Maria Iannone

A phase II trial of single agent bevacizumab in patients with relapsed, aggressive non-Hodgkin lymphoma: Southwest oncology group study S0108

This is the first report of the Southwest oncology group phase II trial of single agent bevacizumab in patients with relapsed, aggressive non-Hodgkin lymphoma (NHL). Fifty-two patients in first or second relapse with diffuse large B-cell or mantle cell lymphoma were enrolled. Patients were treated with bevacizumab at 10 mg/kg every 2 weeks. Therapy was well tolerated with no unexpected toxicities observed. Six-month progression-free survival (PFS) was 16% with a response rate of 2% and median duration of response or stable disease of 5.2 months (range 3.5–72.7). Vascular endothelial growth factor A (VEGF) and VEGF receptor expression was observed in 70% and 65% of specimens, respectively. In an exploratory subgroup analysis, baseline urine VEGF and plasma vascular cell adhesion molecule-1 (VCAM) levels correlated with survival. Prolonged PFS in several patients as well as biomarker studies suggest the VEGF pathway plays an important role in aggressive NHL. Clinical trials combining active chemotherapy regimens with VEGF targeted agents are currently in progress.

A phase 2 trial of standard-dose cyclophosphamide, doxorubicin, vincristine, prednisone (CHOP) and rituximab plus bevacizumab for patients with newly diagnosed diffuse large B-cell non-Hodgkin lymphoma: SWOG 0515

S0515 was a phase 2 trial to determine whether the addition of bevacizumab to cyclophosphamide, doxorubicin, vincristine, prednisone (CHOP) plus rituximab (R-CHOP) would improve progression-free survival (PFS) without adding significant toxicity in patients with newly diagnosed advanced diffuse large B-cell lymphoma. A total of 73 patients were enrolled. For the 64 eligible patients, median age was 68 years, and 60% had International Prognostic Index scores more than or equal to 3. The observed 1- and 2-year PFS estimates were 77% and 69%, respectively. These PFS estimates were not statistically different from the expected PFS for this population if treated with R-CHOP alone. Grade 3 or higher toxicities were observed in 81% of patients, including 2 grade 5 events. The majority of serious toxicities were hematologic but also included 5 patients with gastrointestinal perforations, 4 patients with thrombotic events, and 11 patients who developed grade 2 or 3 left ventricular dysfunction. Higher baseline urine VEGF and plasma VCAM levels correlated with worse PFS and overall survival. In conclusion, the addition of bevacizumab to R-CHOP chemotherapy was not promising in terms of PFS and resulted in increased serious toxicities, especially cardiac and gastrointestinal perforations. This study is registered at www.clinicaltrials.gov as #NCT00121199.

A phase 1 trial of 2 dose schedules of ABT-510, an antiangiogenic, thrombospondin-1-mimetic peptide, in patients with advanced cancer.

ABT‐510 is a substituted nonapeptide that mimics the antiangiogenic activity of the endogenous protein thrombospondin‐1 (TSP‐1). The current study was designed to establish the safety of ABT‐510 in the treatment of patients with advanced malignancies on a once‐daily (QD) and twice‐daily dosing schedule.

A phase I clinical trial of bavituximab and paclitaxel in patients with HER2 negative metastatic breast cancer

Bavituximab is a chimeric monoclonal antibody that targets phosphatidylserine (PS). PS is externalized on cells in the tumor microenvironment when exposed to hypoxia and/or other physiological stressors. On attaching to PS, bavituximab is thought to promote antitumor immunity through its effects on PS receptors in monocytes, and myeloid‐derived suppressor cells, as well as trigger antitumor effects by inducing an antibody‐dependent cellular cytotoxicity on tumor‐associated endothelial cells. We conducted a phase I clinical trial of bavituximab in combination with paclitaxel in patients with HER2‐negative metastatic breast cancer. Patients were treated with weekly paclitaxel (80 mg/m2 for 3/4 weeks) and weekly bavituximab (3 mg/kg for 4/4 weeks). Correlative studies included the measurement of circulating microparticles, endothelial cells, and apoptotic tumor cells by flow cytometry. Fourteen patients with metastatic breast cancer were enrolled; all were evaluable for toxicity and 13 were evaluable for response. Treatment resulted in an overall response rate (RR) of 85% with a median progression‐free survival (PFS) of 7.3 months. Bone pain, fatigue, headache, and neutropenia were the most common adverse effects. Infusion‐related reactions were the most common adverse event related to bavituximab therapy. Correlative studies showed an increase in the PS‐expressing apoptotic circulating tumor cells in response to bavituximab, but not with paclitaxel. No changes in the number of circulating endothelial cells or apoptotic endothelial cells were observed with therapy. Platelet and monocyte‐derived microparticles decreased after initiation of bavituximab. Bavituximab in combination with paclitaxel is well tolerated for treatment of patients with metastatic breast cancer with promising results observed in terms of clinical RRs and PFS. The toxicity profile of bavituximab is notable for manageable infusion‐related reactions with no evidence for increased thrombogenicity. Recent preclinical data suggest that bavituximab can also promote antitumor immune activity that should be explored in future clinical trials.

Circulating Carbonic Anhydrase IX and Antiangiogenic Therapy in Breast Cancer

Introduction. Carbonic anhydrase IX (CAIX) is a hypoxia regulated metalloenzyme integral to maintaining cellular pH. Increased CAIX expression is associated with poor prognosis in breast cancer. To explore CAIX as a biomarker for breast cancer therapies, we measured plasma CAIX levels in healthy control subjects and in breast cancer patients. Methods. In control subjects we evaluated plasma CAIX stability via commercially available ELISA. We then similarly quantified plasma CAIX levels in (1) locally advanced breast cancer (LABC) patients treated with neoadjuvant paclitaxel + sunitinib (T + S) followed by doxorubicin and cyclophosphamide (AC); (2) metastatic breast cancer (MBC) patients treated with systemic chemotherapy. Results. Plasma CAIX levels were stable at room temperature for at least 48 hours in control subjects. Mean baseline plasma CAIX levels were lower in controls compared to patients with LABC or MBC. In LABC, CAIX levels rose significantly in response to administration of antiangiogenic therapy (T + S) (p = 0.02) but not AC (p = 0.37). In patients with MBC treated without an antiangiogenic agent CAIX levels did not change with therapy. Conclusions. Our results suggest that CAIX may be an easily obtained, stable measure of tumor associated hypoxia as well as a useful pharmacodynamic biomarker for antiangiogenic therapy.

On the minimum detection limit of circulating tumor cells in an antibody-functionalized microchannel array

The minimum detection limit in isolation of circulating tumor cells (CTCs) from binary mixtures is experimentally explored utilizing microchannel arrays functionalized with EpCAM antibodies. Hence, the tested binary mixtures contained EpCAM-positive and EpCAM-negative cells serving as target and non-target cells, respectively. The ratio of target to non-target cells in the mixtures ranged from 1:1 to 1:100,000. The dependence of the device performance, particularly its sensitivity and specificity in isolating target cells, on the applied flow shear rate is characterized. The results demonstrate capture of circulating tumor cells from mixtures with high sensitivity and high specificity. The multichannel array devices allow testing of samples within a shorter time, which is critical for high throughput applications.

Abstract P1-03-01: Circulating CAIX as a biomarker in breast cancer

Introduction: Carbonic anhydrase-IX (CAIX) facilitates the reversible hydration of carbon dioxide to bicarbonate and protons, a process integral to maintaining pH differences across the cancer cell plasma membrane. CAIX is regulated by hypoxia inducible factor-1 alpha (HIF-1 alpha) and is essential for the elimination of acid loads generated by glycolysis. High CAIX expression is associated with poor prognosis and chemoresistance in breast cancer patients (pts) (1-3). To explore the role of CAIX as a possible biomarker for predicting breast cancer therapies, we measured plasma CAIX levels in response to various chemotherapy regimens, including anti-angiogenics, in several breast cancer clinical trials. Methods: Circulating plasma CAIX was quantified using a commercially available enzyme-linked immunosorbent assay (ELISA) kit (R & D Systems). We evaluated the plasma stability of CAIX by quantifying levels within 1 hour as well as at 24 and 48 hours post phlebotomy in healthy controls (n = 10). We also evaluated the ideal anticoagulant for sample collection and stability of CAIX levels over time in healthy controls. For our analysis in breast cancer pts, we quantified plasma CAIX levels in two populations treated on chemotherapeutic clinical trials: 1) locally advanced breast cancer (LABC) pts treated in the neoadjuvant setting with paclitaxel in combination with sunitinib followed by anthracycline (AC) based chemotherapy (n = 63); 2) metastatic breast cancer (MBC) pts treated with systemic chemotherapy with either irinotecan + etoposide; or paclitaxel + a novel immunomodulatory agent (n = 22). Results: In healthy control subjects, plasma levels of CAIX were stable at all time points tested (within1 hour, 24 hrs, 48 hours post phlebotomy) with no significant change on repeat testing at 6 months. Average baseline plasma CAIX levels were lowest in normal controls (20.5 pg/ml) compared to pts with LABC (34.1 pg/ml) or MBC (90.7 pg/ml) (p = Discussion: Plasma CAIX is a robust biomarker that is stable at room temperature in plasma for at least 48hrs and over time in healthy controls. Plasma CAIX levels are elevated in pts with MBC when compared to those with LABC or normal controls. CAIX levels rise in response to anti-angiogenic therapy but not in response to cytotoxic chemotherapy. Our results suggest CAIX may be a robust and easily measured pharmacodynamic biomarker of anti-angiogenic induced hypoxia and HIF-1 alpha upregulation. 1. Potter CP and Harris AL. Br J Cancer. 89:2-7, 2003. 2. Betof AS, Rabbani ZN, Hardee ME, et al. BJ Cancer. 106:916-922, 2012. 3. Generali D, Fox Berruti A, et al. Endocrine-Related Cancer. 13:921-30, 2006. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-03-01.

Abstract 4404: Microparticle generation and activation after treatment with paclitaxel and bavituximab combination therapy in metastatic breast cancer

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Background: Breast cancer is the leading cause of life-threatening malignancy affecting women and the second leading cause of female cancer death in the United States. Weekly paclitaxel, alone or in combination with other chemotherapies, has proven to be an effective and well-tolerated therapy for patients with metastatic disease. Due to the tumors dependence on vascularization for progression, survival and dissemination, targeting a tumors vascular network is an important additional cancer management strategy. Bavituximab, a monoclonal antibody developed by Peregrine Pharmaceuticals against phosphatidylserine (PS), is a vascular disrupting agent designed to selectively attack tumor blood vessels already in existence. Under normal conditions, PS is localized to the internal surface of the plasma membrane. However, PS is preferentially localized on the outer surface of vascular endothelial cells in tumors, possibly due to stress conditions in the tumor microenvironment. Bavituximab is able to localize and bind specifically to PS in tumor vessels in a α2-glycoprotein 1 dependent manner, mediating the binding of host effector cells to the tumor vascular endothelium. This leads to vessel damage, vascularity reduction, necrosis, and growth retardation within the tumor. Microparticles are vesicles that are released from cells after activation, stress, death, or malignant transformation. Elevated levels of microparticles derived from platelets, endothelial cells, and/or leukocytes have been associated with several disease states, including cancer, however, the effect of anti-angiogenic or vascular disrupting agents on microparticle production is unclear. We investigated microparticle formation in our patients at baseline, in response to Paclitaxel chemotherapy, and after addition of Bavituximab. Patients and Methods: We initiated a phase I clinical trial in patients with Her-2 negative metastatic breast cancer treated with paclitaxel (80 mg/m2)on a weekly schedule for 3 out of 4 weeks, and weekly bavituximab (3 mg/kg) for 4 out of 4 weeks. Each cycle was defined as 4 weeks of therapy. Microparticles were isolated from peripheral blood and examined by flow cytometric phenotyping. Leukocyte, endothelial cell, and activated platelet microparticles were quantified and longitudinal trends analyzed. Five patients have been enrolled to date with additional patients accruing. At presentation, the longitudinal trends in microparticle formation from platelets, endothelial cells, and leukocytes will be presented in response to weekly Paclitaxel versus combined Paclitaxel and Bavituximab therapy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4404. doi:1538-7445.AM2012-4404