To monitor noninvasively potentially therapeutic adenoviruses for cancer, we have developed a methodology based on the sodium iodide symporter (NIS). Men with clinically localized prostate cancer were administered an intraprostatic injection of a replication-competent adenovirus, Ad5-yCD/utTKSR39rep-hNIS, armed with two suicide genes and the NIS gene. NIS gene expression (GE) was imaged noninvasively by uptake of Na99mTcO4 in infected cells using single photon emission–computed tomography (SPECT). The investigational therapy was safe with 98% of the adverse events being grade 1 or 2. GE was detected in the prostate in seven of nine (78%) patients at 1 × 1012 virus particles (vp) but not at 1 × 1011 vp. Volume and total amount of GE was quantified by SPECT. Following injection of 1 × 1012 vp in 1 cm3, GE volume (GEV) increased to a mean of 6.6 cm3, representing, on average, 18% of the total prostate volume. GEV and intensity peaked 1–2 days after the adenovirus injection and was detectable in the prostate up to 7 days. Whole-body imaging demonstrated intraprostatic gene expression, and there was no evidence of extraprostatic dissemination of the adenovirus by SPECT imaging. The results demonstrate that noninvasive imaging of adenovirus-mediated gene therapy in humans is feasible and safe.

Dosimetry studies in patients with non-Hodgkin's lymphoma were performed to estimate the radiation absorbed dose to normal organs and bone marrow from 90Y-Zevalin (yttrium-90 ibritumomab tiuxetan, IDEC-Y2B8) treatment in this phase I/II, multicenter trial. The trial was designed to determine the dose of Rituximab (chimeric anti-CD20, Rituxan, IDEC-C2B8, MabThera), the unlabeled antibody given prior to the radioconjugate to clear peripheral blood B cells and optimize distribution, and to determine the maximum tolerated dose of 90Y-Zevalin [7.4, 11, or 15 MBq/kg (0.2, 0.3, or 0.4 mCi/kg)]. Patients received (111)In-Zevalin (indium-111 ibritumomab tiuxetan, IDEC-In2B8 ) on day 0 followed by a therapeutic dose of 90Y-Zevalin on day 7. Both doses were preceded by an infusion of the chimeric, unlabeled antibody Rituximab. Following administration of (111)In-Zevalin, serial anterior/posterior whole-body scans were acquired. Major-organ radioactivity versus time estimates were calculated using regions of interest. Residence times were computed and entered into the MIRDOSE3 computer software program to calculate estimated radiation absorbed dose to each organ. Initial analyses of estimated radiation absorbed dose were completed at the clinical site. An additional, centralized dosimetry analysis was performed subsequently to provide a consistent analysis of data collected from the seven clinical sites. In all patients with dosimetry data (n=56), normal organ and red marrow radiation absorbed doses were estimated to be well under the protocol-defined upper limit of 20 Gy and 3 Gy, respectively. Median estimated radiation absorbed dose was 3.4 Gy to liver (range 1.2-7.8 Gy), 2.6 Gy to lungs (range 0.72-4.4 Gy), and 0.38 Gy to kidneys (range 0.07-0.61 Gy). Median estimated tumor radiation absorbed dose was 17 Gy (range 5.8-67 Gy). No correlation was noted between hematologic toxicity and the following variables: red marrow radiation absorbed dose, blood T(1/2), blood AUC, plasma T(1/2), and plasma AUC. It is concluded that 90Y-Zevalin administered at nonmyeloablative maximum tolerated doses results in acceptable radiation absorbed doses to normal organs. The only toxicity of note is hematologic and is not correlated to red marrow radiation absorbed dose estimates or T(1/2), reflecting that hematologic toxicity is dependent on bone marrow reserve in this heavily pretreated population.

The GliaSite RTS performs safely and efficiently. It delivers a readily quantifiable dose of radiation to tissue at the highest risk for tumor recurrence.

We have developed a replication-competent adenovirus (Ad5-yCD/mutTK(SR39)rep-hNIS) armed with two suicide genes and the human sodium iodide symporter (hNIS) gene. In this context, hNIS can be used as a reporter gene in conjunction with nuclear imaging and as a potentially therapeutic gene when combined with (131)I radioiodine therapy. Here, we quantified the volume and magnitude of hNIS gene expression in the human prostate following injection of a high Ad5-yCD/mutTK(SR39)rep-hNIS dose using a standardized injection algorithm, and estimated the radiation dose that would be delivered to the prostate had men been administered (131)I with curative intent. Six men with clinically localized prostate cancer received an intraprostatic injection of Ad5-yCD/mutTK(SR39)rep-hNIS under transrectal ultrasound guidance. All men received 2 × 0.5 ml deposits (5 × 10(11) vp/deposit) in each of the four base and midgland sextants and 2 × 0.25 ml deposits (2.5 × 10(11) vp/deposit) in each of the two apex sextants for a total of 12 deposits (5 × 10(12) vp) in 5 ml. On multiple days after the adenovirus injection, men were administered sodium pertechnetate (Na(99m)TcO(4)) and hNIS gene expression in the prostate was quantified by single photon emission computed tomography (SPECT). hNIS gene expression was detected in the prostate of six of six (100%) men. On average, 45% (range 18-83%) of the prostate volume was covered with gene expression. Had men been administered 200 mCi (131)I, we estimate that the mean absorbed dose to the prostate would be 7.2 ± 4.8 Gy (range 2.1-13.3 Gy), well below that needed to sterilize the prostate. We discuss the obstacles that must be overcome before adenovirus-mediated hNIS gene transfer and (131)I radioiodine therapy can be used as a definitive treatment for localized prostate cancer.

High-volume surgeons identified more SLNs with IOGP (at the AMC) than without (at the SSCs). They also were more efficient than low-volume surgeons when blue dye alone was used. Low-volume surgeons were almost as efficient as high-volume surgeons when they used IOGP. Optimal identification of SLNs requires nuclear medicine facilities.