversely, both Ty1 and Ty2 differed from JAK2 V617F mut counterpart for younger age, lower leukocyte and higher platelet counts; males were more represented among Ty1 pts than other genotypes. Among CALR Ty1, more pts were in lower (low+Intermediate-1) IPSS risk categories (80%) compared to Ty2 (62%; P=0.04). With a median follow-up of 6.4 and 5.4 yrs for CALR mut Ty1 and Ty2 pts, respectively, there were less pts who died among Ty1 (17%) compared to Ty2 (47.6%) (P=0.007). Median survival of CALR Ty1 was 26.4 yr (range, 15.5-37.3) vs 7.4 yr (4.6-10.2) for CALR Ty2, 7.2 yr (5.7-8.6) for JAK2 V617F and 2.0 (1.6-2.4) for TN (P<.0001). The corresponding hazard ratio, taking CALR Ty1 pts as the reference, was 4.9 (95% CI, 1.8-12.9), 6.0 (95% CI, 2.7-13.4) and 20.6 (95% CI, 8.9-48.4) for CALR Ty2, JAK2 V617F and TN pts, respectively. In a multivariable Cox proportional hazard regression model, CALR Ty2 (HR 4.4, 95% CI 1.6-11.7), JAK2 V617F (HR 3.8, 95% CI 1.7-8.7) and TN (HR 9.2, 95%CI 3.8-22.2) all retained IPSS-independent prognostic impact on survival.Since some subclonal mutations are prognostically relevant in PMF (Leukemia 2013; 27:1861), we compared the mutational profile of 17 such genes, functionally clustered as epigenetic (DNMT3A, EZH2 TET2, IDH2, IDH1, ASXL1), of thespliceosome (SF3B1, SH2B3 U2AF1, SRSF2) orassociated with LT (cKIT, RUNX1, NRAS, KRAS, IKZF1, TP53 CBL) in 44 and 20 CALR mut Ty1 and Ty2 pts, respectively. There was a greater proportion of pts harboring at least one mutated gene among CALR Ty2 than Ty1 (70% vs 56.8%; P=0.02). Also, the proportion of pts with >2 mut was significantly greater in CALR mut Ty2 compared to Ty1 (40% vs 18%; P=0.01); in particular, 15% of CALR Ty2 mut pts had >3 mut compared to 2.2% in Ty1 (P=0.04). Frequency of individual mutations in Ty2 vs Ty1 was: epigenetic, 50% vs 50%; spliceasome 30% vs 4.5% (P=0.009); LT 30% vs 13.6% (P=0.06). Of note, SF3B1 mutations were 10-fold more represented in CALR mut Ty2 (25%) compared to Ty1 (2.2%; P<0.01). TP53 mutations were found in 10% of Ty2 and 0 in Ty 1.CONCLUSIONS. These findings support previous report that the prognostic advantage of CALR mutation in PMF regards only pts harboring type 1/type 1-like abnormalities. A greater mutational complexity involving subclonal mutations, particularly in genes of the spliceosome with an unusually high incidence of SF3B1 mutations, as well as increased number of mutated genes, may contribute to the dismal outcome of CALR mut Ty2 pts. DisclosuresVannucchi:Novartis Pharmaceuticals Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Baxalta: Membership on an entity's Board of Directors or advisory committees; Shire: Speakers Bureau.

445P Overall survival (OS) with afatinib (A) vs chemotherapy (CT) in patients (pts) with NSCLC harboring EGFR mutations (mut): Subgroup analyses by race in LUX-Lung 3 (LL3) and LUX-Lung 6 (LL6)

Aim/Background: In the LL3 (345 pts recruited globally) and LL6 (364 Asian-only pts [no Japanese]) phase 3 randomized trials, first-line A, an irreversible ErbB family blocker, significantly improved OS vs cisplatin/pemetrexed (33.3 vs 21.1 months; HR 0.54; p = 0.0015) and gemcitabine/cisplatin (31.4 vs 18.4 months; HR 0.64; p = 0.023) in pts with advanced NSCLC harboring EGFR Del19 mut; no significant difference in OS was observed in EGFR L858R mut-positive patients in either study. Pre-planned subgroup analyses of OS by race including Asian, non-Asian (LL3 only), and Japanese patients (LL3 only) are reported. Methods: In each study, pts were randomized (2:1) to 40 mg/day oral A or up to 6 cycles of CT, stratified by EGFR mut (Del19/L858R/other) and race (LL3 only; Asian/non-Asian). Results: Significant improvements in OS in NSCLC pts harboring EGFR Del19 mut were observed in all race subgroups analyzed. In the Asian subgroup of LL3, median OS in Del19 pts (n = 123) was 33.3 months with A vs 22.9 months with CT (HR 0.57 [95% CI 0.36–0.90]; p = 0.015). In the non-Asian subgroup of LL3, median OS in Del19 pts (n = 46) was 33.6 months with A vs 20.0 months with CT (HR 0.45 [95% CI 0.21–0.95]; p = 0.03). In the Japanese subgroup of LL3, median OS in Del19 pts (n = 39) was 46.9 months with A vs 31.5 months with CT (HR 0.34 [95% CI 0.13–0.87]; p = 0.018). Significant improvement in OS with A vs CT was also observed in the combined analysis of Asian Del19 pts (n = 309) in LL3 and LL6 (median 31.7 vs 21.1 months; HR 0.61 [95% CI 0.46–0.82]; p = 0.001). No statistically significant difference in OS with A vs CT was observed for L858R mut pts in any of the race subgroups analyzed. Subsequent EGFR tyrosine kinase inhibitor therapy was received by 69%, 65% and 100% of non-Asian, Asian and Japanese patients, respectively, in the CT arm. Conclusions: Significant improvement in OS with first-line A vs CT in pts with NSCLC harboring EGFR Del19 mut was demonstrated in subgroup analyses of Asian, non-Asian, and Japanese pts. These findings are consistent with analysis of the overall LL3 and LL6 pooled population. Clinical trial identification: NCT00949650; NCT01121393 Disclosure: Y.-L. Wu: honoraria from Boehringer Ingelheim, Roche, AstraZeneca, Eli Lilly and Pfizer. L.V. Sequist: advisory board involvement in an uncompensated role for Boehringer Ingelheim, AstraZeneca, Clovis, Novartis, Genetech, Merrimack, and Taiho. M. Schuler: advisory board participation for AstraZeneca, Boehringer Ingelheim, Celgene, Lilly and Novartis; corporate-sponsored research for Boehringer Ingelheim and Novartis; and honoraria from Alexion, Boehringer Ingelheim, Celgene, Lilly, Novartis and Pfizer. N. Yamamoto: advisory board involvement, corporate-sponsored research and honoraria with Boehringer Ingelheim. K. O'Byrne, V. Hirsh: honoraria for advisory board involvement with Boehringer Ingelheim. T. Mok: Speaker's Bureau participant with AstraZeneca, Roche/Genentech, Pfizer, Eli Lilly, Boehringer Ingelheim, MSD, Amgen, Janssen, Clovis Oncology, GSK, and Novartis; advisory board participation for AstraZeneca, Roche/Genentech, Pfizer, Eli Lilly, BI, Merck Serono, MSD, Janssen, Clovis Oncology, BioMarin, GSK, Novartis, SFJ Pharmaceutical, and ACEA Biosciences, Inc.; honoraria from AstraZeneca, Roche/Genentech, Pfizer, Eli Lilly, BI, MSD, Amgen, Janssen, Clovis Oncology, GSK, and Novartis; and major stock shareholder in Sanomics Ltd. V. Zazulina: employment with Boehringer Ingelheim. J.C.-H. Yang: advisory board participation for Astrazeneca, Roche/Genentech, Boehringer Ingelheim, MSD, Merck Serono, Novartis, Clovis Oncology, Eli Lilly, Bayer, Celgene, Astellas, Innopharma, and Ono Pharmaceutical; and honoraria from Astrazeneca, Roche/Genentech, Boehringer Ingelheim, MSD, Merck Serono, Novartis, Clovis Oncology, Eli Lilly, Bayer, Celgene, Astellas, Innopharma, and Ono Pharmaceutical. All other authors have declared no conflicts of interest.

Assessment Of Human Equilibrative Nucleoside Transporter 1 (hENT1) – Expression By Flow Cytometry In Acute Myeloid Leukemia and Myelodysplastic Syndromes and Correlation To Clinical Outcome In Acute Myeloid Leukemia Patients Treated With Intensive Chemotherapy

Assessment Of Human Equilibrative Nucleoside Transporter 1 (hENT1) – Expression By Flow Cytometry In Acute Myeloid Leukemia and Myelodysplastic Syndromes and Correlation To Clinical Outcome In Acute Myeloid Leukemia Patients Treated With Intensive Chemotherapy

Analysis of NRAS mutation as poor prognostic indicator and predictor of resistance to anti-EGFR monoclonal antibodies (anti-EGFRs) in metastatic colorectal cancer (mCRC) patients (pts).

3613 Background: NRAS belongs to RAS family. NRAS mutations are mutually exclusive with KRAS and BRAF mutations and contribute to the activation of Ras/Raf/MAPK pathway. Previous experiences evaluated the prognostic/predictive role of NRAS mutations suggesting a poorer prognosis and resistance to anti-EGFRs for NRASmutant (mut) mCRC pts. The aim of the present study was to confirm such preliminary findings in a large cohort of mCRC pts. Methods: Data on KRAS (codons 12, 13 and 61) and BRAF-V600E mutational status of mCRC pts referred to our pathology from '09 to '12 were collected. NRAS mutational status (codons 12, 13 and 61) was evaluated in KRAS and BRAF wt pts. OS was calculated from date of diagnosis of metastatic disease. Data on response and PFS according to RECIST were collected for NRASmut irinotecan-refractory pts treated with anti-EGFRs +/- irinotecan. Results: 774 mCRC pts were included. KRAS/BRAF mutations were found in 384 (50%)/69 (9%) cases. NRAS was mut in 47 (15%) out of 318 KRAS and BRAF wt pts. NRAS mut pts had significantly shorter OS in comparison to KRAS-BRAF-NRAS wt pts (HR=0.60 [0.29-0.99] p=0.045). BRAF mut pts had significantly worse OS in comparison to NRAS mut pts (HR=1.75 [1.073-2.87] p=0.03). No difference was observed between NRAS mut and KRAS mut pts (HR=0.86 [0.51-1.43] p=0.61). 18 pts out of 47 NRAS mut pts received anti-EGFRs in advanced lines. 8 pts (7 cetuximab-based, 1 panitumumab monotherapy) were evaluable according to RECIST criteria and therefore eligible for the present analysis. None of them responded and only 1 SD was observed. Pooling our results with available data on anti-EGFRs’ activity in NRASmut pts in advanced lines of treatment (De Roock, 2010; Peeters, 2013; Andrè, 2012), only 1 response is described out of 35 treated pts (2,9%). Conclusions: Our data demonstrate that NRAS mutations have a relevant incidence in KRAS and BRAF wt mCRC pts. Present results are consistent with previous experiences and confirm that NRAS mutations affect prognosis of mCRC patients and predict lack of response to anti-EGFRs. Further insights into NRAS mut mCRC biology and prospective validation are warranted.

Comparative study of the efficacy of breast cancer neoadjuvant chemotherapy (NAC) in patients (pts) with BRCA1/2 mutation vs sporadic cancer cases versus pts with a family history but no BRCA1/2 mutation.

1533 Background: During NAC, impaired DNA repair mechanisms may account for the higher response rate of BRCA mutation carriers (group #1) when compared to sporadic cases with no history of breast/ovarian cancer (group #2). In this study, we investigated whether pts with possible BRCAX mutation (i.e. with a family history but no BRCA1/2 mutation, group #3) treated by NAC exhibit a different efficacy (response rate, survival) pattern. Methods: All pts screened for a BRCA1/2 mutation between 1999 and 2010 were selected from the prospectively registered cancer genetics database of Institut Curie. Pts younger than 36 years old were excluded. Pts who received NAC were classified in groups #1 (n=23 mutated pts) or #3 (n=64 non-mutated pts). Group #2 (n=87 sporadic cancer pts) was built to match groups #1 and #3 according to age (+/- 5 years), year of treatment (+/- 2 years), hormone receptor status and taxane or trastuzumab use. Results: Median follow-up was 65 months. Fifty % of pts had cytologically proven axillary nodal involvement before NAC. Taxanes were used in 63% of pts and trastuzumab in 9% of pts. Pathological complete response (pCR) rates were 39.1% in group #1, 17.2% in group #2 and 20.3% in group #3 (p=0.07). For locoregional relapse (LR), the difference between groups was statistically significant (p=0.007). The hazard ratio (HR) for LR was higher in group #1 (HR=7.86, p=0.002) than in group #2. No significant difference was seen between group #3 and group #2 (HR=2.37, p=0.15). The difference between groups was also statistically significant for distant metastasis relapse (DMR) (p=0.009). The HR for DMR was higher in group #1 than in group #2 (HR=4.57, p=0.01) and in group #3 than in group #2 (HR=2.81, p=0.01). Conclusions: While pts with BRCA1/2 mutations have a trend towards higher pCR rates with NAC, they have higher rates of LR and DMR than sporadic cases. Pts with a positive family history but no BRCA1/2 mutation have similar pCR and LR rates than sporadic cases, but they have higher rates of DMR. Whether these differences translate into overall survival differences remains to be studied.

Association of KRAS mutation with worse recurrence-free survival and site of metastatic progression after resection of hepatic colorectal metastases.

3609 Background: There are conflicting results regarding the influence of KRAS mutation status and outcome in patients (pts) with colorectal cancer. A recent report suggested worse outcome in KRAS mutated (MUT) pts who underwent resection of hepatic metastases (Karagkounis et al, ASCO 2012). Methods: Recurrence patterns and survival were evaluated in 169 patients who had undergone resection of liver metastases, then received adjuvant hepatic arterial infusion and systemic chemotherapy, and for whom KRAS data were available. Kaplan-Meier methods were used to estimate recurrence free survival (RFS) and overall survival (OS). Log-rank test was used to determine whether survival functions differed by KRAS mutation status. Cumulative incidence function was used to estimate the probability of time from adjuvant therapy to bone, brain, lung and liver metastases separately. Mutations in KRAS (codons 12, 13) were detected using the iPLEX assay (Sequenom, Inc). Results: Median follow-up for the entire cohort was 38.8 months. 118 were KRAS wildtype (WT), and 51 were KRAS MUT (45 G12, 5 G13, 1 K117N). The 3 year RFS was 48% [95%CI: 37-58%] for KRAS WT pts and 30% [15-44%] for MUT pts (p&lt;0.01). OS at 3 years was 96% [88-98%] for KRAS WT and 80% [61-90%] for MUT pts (p=0.08). Cumulative incidence of developing bone, brain, lung, and liver metastases by 2 years is presented in Table 1. The cumulative incidence of metastases to bone at 2 years was 0% and 13.7% in KRAS WT versus MUT pts (p&lt;0.01), to brain 0% versus 4.6% for KRAS WT versus MUT (p=0.05), and to lung 27% versus 47.5% in KRAS WT versus MUT pts (p&lt;0.01). Conclusions: In pts who have had liver resection followed by adjuvant therapy, those with KRAS MUT have a worse RFS and seemingly worse OS than those who are KRAS WT. Also, patients with KRAS MUT appear more likely to develop bone, brain, and lung metastases. Further investigation of a larger number of patients is warranted. [Table: see text]

Prognostic implication of KIT mutations in melanoma.

9049 Background: The natural history of BRAF and NRAS mutant (mut) melanoma (mel) has been described, but prognostic implications of KIT mut mel have not. Methods: We performed a single-center retrospective review of 180 patients (pts) enriched for mucosal, acral or chronic sun-damaged skin (CSD) mel and screened for KIT, BRAF, and NRAS mut from 4/07 - 4/10 as a part of a phase II imatinib study. Pt/disease characteristics were compared using the Kruskal-Wallis or Chi-square tests. Factors associated with outcomes were assessed by Kaplan-Meier methods and multivariable Cox regression. Results: Median age, 63.7 years; 54.4% male. Primary site: 40% mucosal, 29% acral, 22% CSD, 9% others. Mut rate: 18% KIT, 16% BRAF, 14% NRAS, 52% wild-type (wt). Pathologic subtype differed by genetic subgroup (p&lt;.001) while age, gender, and stage did not (all p&gt;0.05). 18/26 (69%) KIT mut pts received imatinib in the metastatic (met) setting; 6/18 received &gt; 1 other KIT inhibitor. 3/25 (12%) BRAF mut pts received vemurafenib. 8/27 (30%) KIT mut, 4/27 (15%) BRAF mut, 6/20 (30%) NRAS mut, and 6/20 (30%) wt pts received ipilimumab. 149/180 (83%) pts developed mets at a median of 2.15 years (95% CI: 1.72, 2.72). Median follow-up (FU) of pts not developing mets was 3.91 yrs (range: 0.25, 14.34). Older age (HR: 1.02, 95% CI: 1.00, 1.03) and pathologic subtype (mucosal vs CSD HR: 1.70, 95% CI: 1.02, 2.84; non-CSD/unknown vs CSD HR: 2.05, 95% CI: 1.00, 4.21) were associated with increased risk of mets but not with time from mets to death. Of 149 pts who progressed, 123 (83%) died during FU. Median time from met to death was 1.21 years (95% CI: 0.91, 1.67). Median FU from time of mets among those alive at last FU was 2.53 yrs (range: 0.06, 6.85). Mut status including KIT mut was not associated with time to first met or time from met to death. Pts who received ipilimumab from time of first distant met had reduced risk of death (HR: 0.55, 95% CI: 0.36, 0.87) independent of mut status. No impact was observed with KIT inhibition. Conclusions: KIT mut status is not an independent predictor of time to mets or survival in pts with mets. Ipilimumab improved pt outcomes regardless of mut status. The lack of impact of KIT inhibitors is likely due to the heterogeneity of KIT mut in mel but does not preclude efficacy in appropriately selected pts.

A French prospective pilot study for identifying dihydropyrimidine dehydrogenase (DPD) deficiency in breast cancer patients (pts) receiving capecitabine (cap).

e13519 Background: For fluoropyrimidines, and especially cap, Health Authorities point out that DPD deficiency confers a significant risk of major toxicity (tox). Identification of at-risk pts is thus relevant. This multicentric prospective study of the French GPCO group (Groupe de Pharmacologie Clinique Oncologique, Unicancer) evaluated the sensitivity, specificity and predictive values of DPD phenotyping and genotyping for predicting severe cap-related tox in metastatic breast cancer pts. Methods: 303 pts were included (15 institutions), 88% received cap as monotherapy, 28% were treated as first line (mean dose at 1st cycle 1957 mg/m2/d). Pre-treatment dihydrouracil (UH2) and uracil (U) plasma concentrations were measured in 286 pts (HPLC assay). DPD genotyping (IVS14+1G&gt;A, 2846A&gt;T, 1679T&gt;G, 464T&gt;A) was done on 281 pts. Severe tox (G3-4 CTCAE v3 criteria) was measured over cycles 1-2. Results: Grade 3-4 tox (diarrhea, vomiting, hematoxicity, hand-foot syndrome) was observed in 19.6% of pts (one toxic death). A marked trend for higher U (median 12.7 vs 10.2 ng/ml, p=0.014) and UH2 (median 110 vs 93 ng/ml, p=0.011) concentrations was observed in pts developing severe tox vs those who didn’t. However, ROC curves showed that these differences were too small for use as reliable tox predictors. The distribution of UH2/U ratio was similar between pts with or without tox (median 9.1 vs 9.6, respectively, p=0.80). The patient with toxic death had a UH2/U ratio of 6.5 and U concentration of 17 ng/ml. Among the 7 pts with a DPD mutation (3 pts IVS14+1, 3 pts 2846A&gt;T, one 1679T&gt;G, all heterozygous), 5 developed severe tox (including toxic death, 2846A&gt;T), one did not, and the last one was not documented. Relative risk for developing severe tox was 4.60 in mut pts vs wt pts (95%CI 2.95-7.16, p=0.001); positive and negative predictive values were 83.3% and 81.9%, respectively; specificity was 99.5% and sensitivity was 9.8%. Conclusions: These data point out that breast cancer pts harbouring a DPD variant allele are candidate to develop severe, up to lethal, cap-related tox. In contrast, pre-treatment UH2/U ratio and U measurements are not reliable predictors of cap tox. Clinical trial information: Eudract 2008-004136-20.

Influence of KRAS mutation on recurrence patterns in patients undergoing hepatic resection of colorectal metastases.

398 Background: There have been conflicting results about whether KRAS mutation influences outcome in patients (pts) with colorectal cancer. In pts who underwent liver resection, Karagkounis reported a worse recurrence and survival in KRAS mutated (MUT) patients (ASCO 2012, abs 3616). Methods: In 105 pts who underwent liver resection and received adjuvant (adj) hepatic arterial infusion and systemic chemotherapy and in whom KRAS data was available, we evaluated recurrence patterns and survival. Correlation between KRAS and clinical factors such as prior chemotherapy, post operative CEA, clinical risk score, and stage at diagnosis was evaluated using Fisher’s exact test and the Wilcoxon rank sum test. Kaplan-Meier methods were used to estimate median overall recurrence free survival (RFS) and overall survival (OS) at 4 years. Log-rank test was used to determine whether survival functions differed by KRAS mutation status. Cumulative incidence function was used to estimate the probability of time from adj therapy to bone, brain, lung and liver metastases separately. Results: Of 105 patients, 76 were KRAS wildtype (WT), and 29 were KRAS MUT (26-G12 and 3-G13). The median RFS was 26 months for KRAS WT pts and 15 months for KRAS MUT pts (p=0.08). OS at 4 years was 88% [95% CI: 78%-94%] for KRAS WT and 78% [95% CI: 57%-90%] for KRAS MUT pts (p= 0.15). Cumulative incidence of developing bone, brain, lung, and liver metastases by 2 years is presented in the Table. The cumulative incidence of bone and brain metastases at 2 years was 0% and 0% in KRAS WT pts versus 16.4% [95% CI: 1.1%-31.7%] and 4.7% [95% CI: 0%-14.1%] in KRAS MUT pts (Table). There was no association between clinical factors and KRAS status. Conclusions: KRAS MUT pts appeared to have worse OS and RFS, although we were unable to show a significant difference between KRAS WT and MUT for OS and RFS. In addition, cumulative incidence of bone and brain metastases at 2 years appeared to be higher for KRAS MUT pts as compared to WT pts. Results are based on small sample size and further investigation is needed. [Table: see text]

Exome Sequencing Identifies Recurring DNMT3A Mutations in Adult ETP-ALL

AbstractAbstract 1377 Introduction:Early T-cell precursor (ETP) ALL accounting for 10% of all T-ALL cases is of special interest because of its proposed origin from early thymic progenitors with multilineage differentiation potential. ETP-ALL is associated with a poorer outcome in pediatric and adult patients. On the molecular level, ETP-ALL is characterized by a specific immunophenotype (CD1-, CD5weak, CD8-, co-expression of stem cell and/or myeloid antigens) and distinct molecular features (expression of stem cell genes, high frequency of FLT3 mutations with absence of NOTCH1 mutations). Whereas a highly heterogeneous genetic pattern was revealed by whole genome sequencing in pediatric patients, the genetic background of adult ETP-ALL remains largely unknown. Here we investigated genetic alterations in adult ETP-ALL by whole exome sequencing and subsequently analyzed specific target genes. Patients and methods:We performed whole exome sequencing of five paired (diagnosis/remission) adult ETP-ALL patients enrolled in German Acute Lymphoblastic Leukemia Multicenter Study Group (GMALL) trials. Using exon capturing from genomic DNA, followed by 76-bp paired-end sequencing on an Illumina Genome Analyzer IIx platform, we generated at least 5 Gb of exome sequence from each ETP-ALL and remission samples. Somatic mutations were identified by comparing the ETP-ALL with the remission exome sequence, excluding all annotated polymorphisms (dbSNP130), non-coding positions and positions with evidence of a variant in the corresponding remission samples. Candidate variants were confirmed by capillary sequencing of genomic DNA. The DNMT3A mutations status was analyzed by Sanger sequencing of exons 11–23 in additional 68 adult ETP-ALL (55 male, 13 female, median age: 38 years) as well as the mutation status of the polycomb repressor complex (PRC) genes EZH2 and SUZ12. For 52 of 68 patients clinical follow-up data were available. Results:Using whole exome sequencing we found a total of 56 non-synonymous somatic mutations or indels in the five ETP-ALL patients (range: 6 to 16 per patient). Eleven mutations/indels affected cancer genes. DNMT3A (2/5) and FAT3 (2/5) were recurrently mutated in the five patients. The DNA-methyl-transferase DNMT3A is a frequent mutational target in acute myeloid leukemia (AML; 20%), whereas FAT3 (FAT, tumor suppressor homolog 3) mutations were recently reported in ovarian carcinoma (TCGA, Nature 2011). Novel mutations identified in adult ETP-ALL involved genes in epigenetic regulation (e.g. MLL2, MLL3, BMI1), and in genes previously reported to be mutated in ETP-ALL (e.g. in JAK1, ETV6, NOTCH1, DNM2).By Sanger sequencing, we screened for DNMT3A mutations in a larger cohort of adult ETP-ALL. DNMT3A mutations were present in 11 of the 68 (16%) patients, a mutation rate similar to AML. Amino acid R882 (exon 23), the most frequently mutated amino acid in AML, was mutated in five ETP-ALL. The remaining six mutations occurred in single spots, with one exception in the ZNF or the MTF domain. Patients with a DNMT3A mutation were significantly older (median: 63 vs 37 years, P=0.016). No correlation was found between DNMT3A and FLT3 mutations (27% in DNMT3A mut pts. vs. 37% in DNMT3A wt pts., P=0.41) or NOTCH1 mutations (10% in DNMT3A mut pts. vs. 16% in DNMT3A wt pts., P=0.47).In addition, we investigated genetic alterations in epigenetic regulators including members of the polycomb repressor complex (PRC). Mutations were seen in EZH2 in 4/68 (6%), SUZ12 in 1/68 (1%) and SH2B3 in 4/69 (6%) of ETP-ALL. Interestingly, patients with at least one mutation in an epigenetic regulator gene (DNMT3A, SUZ12, SH2B3, MLL2, or EZH2) showed a trend towards an inferior survival (one-year-survival: 50% vs. 85%, P=0.08). Conclusion:Adult ETP-ALL patients display a heterogenous spectrum of mutations, particularly affecting genes involved in epigenetic regulation. The spectrum is different to pediatric patients with a lower rate of polycomb repressor complex and a higher rate of DNMT3A mutations. The higher rate of DNMT3A mutations in older patients might point to a different pathogenesis compared to pediatric ETP-ALL. Like in AML, DNMT3A mutations in adult ETP-ALL show a similar frequency, within the same hot spots and are correlated with an adverse prognostic value, underscoring the myeloid character of ETP-ALL. Thus, these data may provide a rationale to use epigenetic therapy in ETP-ALL. Disclosures:Krebs:Illumina: Honoraria. Greif:Illumina: Honoraria.

438O - Phase II Activity of the HSP90 Inhibitor AUY922 in Patients with Alk-Rearranged (ALK+) or Egfr-Mutated Advanced Non-Small Cell Lung Cancer (NSCLC)

ABSTRACT Background AUY922 is a highly potent, non-geldanamycin, HSP90 inhibitor. HSP90 is a chaperone of client proteins relevant in NSCLC pathogenesis, including ALK and EGFR. Oncogenic fusion genes giving constitutive ALK activity (ALK+) occur in up to 6% of NSCLCs, and EGFR mutation (mut) occurs in 10–20% of cases. We report data from a Phase II study of AUY922 in patients (pts) with previously treated, advanced NSCLC, stratified by molecular status. Methods Pts with advanced NSCLC who progressed following ≥1 prior line of chemotherapy, received AUY922 (70 mg/m2) as a once-weekly, 1-hr infusion. Pts were assigned to 1 of 4 strata: ALK + , EGFR-mut, KRAS-mut, or EGFR/KRAS/ALK wild-type. A Bayesian partially exchangeable multinomial model was used in the statistical analysis of the study. Primary endpoint was confirmed objective response rate or stable disease at 18 wks. Secondary endpoints included OS, PFS, and safety/tolerability. Results On 6 April 2012 cutoff, 121 pts had been treated (ALK+ [n = 22; both crizotinib (CRZ) treated and naive], EGFR-mut [n = 35], KRAS-mut [n = 28], EGFR/KRAS/ALK wild-type [n = 33], undetermined [n = 3]); pts were heavily pretreated (61% had received ≥3 prior regimens). Clinical activity of AUY922 was seen in pts with ALK+ and EGFR-mut NSCLC, with partial responses in 6/21 (29%) pts and 7/35 (20%) pts, respectively. 4/6 ALK+ responders were CRZ-naive and 2/6 were pretreated. Estimated median PFS rates (FAS) were 42% and 34% at 18 wks in ALK+ and EGFR mut pts, respectively. In EGFR-mut pts who had progressed just after EGFR tyrosine kinase inhibitor (TKI) therapy, median PFS rate at 18 wks was 45% vs 21% in pts who had not received a TKI as their immediate pre-AUY922 therapy. The most frequent adverse events (AEs) were eye disorders (77%), diarrhea (74%), and nausea (46%). Most AEs were grade (Gr) 1/2; Gr 3/4 AEs were rare (all Conclusions AUY922 had an acceptable safety profile. Activity was demonstrated in both ALK+ and EGFR-mut pts. Response and PFS rates suggest further studies are warranted in these patient populations, particularly in EGFR-mut pts who progressed following treatment with TKIs. Disclosure L.V. Sequist: I have a paid consulting role for Clovis, Celgene and GSK, and unpaid consulting for Daiichi-sankyo and Merrimack. H.J.M. Groen: Roche and Eli Lilly sponsored investigator initiated studies - paid to institution UMCG. M. Akimov: I am an employee of Novartis Pharma AG and have stock ownership in Novartis. E. Avsar: Empoyee of Novartis. S. Bailey: Employee of Novartis. W. Ofosu-Appiah: Employee of Novartis. E. Garon: I have received reaserch funding from Novartis. All other authors have declared no conflicts of interest.

1302P - Clinical Impact of Presence and Type of Kras Mutation in a Population of EGFR Wild Type (WT) Advanced Non-Small Cell Lung Cancer (NSCLC) Patients (PTS) Treated with Platinum-Based Chemotherapy: A Retrospective Analysis

ABSTRACT Background In this retrospective analysis we assessed whether KRAS mutation would affect the clinical outcome of EGFR WT advanced NSCLC pts treated with a first-line platinum-based chemotherapy. Moreover, the effect of specific mutant KRAS was evaluated. Methods One hundred and ninety-five EGFR WT, advanced NSCLC pts were included in the analysis. Study pts were treated at the Medical Oncology of the Perugia Hospital from Jan 2005 to March 2012. EGFR (exons 18 to 21) and KRAS (codons 12, 13 and 61) genes were amplified by nested PCR and sequenced in both sense and antisense directions. Results Median age was 60 years (29-81); 181 pts (92.8%) were PS 0 or 1; 155 pts (79.4%) belonged to the non-squamous subtype and 39 pts (20.0%) were never-smokers. Treatment was as follows: platinum + a third generation agent in 103 pts (52.8%); platinum + pemetrexed in 81 pts (41.6%); platinum-based doublet + bevacizumab in 11 pts (5.6%). Seventy-five pts (38.4%) were KRAS mutant (MUT), of which 60 pts at codon 12 (COD 12 MUT), 12 pts at codon 13 (COD 13 MUT) and 3 pts at codon 61 (COD 61 MUT). The most common amino acid changes found were: Gly12Cys (29 pts), Gly12Val (11 pts) and Gly13Cys (10 pts). In the whole study population, 69 pts (35.3%) responded to treatment and 62 pts (31.7%) achieved stable disease, for a disease control rate of 67.0%. At a median follow-up of 14 months (2-102), median progression-free survival (PFS) and overall survival (OS) were 6.2 and 21.6 months, respectively. When analyzed according to KRAS mutation status, a significantly shorter PFS was noted for the EGFR WT/KRAS MUT subgroup (n = 75) compared with the EGFR WT/KRAS WT population (n = 120) [5.1 vs 6.6 months, respectively, P = 0.02; HR = 1.43 (95% CI, 1.05 to 1.95)]. Similarly, a significant difference was observed between the two groups in terms of OS [13.7 vs 26.1 months, respectively, P = 0.02; HR = 1.56 (95% CI, 1.06 to 2.30)]. In the EGFR WT/KRAS MUT subrgoup, OS for COD 12 MUT, COD 13 MUT and COD 61 MUT was 17.2, 10.2 and 8.0 months, respectively, P = 0.17. Multivariate analysis for PFS and OS confirmed that KRAS mutation was an independent predictor of poorer oucome. Conclusions EGFR WT/KRAS MUT pts appear to experience a less favorable prognosis compared with the EGFR WT/KRAS WT genotype, with a significant difference in clinical outcome according to the mutant codon of KRAS. Disclosure All authors have declared no conflicts of interest.

KRAS mutational status and sensitivity to a reversible epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) in EGFR wild type (WT) advanced non-small cell lung cancer (NSCLC) patients (pts).

e18023 Background: Treatment with a reversible EGFR-TKI may benefit pts with EGFR WT advanced NSCLC, though to a much lesser extent than pts carrying an activating mutation in the EGFR gene. We assessed whether KRAS mutational status would help predict sensitivity to gefitinib or erlotinib in EGFR WT advanced NSCLC pts. Methods: Sixty-seven EGFR WT, advanced NSCLC pts treated with a reversible EGFR-TKI in any line setting were included. Pts were treated from May 2005 to March 2011 at the Medical Oncology of the Perugia Hospital. EGFR (exons 18 to 21) and KRAS (codons 12, 13 and 61) genes were amplified by nested PCR and sequenced in both sense and antisense directions. Results: Median age was 60 years (39-84); 52 pts (77.6%) were PS 0 or 1; 58 pts (86.6%) belonged to the non-squamous subtype and 22 pts (32.8%) were never-smokers. Eighteen pts (26.8%) were KRAS mutant (MUT), of which 14 pts at codon 12 (COD 12 MUT) and 4 pts at codon 13 (COD 13 MUT). Overall, 11 pts (16.4%) responded to treatment and 8 pts (11.9%) achieved stable disease, for a disease control rate of 28.3%. At a median follow-up of 25.2 months, median progression-free survival (PFS) and overall survival (OS) were 2.9 and 29.5 months, respectively. When analyzed according to KRAS status, a significantly shorter PFS was noted for the EGFR WT/KRAS MUT subgroup (N=18) compared with the EGFR WT/KRAS WT population (N=49) (1.6 vs. 3.0 months, respectively, p=0.04). However, no significant difference was observed between the two groups in terms of OS (18.0 vs. 34.8 months, respectively, p=0.42). Within the EGFR WT/KRAS MUT subrgoup a significantly longer PFS was reported for COD 12 MUT pts compared with COD 13 MUT pts (1.7 vs 0.7 months, respectively, p=0.04). Similarly, KRAS COD 12 MUT pts experienced a statistically significant superior OS compared with COD 13 MUT pts (36.2 vs 7.4 months, respectively, p=0.003). Conclusions: EGFR WT/KRAS MUT pts appear to be more resistant to treatment with a reversible EGFR-TKI, the greatest resistance occurring in COD 13 MUT pts. KRAS COD 12 MUT pts may represent a clinically distinct subgroup of KRAS mutants with a particularly favorable prognosis.