Citations

34 Background: Phase II clinical trials aim to identify promising experimental regimens for further testing in phase III trials. Testing targeted therapies with predictive biomarkers mandates efficient trial designs. Current biomarker-based trial designs, including the enrichment, all-comers, and adaptive designs, randomize patients to receive treatment or not throughout the entire duration of the trial. Recognizing the need for randomization yet acknowledging the possibility of promising but nonconclusive results after a preplanned interim analysis (IA), we propose a two-stage phase II design that allows for the possibility of direct assignment (i.e., stop randomization and assign all patients to the experimental arm in stage II) based on IA results. Methods: Using simulations, we compared properties of the direct assignment option design to a 1:1 randomized phase II design and assessed the impact of the timing of IA (after 33%, 50%, or 67% of accrual) and number of IA (one versus two with option for direct assignment at the first and second) over a range of response rate ratios (between 1.0 and 3.0). Results: Between 12% and 30% of the trials (out of 6,000 simulated trials) adopt direct assignment in stage II, with direct adoption depending on the treatment effect size and specified type I error rate (TIER). The direct assignment option design has minimal loss in power (<1.8%) and minimal increase in T1ER (<2.1%) compared to a 1:1 randomized design. The maximum loss in power across possible timings of IA was <1.2%. For the direct assignment option design, there was a 20%-50% increase in the number of patients treated on the experimental (vs. control) arm for the 1 IA case, and 40%-100% increase for the 2 IA case. Conclusions: Testing predictive biomarkers in clinical trials requires new design strategies. In the spectrum of phase II designs from adaptive to balanced randomized all-comers or enrichment designs, the direct assignment design provides a middle ground with desirable statistical properties that may appeal to both clinicians and patients.

11 Background: Currently there are no serum markers of response to AA. We performed a proteome based analysis of serum from prostate cancer patients, followed by mapping of candidate markers to networks based on known molecular interactions in Ingenuity Knowledge Base (IKB). Methods: Isobaric mass tags for relative and absolute quanititation (iTRAQ) analyzed by reverse-phase liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS) was performed in serum of 3 non-localized prostate cancer cohorts. The first cohort included 15 paired untreated hormone-sensitive “pre AA” and 3-month “post AA” specimens; the second included 10 “early AA failure” (median failure time: 11 months) and the third included 10 “late AA failure” specimens (median failure time: 95 months). Differentially expressed candidate proteins were identified by comparisons of (i) paired pre/post AA proteomes and (ii) post AA proteome with the combined AA failure cohorts at a False Discovery Rate of 0.2. To facilitate biological interpretation of multiple candidates identified in the comparisons, IPA was used. Candidate markers implicated in IPA networks with statistical significance were pursued in a second, independent patient cohort for association with time to AA failure using univariate Cox regression analysis. Results: Median PSA for pre/post AA first cohort were 3.15 and 0.29 ng/ml. Median PSA for the second and third cohorts were 27.3 and 4.3 ng/ml. Between post AA and AA failure cohorts, 149 proteins were differentially expressed. Between early and late AA failure 98 proteins were differentially expressed; 47 proteins were common in both comparisons. Network enrichment analysis of the 47 proteins by IPA identified four interaction networks (p<0.01), one of which highlighted a role for 17-β-estradiol (E1). Gas chromatography used for measuring 3-month post AA initiation serum E1, estrone (E2) and testosterone levels (N=38) detected high E1, E2 levels associated with longer time to AA failure (P=0.07 for E1; P=0.08 for E2) in the independent cohort. Conclusions: A global proteomic analysis identified post AA initiation serum E1, E2 levels as potential response markers, which needs validation.

7 Background: The organ preserving strategy of selective esophageal resection after definitive chemoradiation was evaluated in a multi-center, prospective Phase II trial. Methods: Treatment involved induction chemotherapy with 5-FU (650 mg/mg2/d), cisplatin (15 mg/mg2/d) and paclitaxel (200 mg/mg2/d) for 2 cycles followed by concurrent chemoradiation with 50.4 Gy (1.8 Gy/fx) and daily 5-FU (300 mg/mg2/d) with cisplatin (15 mg/mg2/d) over the first 5 days. Following definitive chemoradiation, pts were evaluated for residual locoregional disease with chest and abdominal CT scans, EUS and optional PET scans. If there was no suspected residual disease patients were observed and monitored serially for recurrent disease at 3 mos x 2, 6 mos x 3 and then yrly. Esophageal resection was considered only for pts with suspected residual or recurrent locoregional esophageal cancer that did not have systemic disease. Results: 43 pts from Sept 2003 to March 2006 with non-metastatic resectable esophageal cancer were entered from 19 sites to RTOG 0246. 41 pts were eligible for analysis. 29 pts (73%) were adenocarcinoma histology with pretreatment clinical stage T3 or greater in 31 pts (76%) and N1 in 29 pts (71%). Following induction chemotherapy and chemoradiation 3 pts (7.3%) died of treatment related deaths and 1 pt died of disease progression. 21 pts (51%) underwent surgical resection following chemoradiation because of suspected residual disease 17 pts (41%), pt choice (1) or recurrent locoregional disease 3 pts (7%). 1 pt died postoperatively from esophageal anastomotic leak. 11 pts (27%) are alive and free of disease 70 to 90 months after chemoradiation, of which 5 (12%) did not have esophagectomy. With a median follow-up of 6.7 yrs (for 16 alive pts), the estimated overall 2.5 and 5-year survival rates (95% CI) are 46.3% (30.7%-60.6%) and 36.6% (22.3%-51.0%). Conclusions: The long-term results from this multi-center, prospective Phase II trial demonstrates the efficacy of a selective surgical resection approach following definitive chemoradiation in a predominantly adenocarcinoma population of locoregionally advanced esophageal cancer. Clinical trial information: NCT00081289.

572 Background: There is limited data regarding chemotherapy dosing in obese mCRC patients. Methods: A retrospective, single institution, cohort study of mCRC patients receiving mFOLFOX6 (fluorouracil (5-FU) bolus omitted) was conducted between January 2002 and January 2011. Patients were stratified into: obese (BMI > 30) full dose, obese dose reduced (oxaliplatin (OX) and/or 5-FU), non-obese (BMI 18-29.9) full dose, and non-obese dose reduced. The primary endpoint was incidence of grade 3/4 myelosuppression within the first 12 wks of therapy. Secondary endpoints included incidence of any grade diarrhea and neuropathy, progression free (PFS) and overall survival (OS). Results: Of the 236 patients (72 obese, 164 non-obese), 15 obese and 37 non-obese received a dose reduction. Grade 3/4 myelosuppression occurred in 0 obese OX dose reduced, 3 (7.5%) obese full dose, 1 (8.3%) non-obese dose reduced, and 7 (7.8%) non-obese full dose patients (p=0.93). Grade 3/4 myelosuppression occurred in 0 obese 5-FU dose reduced, 3 (7.5%) obese full dose, 2 (12.5%) non-obese dose reduced, and 6 (7%) non-obese full dose patients (p=0.8). There were no statistically significant differences in the incidence of neuropathy or diarrhea between groups. PFS was longer in OX full dose patients (obese dose reduced, 8.8 mos; obese full dose, 10 mos; non-obese dose reduced, 3.7 mos; non-obese full dose, 10.4 mos; p=0.0094). No difference in PFS was found with 5-FU dosing (p=0.0615). OS favored OX full dose patients (obese dose reduced, 1.6 yrs; obese full dose, 2.4 yrs; non-obese dose reduced, 0.7 yrs; non-obese full dose, 2 yrs; p=0.0006) and 5-FU full dose patients (obese dose reduced, 1.6 yrs; obese full dose, 2.2 yrs; non-obese dose reduced, 1.6 yrs; non-obese full dose, 1.9 yrs; p=0.0287). Conclusions: There is no difference in the incidence of grade 3/4 myelosuppression, diarrhea or neuropathy in obese versus non-obese patients, dose reduced or not. OX dose reductions were associated with reduced PFS and OS. 5-FU dose reductions were associated with reduced OS. Our study supports ASCO recommendations against dose reductions in obese patients receiving chemotherapy.

535 Background: The most effective management of locally recurrent colorectal cancer (CRC) is resection. This is also true for hepatic metastases (HM). Data remains limited, however, regarding concomitant resection of recurrent CRC and HM. The aims of this study were to determine the feasibility, safety and outcomes in terms of disease-free survival (DFS) and overall survival (OS) in patients undergoing concomitant resection of recurrent CRC with HM. Methods: All patients who underwent resection of recurrent CRC from 1/1995 to 1/2007 at Mayo Clinic, Rochester were reviewed (n=406). The study group consisted of patients who underwentconcomitant resection of locally recurrent CRC and hepatic resection for metastatic CRC (n= 45). Kaplan-Meier Survival was used to estimate DFS and OS. Results: The study group consisted of 27 men and 18 women. The median age was 59 years. Surgical management involved pelvic dissection in 43 patients and ileotransverse colectomy in two. 17 patients required resection of contiguous organs. 24 patients received intra-operative radiation. 34 patients underwent multiple hepatic wedge resections, 6 patients segmentectomy, 3 left hepatectomy, and 2 right hepatectomy. There was no perioperative mortality. Morbidity was 37%, 2 patients required re-operation. The 1, 3, and 5 year DFS was 72.2, 42.3, and 18.5%, respectively. The 1, 3, and 5 year OS was 87.7, 47.6, and 36.2%, respectively. Conclusions: Synchronous resection of locally recurrent CRC and HM is safe and feasible; morbidity is reasonable and mortality zero. DFS and OS in this patient population appear comparable to that of patients undergoing separate, staged resections.

523 Background: This study was done to assess the toxicity and efficacy of IMRT for anal cancer in a multi-institutional setting. Methods: Records of 152 total patients (pts) were reviewed retrospectively. Data on disease control and toxicity were collected as well as pt and treatment characteristics. Acute (<6 months) and late (>=6 months) severe toxicity (grade >=3) were recorded at each institution. Four were excluded for either presence of metastatic disease (2) or stage TX (2). There was data for late toxicity on 120 pts. Results: T stage was T1 in 28, T2 in 79, T3 in 29 and T4 in 12 pts. N stage was N0 in 77, N1 in 40, N2 in 19 and N3 in 12 pts. The median age was 56 yrs and median follow-up was 26.8 months. Cumulative IMRT dose was 51.25 Gy (median) (range: 4.32-61.2 Gy) in a median of 28 fractions (2-34). Chemotherapy was given in all but 2 pts and the most common regimen was 5- fluorouracil plus mitomycin-C. The median total elapsed treatment time was 40 days. Local control at 3 yrs was 87% and was significantly worse for patients with T3-4 disease (79% vs 90% at 3 years; p=0.04). There was no correlation between dose and local control. Regional control, distant control and overall survival were 97%, 91%, and 87% at 3 yrs, respectively. Nodal status was associated with regional and distal control as well as overall survival (p<0.01 for each). The most common acute severe toxicity was hematologic (41%). Severe acute GI, skin or other toxicity was 11%, 20% and 1% respectively. There were two grade 5 toxicities (hematologic and GI). Severe late toxicity was limited to skin (1%) and GI (3%). Conclusions: IMRT resulted in excellent local control in this multi-institutional cohort of pts. Although T stage did predict for worse local control, most pts with T3-4 disease were controlled with IMRT. Nodal status predicts for regional and distal control as well as overall survival. Severe toxicity was acceptable with this technique.

514 Background: Randomized trials and OCSs have demonstrated that BV treatment in 1st-line (1L), in 2L, and across multiple lines is associated with longer survival in patients (pts) with mCRC. This analysis was aimed at comparing the effectiveness of BV after 1st disease progression (PD) between male and female mCRC pts who received 1L BV-containing therapy in a real-world setting. Methods: ARIES is a large, prospective OCS that enrolled pts who received BV and chemotherapy (CT) for 1L mCRC. Post-PD effectiveness was assessed for men and women characterizing BV use by cumulative and dichotomous approaches. The primary analysis treated BV exposure as cumulative BV doses after 1st PD and post-progression overall survival (ppOS) as the time from 1st PD to death. A time-dependent Cox regression model was fitted to assess the effect of cumulative BV exposure on ppOS, while controlling for potential confounders. A dichotomous secondary analysis characterized BV exposure as receipt of CT + BV (BBP) or CT alone (No BBP) within 2 months after PD and ppOS as time from 1st PD + 2 months to death. Results: Among the 1,550 1L mCRC pts enrolled, 1,199 (532 women) had PD. In the primary analysis, hazard ratios (HRs) for ppOS decreased, on average, by 1.2% with each additional BV dose. When stratified by sex, the average risk reduction per BV dose over 15 doses was 1.8% in women and 0.7% in men. In the secondary analysis that included 331 women (BBP, 180; No BBP, 151) and 417 men (BBP, 245, No BBP, 172) who received BV ± CT within 2 months post-PD, the HRs for ppOS with BBP treatment were 0.46 (95% CI, 0.35–0.59) in women and 0.52 (95% CI, 0.41–0.67) in men. Statistical interaction tests for differences in the effectiveness of BV between men and women were negative for primary and secondary analyses (P of 0.58 and 0.77). Protocol-specified adverse events occurred in 17.8% of women and 10.2% of men in the BBP population; this difference was largely related to rates of hypertension (8.3% vs 2.4%, respectively). Conclusions: In ARIES, the effectiveness of BV after first PD was not statistically different between women and men with mCRC. Clinical trial information: NCT00388206.

479 Background: Recent long-term clinical trial follow-up suggests that adding Ox to a fluoropyrimidine (FP) may provide less benefit in adjuvant CC than originally believed (Tournigand JCO 2012). In addition, emerging data on tissue biomarkers such as microsatellite mismatch repair (MMR) and the 12-gene Recurrence Score (RS) suggest these assays may be helpful in better defining treatment benefit, and a new report provides evidence that RS may specifically predict the value of Ox. (O’Connell ASCO 2012) In view of these developments we sought to document current use of adjuvant chemotherapy and physician perceptions about these decisions. Methods: US-based oncologists were recruited to complete a survey and contribute treatment data for their last 3 patients (pts) with stage II disease and last pt with a stage III tumor. Results: 25 gastrointestinal cancer clinical investigators and 77 practicing oncologists participated, providing data from a total of 408 cases (92% treated since 2011). Findings from the 2 groups are similar and are presented in aggregate. A median of 9 and 15 pts annually were evaluated with stage II and III tumors, respectively. Clinicians stated that they require a median of a 5% absolute reduction in relapse rate to use a FP alone and an additional 5% reduction to add Ox. Ox/FP was administered to 95 of 102 pts with stage III tumors (93%) and 85 of 306 pts with stage II disease (28%), particularly to those under age 70 or with T4 tumors (Table). MMR was evaluated in 127 pts (42%) with stage II and 20 pts (20%) with stage III disease. RS was obtained for 46 pts (15%) with stage II tumors, but only 2 pts (2%) with stage III. Conclusions: Adjuvant Ox is employed extensively in spite of the fact that it may provide less benefit than many oncologists report requiring to initiate its use. However, several recent research developments may be laying the groundwork for a change in this treatment practice. [Table: see text]

467 Background: Regorafenib (REG) is an oral multikinase inhibitor that has recently demonstrated significant overall survival benefit vs placebo in the randomized phase III CORRECT study. We examined the time course of adverse events (AEs) in the CORRECT study. Methods: Regorafenib (REG) is an oral multikinase inhibitor that has recently demonstrated significant overall survival benefit vs placebo in the randomized phase III CORRECT study. We examined the time course of adverse events (AEs) in the CORRECT study. Results: The safety population comprised 753 patients (pts): REG n=500; placebo n=253. The mean treatment duration was 12.1 ± 9.7 weeks in the REG group and 7.8 ± 5.2 weeks in the placebo group. Treatment-emergent AEs occurred at any grade in 99.6% of REG pts and 96.8% of placebo pts, at grade 1/2 in 21.6% and 47.8%, respectively, at grade 3 in 56.0% and 26.5%, respectively, and at grade 4/5 in 22.0% and 22.5%, respectively. AEs occurring in ≥10% more REG than placebo pts were fatigue, hand–foot skin reaction (HFSR), anorexia, diarrhea, weight loss, voice changes, hypertension, rash/desquamation, oral mucositis, fever, hyperbilirubinemia, low platelet count. The most frequent AEs deemed to be regorafenib related were HFSR, fatigue, diarrhea, hypertension, and rash/desquamation. The frequency of these AEs over time is shown in the Table. The incidence of HFSR, fatigue, hypertension, and rash/desquamation peaked in cycle 1 and tapered to a relatively stable lower incidence over later cycles. The incidence of diarrhea remained relatively constant throughout treatment. AEs led to dose modification in 66.6% of pts in the REG group and 22.5% in the placebo group. Data on dose intensity across treatment cycles will be presented. Conclusions: In the CORRECT trial, the incidences of the most common AEs in the REG group peaked early during treatment. There appeared to be no evidence for cumulative toxicity of REG. Clinical trial information: NCT01103323. [Table: see text]

453 Background: A 12-gene assay (Oncotype DX Colon Cancer) has been clinically validated as a predictor of recurrence risk in stage 2 colon cancer patients following surgery. We conducted the first prospective study to characterize the impact of Recurrence Score results on medical oncologists’ recommendations regarding adjuvant chemotherapy in T3, Mismatch Repair-proficient (MMR-P) stage 2 colon cancer patients. Methods: Consecutive patients with resected stage 2A colon cancer who were candidates for adjuvant chemotherapy were consented and enrolled by 105 medical oncologists from 17 sites in the Mayo Clinic Cancer Research Consortium. Each patient’s tumor specimen was assessed by the Recurrence Score test (quantitative RT-PCR) and MMR (IHC). Prior to and after receiving these results, physicians completed surveys indicating their planned treatments given hypothetical or known MMR results, recorded as Observation (Obs), 5FU-based chemotherapy (5FU), or 5FU + Oxaliplatin (Oxal). Change in treatment recommendation intensity from baseline to follow-up was defined as: increased if change from Obs to 5FU +/- Oxal or from 5FU to 5FU+Oxal, decreased if change from 5FU + Oxal to 5FU or Obs, or from 5FU to Obs, or no change. Results: 187 of 221 patients enrolled were evaluable including 141 who were MMR-P (avg age 63, 65% ECOG PS 0, med tumor size 5 cm, 11% high grade, 91% with 12+ nodes examined). In the primary analysis treatment recommendations changed for 63 (45%) of 141 MMR-P patients, with intensity decreasing for 47 (33%) and increasing for 16 (11%). Recommendations for chemotherapy (5-FU +/- Oxal) decreased from 73 (52%) patients pre-assay to 42 (30%) post-assay. Increased treatment intensity was more likely at higher Recurrence Score values and decreased intensity at lower Recurrence Score values (p=0.011), and any change was more likely when MMR status was unknown at baseline (p = 0.041). Conclusions: In this prospective study, quantitative recurrence risk information provided by the Recurrence Score test was associated with treatment recommendation changes for 45% of T3 MMR-P stage II colon cancer patients. Use of the 12-gene assay may lead to overall reductions in chemotherapy.