Citations

Abstract It is now widely accepted that a spectrum of somatic alterations occur in human cancer and that particular alterations are associated with response or lack of response to anti-cancer therapies. Here, we undertook a systematic correlation analysis of somatic mutations, copy number aberrations and drug response across 300+ human cancer cell lines. We studied the RAF and VEGFR inhibitor, sorafenib, evaluating associations between sorafenib response and somatic mutations in 35 common cancer genes and high-level amplifications and homozygous deletions in more than 100 minimal common regions of gain and loss, which include many known oncogenes and tumor suppressor genes. Notably, we found that NRAS mutations, among other alterations, were significantly associated with sensitivity to sorafenib (odds ratio = 7, p-value = 0.003), whereas activating BRAF mutations were strongly associated with a lack of response (odds ratio = 4.9, p-value = 0.012). Specifically, 64% (7 of 11) of NRAS mutant cell lines were sensitive to sorafenib, while only 20% (34 of 170) of NRAS wild-type lines were sensitive. On the contrary, just 6.7% (2 of 30) of BRAF mutant lines were sensitive to sorafenib. Because NRAS mutations occur frequently in leukemia and no leukemia cell lines were included in the original analysis, we selected 5 NRAS mutant and 5 NRAS wild-type leukemia cell lines for further evaluation. Consistent with our previous observation, the four most sensitive leukemia cell lines were all NRAS mutant, each line exhibiting greater than 50% growth inhibition after 72 hours of exposure to 4μM sorafenib. These results confirm the original association and suggest that across both solid tumors and hematologic malignancies, NRAS mutations may identify a subset of cancers that are likely to respond sorafenib. In addition, this work demonstrates that systematic analysis of somatic alterations and drug response across a large collection of cancer cell lines is capable of discovering novel predictive biomarkers. Citation Information: Clin Cancer Res 2010;16(7 Suppl):A41

Abstract Background: N9831 is the only randomized phase III trial comparing safety and efficacy of the addition of trastuzumab (H) to doxorubicin and cyclophosphamide then paclitaxel (Arm A: AC→T) either following (Arm B: AC→T→H) or starting concurrently with paclitaxel (Arm C: AC→T+H→H) for women with resected Stage I-III invasive HER2+ breast cancer. The 3 yr cumulative incidence of NYHA class III or IV congestive heart failure or sudden cardiac death was previously reported: 3.3% in Arm C, 2.8% in Arm B (Perez EA, et al. JCO 2008). The comparison of AC→T to AC→T+H→H was reported in a joint analysis of N9831 and NSABP B-31 in 2005 and updated in 2007, demonstrating a 52% reduction in risk of a disease event (Romond E et al., NEJM 2005; Perez EA, et al. ASCO 2007).Materials and Methods: Primary endpoint is disease-free survival (DFS). At the second planned interim analysis of Arm A vs. Arm B, the O’Brien-Fleming boundary (OFB) was crossed. NCCTG Independent Data Safety Monitoring Committee approved the release of these data as well as the data pertaining to Arm B vs. Arm C due to slow pace of events [expected 647 events in 4 yr follow-up period (f/u) vs. actual 334 events in 4.5 yr f/u]. Shortly thereafter, there were sufficient events to perform the first planned interim analysis of B vs. C. We present the results of each of these pairwise comparisons taking into account the potential for crossover to Arm C after the release of the joint analysis findings in 2005.Results: From 5/2000 to 4/2005, 2448 eligible women were enrolled for the Arm A (n=1087) vs. Arm B (n=1097) comparison. Median f/u is 5.5 yrs. with 386 events. The addition of trastuzumab sequentially to AC→T significantly improved DFS, univariately [HR(Arm B/Arm A)=0.70, 95% CI: 57-86%, logrank p=0.0005] and after adjusting for age, tumor size, number of positive nodes, and ER [PPH: HRadj=0.67 (95% CI: 0.55-0.82)]. 5 yr DFS was increased from 72% with AC→T to 80% with AC→T →H.From 5/2000 to 4/2005, 1903 eligible women were enrolled for the Arm B (n=954) vs. Arm C (n=949) comparison. Median f/u is 5.3 yrs. with 312 events. The log-rank p-value testing whether DFS differs with respect to starting time of trastuzumab was 0.019. [Not crossing pre-specified OFB for statistical significance]. After adjusting for tumor size, number of positive nodes, and ER, HRadj(Arm C/Arm B)=0.75 (95% CI: 0.60-0.94)]. 5 yr DFS was increased from 80% with AC→T →H to 84% for AC→T+H →H.Conclusions: DFS is significantly improved with the addition of 52 weeks of H (sequentially or concurrently) to AC→ T. There is a statistically significant 33% reduction in the risk of an event with the sequential addition of H following AC→T. There is a strong trend for a 25% reduction in the risk of an event with starting H concurrently with T relative to sequentially after T. Therefore, based on a positive risk/benefit ratio, we recommend that trastuzumab be incorporated in a concurrent fashion with T chemotherapy.Acknowledgements: NIH CA25224, Breast Cancer Research Foundation, Genentech. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 80. NOTE: This abstract was accepted for presentation at the Symposium after the Abstract Book went to press.

Abstract Background: The decision to use adjuvant chemotherapy in patients with early stage breast cancer is based in part on the estimation of risk of tumor recurrence by physicians, which traditionally relies heavily on tumor size, nodal status and a set of biologic tumor characteristics such as hormone receptor and HER2 expression. The Oncotype DX® assay is a 21-gene expression profile aiming to improve risk stratification, recurrence prediction and optimize selection of patients for adjuvant chemotherapy.Methods: We selected 154 consecutive patients with early stage estrogen receptor (ER) positive breast cancer and available Oncotype Dx® recurrence score (RS) for the study. Clinicopathologic data, including patient age, menopausal status, tumor size, histologic type, grade, mitotic activity, presence of lymphatic invasion (LVI), nodal status, hormone receptor and HER2 status on all patients were provided to four surgical oncologists, four medical oncologists and three pathologists, specializing in breast cancer diagnosis and management. Participants were asked to estimate the risk of recurrence of tumors based on available clinicopathologic data and to provide the three most important tumor features their risk estimates were based on. Risk estimates of participants were compared with RS results.Results: Based on the Oncotype Dx® results, 95 (61.7%), 45 (29.2%) and 14 (9.1%) tumors were of low (RS <18), intermediate (RS 18-30) and high (RS ≥31) risk, respectively. RS values showed a highly significant correlation with tumor grade, mitotic activity, LVI, hormone receptor and HER2 status, while no correlation with patient age, menopausal status, tumor size and histologic type was found. Participants' risk estimates agreed with those of the Oncotype Dx® assay in 54.2 ± 2.3 % (mean ± SEM, range 41.6 - 63.0%) of cases, while the risk of recurrence was over- and underestimated compared to RS results in 31.8 ± 3.1% (16.2 - 43.5%) and 14.1 ± 1.4% (7.1 - 22.7%), respectively. The rates of overestimation were significantly higher than those of underestimation (p = 0.0003). Although medical oncologists tended to overestimate the risk more frequently (38.1 ± 2.0%) compared to surgeons (28.7 ± 5.9%) and pathologists (27.5 ± 7.8%), the difference did not reach statistical significance. Estimation of the agreement of participants' risk assessment with RS results showed a mean kappa value of 0.2955 (range 0.1506 - 0.4123). No statistically significant difference in overall concurrence with RS results was found between surgeons, medical oncologists and pathologists. Participants ranked tumor stage/nodal status, hormone receptor status and tumor size to be the most important features when estimating recurrence risk.Conclusions: Based on traditional clinicopathologic features alone, surgeons, medical oncologists and pathologists tend to overestimate the risk of tumor recurrence as compared to Oncotype Dx® assay results. The RS may provide additional information regarding the intrinsic biological features of ER positive breast cancers and help tailoring treatment recommendations. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4061.

Abstract Background: Current guidelines recommend administration of chemotherapy for patients with breast carcinomas >1 cm in size, with consideration for patient age, comorbidities and tumor grade. However, it is unknown which patients actually benefit from therapy and overtreatment of a significant proportion of patients is a major concern. We investigated the impact of the Oncotype Dx® Recurrence Score (RS) on chemotherapy recommendations in early stage estrogen receptor (ER) positive breast cancer patients.Methods: We selected 154 patients with early stage ER positive breast cancer and available RS for the study. Clinicopathologic data, including age, menopausal status, tumor size, type, grade, mitotic activity, presence of lymphatic invasion, nodal status, hormone receptor and HER2 status on all patients were provided to four surgical oncologists, four medical oncologists and three pathologists, specializing in breast cancer diagnosis and management. Assuming that all patients were in good general health and would receive endocrine therapy, participants were asked whether they would also advovate adjuvant chemotherapy based on clinicopathologic data with and without knowledge of the RS, and to provide the three salient clinicopathologic features on which their recommendations were based. Changes in recommendations of participants following inclusion of RS data were compared.Results: Based on RS results, 95 (61.7%), 45 (29.2%) and 14 (9.1%) tumors were of low (RS <18), intermediate (RS 18-30) and high (RS ≥31) risk, respectively. The results are summarized in Table 1. Assuming that the hypothesis previously put forward that patients with low to intermediate risk RS are not likely to benefit from chemotherapy, 82.3 ± 1.3% (75.5 - 89.0%) and 69.0 ± 6.9% (5.9 - 85.7%) of patients for whom chemotherapy was recommended by the participants would be "overtreated" without and with the use of RS results (p = 0.0322). No statistically significant difference was found among surgeons, medical oncologists and pathologists. Participants ranked patient age/menopausal status, hormone receptor status and tumor stage/nodal status to be the most important features when recommending chemotherapy.Conclusions: Although current recommendations for adjuvant chemotherapy for early stage ER positive breast cancer patients are largely in line with published guidelines, inclusion of RS alters recommendations in about 25% of cases. While medical oncologists recommended chemotherapy more frequently compared to surgeons and pathologists, they were more likely to change recommendations in light of RS results.Table 1. Summary of results SurgeonsMedical oncologistsPathologistsp* Mean ± SEMRangeMean ± SEMRangeMean ± SEMRange Chemo without RS (%)29.2 ± 1.824.0 - 31.859.0 ± 5.046.8 - 70.846.8 ± 3.741.6 - 53.90.0156Chemo with RS (%)27.0 ± 5.611.0 - 36.438.6 ± 9.517.5 - 63.644.4 ± 5.833.8 - 53.90.1794No change (%)75.3 ± 7.054.5 - 85.766.7 ± 6.851.3 - 83.885.9 ± 6.478.6 - 98.70.3682Add chemo (%)11.2 ± 4.13.2 - 22.76.5 ± 1.93.2 - 11.75.8 ± 3.20.6 - 11.70.6882Avoid chemo (%)13.5 ± 3.94.5 - 22.726.8 ± 7.94.5 - 41.68.2 ± 4.50.6 - 16.20.2186*Kruskal-Wallis test Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4058.

Abstract Abstract #106 Breast cancer has been proposed as a stem cell-derived disorder based on studies identifying cancer stem cells (CSCs) in breast tumors and established cell lines. These self-renewing CSCs are thought to be responsible for breast cancer formation, progression and recurrence; therefore, a deeper understanding of the signaling pathways regulating CSC survival will benefit development of novel therapeutic strategies. Notch signaling, which is known to be dysregulated in breast cancer and has been implicated in mammary stem cell self-renewal, can be effectively blocked by gamma-secretase inhibitors (GSIs). While GSIs are currently in clinical trials for breast cancer, it is unclear how these compounds will affect CSCs or if CSCs from different breast cancer phenotypes (estrogen receptor-alpha (ER)-positive and negative) will be differentially affected. Here, we demonstrate stem-like cells derived from the T47D breast cancer cell line show elevated levels of Notch signaling, with an ER-negative subclone (T47D-C42) having higher intrinsic levels of Notch activity compared to an ER-positive subclone (T47D-A18). Blockade of Notch signaling with three structurally distinct GSIs reduced the number of stem-like cells, and completely abolished secondary mammosphere formation, which is a measure of stem cell self-renewal. Importantly, this effect was irreversible with MRK-003, but not with the two other GSIs. Moreover, our results suggest that the ER-negative cell line was more sensitive to the GSIs compared to the ER-positive line. This is consistent with our recent report that loss of estrogen signals results in Notch activation. These novel findings support a role for Notch signaling in CSC self-renewal and proliferation, and they suggest Notch inhibition may have clinical benefits in targeting CSCs. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 106.

Purpose Cumulative sensory neurotoxicity (sNT) is the dose-limiting toxicity of oxaliplatin, which commonly leads to early discontinuation of oxaliplatin-based therapy in the palliative and adjuvant settings. In a nonrandomized, retrospective study, intravenous (IV) calcium/magnesium (Ca/Mg) was associated with reduced oxaliplatin-induced sNT. Methods Patients with colon cancer undergoing adjuvant therapy with infusional fluorouracil, leucovorin, and oxaliplatin (FOLFOX) were randomly assigned to Ca/Mg (1g calcium gluconate plus 1g magnesium sulfate pre- and post-oxaliplatin) or placebo, in a double-blinded manner. The primary end point was the percentage of patients with grade 2 or greater sNT at any time during or after oxaliplatin-based therapy by National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE; version 3) criteria. An oxaliplatin-specific sNT scale and patient questionnaires were also used to assess sNT. After 104 of 300 planned patients were enrolled, the study was closed. This was due to preliminary reports from another trial that suggested that Ca/Mg decreased treatment efficacy; these data were subsequently found to be incorrect. Results Overall, 102 patients were available for analysis. Ca/Mg decreased the incidence of chronic, cumulative, grade 2 or greater sNT, as measured by NCI CTCAE (P = .038) and also by the oxaliplatin-specific sNT scale (P = .018). In addition, acute muscle spasms associated with oxaliplatin were significantly reduced (P = .01) No effect on acute, cold-induced sNT was found. No substantial differences in adverse effects were noted between Ca/Mg and placebo. Conclusion Despite early termination and decreased statistical power, this study supports IV Ca/Mg as an effective neuroprotectant against oxaliplatin-induced cumulative sNT in adjuvant colon cancer.

A session about educating translational scientists was held at a 2010 NIH forum on promoting collaborations between academia, government, and industry.