Crizotinib in patients with tumors harboring ALK or ROS1 rearrangements in the NCI-MATCH trial

The NCI-MATCH was designed to characterize the efficacy of targeted therapies in histology-agnostic driver mutation-positive malignancies. Sub-protocols F and G were developed to evaluate the role of crizotinib in rare tumors that harbored either ALK or ROS1 rearrangements. Patients with malignancies that progressed following at least one prior systemic therapy were accrued to the NCI-MATCH for molecular profiling, and those with actionable ALK or ROS1 rearrangements were offered participation in sub-protocols F or G, respectively. There were five patients who enrolled on Arm F (ALK) and four patients on Arm G (ROS1). Few grade 3 or 4 toxicities were noted, including liver test abnormalities, and acute kidney injury. For sub-protocol F (ALK), the response rate was 50% (90% CI 9.8-90.2%) with one complete response among the 4 eligible patients. The median PFS was 3.8 months, and median OS was 4.3 months. For sub-protocol G (ROS1) the response rate was 25% (90% CI 1.3-75.1%). The median PFS was 4.3 months, and median OS 6.2 months. Data from 3 commercial vendors showed that the prevalence of ALK and ROS1 rearrangements in histologies other than non-small cell lung cancer and lymphoma was rare (0.1% and 0.4% respectively). We observed responses to crizotinib which met the primary endpoint for ALK fusions, albeit in a small number of patients. Despite the limited accrual, some of the patients with these oncogenic fusions can respond to crizotinib which may have a therapeutic role in this setting.

Ado-trastuzumab emtansine (T-DM1) in patients with HER2-amplified tumors excluding breast and gastric/gastroesophageal junction (GEJ) adenocarcinomas: results from the NCI-MATCH trial (EAY131) subprotocol Q

BACKGROUND

The National Cancer Institute-Molecular Analysis for Therapy Choice (NCI-MATCH) is a national precision medicine study incorporating centralized genomic testing to direct refractory cancer patients to molecularly targeted treatment subprotocols. This treatment subprotocol was designed to screen for potential signals of efficacy of ado-trastuzumab emtansine (T-DM1) in HER2-amplified histologies other than breast and gastroesophageal tumors.

METHODS

Eligible patients had HER2 amplification at a copy number (CN) >7 based on targeted next-generation sequencing (NGS) with a custom Oncomine AmpliSeq™ (ThermoFisher Scientific) panel. Patients with prior trastuzumab, pertuzumab or T-DM1 treatment were excluded. Patients received T-DM1 at 3.6 mg/kg i.v. every 3 weeks until toxicity or disease progression. Tumor assessments occurred every three cycles. The primary end point was centrally assessed objective response rate (ORR). Exploratory end points included correlating response with HER2 CN by NGS. The impact of co-occurring genomic alterations and PTEN loss by immunohistochemistry were also assessed.

RESULTS

Thirty-eight patients were enrolled and 36 included in efficacy analysis. Median prior therapies in the metastatic setting was 3 (range 0-9; unknown in one patient). Median HER2 CN was 17 (range 7-139). Partial responses were observed in two (5.6%) patients: one mucoepidermoid carcinoma of parotid gland and one parotid gland squamous cell cancer. Seventeen patients (47%) had stable disease including 8/10 (80%) with ovarian and uterine carcinomas, with median duration of 4.6 months. The 6-month progression-free survival rate was 23.6% [90% confidence interval 14.2% to 39.2%]. Common toxicities included fatigue, anemia, fever and thrombocytopenia with no new safety signals. There was a trend for tumor shrinkage with higher levels of gene CN as determined by the NGS assay.

CONCLUSION

T-DM1 was well tolerated. While this subprotocol did not meet the primary end point for ORR in this heavily pre-treated diverse patient population, clinical activity was seen in salivary gland tumors warranting further study in this tumor type in dedicated trials.

Dynamic self-assembly of DNA minor groove-binding ligand DB921 into nanotubes triggered by an alkali halide

We describe a novel self-assembling supramolecular nanotube system formed by a heterocyclic cationic molecule which was originally designed for its potential as an antiparasitic and DNA sequence recognition agent. Our structural characterisation work indicates that the nanotubes form via a hierarchical assembly mechanism that can be triggered and tuned by well-defined concentrations of simple alkali halide salts in water. The nanotubes assembled in NaCl have inner and outer diameters of ca. 22 nm and 26 nm respectively, with lengths that reach into several microns. Our results suggest the tubes consist of DB921 molecules stacked along the direction of the nanotube long axis. The tubes are stabilised by face-to-face π-π stacking and ionic interactions between the charged amidinium groups of the ligand and the negative halide ions. The assembly process of the nanotubes was followed using small-angle X-ray and neutron scattering, transmission electron microscopy and ultraviolet/visible spectroscopy. Our data demonstrate that assembly occurs through the formation of intermediate ribbon-like structures that in turn form helices that tighten and compact to form the final stable filament. This assembly process was tested using different alkali-metal salts, showing a strong preference for chloride or bromide anions and with little dependency on the type of cation. Our data further demonstrates the existence of a critical anion concentration above which the rate of self-assembly is greatly enhanced.

Steroid induction of therapy-resistant cytokeratin-5-positive cells in estrogen receptor-positive breast cancer through a BCL6-dependent mechanism

Therapy resistance remains a major problem in estrogen receptor-α (ERα)-positive breast cancer. A subgroup of ERα-positive breast cancer is characterized by mosaic presence of a minor population of ERα-negative cancer cells expressing the basal cytokeratin-5 (CK5). These CK5-positive cells are therapy resistant and have increased tumor-initiating potential. Although a series of reports document induction of the CK5-positive cells by progestins, it is unknown if other 3-ketosteroids share this ability. We now report that glucocorticoids and mineralocorticoids effectively expand the CK5-positive cell population. CK5-positive cells induced by 3-ketosteroids lacked ERα and progesterone receptors, expressed stem cell marker, CD44, and displayed increased clonogenicity in soft agar and broad drug-resistance in vitro and in vivo. Upregulation of CK5-positive cells by 3-ketosteroids required induction of the transcriptional repressor BCL6 based on suppression of BCL6 by two independent BCL6 small hairpin RNAs or by prolactin. Prolactin also suppressed 3-ketosteroid induction of CK5+ cells in T47D xenografts in vivo. Survival analysis with recursive partitioning in node-negative ERα-positive breast cancer using quantitative CK5 and BCL6 mRNA or protein expression data identified patients at high or low risk for tumor recurrence in two independent patient cohorts. The data provide a mechanism by which common pathophysiological or pharmacologic elevations in glucocorticoids or other 3-ketosteroids may adversely affect patients with mixed ERα+/CK5+ breast cancer. The observations further suggest a cooperative diagnostic utility of CK5 and BCL6 expression levels and justify exploring efficacy of inhibitors of BCL6 and 3-ketosteroid receptors for a subset of ERα-positive breast cancers.

Abstract P1-08-20: Increased risk of hormone therapy failure in breast cancers expressing low phospho-Stat5: Validation of quantitative immunofluorescence assay parameters

Previous analyses of three breast cancer cohorts revealed that loss of phospho-Stat5 in breast cancer is associated with significantly elevated risk of hormone therapy failure (1, 2). Nuclear localized tyrosine phosphorylated Stat5 (Nuc-pYStat5) may therefore have clinical value as a predictive marker. Analysis of two of the three previously reported anti-estrogen treated patient cohorts used pathologist scoring of diaminobenzidine (DAB) chromogen-stained Stat5. However the third cohort, analyzed by quantitative immunofluorescence analysis (QIF) on the Genoptix/HistoRx AQUA platform, revealed a greater hazard ratio than the cohorts analyzed by pathologist DAB-scoring. To extend and validate these observations, we applied the Nuc-pYStat5 cutpoint derived in our previous study (2) to an independent cohort of anti-estrogen-treated breast cancer patients using two distinct QIF software platforms, AQUA and Definiens Tissue Studio. Tissue Studio relies on supervised machine learning and multiparametric features of a high-resolution whole slide image to identify cancer cell regions, while AQUA software relies on costaining of a tumor marker to identify cancer cell regions. The two QIF platforms produced highly concordant Nuc-pYStat5 levels (R2 linear = 0.96, P<0.001, N = 344) and confirmed a significant elevated risk of failing antiestrogen therapy in patients whose tumors had lost Nuc-pYStat5 (Hazard ratio 3.6; 95% CI 1.8-7.4; P<0.02; N = 98). On both QIF platforms, Nuc-pYStat5 remained an independent marker after multivariate adjustment for standard pathology parameters, including ER/PR, HER2, age, node status and grade, with a hazard ratio of 5.8 (95% CI 1.3-22.2; P = 0.02; N = 52). High concordance between Nuc-pYStat5 levels produced by the two QIF platforms held up in a second independent dataset of more than 300 breast cancer specimens (R2 linear = 0.97, P<0.001, N = 382). Nuc-pYStat5 levels by the two QIF methods remained highly concordant across the entire dynamic range in both patient cohorts. Furthermore, high concordance was also observed between replicate QIF analyses of Nuc-pYStat5 on serial tumor microarray sections stained in the same run on an automated immunostainer (Concordance Correlation Coefficient (CCC) = 0.96; 95% CI 0.96-0.97). Modest inter-assay staining variation (CCC = 0.84; 95% CI 0.82-0.87) for Nuc-pYStat5 when serial tumor microarrays were stained on different runs several days apart could be corrected for by normalization procedures (CCC = 0.94; 95% CI 0.92-0.95). This progress supports the utility of QIF analysis of Nuc-pYStat5 levels in human breast cancer and further documents the potential value of Nuc-pYStat5 as a predictive marker of response to antiestrogen therapy. The study confirms that further retrospective and prospective validation studies are warranted.

References:

1) Yamashita et al. Stat5 expression predicts response to endocrine therapy and improves survival in estrogen receptor-positive breast cancer. Endocr Relat Cancer. 2006;13:885-93.

2) Peck et al. Loss of nuclear localized and tyrosine phosphorylated Stat5 in breast cancer predicts poor clinical outcome and increased risk of antiestrogen therapy failure. J Clin Oncol. 2011;29:2448-58.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-20.

A randomized, placebo-controlled phase 2 study of ganitumab or conatumumab in combination with FOLFIRI for second-line treatment of mutant KRAS metastatic colorectal cancer

BACKGROUND

Targeted agents presently available for mutant KRAS metastatic colorectal cancer (mCRC) are bevacizumab and aflibercept. We evaluated the efficacy and safety of conatumumab (an agonistic monoclonal antibody against human death receptor 5) and ganitumab (a monoclonal antibody against the type 1 insulin-like growth factor receptor) combined with standard FOLFIRI chemotherapy as a second-line treatment in patients with mutant KRAS mCRC.

PATIENTS AND METHODS

Patients with mutant KRAS metastatic adenocarcinoma of the colon or rectum refractory to fluoropyrimidine- and oxaliplatin-based chemotherapy were randomized 1 : 1 : 1 to receive intravenous FOLFIRI plus conatumumab 10 mg/kg (Arm A), ganitumab 12 mg/kg (Arm B), or placebo (Arm C) Q2W. The primary end point was progression-free survival (PFS).

RESULTS

In total, 155 patients were randomized. Median PFS in Arms A, B, and C was 6.5 months (HR, 0.69; P = 0.147), 4.5 months (HR, 1.01; P = 0.998), and 4.6 months, respectively; median overall survival was 12.3 months (HR, 0.89; P = 0.650), 12.4 months (HR, 1.27; P = 0.357), and 12.0 months; and objective response rate was 14%, 8%, and 2%. The most common grade ≥3 adverse events in Arms A/B/C included neutropenia (30%/25%/18%) and diarrhea (18%/2%/10%).

CONCLUSIONS

Conatumumab, but not ganitumab, plus FOLFIRI was associated with a trend toward improved PFS. Both combinations had acceptable toxicity.

Abstract P5-14-03: Breast cancer screening and follow-up of abnormal mammogram results: A population-based study comparing results from an urban university cancer center to a national database

Background: To improve access to screening, the National Breast and Cervical Cancer Early Detection Program (NBCCEDP) was developed through the Centers for Disease Control and Prevention (CDC) to provide low-income, and uninsured underserved women access to timely breast and cervical cancer screening and diagnostic services. This population-based study investigates the demographics and diagnostic outcomes of women who underwent breast cancer screening through this program established at an urban university cancer center compared to data obtained from the national program database.

Methods: The Kimmel Cancer Center at Jefferson (KCC) launched its screening program with resources from the CDC, the State of Pennsylvania, and the Susan G. Komen Foundation in 2008. The core of the program is staff lead by a Social Worker/Navigator who connects patients to education and screening services, institutional information and guidance, and follow-up to minimize barriers to access, lessen dropout, and ensure follow-through for timely diagnosis and treatment. Working with our Community-Based partner organizations, uninsured and underinsured women in Philadelphia are able to seamlessly travel from education and screening through to treatment and support. All KCC patients evaluated through this program from 2008–2011 were included and records of the NBCCDP database 2006–2010 for this study and analyses.

Results: KCC has a substantially larger African American (54.44% vs. 13.8%), smaller Hispanic (8.59% vs. 27.6%), larger percentage of abnormal mammograms (25.96% vs. 14%), higher breast cancer diagnosed per mammogram (2.13 vs 1.0) and a much younger population than the national cohort. Fewer than 1% of KCC patients have been lost to follow-up.

Conclusions: The KCC Breast and Cervical Screening and Treatment Program Services reaches a highly vulnerable and at-risk population, has a higher abnormal mammogram and breast cancer detection rate, and a higher continued participation rate than the national cohort. The Social/Worker/Navigator has a distinct role in providing follow-up for abnormal findings to minimize no-shows by providing creative problem-solving, support, counseling, finding resources to minimize barriers, and contributes significantly to the ease of operation and the continued participation of patients in the program.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-14-03.

Abstract P5-01-07: Fibroadenomatoid changes are more prevalent in middle-aged women and have a positive association with invasive breast cancer

Background: The role of benign breast diseases (BBDs) in the development of invasive breast cancers (IBCs) has been studied for many years. Some BBDs have been studied comprehensively (e.g., fibrocystic changes (FCC)) while less is known about other BBDs (e.g., fiboadenomatoid changes (FAC)). FAC has been considered by some researchers as a precursor of fibroadenoma (FA). Conclusions from different studies vary, partially due to different interpretation methods and diagnostic criteria when multiple hospitals and pathologists were involved. In this study, we used subjects in the Clinical Breast Care Project (CBCP) from a military medical center where pathology slides were reviewed by a single breast pathologist to study FAC, FA, and FCC in comparison to the published literature.

Methods: Subjects were enrolled in the study following IRB-approved, HIPAA-compliant protocols. All the clinicopathologic data are available from the CBCP data warehouse (DW4TR). In the CBCP, FCC is composed of 4 components: stromal fibrosis, cysts, apocrine metaplasia, and sclerosing adenosis. Two modeling studies were performed. i) For the BBDs and IBC association study, two groups of subjects were identified: 1136 subjects diagnosed with “Benign” or “Atypical” diseases, and 619 cases diagnosed with IBCs. A logistic regression model was developed for the prediction of IBCs by the 3 BBDs and 2 well-established risk factors (RF): age (younger, <=40; middle-aged, 41–60; older, >60) and race (Caucasian, African American, Asian, and other). ii) For the RF association study with the BBDs, 6 additional RFs reported to be associated with these BBDs were identified from the literature: current use of oral contraceptives, number of live births, education, body mass index, hormonal replacement therapy, and IBC family history. These 8 RFs were used to develop a logistic regression model for each of the BBDs. The analyses were performed in SAS.

Results: In the first study, age and race were confirmed as RFs for IBCs. FAC was positively associated with IBC (OR = 3.04, 95%CI=2.06 to 4.50). FA was negatively associated with IBC, and the level of the association was stronger in women without FCC (OR = 0.15, 95%CI=0.08 to 0.28), compared to women with FCC (OR = 0.40, 95%CI=0.24 to 0.65). FCC was not significantly associated with IBC. Results from the second study indicated that, age was significantly associated with FAC (p = 0.015), specifically the middle-aged women were more likely to have FAC compared to younger women (OR = 2.03, 95%CI=1.23 to 3.34), while the older women were at a non-significantly increased risk. Trends of association with FAC were also noted for the number of live birth (p = 0.095), ethnicity (p = 0.096), and current oral contraceptive pill use (p = 0.077). The FCC model results were in general consistent with the literature, and we also confirmed that age was negatively associated with the diagnosis of FA.

Discussion: Our study was consistent with FCC findings in the literature. We observed that FAC was positively associated with IBC, whereas FA was negatively associated. Also, FAC occurred more often in middle-aged women while FAs occurrence was higher in younger women. Our results suggest that FAC and FA may be two different diseases.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-01-07.

Gemcitabine, oxaliplatin, and bevacizumab (GEMOX-B): A promising regimen for the treatment of advanced biliary tract cancers

355

Background: Biliary-tract cancers (BTCs) arise from the epithelium of the gallbladder and bile ducts and are relatively rare, affecting 9-12,000 people in the United States annually. Peak incidence is in the seventh decade of life. Prognosis of advanced BTCs is poor with median overall survival of approximately 10 months. There has been no standard treatment regimen because of lack of randomized clinical trials data. Phase II trials have demonstrated the efficacy of the combination of gemcitabine and oxaliplatin with the response rate of ∼50%. In a recently published phase II trial, the addition of bevacizumab to this regimen (GEMOX-B) resulted in 63% progression-free survival (PFS) at 6 months. In this retrospective study, we evaluated the efficacy of GEMOX-B in patients with advanced biliary tract cancers treated at Thomas Jefferson University.

Methods: All patients received treatment on day 1 and 15 of 28-day cycle: bevacizumab 10 mg/kg, followed by gemcitabine 1000 mg/m2 and oxaliplatin 85 mg/m2. All patients were administered diphenhydramine, dexamethasone, and ondansetron prior to chemotherapy. Response was assessed using the RECIST criteria. PFS was measured from start of chemotherapy to disease progression or death.

Results: A total of 6 patients with BTCs were treated with GEMOX-B. One patient was male and 5 were female. The median age was 45 years (40-64 years). All patient had ECOG performance score 0-1. Three patients had progressed on prior therapy. A total of 65 cycles were administered with the median being 9 (range: 7-21) cycles. Two patients (33%) had partial response and 4 patients (66%) had stable disease. One patient progressed after 6.4 months of therapy. One patient died due to pneumonia but had stable disease at time of death. One patient developed encephalopathy, likely due to bevacizumab. Two patients are still receiving treatment. The median PFS has not been reached (range: 6-42 months).

Conclusions: This retrospective study further suggests that GEMOX-B is an active regimen in BTCs. Additional studies are needed to further evaluate the toxicity and efficacy of this regimen and understand molecular pathways governing sensitivity to chemotherapy.

No significant financial relationships to disclose.

Racial disparity trends in clinical presentation and outcomes in colorectal cancer: Findings from an urban university hospital

518

Background: African Americans (AA) have a higher incidence and lower survival rates from colon and rectal cancer than Caucasian Americans (C). This disparity has been attributed to many factors, including diagnosis at later stage, unfavorable histopathologic features, inadequate treatment, and socioeconomic factors. The multidisciplinary management setting ensures similarity in management and treatment planning. In this study, we assessed the pathological features and evaluated survival outcomes in patients with CRC in AA and CA using a large single institutional database.

Methods: We compiled data from 3,826 patients with colon and rectal cancer treated at Thomas Jefferson University Hospital from 1988-2009 and used Surveillance Epidemiology and End Results registry data from 1988-2004 to compare survival rates. Independent variables included age, racial background, site of primary tumor, degree of differentiation, stage at presentation, recurrence-free survival and overall survival rates for colon and rectal cancer and for each stage of disease. We compared survival rates using statistical modeling to account for differences in patient and disease characteristics between the two groups.

Results: At diagnosis, AA pts presented with more advanced stage of disease (p < 0.0001), were more likely to have proximal disease (p < 0.000000528), had worse overall 5-year survival, and worse survival stage-by-stage than C patients. Data also showed that the odds ratio for risk of nodal involvement was greater for AA pts than C pts with lower T tumors. AA pts were more likely to have less well differentiated colon tumors, but more well differentiated rectal tumors, younger age and worse survival stage-by stage than C pts. Although C pts were more likely to have rectal cancer (p < 0.0001), they were less likely to have stage IV disease at presentation.

Conclusions: AA pts with CRC are more likely to present at a younger age with later stage, more proximal tumors, have higher nodal involvement with lower T lesions, and less well differentiated tumors than C. Additional studies on biological feature sand molecular markers are ongoing to and will be presented.

No significant financial relationships to disclose.

A randomized, phase I/II trial of AMG 102 or AMG 479 in combination with panitumumab (pmab) compared with pmab alone in patients (pts) with wild-type (WT) KRAS metastatic colorectal cancer (mCRC): Safety and efficacy results

366

Background: Pmab is a fully human anti-epidermal growth factor receptor monoclonal antibody (mAb) approved as monotherapy for pts with mCRC. AMG 102 and AMG 479 are investigational, fully human mAbs against hepatocyte growth factor (HGF) and insulin-like growth factor receptor 1 (IGF1R), respectively. This 3-part study evaluated the safety and efficacy of AMG 102 or AMG 479 in combination with pmab.

Methods: Part 1 was a phase 1b, open-label, dose-finding study to determine a tolerable dose of AMG 102 in combination with pmab. Part 2 was a phase II, randomized, blinded, placebo-controlled trial that explored pmab + the dose of AMG 102 selected in Part 1 vs pmab + AMG 479 vs pmab + placebo. Part 3 is a 2-arm randomized extension study for pts who developed disease progression (PD) or intolerability to pmab + placebo in part 2. Eligible pts were ≥ 18 years old with WT KRAS mCRC and ECOG PS 0/1. In part 1, all pts received 6 mg/kg pmab + 10 mg/kg AMG 102 Q2W IV until PD or intolerability. The primary endpoint of part 1 was the incidence of dose-limiting toxicities (DLTs). The primary endpoint for part 2 is objective response rate (ORR).

Results: In part 1, no DLTs were reported for the first 6 DLT-evaluable pts. A total of 11 pts were enrolled in part 1 prior to the decision to use the 10 mg/kg Q2W AMG 102 dose in part 2; 5 pts were men; mean (range) age was 56 (37-75) yrs; ECOG 0/1 was 55%/45%. Grade 3 treatment-related adverse events (AEs) were acneiform dermatitis or rash (55%), paronychia (18%), infection (9%), capillary leak syndrome (9%), erythema (9%), nail disorder (9%), and pruritus (9%). There were no grade 4 or 5 treatment-related AEs. Serious AEs included acneiform dermatitis (n = 1), intestinal obstruction (n = 1), cerebrovascular accident (n = 1), capillary leak syndrome (n = 1), and anemia/general health deterioration (n = 1). One pt died on study from PD. In part 2, 142 pts received at least one dose of study drug; enrollment is complete, and data analyses are ongoing.

Conclusions: In part 1, 6 mg/kg pmab + 10 mg/kg AMG 102 Q2W was well tolerated. Primary efficacy results from part 2, including ORR and progression-free survival, will be presented.

[Table: see text]

Sweet neutron crystallography

Extremely sweet proteins isolated from tropical fruit extracts are promising healthy alternatives to sugar and synthetic sweeteners. Sweetness and taste in general are, however, still poorly understood. The engineering of stable sweet proteins with tailored properties is made difficult by the lack of supporting high-resolution structural data. Experimental information on charge distribution, protonation states and solvent structure are vital for an understanding of the mechanism through which sweet proteins interact with taste receptors. Neutron studies of the crystal structures of sweet proteins allow a detailed study of these biophysical properties, as illustrated by a neutron study on the native protein thaumatin in which deuterium labelling was used to improve data quality.

Final STEPP results of prophylacatic versus reactive skin toxicity (ST) treatment (tx) for panitumumab (pmab)-related ST in patients (pts) with metastatic colorectal cancer (mCRC)

CRA4027

Background: Pmab, a fully human monoclonal antibody targeting the epidermal growth factor receptor (EGFR), is approved as monotherapy in the US for mCRC following disease progression (PD) and in the EU and Canada for tumors bearing wild-type (WT) KRAS. The most common toxicity with anti-EGFR inhibitors are ST. This study of pmab+ chemotherapy (CT) estimates the difference in the incidence of specific ≥ grade 2 ST of interest between pts receiving prophylactic (P) or reactive (R) skin tx. Methods: Pts had unresectable mCRC after PD with 1st-line fluoropyrimidine and oxaliplatin-based CT ± bevacizumab. Pts received either pmab 6.0mg/kg/FOLFIRI Q2W or pmab 9 mg/kg/irinotecan Q3W. Within each stratum, pts were randomized 1:1 to either P ST tx 24 hrs before the 1st dose daily for 6 wks or R ST tx after ST occurred. Tx for ST included: moisturizers, sunscreen, topical steroid, and doxycycline. Efficacy and safety were evaluated by P vs R tx groups, KRAS status (mutant [MT] vs WT), and chemotherapy status. Responses were assessed using modified RECIST with confirmation. Quality of life was assessed using the Dermatology Life Quality Index at screening, wks 2–7, and follow-up. Results: 95 pts were enrolled and randomized: 48 pts to P and 47 pts to R. During the 6 wk ST tx period, 29% of pts in the P group vs 62% of pts in the R group had protocol-specified ≥grade 2 ST. Of the 87 KRAS evaluable pts, 49 (56%) pts had WT KRAS and 38 (44%) pts had MT KRAS. Efficacy and safety are shown. Mean (SD) change in DLQI from baseline was 1.3 (2.6) for P and 4.2 (5.8) for R at wk 3 (when the median time to 1st ≥grade 2 ST was reached in the R group) and was 2.0 (2.8) for P and 2.6 (4.4) for R at wk 7. Conclusions: Prophylactic use of the skin tx regimen resulted in >50% reduction in the rate of specific ≥ grade 2 STs and improved QOL during the 6-week skin tx period vs R use. Numerical differences in favor of the P group were observed for all endpoints.

[Table: see text]

[Table: see text]

Final STEPP results of prophylacatic versus reactive skin toxicity (ST) treatment (tx) for panitumumab (pmab)-related ST in patients (pts) with metastatic colorectal cancer (mCRC)

CRA4027

The full, final text of this abstract will be available in Part II of the 2009 ASCO Annual Meeting Proceedings, distributed onsite at the Meeting on May 30, 2009, and as a supplement to the June 20, 2009, issue of the Journal of Clinical Oncology.

[Table: see text]

Phase III study of standard triweekly versus dose-dense biweekly capecitabine (C) + oxaliplatin (O) + bevacizumab (B) as first-line treatment for metastatic colorectal cancer (mCRC): XELOX-A-DVS (dense versus standard): Interim analysis

4078

Background: Every 3 week (Q3W) COB has been shown to be highly active and non-inferior to FOLFOX+B in first-line mCRC. Phase II data suggest that dose-dense every 2 week (Q2W) COB may be significantly more active and better tolerated than Q3W COB. Methods: XELOXA-DVS was a phase III, open-label study of 435 patients with chemonaive mCRC who met standard eligibility criteria. Patients were randomized to Q3W: C 850 mg/m2 BID d1–14 + O 130 mg/m2 d1 + B 7.5 mg/kg d1 or Q2W: C 1500 mg/m2 BID d1–7 + O 85 mg/m2 d1 + B 5 mg/kg d1 for up to 72 weeks. Complete surgical resection was allowed using pre-defined criteria. The primary endpoint, progression-free survival (PFS), was estimated using the Kaplan- Meier method, while the hazard ratio and 95% CI were estimated using Cox regression analysis, based on the intent-to-treat population. No formal statistical testing was conducted. Results: The median PFS was 8.4 months (Q2W) and 9.7 months (Q3W) (hazard ratio [HR]=0.84; 95% CI=0.62–1.13). The median PFS (on-treatment) was 9.1 months and 10.2 months, respectively (HR=0.81). Of the 72 and 73 patients with disease progression (DP), the median time to DP was 9.4 and 10.8 months, respectively (HR=0.86). The objective response rates were 21.7% vs 29.4%, respectively (HR=1.05). Patients in the Q2W vs Q3W group experienced higher rates of grade 3/4 diarrhea (29% vs 24%), hand-foot syndrome (12% vs 8%), and treatment discontinuation rates (40% vs 20%), respectively. Other grade 3/4 toxicities (>5%, Q2W vs Q3W) included fatigue (13% vs 13%), dehydration (12% vs 10%), nausea (8% vs 9%), peripheral neuropathy (5% vs 9%), anorexia (5% vs 7%), and abdominal pain (5% vs 7%). Conclusions: At the dose and schedule used, dose-dense Q2W COB was not superior to standard Q3W COB. These data further confirm the activity and tolerability of Q3W COB. The activity and tolerability of a lower C dose Q2W, with more aggressive dose reduction, combined with B and O or irinotecan is currently being evaluated (X-BIO).

[Table: see text]

Panitumumab activity in metastatic colorectal cancer (mCRC) patients (pts) with low or negative tumor epidermal growth factor receptor (EGFr) levels: An updated analysis

4082

Background: Panitumumab, a fully human monoclonal antibody against EGFr, is approved for EGFr-expressing mCRC pts with disease progression (PD) on or after fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy. However, the predictive value of EGFr tumor-membrane staining as measured by immunohistochemistry (IHC) is undetermined. Methods: This multicenter, single arm, phase 2 study enrolled pts with documented PD during or after fluoropyrimidine and adequate doses of irinotecan and oxaliplatin, and within 6 months after the most recent chemotherapy regimen (determined by an independent eligibility review committee [IERC]), 2–3 prior regimens, and low (1%-9%) or negative (<1%) EGFr tumor membrane staining (by IHC). Pts received panitumumab 6mg/kg Q2W until PD or intolerability. Tumor assessments (modified WHO, blinded central review) were performed every 8 weeks until PD or discontinuation. Endpoints were objective response rate (ORR) through wk 16 (+ =4 wk confirmation; primary), overall ORR, response duration, progression-free survival (PFS), and safety (secondary). Results: In this interim analysis, 91 pts had =20 wks of potential follow-up and comprised the IERC efficacy set; 118 pts comprised the evaluable safety set (=20 wks potential follow-up). In the IERC efficacy set, 57% were male, 86% were white, and median age (range) was 61 (26–85) years. ORR through week 16 is shown; overall ORR was the same ( Table ). The most common adverse events (all, grade 3/4) were dermatitis acneiform (72%, 6%), erythema (69%, 6%), pruritus (65%, 4%), and hypomagnesaemia by lab values (53%, 10%). Four pts (3%) had an infusion reaction per investigator (1 was grade 3). Conclusions: This analysis confirms earlier findings that panitumumab has anti-tumor activity in pts with low or undetectable EGFr tumor membrane levels as measured by IHC. This study has completed enrollment, and updated data will be presented.

[Table: see text]

No significant financial relationships to disclose.

Biomarker analysis by breast cancer phenotype in African-American versus Caucasian patients: Correlates with survival

10551

Background: Breast carcinomas in African-American (AA) patients (pts) have poorer prognosis and higher likelihood of aggressive basal phenotype (triple negative for ER, PR, HER2) than those in Caucasian (C) patients (Carey et al, JAMA 2006, 295(21):2492; Morris et al, Breast Cancer Res Treat 2006, abstr 3055). We have additionally examined biomarker expression by phenotype in AA pts in our registry to further explain more aggressive behavior in this population. Methods: Stage, grade, ER, PR, Ki-67, HER2, and p53 expressions were compiled for breast carcinomas in 2,230 AA and C pts diagnosed between 1995–2004. Immunohistochemical markers were assayed using antibodies to the above proteins on paraffin-embedded formalin-fixed tissue. Differences in expression were analyzed by Chi- squared and Wilcoxon tests, and survival by Kaplan-Meier estimates. Results: AA pts have higher propensity for basal phenotype breast cancers (20.8% vs 10.4%, p<0.001) and lower propensity for Luminal A/B (ER+/PR+-/HER2-) phenotype (44.2% vs. 54.1%, p<0.001) as compared with C pts. Higher ki-67 proliferation index was found in AA pts (86.4% vs 78.8% in basal, p=0.3423; 37.1% vs. 26.7% in Luminal A/B p=0.0233) as compared with C pts. p53-positivity was higher in AA and C pts in all cases (p=0.0158), higher in AA pts with basal phenotype (p=0.2597), but identical in AA and C pts with luminal phenotypes (p=0.881). Survival was similar in basal phenotypes between races in all cases stage for stage, and controlled for ki-67 and p53 status, with a trend toward poorer survival among luminal phenotypes between races. Conclusions: AA pts have higher propensity for basal phenotype breast cancers than C pts, with higher ki-67 expression in both basal and luminal phenotypes, and higher p53 expression in basal phenotype, but these do not correlate with significant differences in survival by phenotype between races. As neither ki-67 index nor p53 expression can therefore solely explain differences in survival rates seen between races, molecular array studies between races and matched by phenotype are proposed.

[Table: see text]

Response to the combination of cetuximab, bevacizumab and irinotecan (cetux/bev/iri) in patients (pts) previously treated with 3rd-line panitumumab, following disease progression on oxaliplatin, irinotecan and a fluoropyrimidine

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Background: There are 2 monoclonal antibodies (mAbs) targeting the epidermal growth factor receptor (EGFR) available for the treatment of advanced metastatic colorectal cancer- panitumumab, a fully human IgG2 kappa mAb and cetuximab, a chimeric IgG1 mAb. The ability to administer one agent after prior treatment with the other is unknown and further, not trivial given the possibility for cross-reactivity. In our institution, we evaluated an exploratory treatment schedule. Methods: We report the status of 8 colon cancer pts treated with panitumumab monotherapy as 3rd-line and subsequently treated with cetux/bev/iri as salvage chemotherapy. All were initially treated on 1 of 2 multicenter phase 2 studies enrolling pts on panitumumab; all pts had documented progressive disease (PD) during or after fluoropyrimidine and adequate doses of irinotecan and oxaliplatin, and low (1–9%) or high (=10%) EGFR tumor membrane staining by IHC. Pts received panitumumab 6 mg/kg q2weeks (wks) until PD or intolerability. Following PD they received bev 5 mg/kg and iri 250 mg/m2 q2wks and cetux 400 mg/m2, then 250 mg/m2 qwk. The endpoint was time to tumor progression (TTP). Results: The 8 pts (2 men, 6 women) were among those enrolled in 1 center. Median age was 67 years (range 51–81); 6 pts had low and 2 pts had high EGFR tumor expression. The median number of cycles of panitumumab was 8 (range 3–14); 1 had a partial remission (PR) for 24 wks, 4 had stable disease (SD) for a median of 14 wks (range 12–16) and 3 pts had PD. Following PD on panitumumab pts received cetux/bev/iri. The median number of cycles was 13 (range 2–17+); 1 had a PR of 20 wks, 6 had SD for a median of 20 wks (range 8–32+) and 1 pt had PD after 4 cycles. Median TTP was 24 wks (range 7–36+). Conclusion: In these 8 pts, prolonged TTP to the combination of cetux/bev/iri was observed following PD on panitumumab and standard chemotherapy. This combination may provide a potential treatment strategy for these heavily pretreated pts with advanced colon cancer. However, further investigation is needed.

No significant financial relationships to disclose.

Outcomes differences for African Americans and Caucasians treated with bevacizumab, FOLFOX4 or the combination in patients with metastatic colorectal cancer (MCRC): Results from the Eastern Cooperative Oncology Group Study E3200

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Background: The relationship between race and clinical outcomes with systemic chemotherapy in patients with metastatic colorectal cancer is uncertain. E3200 is a large, randomized, multicenter phase III trial that demonstrated a gain in overall survival (OS), progression free survival (PFS) and response (RR) for the addition of bevacizumab to FOLFOX4 in previously treated patients with MCRC. We analyzed outcomes for African Americans and Caucasian patients enrolled in E3200. Methods: Patients enrolled in E3200 were randomized to one of three treatments: FOLFOX4, bevacizumab, or the combination. OS, PFS, RR and cycles of chemotherapy were examined as a function of race in 779 patients. Demographic information including race was collected by data management personnel at study sites and reported at registration. Results: There were no differences noted for Caucasians and African Americans with regards to: disease extent, performance status, gender, prior therapy and age distribution (not shown). Outcomes by race are tabulated. Conclusion: These results suggest outcomes differences based on race in the treatment of patients with MCRC. Additional studies are required to elucidate the cause for the observed variation.

[Table: see text]

No significant financial relationships to disclose.

A phase II trial of perifosine in locally advanced, unresectable, or metastatic pancreatic adenocarcinoma

BACKGROUND

Perifosine, a heterocyclic alkylphosphocholine signal transduction inhibitor, has activity against multiple cell types in vitro. This is a phase II study to determine activity and toxicity of perifosine in pancreatic adenocarcinoma.

PATIENTS AND METHODS

Previously untreated patients with locally advanced, unresectable, or metastatic pancreatic adenocarcinoma, performance status Eastern Cooperative Oncology Group 0 or 1, were enrolled. An oral loading dose of 900 mg was followed by 100 mg per day until progression or unacceptable toxicity. Response criteria in solid tumors (RECIST) methodology and a 2-stage design were used. Suspension could occur for inadequate response in the first cohort or for more than 25% grade 3 or greater toxicity.

RESULTS

Ten patients were enrolled. Six received 1 month and 4 received 2 months of treatment. Four discontinued therapy as a result of progression and 2 because of clinical deterioration. Three died during treatment. One patient had stable disease but discontinued therapy as a result of unacceptable adverse events (95% confidence interval: 0.3-45%). There were no objective responses and all patients died of progressive disease. Median overall and progression-free survival was 1.85 months (95% confidence interval: 0.9-2.7) and 1.5 months (95% confidence interval: 0.9-1.9) respectively.

CONCLUSION

The study was suspended and subsequently terminated as a result of unacceptable adverse events during the first stage. Perifosine does not appear to be worthy of further study in this group of patients.

The crystal structure of the Dps2 from Deinococcus radiodurans reveals an unusual pore profile with a non-specific metal binding site

The crystal structure of recombinant Dps2 (DRB0092, DNA protecting protein under starved conditions) from the Gram-positive, radiation-resistant bacterium Deinococcus radiodurans has been determined in its apo and iron loaded states. Like other members of the Dps family, the bacterial DrDps2 assembles as a spherical dodecamer with an outer shell diameter of 90 A and an interior diameter of 40 A. A total of five iron sites were located in the iron loaded structure, representing the first stages of iron biomineralisation. Each subunit contains a mononuclear iron ferroxidase centre coordinated by residues highly conserved amongst the Dps family of proteins. In the structures presented, a distinct iron site is observed 6.1 A from the ferroxidase centre with a unique ligand configuration of mono coordination by the protein and no bridging ligand to the ferroxidase centre. A non-specific metallic binding site, suspected to play a regulative role in iron uptake/release from the cage, was found in a pocket located near to the external edge of the C-terminal 3-fold channel.

Cloning, expression, purification, crystallization and preliminary structure determination of glucose-1-phosphate uridylyltransferase (UgpG) from Sphingomonas elodea ATCC 31461 bound to glucose-1-phosphate

The cloning, expression, purification, crystallization and preliminary crystallographic analysis of glucose-1-phosphate uridylyltransferase (UgpG) from Sphingomonas elodea ATCC 31461 bound to glucose-1-phosphate are reported. Diffraction data sets were obtained from seven crystal forms in five different space groups, with highest resolutions ranging from 4.20 to 2.65 A. The phase problem was solved for a P2(1) crystal form using multiple isomorphous replacement with anomalous scattering from an osmium derivative and a SeMet derivative. The best native crystal in space group P2(1) has unit-cell parameters a = 105.5, b = 85.7, c = 151.8 A, beta = 105.2 degrees . Model building and refinement are currently under way.

Phase I trial of thalidomide and capecitabine for treatment of metastatic colorectal cancer

13552

Background: Survival of patients with metastatic colorectal cancer (CRC) has increased with the advent of new chemotherapeutic and biologic agents. Yet, there remains a need for more effective third- and fourth-line chemotherapy. Thalidomide (Thal) has angiogenic and immunomodulatory properties and antitumor effects have been consistently demonstrated in pts with multiple myeloma and occasionally in pts with advance solid tumors. Capecitabine (Cape) has demonstrated efficacy as a single agent and in combination therapy in pts with metastatic CRC. We conducted a phase I study of Thal/Cape in pts with refractory metastatic CRC previously treated with irinotecan, oxaliplatin and fluoropyrimidines. Methods: Pts with metastatic CRC who had received two or more prior chemotherapy regimens were eligible. Treatment consisted of Cape at 1500 mg/m2 po daily for 14 days every three weeks with dose levels increasing to 2500mg/m2; Thal dosing was initially 100 mg with escalations individually to 400 mg per day. Toxicity rates, response and overall survival were analyzed. Results: Twenty-five eligible pts were enrolled; median age= 58 (20–79); M/F=13/12; ECOG PS 0/1/2=11/12/2. The median number of Thal/Cape cycles administered was 3 (range 1–9). Treatment was well tolerated; grade 3–4 non-hematologic toxicities included somnolence/syncope (20%), fatigue (20%), constipation (10%), diarrhea (10%), infections (10%) and neuropathy, thrombosis, hypoglycemia, nausea/vomiting each occurred in 5% of pts; grade 3–4 hematological toxicities anemia (15%), neutropenia (5%), prolonged prothrombin time (15%), increased LFTs (10%). Grade 3–4 hand-foot syndrome occurred in 2 pt (8%). There were no radiographic responses, but 6 pts achieved a decline in CEA of 50% or greater and 6 pts achieved stable disease. Conclusion: The MTD is Cape 2500mg/m2 per day. The combination of Thal/Cape was well tolerated; the recommended dose is thal 200mg and cape 2000mg/m2. Despite the lack of radiographic responses, the rate and duration of disease stabilization observed in this heavily pretreated pt population suggest that this regimen may offer some benefit.

[Table: see text]

Combined modality therapy of locally advanced adenocarcinoma of the rectum: Update of a phase I trial of preoperative radiation (RT) with concurrent capecitabine (Cap) and irinotecan (Ir)

13547

Background: We previously reported the combination of preoperative radiation (RT) with concurrent Irinotecan and 5-FU in locally advanced rectal cancer, was well tolerated and had an excellent pathologic complete response rate (CR) of 25%, but with catheter related infections and thromboses as major toxicities (Proc Am Soc Clin Onc 22: 2003). With the potential benefits of capecitabine (Cap) and no need for an implanted catheter, a phase I study was initiated to determine the toxicity and maximum tolerated dose (MTD) of Cap with concurrent Ir and RT. Methods: Eligible patients (pts) had primary or recurrent Stage II or III rectal adenocarcinoma, without a history of prior RT or chemotherapy. The treatment regimen was as follows: external beam RT at 1.8Gy daily M-F, to a total dose of 50.4 or 54 Gy; Ir 50 mg/m2 IV, d 1, 8, 15, 22; dose escalating Cap starting at 825 mg/m2 PO divided in 2 doses, Q 12h. Surgical resection occurred at 6–10 weeks. Dose limiting toxicity is defined as Gr4 heme or non-heme Gr3. Results: A total of 16 pts have enrolled on the study, 10 male and 6 female;the median age was 57 (range 44–77). All are evaluable for toxicity. The Table reviews the maximum toxicities. Grade three diarrhea is the only dose-limiting toxicity to date. There has also been 3 pts with Gr 3 hematologic toxicity. There has been no Gr 4 toxicity. Patients are currently accruing on the 4th dose level of capecitabine. A total of 13 pts have completed the preoperative phase and three are currently on treatment. Eleven pts have had surgical resection. One pt refused surgery due to a biopsy proven CR to chemoradiation. One pt refused surgery and died of disease. Of the 11 pts undergoing surgical resection, there have been 3 pathologic CR. Conclusions: The preoperative combination of capecitabine, irinotecan and radiation in locally advanced rectal cancer pts is feasible and well tolerated. The study continues to accrue, and the MTD has not been achieved. [Table: see text]

[Table: see text]

Circulating endothelial cells (CEC) and circulating tumor cells (CTC) in patients (pts) with metastatic colorectal cancer (mCRC)

3531

Background: Lack of validated surrogate endpoints is an impediment to developing new cancer therapy. We hypothesized that CTC and CEC could predict outcome in pts undergoing treatment for mCRC. Methods: Eligible pts for this multicenter study had mCRC, and were initiating 1st, 2nd, or 3rd-line systemic therapy. Blood was obtained at baseline and 3–4 weeks after treatment initiation for enumeration of CTC/CEC. CTC/7.5ml and CEC/4ml of blood were measured with the CellSearch System. CTC were immunomagnetically enriched targeting CD326 (EpCAM), stained with DAPI, cytokeratin 8,18,19, and CD45. CEC expressing CD146 were immunomagnetically enriched and stained with DAPI, CD105, and counterstained with CD45. Cell morphology was confirmed in all cases. Results: In 139 controlsCTC were virtually absent (0 CTC in 135 and 1 CTC in 4). For 131 pts with mCRC, >1CTC was detected before therapy in 40/131(31%) (range 0–73) and 3–4 weeks after starting therapy in 12/131 (9%) (range 0–100) (p<0.0001, McNemar’s test). Pts with >1 CTC at baseline and 3–4 weeks did not differ by line of therapy (1st line: 28/93 [30.1%] at baseline, 7/93 [7.5%] at 3–4 weeks; second/third-line: 6/24 [25%] at baseline, 3/24 [12.5%] at 3–4 weeks, p=0.57, Breslow-Day test). For 15/131 (11.5%) a 2-fold increase and for 53/131 (40.5%) a 2-fold decrease in CTC was found after treatment. Using 249 controls, a normal reference range of 4–80 CEC/4 ml of blood was established. In 16/131 (12.2%) pts >80 CEC were detected before (range 1–1342) and in 18/131(13.7%) after start of therapy (range 2–519) (p=0.71, McNemar’s test). Pts with >80 CEC at baseline and 3–4 weeks did not differ by line of therapy (1st line: 9/93 [9.7%] at baseline, 13/93 [14%] at 3–4 weeks; 2nd/3rd line: 5/24 [20.8%] at baseline, 2/24 [8.3%] at 3–4 weeks, p=0.16, Breslow-Day test). In 37/131 (28.2%) a 2-fold increase and in 35/131 (26.7%) a 2-fold decrease in CEC was found after initiation of therapy. Conclusions: Isolating and enumerating CTC/CEC in pts receiving therapy for mCRC is feasible. CTC generally decrease with therapy, while change in CEC has greater variability. Enrollment in this 400 patient multicenter study is nearing completion, and definitive analysis of relationship of CTC/CEC change to clinical outcome is planned.

[Table: see text]

Glucose analogue inhibitors of glycogen phosphorylase: from crystallographic analysis to drug prediction using GRID force-field and GOLPE variable selection

Several inhibitors of the large regulatory enzyme glycogen phosphorylase (GP) have been studied in crystallographic and kinetic experiments. GP catalyses the first step in the phosphorylysis of glycogen to glucose-l-phosphate, which is utilized via glycolysis to provide energy to sustain muscle contraction and in the liver is converted to glucose. alpha-D-Glucose is a weak inhibitor of glycogen phosphorylase form b (GPb, K(i) = 1.7 mM) and acts as a physiological regulator of hepatic glycogen metabolism. Glucose binds to phosphorylase at the catalytic site and results in a conformational change that stabilizes the inactive T state of the enzyme, promoting the action of protein phosphatase 1 and stimulating glycogen synthase. It has been suggested that in the liver, glucose analogues with greater affinity for glycogen phosphorylase may result in a more effective regulatory agent. Several N-acetyl glucopyranosylamine derivatives have been synthesized and tested in a series of crystallographic and kinetic binding studies with GPb. The structural results of the bound enzyme-ligand complexes have been analysed together with the resulting affinities in an effort to understand and exploit the molecular interactions that might give rise to a better inhibitor. Comparison of the N-methylacetyl glucopyranosylamine (N-methylamide, K(i) = 0.032 mM) with the analogous beta-methylamide derivative (C-methylamide, K(i) = 0.16 mM) illustrate the importance of forming good hydrogen bonds and obtaining complementarity of van der Waals interactions. These studies also have shown that the binding modes can be unpredictable but may be rationalized with the benefit of structural data and that a buried and mixed polar/non-polar catalytic site poses problems for the systematic addition of functional groups. Together with previous studies of glucose analogue inhibitors of GPb, this work forms the basis of a training set suitable for three-dimensional quantitative structure-activity relationship studies. The molecules in the training set are void of problems and potential errors arising from the alignment and bound conformations of each of the ligands since the coordinates were those determined experimentally from the X-ray crystallographic refined ligand-enzyme complexes. The computational procedure described in this work involves the use of the program GRID to describe the molecular structures and the progam GOLPE to obtain the partial least squares regression model with the highest prediction ability. The GRID/GOLPE procedure performed using 51 glucose analogue inhibitors of GPb has good overall predictivity [standard deviation of error predictions (SDEP) = 0.98 and Q(2) = 0.76] and has shown good agreement with the crystallographic and kinetic results by reliably selecting regions that are known to affect the binding affinity.