ACCOMPLISHMENTS AND FUTURE PLANS
Therapeutic Modulation
Therapeutic Modulation focuses on novel local, regional, and systemic treatments for cancer, many of which are translated from basic research discoveries from the Cancer Center’s two basic research programs, DNA Damage & Cellular Defense and Cell Growth & Survival, into the clinic.
Radiosensitizers
Over the last five years, clinical research on radiosensitizers has focused on upper aerodigestive tract cancers, including pancreatic, non-small cell lung, and esophageal cancers. Two strategies have been utilized; gemcitabine + radiation therapy (RT) and more recently oxaliplatin + RT. The pre-clinical studies for both of these approaches are being performed by William Blackstock, M.D., clinician-scientist and member of the Clinical Research Program, Suzanne Hess, Ph.D., former member of the DNA Damage and Cellular Defense Program, and Costas Koumenis, Ph.D. The clinical trials were performed at CCCWFU through multidisciplinary collaborations between Clinical Research Program members in surgical oncology (Drs. Edward Levine and Perry Shen), medical oncology (Drs. Tony Miller, Glenn Lesser and Susan Melin), gastroenterology (Dr. Girish Mishra), and radiation oncology (Dr. Blackstock). External collaborators include the University of North Carolina (UNC) at Chapel Hill (Dr. Joel Tepper and colleagues), and Lyon-Sud University Hospital, Lyon, France (Dr. Francoise Mornex and colleagues).
The Phase I study establishing the safety of the twice-weekly gemcitabine plus radiation therapy (RT) regimen in pancreatic cancer was performed at Wake Forest in the previous grant cycle. Phase II studies of gemcitabine/RT in both resected (protocol 57198) and unresectable (protocol 57100) pancreatic cancer were conducted both at the CCCWFU and in the CALGB. In the patients with resected pancreas cancer treated with adjuvant gemcitabine-RT, a median survival time of 18.3 months was observed. The CALBG is now considering moving this strategy into the Phase III setting. A CCCWFU Phase I study combining gemcitabine/RT demonstrated the safety and feasibility of combining twice-weekly gemcitabine with 3Dconformal high dose localized thoracic radiation therapy in patients with unresectable non-small cell lung cancer (NSCLC) (protocol 62197). The CALGB is now performing a randomized Phase II trial (protocol 30105) based in part on the Wake Forest Phase I gemcitabine/RT study, in which patients with unresectable NSCLC are randomized to gemcitabine-carboplatin + 3D conformal RT versus taxol-carboplatin + 3D conformal RT.
More recently, the Blackstock and Koumenis labs have assessed oxaliplatin as a radiosensitizer. Preclinical work in two esophageal cancer cell lines formed the basis of a clinical trial, as well as an R01 grant application, of preoperative oxaliplatin-RT in patients with locally advanced esophageal cancer. This R01 is in followup to a prior NCI R21 grant utilizing PET staging/restaging following preoperative 5FU, cisplatin, and hyperfractionated RT for locally advanced esophageal cancer in which Dr. Edward Levine, chief of surgical oncology and a Clinical Research Program member, served as PI. A CCCWFU Phase I study of oxaliplatin, RT, and pemetrexed (Altima) is actively accruing patients, and will be followed by a joint Wake Forest/University of North Carolina Phase I trial of gemcitabine, oxaliplatin, RT, and bevacizumab (Avastin). The combination of chemotherapy, RT, and targeted therapies is also being explored in rectal cancer and NSCLC. A Wake Forest Phase I study of 5FU, RT, and the proteosome inhibitor PS-341 for locally advanced rectal cancer is actively accruing patients, as is another Wake Forest Phase I trial of docetaxel, 3D conformal RT, and ZD1839 (Iressa) in unresectable non-small cell lung cancer. The preclinical efforts performed in the Blackstock, Hess, and Koumenis labs have resulted in a number of Wake Forest Phase pilot, Phase I, and Phase II clinical trials, several of which have led to Cooperative Group studies. The following lists those national studies emanating from CCCWFU Phase I/II trials:
· CALGB 89805: Phase II Gemcitabine + Radiation Therapy for Locally Advanced Pancreatic Cancer
· CALGB 89801: Phase II Oxaliplatin + Radiation Therapy for Locally Advanced Rectal Cancer
· NSABP R-04: Phase III Pre-Op Capecitabine + Radiation Therapy versus CI 5FU + Radiation Therapy versus CI 5FU + Oxaliplatin + Radiation Therapy for Operable Rectal Cancer
· CALGB 30105: Randomized Phase II Gemcitabine-Carboplatin + 3D Radiation Therapy versus Taxol-Carboplatin + 3D Radiation Therapy for Unresectable Stage IIIA/B Non-Small Cell Lung Cancer
In summary, this research effort in radiosensitizers truly represents a bench to bedside translational effort, starting with in vitro studies in the labs of Blackstock and Koumenis, to investigator-initiated Phase I and II studies at Wake Forest, to Phase II and III trials both at Wake Forest and in the Cooperative Group setting.
Future plans for radiosensitizer research include identifying the next generation of radiosensitizers and developing the associated radiosensitizer clinical trials. Laboratory investigations will focus on the combination of RT +/- chemotherapy and a number of other targeted therapies that block EGF, VEGF, PKC-beta, PI3 kinase/AKT, and TK signaling. In addition, the Koumenis lab has initiated a project entitled “Screening of Chemical Libraries for Novel Radiosensitizers”, the goals of which are (a) to identify compounds within a large, complex chemical library that are radiation sensitizers and enhance the cytotoxicity of radiation to U251 glioma cells, (b) verify in in vitro studies that the identified compounds have minimal cytotoxicity to normal human astrocytes both by themselves and in the presence of radiation, (c) perform in vivo studies with the most promising compounds in animals studies. Dr. Koumenis recently obtained a chemical library of 10, 000 compounds from Nanosyn, Inc. (Menlo Park, CA). Nanosyn’s library consists of compounds selected by medicinal chemists because the compounds conform to widely accepted guidelines for pharmaceutical hit structures: “drug-like” structure, low molecular weight, and absence of reactive fragments. Current technology allows for mass screening of the library in 96 well plates for assays. Using the U251 glioma cell line (chosen for its radioresistance), the Koumenis lab has investigated the radiosensitizing capability of 870 compounds within the library. Four potential tumor radiosensitizing agents have already been identified, and one of them has already shown potent radiosensitizing ability in clonogenic survival assays with U251 cells. Plans are underway to extend these observations in vitro utilizing additional tumor and normal cells and in vivo studies of animal tumor xenografts.
Recombinant cytotoxins
Targeted recombinant chimera cytotoxic fusion proteins, also referred to as recombinant cytotoxins, are anew class of small, water soluble anti-cancer therapeutic molecules deliverable by intravenous infusion or intratumorally, and potent (even at fentimolar concentrations) in a variety of both liquid and solid tumors. Recombinant cytotoxins are composed of bacterial toxins, such as Diphtheria toxin (DT) or Pseudomonas exotoxin A (PE), and either antibodies or naturally occurring growth factors/cytokines. Recombinant cytotixns are usually directed to a variety of cell surface receptors, including one of several interleukin receptors (IL2, IL3, and IL13) and the GMCSF receptor. The recombinant cytotoxin program at the CCCWFU has been active since the late 1990s, with an earlier focus on leukemia and lymphoma (under the direction of Dr. Art Frankel, former member of the Clinical Research Program, who moved to Scott and White Clinic in Temple, Texas as Cancer Center Director). Given the outstanding expertise and opportunities available in glioma anti-cancer therapy, Dr. Shaw led a CCCWFU initiative to place malignant glioma at the center of our recombinant cytotoxin research. This culminated in the recruitment of Waldemar Debinski, M.D., Ph.D., member of the Clinical Research Program and Director of the Cancer Center’s Brain Tumor Center of Excellence in April2004. Dr. Debinski is an internationally recognized translational cancer researcher who has been at the forefront of cytotoxic-based glioma therapy. Within two years of his recruitment, Dr. Debinski has successfully renewed an existing R01, been awarded a second R01 that was scored at the 2.4 percentile, and will be co-PI of a joint Brain Tumor SPORE application between Wake Forest and Johns Hopkins University (Stuart Grossman, M.D., from Hopkins will be the other co-PI). Dr. Debinski works closely with Stephen Tatter, M.D., Ph.D., a neurosurgeon with expertise in the use of convection enhanced delivery of drugs into the brain.
Wake Forest is currently the lead accruing center nationwide multi-institutional Phase III clinical trial inpatients with recurrent glioblastoma (GBM) at first relapse (protocol 91104). Patients undergo maximum resection followed by “standard treatment” with BCNU wafers (Gliadel) versus investigational treatment withIL13-PE via convection enhanced delivery. The recombinant cytotoxin, conceived and generated by Dr. Debinski, consists of a derivative of PE fused to wild type IL13 (IL13-PE38QQR). The killing activity of IL13-PE38QQR is dependent on selective over-expression of a restricted receptor for IL13, IL13R alpha 2, in malignant gliomas but not normal brain. IL13-PE38QQR has received fast-track status from the FDA. Although overall phase III study results are not yet available, clear-cut responses have been seen in the subset of Wake Forest patients. The research effort in recombinant cytotoxins is another example of translational research supported and fostered by the Cancer Center, e.g., the in vitro characterization and optimization of recombinant cytotoxins for brain tumors was carried out in the basic science laboratory of Dr. Debinski.
Future plans for recombinant cytotoxin research will build on the success of our preclinical and translational studies in malignant gliomas. We propose to: 1) generate novel recombinant anti-GBM recombinant cytotoxins based on the rational design of ligands and properly engineered bacterial toxins, 2) identify novel ways of increasing immunotoxin efficacy (e.g., by enhancing IL13R alpha 2 expression on GBM cells), 3) explore the use of conventional treatments of malignant glioma, such as radiation therapy and temozolomide chemotherapy, in combination with recombinant cytotoxins, and 4) manufacture investigational agents of high pre-clinical promise utilizing an in-house GLP (or preferably GMP) facility, enabling CCCWFU investigator-initiated Phase I-II clinical trials. We plan on developing the next generation of genetically engineered IL13-based recombinant cytotoxins, which may be combined with surgery, RT, and chemotherapy, for the treatment of both newly diagnosed and recurrent malignant gliomas. Several promising leads are already being investigated. The Debinski lab has identified EphA2, another novel receptor selectively expressed in malignant gliomas that may be appropriate for molecular targeting when targeted with either natural ligand to EphA2, ephrinA1, or combined with, e.g., DT. In conjunction with Costas Koumenis, Ph.D., member of the Cell Growth and Survival Program, the role that hypoxia plays in recombinant cytotoxin response (or resistance) is being explored. In addition, the effects of ionizing radiation on antigen presentation, and the potential radio- and chemosensitizing properties of recombinant cytotoxins, are also being studied pre-clinically. As a result of strong collaboration between the basic scientists and the multidisciplinary clinical neuro-oncology group in the BTCOE, including Drs. Tatter from Neurosurgery, Dr. Lesser from Medical Oncology, and Drs. Shaw, Stieber, and McMullen from Radiation Oncology, the next 5years of recombinant cytotoxin clinical trials may result in significant gains in the now universally fatal disease of malignant glioma.
Vitamin D as an antiproliferative and chemo- and radiosensitizing agent
As a direct result of the leadership of Gary Schwartz, PhD, MPH, Director of the Prostate Cancer Center of Excellence, the antiproliferative effects of vitamin D and its analogues is an active translational area of investigation among members of the Cell Growth and Survival, Clinical Research, and Cancer Control Programs, and the Brain Tumor Center of Excellence. Much of the emphasis on vitamin D is in its potential to contribute to the control of prostate cancer growth, due to the presence, in normal prostate epithelial cells, of one of the key enzymes (25-hydroxyvitamin D-1-α-hydroxylase) that converts the inactive vitamin D3prohormone to its active form, 1, 25-dihydroxyvitamin D3 (1, 25(OH)2D3). The latter has growth-inhibitory effects on prostate cancer cells in vitro and in vivo. Epidemiologic observations have documented that increased exposure to sunlight decreases the risk of prostate cancer. Dr. Schwartz, in conjunction with Istvan Molnar, M.D., medical oncologist and member of the Clinical Research Program, has also demonstrated the antiproliferative effect of the non-calcemic 1, 25(OH)2D3 analogue, paricalcitol (trade name, Zemplar, Abbott Laboratories). Two Wake Forest investigator-initiated clinical trials, one in prostate cancer and the other in myelodysplastic syndrome, are translational research studies assessing the anti-proliferative effects of vitamin D and/or vitamin D analogs in patients. Protocol 85200 was a Phase I/II study of paracalcitol in patients with hormone-refractory metastatic prostate cancer. Eighteen patients were accrued. Transient decreases in serum PSA level were seen. Parathyroid hormone (PTH) levels were measured in study patients and found to be inversely associated with survival. Protocol 29203 is a pilot study of orthomolecular vitamin D3 (2000-4000IU daily x 6 months) in patients with low-intermediate risk myelodysplastic syndrome. It has accrued 25 of a planned 36 patients to date. Dr. Schwartz has recently been awarded an R01 grant from the NCI to determine if an oral dosage of vitamin D is effective in altering serum levels of PSA.
In addition to its antiproliferative effects in prostate cancer, Schwartz, Cramer, and Koumenis have shown that 1, 25(OH)2D3 and Zemplar inhibit the growth of pancreatic cancer cell lines with concomitant upregulation of the cell-cycle inhibitors p21 and /or p27 both in vitro and in animal xenograft models. They have also shown that vitamin D and Zemplar can act as radiosensitizers of prostatic tumor epithelial but not normal cells. Furthermore, they have evidence that the vitamin D receptor is upregulated in response to genotoxic stress, suggesting that this mechanism may lead to synergistic effects between vitamin D3 analogs and radiotherapy/chemotherapy. Based on these findings, future plans for vitamin D research include a series of proposed studies to determine the efficacy of combined Zemplar with gemcitabine and/or radiation in pancreatic and glioblastoma cell lines in vitro and in vivo. The long-term goal of these laboratory studies is to provide preliminary data that will support translation of this strategy into human Phase I, Phase II, and ultimately Phase III clinical trials with these vitamin D analogs for the treatment of human pancreatic cancer and malignant glioma. Dr. Molnar has written a study for patients with myelodysplastic syndrome, combining orthomolecular vitamin D3 with arsenic.
Novel local/regional approaches
Surgical Oncology plays a key role in the development of novel diagnostic and therapeutic strategies piloted at Wake Forest and in the case of intraperitoneal hyperthermic chemotherapy (IPHC), implemented on a national and international level. These strategies include cytoreductive surgery plus intraperitoneal hyperthermic Mitomycin-C chemotherapy for peritoneal carcinomatosis, and sentinel node mapping in breast cancer and melanoma (Drs. Edward Levine and Perry Shen, members of the Clinical Research Program).
Intraperitoneal hyperthermic chemotherapy (IPHC) – Peritoneal carcinomatosis from colorectal and appendiceal cancer is a uniformly fatal pattern of local-regional spread in the absence of aggressive treatment like IPHC, which combines aggressive surgical debulking, locally delivered cytotoxic chemotherapy, and heat to enhance the efficacy of this combined modality regimen. The IPHC effort at Wake Forest is the second largest in the country. Future plans for IPHC research are focused on a multi-institutional effort in the U.S. (12centers) and Canada (one center), led by Dr. Levine, to conduct a large randomized Phase II study of IPHC (between two different temperatures) in appendiceal/colorectal cancer. The study would be led by either the NSABP or ACOSOG.
Sentinal lymph node mapping – This diagnostic approach has dramatically altered the surgical approach to patients with breast cancer and melanoma. In a collaboration between surgical oncologists and pathologists at Duke University Medical Center and WFUSM (Drs. Ed Levine and Kim Geisinger, a pathologist and member of the Clinical Research Program), studies have been performed assessing intraoperative imprint cytology as a novel method of assessing lymph node status. In both breast cancer and melanoma, imprint cytology has a high degree of specificity as well as a positive predictive value, providing additional information to frozen section analysis of lymph nodes. Dr. Perry Shen has also recently published on the value of sentinel lymph node mapping in various abdominal malignancies.
Radiofrequency Ablation (RFA) – the RFA program at Wake Forest represents a multidisciplinary intra and interprogrammatic effort between Ronald Zagoria, M.D. (Diagnostic Radiology), Edward Levine, M.D. and Perry Shen (Surgical Oncology), Craig Hall, M.D., and Peter Clark, M.D. (Urology), Timothy Oaks, M.D., (Cardiothoracic Surgery), and Frank Torti, M.D. Drs. Zagoria, Levine, and Clark are members of the Clinical Research Program; Dr. Torti is a member of the DNA Damage and Cellular Defense Program. The percutaneous image-guided ablation program primarily utilizes RFA, but also has used microwave ablation and cryoablation. Various solid tumors, either primary or metastatic, have been treated in several Wake Forest investigator-initiated clinical trials of RFA (CCCWFU Protocol 59200 [P. Shen, M.D., PI], RFA followed by systemic 5FU/leucovorin chemotherapy for liver metastases; and CCCWFU Protocol 62100 [R. Zagoria, M.D., PI], Phase II study of intraoperative RFA of lung parenchymal tumors prior to resection. In addition, Wake Forest has been an active participant in an American College of Radiology Imaging Network clinical trial (ACRIN Protocol 6660 Protocol [R. Zagoria, M.D., PI], A Phase I/II study of percutaneous radiofrequency ablation of bone metastases using CT guidance). These studies have been reported on extensively in the peer-reviewed medical literature.
Extracranial Stereotactic Radiosurgery (SRS) – In 2002, Wake Forest initiated its extracranial (body) stereotactic radiosurgery (SRS) program under the direction of Volker Stieber, M.D., radiation oncologist and member of the Clinical Research Program. Dr. Stieber is PI of one of the few prospective studies utilizing body SRS in the U.S. CCCWFU Protocol 99502, “A Phase I/II dose-escalation/efficacy study of palliative extracranial radiosurgery”, has enrolled 26 patients with a variety of locally advanced or metastatic tumors involving the lung, liver, or paraspinal region. Depending on the size of the lesion, patients receive either a single large fraction of radiation (15-24Gy), or the same dose in three fractions. Dose escalation is based on dose limiting toxicity utilizing the continuous reassessment method. The study is still actively enrolling patients, however technical aspects of the procedure and initial results have been presented at national and international meetings in abstract form by Dr. Stieber and colleagues. Dr. Stieber will also be a coinvestigator on a soon-to-open RTOG clinical trial utilizing body SRS for medically inoperable Stage I non-small cell lung cancer.