Abstract P2-16-13: Phase I dose escalation clinical trial of the PI3K inhibitor BKM120 and capecitabine (C) in metastatic breast cancer (MBC)

Background: PIK3CA is one of the most frequently mutated genes in human breast cancer, and the high expression of a PIK3CA-pathway signature is associated with the poor prognosis Luminal B and Basal-like expression subtypes. BKM120 is an oral pan-class I phosphatidylinositol-3-kinase (PI3K) inhibitor, which has shown activity in preclinical and early clinical testing, and synergy with both endocrine and chemotherapy. In this trial we sought to evaluate the safety and estimate the maximum tolerated dose (MTD) of the combination of BKM120 and C in patients (pts) with MBC.

Methods: In a 3+3 dose escalation design, we evaluated four cohorts of BKM 120 daily plus C BID x 14 days in 21 day cycles. Standard definitions for DLT and MTD were used and evaluated on the first cycle. Toxicity was graded by CTCAE version 4. Response was evaluated after 2 cycles by RECIST criteria. Pts with MBC appropriate for treatment with C who had <4 prior chemotherapy regimens and normal organ, bone marrow and cardiac parameters were eligible.

Results: 21 pts (11 hormone receptor (HR)+, 3 HER2+, 9 HR/HER2-negative) were enrolled and treated. All were evaluable for toxicity and 14 for response to date. Median age was 54 (range 35-65). Median prior chemotherapy regimens for MBC was 2 (range 1-4). The following dose levels (DL) were evaluated: BKM120 50 mg/d + C 1000 mg/m2/BID x 14(DL 1-4 pts), BKM120 80 mg/d + C 1000 mg/m2/BID x 14 (DL2-3 pts), BKM120 100 mg/d + C 1000 mg/m2/BID x 14 (DL3-9 pts), BKM120 100 mg/d + C 1250 mg/m2/BID x 14 (DL4-5 pts). Most frequent adverse events (all grades) included: Nausea (12), mood disorders (11), PPE (9), diarrhea (8), fatigue (7), vomiting (5) mucositis (4), rash (4), photosensitivity (3), hyperglycemia (3). Grade 3 or higher AEs in any cycle were transaminitis (3) diarrhea (2) mood disorder (2), hyperglycemia, fatigue, photosensitivity, PPE (1 pt each). DLTs: grade 3 hyperglycemia (1/6 pts at DL3), and grade 3 mood disorder in 1/5 pts DL 4. Additionally 4 of 5 patients at DL 4 required dose reduction or delay prior to C3D1. Thus DL 4 exceeded the MTD and DL 3 was expanded for further safety evaluation. Antitumor activity was seen with best responses of 1 CR (at DL 3), 3 PR (DL1 and 4) and 7 SD.

PK analysis, assessment of tumor PIK3CA mutation status and intrinsic subtype by PAM50 is ongoing.

Conclusions: The combination of BKM120 100 mg po q day and C 1000 mg/m2 / BID x 14 d in 21 day cycles is tolerable and appears active. PK and biomarker analysis are ongoing. A phase II trial is planned.

Acknowledgements: This study was funded by Novartis Pharmaceuticals and by a grant from Susan G. Komen for the Cure (SAC 110044).

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-13.

Modular microsystem for the isolation, enumeration, and phenotyping of circulating tumor cells in patients with pancreatic cancer

In this manuscript, we discuss the development and clinical use of a thermoplastic modular microsystem for the high-throughput analysis of CTCs directly from whole blood. The modular system offers some innovative features that address challenges currently associated with many CTC platforms; it can exhaustively process 7.5 mL of blood in less than 45 min with recoveries >90%. In addition, the system automates the postselection CTC processing steps and thus, significantly reduces assay turnaround time (from selection to enumeration <1.5 h as compared to >8 h for many reported CTC platforms). The system is composed of 3 functional modules including (i) a thermoplastic CTC selection module composed of high aspect ratio (30 μm × 150 μm) channels containing anti-EpCAM antibodies that is scalable in terms of throughput by employing channel numbers ranging from 50 to 320; the channel number is user selected to accommodate the volume of blood that must be processed; (ii) an impedance sensor module for label-less CTC counting; and (iii) a staining and imaging module for the placement of released cells into a 2D array within a common imaging plane for phenotypic identification. To demonstrate the utility of this system, blood samples from patients with local resectable and metastatic pancreatic ductal adenocarcinoma (PDAC) were analyzed. We demonstrate the ability to select EpCAM positive CTCs from PDAC patients in high purity (>86%) and with excellent yields (mean = 53 CTCs per mL for metastatic PDAC patients) using our modular system. In addition, we demonstrate the ability to detect CTCs in PDAC patients with local resectable disease (mean = 11 CTCs per mL).