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Background Standard-of-care treatment for newly diagnosed glioblastoma (ndGBM), consisting of surgery followed by radiotherapy (RT) and temozolomide (TMZ), has improved outcomes compared with RT alone; however, prognosis remains poor. Trotabresib, a novel bromodomain and extraterminal inhibitor, has demonstrated antitumor activity in patients with high-grade gliomas. Methods In this phase Ib, dose-escalation study (NCT04324840), we investigated trotabresib 15, 30, and 45 mg combined with TMZ in the adjuvant setting and trotabresib 15 and 30 mg combined with TMZ+RT in the concomitant setting in patients with ndGBM. Primary endpoints were to determine safety, tolerability, maximum tolerated dose, and/or recommended phase II dose (RP2D) of trotabresib. Secondary endpoints were assessment of preliminary efficacy and pharmacokinetics. Pharmacodynamics were investigated as an exploratory endpoint. Results The adjuvant and concomitant cohorts enrolled 18 and 14 patients, respectively. Trotabresib in combination with TMZ or TMZ+RT was well tolerated; most treatment-related adverse events were mild or moderate. Trotabresib pharmacokinetics and pharmacodynamics in both settings were consistent with previous data for trotabresib monotherapy. The RP2D of trotabresib was selected as 30 mg 4 days on/24 days off in both settings. At last follow-up, 5 (28%) and 6 (43%) patients remain on treatment in the adjuvant and concomitant settings, respectively, with 1 patient in the adjuvant cohort achieving complete response. Conclusions Trotabresib combined with TMZ in the adjuvant setting and with TMZ+RT in the concomitant setting was safe and well tolerated in patients with ndGBM, with encouraging treatment durations. Trotabresib 30 mg was established as the RP2D in both settings.

Background The bromodomain and extraterminal protein (BET) inhibitor trotabresib has demonstrated antitumor activity in patients with advanced solid tumors, including high-grade gliomas. CC-90010-GBM-001 (NCT04047303) is a phase I study investigating the pharmacokinetics, pharmacodynamics, and CNS penetration of trotabresib in patients with recurrent high-grade gliomas scheduled for salvage resection. Methods Patients received trotabresib 30 mg/day on days 1–4 before surgery, followed by maintenance trotabresib 45 mg/day 4 days on/24 days off after surgery. Primary endpoints were plasma pharmacokinetics and trotabresib concentrations in resected tissue. Secondary and exploratory endpoints included safety, pharmacodynamics, and antitumor activity. Results Twenty patients received preoperative trotabresib and underwent resection with no delays or cancelations of surgery; 16 patients received maintenance trotabresib after recovery from surgery. Trotabresib plasma pharmacokinetics were consistent with previous data. Mean trotabresib brain tumor tissue:plasma ratio was 0.84 (estimated unbound partition coefficient [KPUU] 0.37), and modulation of pharmacodynamic markers was observed in blood and brain tumor tissue. Trotabresib was well tolerated; the most frequent grade 3/4 treatment-related adverse event during maintenance treatment was thrombocytopenia (5/16 patients). Six-month progression-free survival was 12%. Two patients remain on treatment with stable disease at cycles 25 and 30. Conclusions Trotabresib penetrates the blood–brain-tumor barrier in patients with recurrent high-grade glioma and demonstrates target engagement in resected tumor tissue. Plasma pharmacokinetics, blood pharmacodynamics, and safety were comparable with previous results for trotabresib in patients with advanced solid tumors. Investigation of adjuvant trotabresib + temozolomide and concomitant trotabresib + temozolomide + radiotherapy in patients with newly diagnosed glioblastoma is ongoing (NCT04324840).

Trotabresib, a novel bromodomain and extraterminal protein inhibitor, has demonstrated antitumor activity and blood–brain barrier penetration in patients with high-grade gliomas, and enhanced the antiproliferative effects of temozolomide in preclinical models. CC-90010-GBM-002 (NCT04324840) is a phase 1b/2 study investigating the addition of trotabresib to standard-of-care (SOC) concomitant temozolomide plus radiotherapy and adjuvant temozolomide, followed by maintenance trotabresib, in patients with newly diagnosed glioblastoma. The design of the dose escalation (part A) has been described previously (Vieito M, et al. SNO 2021. Abstract CTNI-51). Primary objectives of part A were to establish the safety, tolerability, and maximum tolerated dose/recommended phase 2 dose (RP2D) of trotabresib. In part A, addition of trotabresib to SOC was safe and well tolerated in the concomitant (N = 14) and adjuvant (N = 18) cohorts; the most frequent grade 3/4 treatment-related adverse event was thrombocytopenia (7/14 and 9/18 patients, respectively). The RP2D for trotabresib was 30 mg/day 4 days on/24 days off in both settings. At data cutoff (February 20, 2022), median duration of treatment was 34 weeks (concomitant cohort) and 33 weeks (adjuvant cohort); progression-free survival data are not yet mature. Trotabresib plasma pharmacokinetics and pharmacodynamics were consistent with monotherapy. At last follow-up, 6 and 5 patients remained on treatment in the concomitant and adjuvant dose-escalation cohorts, respectively, including 1 patient in cycle 20 with ongoing complete response. The ongoing randomized phase 2 dose expansion (part B; planned N = 162) is comparing concomitant trotabresib at the RP2D + SOC followed by adjuvant trotabresib at the RP2D + SOC, followed by maintenance trotabresib 45 mg/day 4 days on/24 days off, versus SOC alone in patients with newly diagnosed IDH–wild-type glioblastoma. Key objectives are to compare progression-free and overall survival, safety, and tolerability. Longer follow-up from part A and the first disclosure of data from part B will be presented.

Inhibidor de BET; Limfoma no Hodgkin; Tumors sòlids Inhibidor de BET; Linfoma no Hodgkin; Tumores sólidos BET inhibitor; Non-Hodgkin's lymphoma; Solid tumors Background Bromodomain and extra-terminal (BET) proteins are epigenetic readers that regulate expression of genes involved in oncogenesis. CC-90010 is a novel, oral, reversible, small-molecule BET inhibitor. Patients and methods CC-90010-ST-001 (NCT03220347; 2015-004371-79) is a phase I dose-escalation and expansion study of CC-90010 in patients with advanced or unresectable solid tumors and relapsed/refractory (R/R) non-Hodgkin's lymphoma (NHL). We report results from the dose escalation phase, which explored 11 dose levels and four dosing schedules, two weekly (2 days on/5 days off; 3 days on/4 days off), one biweekly (3 days on/11 days off), and one monthly (4 days on/24 days off). The primary objectives were to determine the safety, maximum tolerated dose (MTD) and/or recommended phase II dose (RP2D) and schedule. Secondary objectives were to evaluate signals of early antitumor activity, pharmacokinetics, and pharmacodynamics. Results This study enrolled 69 patients, 67 with solid tumors and two with diffuse large B-cell lymphoma (DLBCL). The median age was 57 years (range, 21–80) and the median number of prior regimens was four (range, 1–9). Treatment-related adverse events (TRAEs) were mostly mild and manageable; grade 3/4 TRAEs reported in more than two patients were thrombocytopenia (13%), anemia, and fatigue (4% each). Six patients had dose-limiting toxicities. MTDs were 15 mg (2 days on/5 days off), 30 mg (3 days on/11 days off), and 45 mg (4 days on/24 days off). The RP2D and schedule selected for expansion was 45 mg (4 days on/24 days off). As of 8 October 2019, one patient with grade 2 astrocytoma achieved a complete response, one patient with endometrial carcinoma had a partial response, and six patients had prolonged stable disease ≥11 months. Conclusions CC-90010 is well tolerated, with single-agent activity in patients with heavily pretreated, advanced solid tumors. This work was supported by Celgene Corporation, Summit, NJ, USA. (no grant number).

Trotabresib is a potent, reversible oral BETi with antitumor activity in patients with advanced malignancies (Moreno et al. ESMO 2020. Abstract 5270). The CC-90010-GBM-001 study (NCT04047303) enrolled patients with progressive or recurrent astrocytoma or recurrent glioblastoma scheduled for salvage resection. Patients were treated with trotabresib 30 mg daily for 4 days before surgery, then trotabresib 45 mg daily 4 days on/24 days off after recovery. Primary objectives were trotabresib tumor tissue concentration and plasma pharmacokinetics (PK). Secondary and exploratory objectives included safety, antitumor activity, cerebrospinal fluid concentration, and pharmacodynamics (PD). Twenty patients were enrolled; blood PK, blood PD, and tumor PD data were available for 14, 12, and 11 patients, respectively. Geometric mean peak trotabresib plasma concentration on day 4 was 1.92 μM; median time to peak concentration was 1.5 hours. At the time of resection, geometric mean trotabresib concentrations in plasma and brain tumor tissue were 1.01 and 0.68 μM, respectively. Blood CCR1 mRNA was reduced ≥ 50% from baseline after dose 4. Blood HEXIM1 mRNA increased at 72–96 hours following first dose, and at the time of surgery the percentage increase was related to plasma trotabresib concentration. Tumor HEXIM1 RNA increased in 10 of 11 patients. Eighteen patients (90%) had ≥ 1 treatment-related adverse event (TRAE). Nine patients (45%) had grade 3/4 TRAEs, most frequently thrombocytopenia (5 patients [25%]). Only 1 patient had serious TRAEs (hemiparesis and lethargy). Two patients died of intracranial hemorrhage unrelated to study drug. Of 16 patients evaluable for antitumor response, 7 had stable disease per RANO criteria, with 3 ongoing beyond data cutoff at cycles 4–11. Median progression-free survival was 1.9 months (95% CI, 1.4–3.3). Overall, trotabresib showed good tumor tissue penetration, with PD signals of response, and was well tolerated. A study of trotabresib + temozolomide in first-line glioblastoma is ongoing (NCT04324840).

Background: Cluster of differentiation 47 (CD47), a widely expressed cell-surface ligand,is overexpressed in various malignancies and is correlated with worse outcomes in NHL. Interaction of CD47 and signal regulatory protein-α (SIRPα) delivers an antiphagocytic 'don't eat me' signal to promote tumor cell evasion from macrophages. CC-90002 is a humanized IgG4-PE CD47 antibody that inhibits CD47-SIRPα interaction and enabled phagocytosis across a panel of cancer cell lines (Narla et al. AACR.2017). In addition to high binding affinity, CC-90002 is potentially differentiated from other CD47 immunotherapies by its lack of ability to induce hemagglutination of red blood cells or hemolysis in nonclinical studies. CD47 antibodies can synergize with the CD20 antibody rituximab to induce phagocytosis of NHL cells in vitroand to eliminate lymphoma in mouse models (Chao et al. Cell.2010). We therefore examined CC-90002 plus rituximab for treatment of R/R NHL. Methods: This 2-part, phase I, multicenter study (CC-90002-ST-001; NCT02367196) is evaluating CC-90002 in subjects with advanced solid and hematologic malignancies. Part B of the study (reported here) is examining CC-90002 in combination with rituximab in subjects with CD20-positive R/R NHL. Dose escalation followed a modified 3+3 design. Subjects received escalating doses of CC-90002 intravenously at 4, 8, 15, 20, or 30 mg/kg every 2 weeks (Q2W) on days 1 and 15 plus rituximab 375 mg/m2 given on days −15, −8, and −1 and day 8 of cycles 1-6, 8, 10, and 12 in 28-day cycles. Primary endpoints are dose-limiting toxicities (DLTs), nontolerated dose (NTD), and maximimum tolerated dose. Secondary endpoints are pharmacokinetics, preliminary efficacy per International Working Group Response Criteria for NHL (Cheson et al. J Clin Oncol.2014), and frequency of antidrug antibodies. Results: Overall, 28 subjects have been enrolled and 24 were treated. As of July 5, 2019, 20 subjects had discontinued the study, most commonly for progressive disease (PD; n=9) or death (n=7). The median age at enrollment was 64 years (range, 27−81), and subjects had received a median of 3 prior systemic therapies (range, 2−9). Subjects received a median of 2 cycles of CC-90002 plus rituximab (range, 1−18). There were no CC-90002 dose reductions but 7 subjects had their dose interrupted, mostly because of thrombocytopenia and neutropenia. The NTD was established as 30 mg/kg Q2W.DLTs occurred in 3 subjects; 1 subject developed dyspnea attributed to an infusion-related reaction at 15 mg/kg Q2W CC-90002 and 2 subjects had grade 3 thrombocytopenia requiring platelet transfusion occurring at 30 mg/kg Q2W CC-90002. The most common adverse events (AEs) were hematologic (Table). Although anemia was common, there was no evidence of hemolysis. The most frequent grade 3/4 AEs were neutropenia (38%) and thrombocytoenia (21%). Seven deaths occurred on study or in follow-up, 6 from PD or complications related to NHL and 1 due to an AE (cytokine release syndrome in a subject who discontinued CC-90002 for PD and enrolled in another trial within the follow-up period). There were no treatment-related deaths. The overall response rate was 13% (95% CI, 2.7−32.4) and the disease control rate was 25% (95% CI, 9.8−46.7; Figure). One subject achieved a durable complete response (8 mg/kg; ongoing in cycle 18) and 2 had partial responses (15 mg/kg and 20 mg/kg); 3 subjects had stable disease. Among responders, the median duration of response was 3.9 months (95% CI, 1.9−3.9). CC-90002 exhibited linear pharmacokinetics at doses ≥15 mg/kg, suggesting target saturation at 15 mg/kg. In addition, a longer half-life was observed at higher (≥15 mg/kg) versus lower doses (t1/2≈ 3−7 days vs 1 day). Conclusions: The CD47-SIRPα checkpoint inhibitor, CC-90002,plus rituximab demonstrated tolerability and modest clinical activity in this early-phase study of heavily pretreated R/R NHL subjects. AEs were predominantly grade 1/2; cytopenias were the most common AEs with dose-limiting thrombocytopenia observed at 30 mg/kg Q2W. In contrast to other CD47-targeting immunotherapies and consistent with results of preclinical studies of CC-90002, hemolysis at a starting dose of up to 30 mg/kg CC-90002 was not observed. These preliminary data support further evaluation of targeting the CD47-SIRPα pathway in combination with rituximab in NHL. Disclosures Abrisqueta: Abbvie: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau; Roche: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau. Sancho:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Other: Advisory board; Novartis: Honoraria; Kern Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria; Celltrion: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squib: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sandoz: Consultancy; F. Hoffmann-La Roche Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees. Cordoba:Janssen: Consultancy, Honoraria, Speakers Bureau; Servier: Consultancy, Honoraria, Speakers Bureau; Kyowa-Kirin: Consultancy, Honoraria, Speakers Bureau; Gilead: Consultancy, Research Funding, Speakers Bureau; Roche: Honoraria, Speakers Bureau; FUNDACION JIMENEZ DIAZ UNIVERSITY HOSPITAL: Employment; Celgene: Consultancy, Honoraria, Speakers Bureau; Pfizer: Consultancy. Persky:Sandoz: Consultancy; Morphosys: Other: Member, Independent Data Monitoring Committee; Debiopharm: Other: Member, Independent Data Monitoring Committee; Bayer: Consultancy. Andreadis:Juno: Research Funding; Pharmacyclics: Research Funding; Roche: Equity Ownership; Novartis: Research Funding; Jazz Pharmaceuticals: Consultancy; Celgene: Research Funding; Kite: Consultancy; Gilead: Consultancy; Merck: Research Funding; Genentech: Consultancy, Employment. Huntington:Pharmacyclics: Honoraria; Genentech: Consultancy; Bayer: Consultancy, Honoraria; DTRM Biopharm: Research Funding; AbbVie: Consultancy; Celgene: Consultancy, Research Funding. Carpio:University Hospital Vall D'Hebron: Employment. Morillo Giles:Hospital Universitario Fundacion Jimenez Diaz: Honoraria. Wei:Celgene Corp.: Employment, Equity Ownership. Li:Celgene Corp.: Employment, Equity Ownership. Zuraek:Celgene Corp.: Employment, Equity Ownership, Other: Travel, Accommodations, Expenses. Burgess:University of California: Other: Volunteer clinical faculty, without salary, Patents & Royalties: Patent - T315A and F317I mutations of BCR-ABL kinase domain; Celgene Corporation: Employment, Equity Ownership, Patents & Royalties: Patent - CD47 antibodies and methods of use thereof. Hege:Celgene Corporation: Employment, Equity Ownership, Patents & Royalties; Arcus Biosciences: Membership on an entity's Board of Directors or advisory committees; Mersana Therapuetics: Membership on an entity's Board of Directors or advisory committees; Society for Immunotherapy of Cancer: Membership on an entity's Board of Directors or advisory committees. Martín:iQone: Consultancy; Gilead: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Other: Travel Expenses; Celgene: Consultancy, Honoraria, Other: Travel Expenses, Research Funding; Kiowa Kirin: Consultancy; Servier: Honoraria, Other: Travel Expenses; Teva: Research Funding; Janssen: Honoraria, Other: Travel Expenses, Research Funding.

Adenoid cystic carcinoma (ACC) is a rare subtype of breast malignancy. Patients with ACC and infiltrating ductal carcinoma (IDC) reported to the National Cancer Data Base from 1998 to 2008 were reviewed for patient age, ethnicity, tumor size, nodal status, American Joint Committee on Cancer TNM Stage, tumor grade, initial treatment, hormone receptor status (for patients from 2004 to 2008), and survival (for patients from 1998 to 2003). A total of 933 patients with ACC and 729,938 with IDC were identified. No differences were found for incidence by race/ethnicity (p = 0.97). The group with ACC was older (median 60 vs. 58 years), had larger tumors (median 18 vs. 16 mm), had more grade 1 tumors (46 vs. 18 %), was less likely to undergo axillary lymph node evaluation (75.9 vs. 96.3 %), had fewer node-positive patients (5.1 vs. 35.5 %), had fewer estrogen receptor–positive tumors (15.4 vs. 75.6 %), had fewer progesterone receptor–positive tumors (13.3 vs. 65.2 %), and underwent breast-conserving surgery more often (69.8 vs. 59.8 %). Chemotherapy was provided less often for ACC (11.3 vs. 46.4 %), as was hormone therapy (9.1 vs. 42.3 %). All of these differences were statistically significant (p

To examine gender-specific differences in breast cancer utilizing the National Cancer Data Base (NCDB).Breast cancer patients entered in the NCDB from 1998 through 2007 were compared by gender for demographics, tumor characteristics, treatment, and outcomes.A total of 13,457 men were compared to 1,439,866 women. Men were older, more often African American, less often Hispanic, had larger tumors, less often had low-grade disease, less often had stage 0 or I disease, and were more likely to have metastases to lymph nodes and/or distantly. Cancers in men were less likely lobular and more likely estrogen receptor and/or progesterone receptor positive. Men were more likely to have total mastectomy and less likely to receive radiotherapy. There was no difference in chemotherapy and little difference in hormone therapy rates. Differences in overall survival (OS) were highly significant (p0.0001): 83 % 5-year OS for women with breast cancer (median survival 129 months) versus 74 % for men (median survival 101 months). Women had better 5-year OS (p0.0001) for stage 0 (94 vs. 90 %), stage I (90 vs. 87 %), and stage II (82 vs. 74 %) breast cancer. There were no differences in 5-year OS for stage III (56.9 vs. 56.5 %, p = 0.99) or stage IV (19 vs. 16 %, p = 0.20) disease.At first glance, this large study demonstrated numerous gender-specific differences. However, after accounting for differences in presentation, absence of data on disease-specific survival, and inherent deficiencies in reporting cancer registry data, breast cancer in men and women appears more alike than different.

Background: CC-122, a pleiotropic pathway modifier, modulates the cullin 4 ring E3 ligase complex, which results in recruitment and degradation of Aiolos and Ikaros. This substrate degradation results in cell autonomous anti-lymphoma and immunomodulatory effects on T- and NK-cell function (Gandhi, ASH 2012). The anti-CD20 monoclonal antibody, obinutuzumab, improves direct cell killing and antibody-dependent cell-mediated cytotoxicity (ADCC) activity compared to rituximab (Mössner, 2010; Niederfellner, 2011). The combination of obinutuzumab with CC-122 revealed synergistic effects in follicular lymphoma (FL) and additive effects in diffuse large B-cell lymphoma (DLBCL) in in vivo models when compared to either as single agents (Hsiling Chiu, ASH 2015). CC-122 monotherapy has shown encouraging activity against DLBCL and FL in a Phase I clinical trial (Rasco, ASH 2013). Obinutuzumab has demonstrated efficacy in patients with relapsed/refractory indolent non-Hodgkin lymphoma (iNHL) (Salles, 2013) and DLBCL (Morschhauser, 2013) and has been approved by the FDA and the European Medicinal Agency for patients with previously treated FL. The current study was designed to evaluate the safety and efficacy of escalating doses of CC-122 in combination with obinutuzumab in patients with relapsed/refractory DLBCL and iNHL (NCT02417285). Methods: Subjects with relapsed/refractory DLBCL and iNHL (FL and marginal zone lymphoma [MZL]) were enrolled in this phase 1b study of CC-122 given orally on 5 out of 7 days per week (5/7 days) for 28 day cycles. Subjects were enrolled in cohorts of escalating dose levels of CC-122 (1.0 mg [n=4], 2.0 mg [n = 4], 3.0 mg [n = 7], 4.0 mg [n = 6]), with a fixed dose of obinutuzumab. Obinutuzumab is administered as an intravenous (IV) infusion at a dose of 1000 mg on Days 2, 8, and 15 of Cycle 1 and on Day 1 of Cycles 2 through 8. The initial 4 dose levels evaluated active ingredient in capsule (AIC) CC-122 formulation. In Cohort 5 (3.0 mg, [n = 5]), subjects received CC-122 formulated capsules. Prophylaxis with granulocyte-colony stimulating factor (G-CSF) was not allowed during Cycle 1. As the study is ongoing, the CC-122 dose will be escalated until the maximum tolerated dose (MTD) is established on the CC-122 formulated capsule, using a modified 3+3 design. Subjects are evaluated for efficacy every 2 cycles(c) through c6 then every 3 cycles through c12, then every 6 cycles. Results: As of 1 June 2016, 26 subjects with relapsed/refractory DLBCL or iNHL were enrolled; all were evaluable for safety. The median age was 60 years and 84.6% were male. Thirteen subjects had DLBCL (50%), 13 (50%) had iNHL (12 FL [46.2%], 1 had MZL [3.8%]). All subjects were ECOG 0-1. One subject experienced a dose-limiting toxicity (DLT) of Grade 4 neutropenia (Cohort 3) and no dose was considered a non-tolerated dose (NTD). The most common (≥ 10%) study drug-related treatment emergent adverse events (TEAEs) were neutropenia (50%), thrombocytopenia (30.8%), diarrhea, chills, and increased ALT (11.5% each). Seventeen subjects (65.4%) experienced at least one NCI CTCAE grade 3-4 TEAE related to study treatment (most common [≥ 10%] were neutropenia [42.3%], thrombocytopenia [15.4%], and increased ALT [11.5%]). Seven subjects experienced at least one serious AE suspected to be related to study treatment by the investigator (infusion related reaction [3 subjects], febrile neutropenia, neutropenia, thrombocytopenia, and pneumonia, [1 subject each]). The overall response rate (ORR) for the 26 subjects enrolled, as of the efficacy cut off of 7 July 2016, was 53.8% (14/26); 8 of 12 (66.7%) FL, 5/13 (38.5%) DLBCL, and 1/1 MZL. Responses are ongoing in 12 of 14 of these subjects. ORR in the pooled higher dose cohorts of CC-122 (eg, a dose of 3 mg or higher, cohorts 3, 4, and 5) was 66.7% (12 of 18 subjects). Conclusion: The combination of CC-122 and obinutuzumab was well-tolerated in subjects with relapsed-refractory DLBCL and iNHL. AEs observed were consistent with the toxicity profile of CC-122 or obinutuzumab. Response rates observed were promising in this heavily pretreated population. Response rate appears higher in patients with FL however this warrants further investigation in a larger population. An NTD has not been reached and the MTD has not yet been established. Disclosures Michot: Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees. Vitolo:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria; Gilead: Honoraria; Takeda: Honoraria. Zinzani:Karyopharm: Membership on an entity's Board of Directors or advisory committees; Sandoz: Membership on an entity's Board of Directors or advisory committees; Millennium: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Infinity: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Bayer: Honoraria, Membership on an entity's Board of Directors or advisory committees; TG Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Kersten:Celgene: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding. Chiappella:Teva: Speakers Bureau; Janssen-Cilag: Speakers Bureau; Amgen: Speakers Bureau; Pfizer: Speakers Bureau; Roche: Speakers Bureau; Celgene: Speakers Bureau. Sarmiento:Celgene CITRE: Employment, Equity Ownership. Zuraek:Celgene Corporation: Employment, Equity Ownership. Pourdehnad:Celgene Corporation: Employment, Equity Ownership. Hege:Celgene Corporation: Employment, Equity Ownership. Nikolova:Celgene International: Employment, Equity Ownership. Ribrag:BMS: Membership on an entity's Board of Directors or advisory committees; ArgenX: Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees; Infinity: Membership on an entity's Board of Directors or advisory committees; Esai: Membership on an entity's Board of Directors or advisory committees; Pharmamar: Membership on an entity's Board of Directors or advisory committees; NanoString: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees.

452 Background: The p53 tumor suppressor gene is frequently mutated in colorectal cancer, but reports on the effect of p53 mutations on response to adjuvant chemotherapy and survival are inconclusive. This study investigates whether p53 mutational status (wild-type, zinc or non-zinc binding mutations) impacts survival following adjuvant therapy containing fluorouracil/leucovorin with or without irinotecan (5FU/LV or IFL) in women and men with stage III colon cancer. Methods: As part of a retrospective analysis of prospectively accrued data, p53 mutational status was determined for 609 patients with stage III colon cancer who were randomized on CALGB 89803, a phase III adjuvant chemotherapy trial. p53 exons 5-8 were analyzed by direct sequencing or sequencing by hybridization. p53 mutations were identified in 276 tumors (45%), of which 134 were in the zinc binding and 142 were in the non-zinc binding regions of the core domain. Cox regression was used to study the impact of p53 mutational status, sex, and adjuvant chemotherapy on disease-free (DFS) and overall survival (OS). Results: p53 mutational status did not predict differential survival or response to adjuvant therapy among the 609 patients assessed. However, a significant sex by treatment interaction was observed for both DFS (Pinteraction=0.008) and OS (Pinteraction=0.002). Significant differences in DFS by p53 mutational status were observed among women (logrank P = 0.009). No such differences were observed among men (logrank P = 0.33). Similar results were observed for OS. There was marginal evidence of a treatment-related impact on the interaction between sex and p53 mutational status for both DFS and OS (DFS Pinteraction = 0.07; OS Pinteraction = 0.11). There was a trend toward improved OS when women with zinc binding mutations received IFL versus 5FU/LV (P = 0.08) and toward worse DFS when women with non-zinc binding mutations were treated with IFL versus 5FU/LV (P =0.08). Conclusions: This exploratory subset analysis suggests that p53 mutational status may be used to predict prognosis in a sex- and potentially chemotherapeutic regimen-specific manner.