Bevacizumab continuation beyond initial bevacizumab progression among recurrent glioblastoma patients.

Current research interests have application to the design and analysis of cancer clinical trials. Specifically, interests include the use of time-dependent covariables within survival models, the design of phase II cancer clinical trials which minimize some of the logistical problems associated with their conduct, and the analysis of longitudinal studies with informative censoring (in particular, quality of life studies of patients with advanced cancer).

Katy Peters, MD, PhD, FAAN is a professor of neurology and neurosurgery at the Preston Robert Tisch Brain Tumor Center (PRTBTC) at Duke.   Her academic medical career started at Stanford University School of Medicine, receiving an MD and Ph.D. in Cancer Biology.  After completing a neurology residency at Johns Hopkins University and a fellowship in cognitive neurosciences, Katy joined the PRTBTC as a neuro-oncology fellow.  In 2009, she became a faculty member at PRTBTC.  With a fantastic team of nursing and advanced practice providers, she actively sees and cares for patients with primary brain tumors.  Her research interests include supportive care for brain cancer patients, cognitive dysfunction in cancer patients, and physical function and activity of brain cancer patients.   While she runs clinical trials to treat primary brain tumors, her key interest is on clinical trials that focus on improving brain tumor patients' quality of life and cognition.   In 2019, the PRTBTC designated her as the Director of Supportive Care, thus furthering the PRTBTC and her committee to better the quality of life for brain tumor patients.   She is active in teaching medical school students, residents, fellows, and advanced practice providers and is the Program Director of the PRTBRC neuro-oncology fellowship.     She is board certified by the American Board of Psychiatry and Neurology and the United Council of Neurologic Subspecialties for neuro-oncology.

Current research activities involve the immunotherapeutic targeting of a tumor-specific mutation in the epidermal growth factor receptor. Approaches used to target this tumor-specific epitope include unarmed and radiolabeled antibody therapy and cell mediated approaches using peptide vaccines and dendritic cells. Another area of interest involves drug delivery to brain tumors. Translational and clinical work is carried out in this area to formulate the relationship between various direct intratumoral infusion parameters and drug distribution within brain tumors and normal brain.

The Duke Brain Tumor Immunotherapy Program (BTIP) has an emphasis on translational research in Neuro-Oncology. There are two main areas of study. The first is novel mechanisms of delivery of large molecular weight molecules, such as monoclonal antibodies, throughout brain intersitial space using novel intracerebral infusion techniques developed by this laboratory. Studies exploring this technology are undertaken in both small and large laboratory animals and patients with brain tumors.

The other focus of the BTIP is translational immunotherapy. In this line of work, dendritic cell vaccination strategies and adoptive T-cell strategies have been developed to target novel and well-characterized tumor-specific antigens in patients with brain tumors. The BTIP integrates well with and works closely with the Preston Robert Tisch Brain Tumor Center at Duke. The BTIP is well funded and currently holds seven NIH grants, including a SPORE in Brain Cancer grant. There are a large number of investigators at various levels so that students will get exposure to various levels of research and mentorship.

At the present time, I am participating in collaborative research in the areas of primary malignant brain tumors, epilepsy and subarachnoid hemorrhage.

Primary malignant brain tumors are increasing in frequency. Patients harboring glioblastoma, the most malignant primary brain tumor, have a life expectancy of less than one year. In collaboration with the Division of Neurology and the Department of Pathology, clinical and laboratory trials have been initiated to identify better treatment for this condition. At present, trials of monoclonal antibodies and novel chemotherapeutic agents are being carried out.

Although physicians have been interested in seizures since the time of Hippocrates, the origin of seizures remains obscure. At Duke University we have treated approximately thirty seizure patients a year by removing abnormal portions of brain. Tissue from these resections is being analyzed for genetics and receptor abnormalities. Positron emission tomography and magnetic resonance imaging are being used to ferret out the origin of the patient's seizures.

Approximately 28,000 patients each year suffer a ruptured intracranial aneurysm. Approximately ten percent of these patients have a genetic predisposition to forming intracranial aneurysms. In conjunction with the Division of Neurology, we are screening candidate genes searching for the cause of intracranial aneurysms.

Overview: Our laboratory is pursuing a comprehensive analysis of the biology and therapy of adult and childhood central nervous system malignancies, particularly high-grade medulloblastoma, glioma, and ependymoma.

Laboratory Studies: Active programs, using human adult and pediatric CNS tumor continuous cell lines, transplantable xenografts growing subcutaneously and intracranially in athymic nude mice and rats, and as well as in the subarachnoid space of the athymic nude rats, and patients tumor specimens, are defining:

1) the chemotherapeutic profile of medulloblastoma, adult and childhood glioma and ependymoma
2) mechanisms of resistance to classical bifunctional alkylators, nitrosoureas and methylators operational in malignant glioma and medulloblastoma, particularly DNA adduct and crosslink repair, O6-alkylguanine-DNA alkyltransferase elevation and DNA mismatch repair deficiency.
3) modulations designed to over come or circumvent specific mechanisms of resistance
4) the activity of signal pathway inhibitors of EGFR, m-tor and other targets
5) the therapeutic advantages of intrathecal and intratumoral drug delivery in the treatment of neoplastic meningitis and intracranial malignancies, respectively.

The results of the therapeutic studies to date have demonstrated the marked activity of alkylating agents, particularly melphalan and cyclophosphamide and the role of glutathione, AGT glutathione-S-transferase, abnormal drug transport and alterations in formation and repair of DNA-DNA crosslinks in modulating cytotoxicity of these agents. Modulations shown to be effective in enhancing alkylator activity/reversing alkylator resistance include BSO-mediated glutathione depletion, inhibition of DNA-DNA crosslink repair and inhibition of 06-alkylguanine-DNA alkyltransferase by 06-benzylguanine. Recent studies have demonstrated profound activity of temozolomide, CPT-11 topotecan, irofulven, and karenitecin as well as the combination of CPT-11 or topotecan plus BCNU or temozolomide. Successful treatment of neoplastic meningitis in nude rats with intrathecal 4-hydroperoxycyclophosphamide, melphalan, temozolomide and busulfan, and intracranial glioma in nude rats with intratumoral temozolomide has also been demonstrated. More recent studies have revealed cyclophosphamide resistance secondary to DNA interstrand crosslink repair. Additional studies have shown that cyclophosphamide crosslinks are formed at the 1,3 N7 position, serving as the basis for construction of a defined crosslink in a plasmid vector to assay for crosslink repair and allowing demonstration of the lack of a role of nucleotide excision repair. Mismatch repair deficiency has been shown as a mechanism mediating acquired methylator (procarbazine and temozolomide) resistance in an adult glioblastoma xenograft.

Clinical Studies: Clinical investigations are designed to translate laboratory programs into successful treatment for adults and children with malignant brain tumors, particularly medulloblastoma. Clinical trials for adults include phase II trials of temozolomide, ZD1839 (Iressa), karenitecin, and temozolomide plus O6-BG as well as phase I trials of topotecan plus BCNU, CPT-11 plus temozolomide, and PTK787 ± temozolomide or CCNU. Studies are in progress in children evaluating the activity CPT-11 plus temozolomide, intrathecal busulfan and cyclophosphamide/melphalan or cyclophosphamide/busulfan plus autologous bone marrow support . Extension of these studies to a larger cohort of patients is being performed nationally under the auspices of the Pediatric Brain Tumor Consortium (Henry S. Friedman -- Head of New Agents Committee).

Future studies will address the role of agents designed to decrease repair of interstrand crosslinks when given in combination with alkylating agents, as well as newer signal pathway inhibitors such as RAD001, PKI166, and DB-67.