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Chaitanya Divgi

Publications and source records attributed to Chaitanya Divgi.

9 recordsLinked to original sources
PubMed2007

Whole-body clearance kinetics and external dosimetry of 131I-3F8 monoclonal antibody for radioimmunotherapy of neuroblastoma.

The purpose of this retrospective study was to evaluate the whole-body clearance kinetics of I-3F8 monoclonal antibody, an anti-ganglioside 2 antibody, used in the treatment of pediatric patients with late-stage neuroblastoma (NB). Serial whole-body dose rate measurements were obtained on pediatric patients participating in phase I dose escalation studies of therapeutic I-3F8. Whole-body retention fractions were derived and fit for each treatment to exponential curves to determine both the effective half-lives and corresponding clearance fractions. 27 patients were administered I-3F8 over the course of cyclical administrations with a median administered activity of 2.5 GBq (range, 1-8.14 GBq), typically every 2-4 d for up to 9 treatment cycles. Based on whole-body dose rate measurements, there was a large variability in the calculated mono-exponential clearance effective half-life time, with a mean of 26.4 h (range, 12.4-45.5 h). The data from a subset of 12 treatments were fit to a bi-exponential curve with a rapid clearance component mean effective half-time of 16.9 h (range, 4.3-26 h) and a slower clearance component mean effective half-time of 65.5 h (range, 16.9-136 h). The use of whole-body dose rate measurements, obtained for patient-release and other radiation safety considerations, can be useful in estimating whole-body clearance kinetics for photon emitting radionuclide labeled mAbs and other therapeutic radiopharmaceuticals. In the case of I-3F8 for pediatric NB therapy, the demonstrated variability in effective half-time suggests the need for patient-specific tracer dosimetry for both optimization of treatment and radiation safety precaution decision-making.

Adolescent↗
PubMed2005

Targeting osseous metastases: rationale and development of radio-immunotherapy for prostate cancer.

For patients with metastatic prostate cancer, bone is the primary site of tumor localization and the major cause of disease-related morbidity and mortality. Hormonal therapy and chemotherapy alone cannot eradicate disease harbored in bone. The delivery of radiotherapy to the reservoir of disease is an approach previously only achievable using bone-seeking radiopharmaceuticals. Now, however, with the identification of tumor-specific targets, antibodies are being used to deliver radiotherapy to these sites. In this article, we review the rationale behind this approach, the targets being explored, the radiation sources available, and the antibodies currently under clinical development.

Antibodies, Neoplasm↗
PubMed2005

Imaging: staging and evaluation of lymphoma using nuclear medicine.

The management of lymphoma is dependent on accurate staging of the disease and evaluation of histology and other risk factors. Advances in imaging techniques have improved the assessment of disease status and evaluation of the efficacy of different treatment modalities. While computed tomography remains the cornerstone of imaging for the assessment of disease status, it provides no understanding of the metabolic or functional parameters of the disease. Nuclear medicine techniques permit the evaluation of functional status, and nuclear medicine is likely to have its greatest impact in the detection of viable tumor in persistent masses. Nuclear imaging can be conducted using single photon agents, such as 67 Ga-citrate with SPECT (single photon emission computed tomography), or with positron emitters, such as 18 F-fluorodeoxyglucose (FDG) with PET (positron emission tomography). Many studies have indicated that FDG-PET is as good as or better than 67 Ga-SPECT for the detection of lymphoma. Thus, FDG-PET may be preferable to 67 Ga-SPECT for disease evaluation, staging, and follow-up. The superiority of FDG-PET compared with other imaging modalities strongly argues that it should be incorporated into the treatment paradigm. At present, FDG-PET scanning is not routinely available in all institutions; however, a role can be indicated for FDG-PET in several areas of lymphoma management, including initial staging, predicting response to therapy (during and following chemotherapy), and identification of residual tumor. This article examines the role of the different imaging techniques available and the use of these techniques in the staging and evaluation of patients with Hodgkin's and non-Hodgkin's lymphoma.

Bone Marrow Neoplasms↗
PubMed2005

Current status of therapy of solid tumors.

The recent approval of 2 radiolabeled antibodies against cluster designation 20-positive lymphoma has led to a resurgence of interest in radioimmunotherapy. As was the case with chemotherapy development, progress has been most marked in the hematologic neoplasms, both in myeloablative and in nonmyeloablative therapeutic strategies. Success in the radioimmunotherapy of solid tumors has lagged because of the immunogenicity of murine proteins and the relatively slow clearance of humanized intact immunoglobulins. Genetic engineering has enabled the development of a variety of antigen-binding constructs of various sizes and immunobiologic characteristics. Developments in radiochemistry as well as production of an increasing number of radionuclides with therapeutic potential or optimal imaging characteristics have spurred tailored therapeutic strategies that include dosimetry and considerations of tumor burden. Such progress has generated pivotal studies that will establish the radiobiologic paradigms for successful radioimmunotherapy of solid tumors. This review will describe seminal studies that have paved the way to an understanding of radioimmunotherapy in solid tumors. Finally, the authors' views of the future of this promising cancer therapy will be presented.

Animals↗
PubMed2004

Targeting osseous metastases: rationale and development of radio-immunotherapy for prostate cancer.

For patients with metastatic prostate cancer, bone is the primary site of tumor localization and the major cause of disease-related morbidity and mortality. Hormonal therapy and chemotherapy alone cannot eradicate disease harbored in bone. The delivery of radiotherapy to the reservoir of disease is an approach previously only achievable using bone-seeking radiopharmaceuticals. Now, however, with the identification of tumor-specific targets, antibodies are being used to deliver radiotherapy to these sites. In this article, we review the rationale behind this approach, the targets being explored, the radiation sources available, and the antibodies currently under clinical development.

Antibodies, Monoclonal↗
PubMed2002

A retrospective review of the effectiveness of recombinant human TSH as a preparation for radioiodine thyroid remnant ablation.

UNLABELLED: Radioiodine remnant ablation (RRA) is frequently used after a thyroidectomy for differentiated thyroid carcinoma because it has been reported to reduce the number of local recurrences and to increase overall survival. Although the traditional method of preparation for RRA is thyroid hormone withdrawal, several physicians at our medical center have offered the option of having RRA after preparation by recombinant human thyroid-stimulating hormone (thyrotropin; TSH) over the past 2 y. During this same time period, other patients at our center were prepared for RRA by hormone withdrawal. METHODS: We took this opportunity to retrospectively review the rate of complete remnant ablation in patients having RRA after hormone withdrawal compared with those having RRA after recombinant human TSH. Only patients who had RRA after January 1, 1999, and follow-up diagnostic studies at our medical center, were included in the analysis. A successful ablation was defined as no visible radioiodine uptake on the follow-up diagnostic scans, performed with 185 MBq (5 mCi) (131)I. The 2 groups had comparable patient and tumor characteristics and received similar ablative activities of (131)I. RESULTS: We found that 84% of those prepared by recombinant human TSH, and 81% of those prepared by hormone withdrawal, had complete resolution of visible thyroid bed uptake after RRA (P = not significant). CONCLUSION: Given the biases that exist in retrospective studies, we cannot yet recommend RRA preparation by recombinant human TSH for routine use. However, these preliminary findings are favorable enough to support the design of a prospective randomized trial comparing RRA success rates after preparation by either thyroid hormone withdrawal or recombinant human TSH.

Adult↗