Meyers, Jeffery P.

2562 Background: Empiric chemotherapy (taxane/platinum) is standard for CUP. Because prognosis is poor, novel approaches are needed. The PI3K/mTOR pathway is frequently dysregulated in cancer. Everolimus (E), an mTOR inhibitor, is approved for multiple malignancies. We performed a phase II study of Pac + Carb + E as first-line therapy in metastatic CUP patients (pts). We additionally determined if a gene expression profiling (GEP) test that identifies tissue of origin (Pathwork Tissue of Origin) could identify responsive pts. (NCT00936702) Methods: Newly diagnosed, untreated CUP pts were eligible. Central pathology review confirmed CUP prior to registration; GEP was performed on formalin fixed tumor tissue. Pac (200 mg/m2), Carb (AUC=6) and E (30 mg once weekly) were delivered every 3 wks until progression or intolerable adverse events (AEs). The primary endpoint was confirmed response, with ≥11 of 50 responses (22%) needed for trial success. Secondary endpoints were OS, progression-free survival (PFS) and AEs. Results: 46 pts (median age 61) received a median 4 cycles (range: 1-33). 39 (85%), 21 (46%) and 1 (2%) experienced ≥1 grade (gr) 3+, 4+, or 5 (sepsis) AE, with gr 3+ hematologic AE most common (74%). Of 44 evaluable pts, 15 had a confirmed response (RR 34%, 95% CI: 21-50%), with a median PFS and OS of 4.1 and 10.1 mos, respectively. Adequate tissue for GEP was available in 36 pts and predicted 10 different sites of origin. In pts with a predicted tissue of origin in which taxane/platinum is standardly used, higher RR and significantly longer PFS and OS were observed compared with pts whose GEP identified a malignancy where taxane/platinum is not standard (Table). Conclusions: In pts with untreated CUP, Carb +Pac +E demonstrated promising antitumor activity. The GEP test identified patients clinically responsive to Carb/Pac/E therapy, and may be useful to select CUP pts for specific antitumor regimens. Clinical trial information: NCT00936702. [Table: see text]

3501 Background: 6m of oxaliplatin-based treatment is an option as adj chemotherapy for patients with high risk stage II CC (T4, inadequate nodal harvest, poorly differentiated, obstruction, perforation or vascular/perineural invasion). The IDEA collaboration showed shorter treatment duration to be appropriate for most pts with stage III colon cancer. The results of the 4 IDEA studies with stage II pts are presented here. Methods: A prospective, pre-planned pooled analysis of high-risk stage II patients from 4 concurrently conducted randomized phase III trials (SCOT, TOSCA, ACHIEVE-2, HORG) was performed to evaluate non-inferiority (NI) of 3m compared with 6m (ref) of adj FOLFOX/CAPOX (regimen preselected, not randomized). The primary endpoint was disease-free survival (DFS), NI was to be declared if the 2-sided 80% confidence interval (CI) for DFS hazard ratio (HR 3m v 6m) estimated by a stratified Cox model was below 1.2. 542 DFS events were required to provide 80% power to declare NI. NI was also examined within regimen, T4 (Yes v No) and inadequate nodal harvest (Yes v No) as pre-planned subgroups. Results: The primary analysis included 3273 randomised pts of which 1254 had FOLFOX and 2019 had CAPOX. There were 552 events and the median follow-up was 60.2 m. There was significantly less grade 3-5 toxicity with 3m treatment (p < .0001). The 5-year DFS rate was 80.7% and 84.0% for 3m and 6m treatment with an estimated DFS HR of 1.18 (80% CI:1.05-1.31, p for NI = 0.404). For CAPOX the estimated HR was 1.02 (80% CI: 0.88-1.17, p for NI = 0.087) and for FOLFOX the estimated HR was 1.42 (80% CI: 1.19-1.70, p for NI = 0.894). The test for interaction between duration and regimen was not statistically significant (p = .174 adjusted for multiple testing) but was stronger than that for the other subgroups examined. Conclusions: In the overall population non-inferiority for 3m adj treatment in pts with high-risk stage II CC was not shown. As with the stage III population the choice of adj regimen appears important (although this did not reach statistical significance) with a small difference in DFS between 3 and 6 m treatment if CAPOX is used. Clinical trial information: ISRCTN59757862.