Twelves, Christopher

Intravenous infusion of oncolytic reovirus in patients leads to infection of brain tumors, infiltration by cytotoxic T cells, and up-regulation of PD-L1.

Abstract Background: Etirinotecan pegol (EP) is the first long-acting topoisomerase 1-inhibitor providing sustained level of active metabolite that concentrate in the tumor for an entire chemotherapy cycle. In a Phase 2 study (Lancet Oncology 2013), EP demonstrated a 29% overall response rate in patients with metastatic breast cancer, leading to the Phase 3 global BEACON study in this population. Detection of circulating tumor cells (CTCs) using immunomagnetic EpCAM-based methods have been conceptually accepted as a "liquid tumor biopsy". To circumvent the limited recovery of CTCs these methods provide for molecular profiling applications, we isolated CTCs based on an antibody-independent, continuous flow dielectrophoresis (DEP) technology (ApoStream®). We developed quantitative multiplex immunofluorescent assays for target-specific pharmacodynamics (PD) biomarkers for EP in CTCs isolated pre- and post-treatment. Here we present the distribution of the PD biomarkers in CTC samples collected from BEACON patients. Methods: Donation of blood samples for CTC analysis was voluntary. BEACON patients participating in the substudy had serial (pre-dose, Cycle 2 Day 1, Cycle 4 Day 1, End of Treatment) 7.5-mL whole blood samples drawn in EDTA tubes and shipped ambient to ApoCell (Houston, TX) within 96 hrs for processing. PBMCs were separated by Ficoll® gradient, and CTCs were isolated using ApoStream® technology. Isolated cells were deposited on three slides and stained for DAPI, CD45, and cytokeratin markers, as well as 2-3 of the seven PD markers, and analyzed by iCys® laser scanning cytometer equipped with image analysis software. CTC count, mean fluorescence intensity (MFI) of PD biomarkers, and % marker-positive cells were analyzed for their distribution. Results: 75% of the 852 BEACON patients participated in the CTC substudy, yielding 649 pre-treatment CTC samples. As of Mar14, 538 Cycle 2 Day 1, 281 Cycle 4 Day 1, and 394 End of Treatment samples were collected. 98% of pre-treatment blood samples were successfully processed. 97% had detectable CTCs, with a median of 504 CTCs (interquartile range: 128-1432). PD markers could be analyzed in 83-92% of samples after implementing a minimum requirement of 10 CTCs analyzed. Staining was positive for Top1, Top2, μH2Ax, Rad51, ABCG2, Ki67, and TUNEL in 82%, 71%, 14%, 30%, 20%, 56%, and 94% of samples, respectively. Percent of marker-positive cells varied from 0.2-69%, with 6- to 37-fold interquartile ranges. Median MFI in these cells varied between 25x103 and 100x103, with 1.2- to 1.6-fold interquartile ranges. Conclusions: CTC collection was successfully incorporated into the BEACON study, with 75% patient participation. CTC detection rate using ApoStream® was high, permitting evaluation of biomarkers at baseline and over time. EP target-specific PD biomarkers can be measured in CTCs isolated from patients participating in BEACON and will be assessed for their potential to predict clinical response. Final BEACON efficacy and safety results are expected in early 2015, which will allow further analysis of CTCs with patient outcome (response, PFS, OS) and change in CTCs at time of progression. Citation Format: Edith A Perez, Katie Caygill, Alison L Hannah, Javier Cortes, Ahmad Awada, Joyce O'Shaughnessy, Christopher Twelves, Hope Rugo, Seock-Ah Im, Kenna Anderes, Darren W Davis, Ute Hoch. Etirinotecan pegol target-specific pharmacodynamic biomarkers in circulating tumor cells from patients with metastatic breast cancer in the phase 3 BEACON study [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-10-03.

Purpose Prior studies have suggested that patients with stage II/III colon cancer receive similar benefit from intravenous (IV) fluoropyrimidine adjuvant therapy regardless of age. Combination regimens and oral fluorouracil (FU) therapy are now standard. We examined the impact of age on colon cancer recurrence and mortality after adjuvant therapy with these newer options. Patients and Methods We analyzed 11,953 patients age < 70 and 2,575 age ≥ 70 years from seven adjuvant therapy trials comparing IV FU with oral fluoropyrimidines (capecitabine, uracil, or tegafur) or combinations of fluoropyrimidines with oxaliplatin or irinotecan in stage II/III colon cancer. End points were disease-free survival (DFS), overall survival (OS), and time to recurrence (TTR). Results In three studies comparing oxaliplatin-based chemotherapy with IV FU, statistically significant interactions were not observed between treatment arm and age (P interaction = .09 for DFS, .05 for OS, and .36 for TTR), although the stratified point estimates suggested limited benefit from the addition of oxaliplatin in elderly patients (DFS hazard ratio [HR], 0.94; 95% CI, 0.78 to 1.13; OS HR, 1.04; 95% CI, 0.85 to 1.27). No significant interactions by age were detected with oral fluoropyrimidine therapy compared with IV FU; noninferiority was supported in both age populations. Conclusion Patients age ≥ 70 years seemed to experience reduced benefit from adding oxaliplatin to fluoropyrimidines in the adjuvant setting, although statistically, there was not a significant effect modification by age, whereas oral fluoropyrimidines retained their efficacy.

Abstract Oncolytic viruses consist of a diverse range of DNA and RNA viruses traditionally thought to mediate their effects by exploiting aberrations in tumor pathways, allowing preferential viral replication in, and killing of, tumor cells. Clinical development has progressed to late-phase trials, potentially heralding their introduction into clinical practice. However, despite this promise, the activity of oncolytic viruses has yet to achieve the potential suggested in preclinical models. To address this disparity, we need to recognize the complex interaction among oncolytic viruses, tumor, chemotherapy, and host immune system, and appreciate that direct oncolysis may not be the only factor to play an important role in oncolytic virus-mediated antitumor efficacy. Although key in inactivating viruses, the host immune system can also act as an ally against tumors, interacting with oncolytic viruses under the right conditions to generate useful and long-lasting antitumor immunity. Preclinical data also suggest that oncolytic viruses show synergy with standard therapies, which may offer improved clinical response rates. Here, we explore clinical and preclinical data on clinically relevant oncolytic viruses, highlighting areas of progress, uncertainty, and translational opportunity, with respect to immune recruitment and therapeutic synergy. Clin Cancer Res; 17(13); 4214–24. ©2011 AACR.