Tabernero, Josep

381 Background: In the CORRECT Ph3 trial, regorafenib demonstrated significant improvement in OS and PFS vs. placebo in subjects with metastatic colorectal cancer (mCRC) who had progressed on standard therapies. An exploratory biomarker substudy was conducted on samples collected from subjects enrolled in CORRECT. Methods: DNA was isolated from archival tumor tissue and fresh baseline plasma samples that were available from 239 (31%) and 503 (66%) subjects enrolled in CORRECT, respectively. Mutations in KRAS, PIK3CA and BRAF were evaluated via BEAMing technology. Results: Mutations were readily detected in DNA isolated from both tumor and plasma samples: KRAS: 59/69%; PIK3CA: 12/17% and BRAF: 1.5/3.4%. The frequency of KRAS mutation detected in tumor samples via BEAMing (59%) was identical to the frequency determined from pre-existing “historical” KRAS mutation data that was available from 96% of the subjects enrolled in the study. Concordance among the mutations detected via BEAMing in tumor vs. plasma was 76% (KRAS), 88% (PIK3CA), and 97% (BRAF). A subset of CRC which was found to be KRAS-wildtype in DNA from archival tumor, but KRAS-mutant in DNA from fresh plasma was identified and may represent subjects whose KRAS mutational status had changed during prior therapy. Correlative subgroup analyses demonstrated that regorafenib mediated a trend for clinical benefit vs. placebo in both KRAS wildtype and mutant subgroups identified by plasma BEAMing (OS: KRAS WT, HR: 0.67, 95% CI: 0.41–1.08; KRAS mutant, HR: 0.81, 95% CI: 0.61–1.09; interaction p=0.561). Similar results were noted for PIK3CA WT/mutant subgroups (OS: WT, HR: 0.75, 95% CI: 0.57–0.99; mutant, HR: 0.84, 95% CI: 0.47–1.50; interaction p=0.723). BRAF was not analysed due to the small number of BRAF-mutant samples. Conclusions: The mutational analysis of DNA isolated from fresh plasma is feasible and robust using the BEAMing platform and may better represent the mutational status of the tumor(s) that a mCRC patient harbors at the time of enrollment than does the mutational analysis of archival primary tumor tissue. Regorafenib was associated with clinical benefit (vs. placebo) in all mutational subgroups evaluated. Clinical trial information: NCT01103323.

710 Background: In the CORRECT phase III trial (NCT01103323), the multikinase inhibitor REG significantly improved overall survival (OS) and PFS vs placebo in patients with mCRC who had disease progression after other standard therapies (HR for OS: 0.77; 1-sided p =0.0052; Grothey 2013). A post-hoc exploratory subgroup analysis was conducted to evaluate patients in the REG treatment group who had a PFS longer than 4 months (long-PFS) defined as patients who progressed, died, or discontinued treatment for other reasons after 4 months. Methods: Of the505 patients randomized to REG in CORRECT, 98 (19.4%) were classified as having a long-PFS benefit. Baseline characteristics, safety, and dosing parameters were analyzed descriptively. Results: The long-PFS subpopulation was representative of the overall study population (Table). Long-PFS patients received a median of 6 cycles of REG (1-12), 92% received ≥5 cycles, and 20% had > 8 cycles. Overall 34% of patients had dose reductions and 87% had dose interruptions. The actual mean daily dose was 139 mg and the mean percent of the planned dose was 81%. Adverse events (AE) of any grade were experienced by all long-PFS patients, and the most common grade ≥3 AEs were hand-foot skin reaction (20%), hypertension (17%), diarrhea (17%), and fatigue (16%). Conclusions: A subset of 98 (19.4%) patients treated with REG in the CORRECT study had a PFS > 4 months, confirming the clinical benefit and tolerability of REG as a treatment option for patients with mCRC. Prospective validation of these findings in conjunction with biomarker analysis from real-life clinical experience is needed. Clinical trial information: NCT01103323. [Table: see text]

512 Background: Angiogenesis is an important therapeutic target in CRC; VEGF plays a key role in angiogenesis. RAM is a human IgG1 monoclonal antibody that targets the extracellular domain of VEGFR-2. The RAISE study evaluated the efficacy and safety of adding RAM to standard second-line treatment FOLFIRI. Methods: Eligible pts with mCRC who progressed on or after first-line combination therapy with bev, ox, and fp, had an ECOG PS of 0 or 1, and adequate organ function were randomized 1:1 (stratified by region, KRAS mutation status, and time to progressive disease [PD] after beginning first-line treatment) to receive RAM (8 mg/kg IV) plus FOLFIRI or PBO plus FOLFIRI every 2 weeks until PD, unacceptable toxicity, or death. The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), objective response rate (ORR), and safety. Planned sample size of 1,050 pts ensured 85% power to demonstrate statistical significance at an overall two-sided alpha of 0.05, assuming a hazard ratio (HR) of 0.8. Results: Between Dec 2010 and Aug 2013, 1,072 eligible pts were randomized (RAM 536; PBO 536). Baseline pt characteristics were similar between treatment arms. The OS HR was 0.84 (95% CI: 0.73, 0.98; log-rank p=0.0219). Median OS was 13.3months (m) for RAM vs 11.7m for PBO. The PFS HR was 0.79 (95% CI: 0.70, 0.90; log-rank p = 0.0005). Median PFS with RAM was 5.7m and 4.5m for PBO. ORR was 13.4% RAM; 12.5% PBO (p = 0.6336). Subgroup results were consistent with the OS and PFS results. Grade ≥3 adverse events (AEs) occurring in >5% of pts in RAM+FOLFIRI were: neutropenia (RAM 38.4% vs PBO 23.3% ), hypertension (11.2% vs 2.8%), diarrhea (10.8% vs 9.7%), and fatigue (11.5% vs 7.8%). Conclusions: RAISE met its primary end-point, demonstrating a statistically significant improvement in OS for RAM and FOLFIRI vs PBO and FOLFIRI in second-line mCRC pts. Benefits were similar across important clinical subgroups and no unexpected AEs were identified. Clinical trial information: NCT01183780.

Abstract Purpose: To evaluate safety (primary endpoint), tolerability, pharmacokinetics, pharmacodynamic profile, and preliminary activity of the intravenous, pan-class I isoform PI3K/mTOR inhibitor PF-05212384 in patients with advanced solid tumors. Experimental Design: Part 1 of this open-label phase I study was designed to estimate the maximum-tolerated dose (MTD) in patients with nonselected solid tumors, using a modified continual reassessment method to guide dose escalation. Objectives of part 2 were MTD confirmation and assessment of preliminary activity in patients with selected tumor types and PI3K pathway dysregulation. Results: Seventy-seven of the 78 enrolled patients received treatment. The MTD for PF-05212384, administered intravenously once weekly, was estimated to be 154 mg. The most common treatment-related adverse events (AE) were mucosal inflammation/stomatitis (58.4%), nausea (42.9%), hyperglycemia (26%), decreased appetite (24.7%), fatigue (24.7%), and vomiting (24.7%). The majority of patients treated at the MTD experienced only grade 1 treatment-related AEs. Grade 3 treatment-related AEs occurred in 23.8% of patients at the MTD. No treatment-related grade 4–5 AEs were reported at any dose level. Antitumor activity was noted in this heavily pretreated patient population, with two partial responses (PR) and an unconfirmed PR. Eight patients had long-lasting stable disease (>6 months). Pharmacokinetic analyses showed a biphasic concentration–time profile for PF-05212384 (half-life, 30–37 hours after multiple dosing). PF-05212384 inhibited downstream effectors of the PI3K pathway in paired tumor biopsies. Conclusions: These findings demonstrate the manageable safety profile and antitumor activity of the PI3K/mTOR inhibitor PF-05212384, supporting further clinical development for patients with advanced solid malignancies. Clin Cancer Res; 21(8); 1888–95. ©2015 AACR.

Abstract Background. nab-Paclitaxel in combination with gemcitabine has emerged as a new treatment option for patients with metastatic pancreatic cancer (MPC), based on superiority over gemcitabine demonstrated in the phase III MPACT trial. Previously, Karnofsky performance status (KPS) score and the presence of liver metastases were shown to be predictive of survival with nab-paclitaxel plus gemcitabine treatment. This analysis sought to further explore the relationship between clinical characteristics and survival in the MPACT trial and to identify potential predictors of overall survival and progression-free survival in patients with MPC. Materials and Methods. Cox regression models adjusted for stratification factors and a stepwise multivariate analysis of prespecified baseline prognostic factors were performed. Results. Treatment effect was significantly associated with survival, with a similar magnitude of reduction in risk of death compared with the previously reported primary analysis. Treatment effect consistently favored nab-paclitaxel plus gemcitabine across the majority of the prespecified factors. In addition to KPS score and presence of liver metastases, age and number of metastatic sites were independent prognostic factors of overall and progression-free survival. Baseline carbohydrate antigen 19-9 was not found to be an independent prognostic factor of survival in this analysis. Conclusion. The results of this analysis confirm broad utility of nab-paclitaxel plus gemcitabine for the treatment of MPC. In addition, these findings suggest that KPS score, presence of liver metastases, age, and number of metastatic sites are important predictors of survival that may be useful when making treatment decisions and designing future clinical trials.

Abstract Background: Activation of the PI3K pathway, by PIK3CA mutation or amplification or PTEN deletion, has been implicated in a wide variety of human cancers. PF-05212384 is a dual-specificity inhibitor of PI3K and mTOR that is formulated for intravenous (IV) administration. PF-05213384 is the first IV PI3K/mTOR inhibitor to be tested in a clinical trial. Methods: In this ongoing phase 1 trial, PF-05212384 was administered once weekly, using a modified continual reassessment method (CRM) for estimation of the maximum tolerated dose (MTD). Assessments included safety (NCI CTC AE v4.0), pharmacokinetics (PK), pharmacodynamics (PD), and antitumor activity (RECIST v1.1). PD assessments included blood glucose and immunohistochemistry analysis of phosphoprotein biomarkers in tumor and surrogate tissue (hair follicles). The population was actively enriched for patients with dysregulation in the PI3K pathway. Results: As of 15 March 2011, 47 patients have been enrolled at doses ranging from 10 mg to 319 mg. Median age was 58. Represented tumor types included CRC (8), NSCLC (4), ovarian/endometrial/cervical (8), salivary (3) and gastric/esophageal (3). Analysis of archived tumor biopsies revealed PI3K pathway alterations in 12/26 evaluable patients; alterations included PTEN loss, PIK3CA mutation or amplification. PF-05212384 was well tolerated with the most common AEs being mucositis (44%), nausea (42%), fatigue (28%), rash (28%), and hyperglycemia (26%). DLTs included mucositis, rash, transaminase elevation, and hyperglycemia. An MTD of 154 mg weekly has been estimated. PF-05212384 is eliminated with a half-life of approximately 16 hours, with low clearance (5–9 L/h) and relatively high volume of distribution (54–144 L). Changes in blood glucose have been observed in 13 patients, including 2 patients with Grade 3 hyperglycemia, a known effect of PI3K/Akt pathway suppression. No objective tumor response has been observed; 12 patients have achieved stable disease (SD) in excess of 16 weeks, with 9 patients on study for ≥24 weeks and one patient (salivary) on study for >46 weeks. Enrollment to MTD expansion cohorts is ongoing. Conclusions: Weekly administration of PF-05212384 is safe and tolerable across dose levels with multiple patients deriving clinical benefit with prolonged SD. The occurrence of hyperglycemia is suggestive of target modulation. Updated data for safety, PK, PD and antitumor activity will be presented Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A167.