NeoTect Tc99m Depreotide Injection

NeoTect  Approved by the FDA - August 3, 1999  Used in Imaging Pulmonary Masses  Normal activity in high concentrations noted in:  Kidney  Liver

Clinical Studies  Total of 270 patients either had lung cancer or classified as highly suspect  Following the acquisition Two groups of physicians completed blind interpretation  3 Radiologists  3 Nuclear Physicians  Results where compared to biopsy that had either adenocarcinomas, squamaous cell, small cell, non-small cell, or other magilgnant cell type

Results of Clinical Studies  Nuclear Physicians  70% sensitive, 86% specific, 74% accurate  Radiologist  71% sensitive, 79% specific, 72% accurate  False negative = 29%  1 – 7 cm range on CT  False positive – 17%  Usually some type of inflammation  While CT and NeoTect were completed on most if not all patient comparative data between these two modalities was not completed

Indications  Identifies somatostatin receptor-bearing pulmonary masses in patients presenting with pulmonary lesions on CT and/or Chest x-ray who have known malignancy or who are highly suspect for malignancy.  Is synthetic somatostatin analogue that binds to somatostatin receptor (SSTR) subtypes 2, 3 and 5

Radiopharmaceutical and Dose  Kit is kept refrigrated and must be brought up to room temperature  Add no more than 50 mCi of 99m Tc0 4 -  Mix for at least 10 second  Heat in water bath for 10 minutes  Cool for at least 10 minutes  Vent with 0.22µm filter an extract 1 mL of air  Single dose vial of 50ug of Depreotide peptide labeled with mCi Tc99m in 1ml

Method of Localization and Excretion  Binds to somatostatin receptors  Primarily renal clearance 4 hours post injection  Kidney is the target organ for dosimetry

Patient Prep and Precautions  Well hydrate  Injection can cause anaphylactic reaction  Headache most common complaint  Treat insulinoma patients with IV glucose prior/during injection.  No known reaction to this peptide

Scanning  Planar and SPECT Imaging 2-4 hours post injection  SPECT images of the chest are required for optimal image interpretation.

Findings  Normal Uptake  Liver  Kidneys

A Multicenter Trial With a Somatostatin Analog 99mTc Depreotide in the Evaluation of Solitary Pulmonary Nodules  Results: Of the 114 individuals studied, 88 had a histologic result compatible with malignant neoplasm. 99mTc depreotide scintigraphy correctly identified 85 of this group, with three false- negative determinations compared with histology. There were seven false-positive determinations, including six granulomas and one hamartoma. 99mTc depreotide scintigraphy correctly excluded malignancy in 19 of 26 patients with benign histologic findings. The sensitivity of this method was 96.6% with a specificity of 73.1%.  Conclusion: 99mTc depreotide scintigraphy is a safe and useful method for the noninvasive evaluation of SPN with a sensitivity and accuracy comparable to that reported for fluorine-18 fluorodeoxyglucose positron emission tomography.  

Images From Article

Depreotide Compared to FDG The utility of [sup.99m]Tc depreotide compared with F-18 fluorodeoxyglucose Positron emission tomography and surgical staging in patients with suspected non-small cell lung cancer *. (clinical investigations). Daniel Kahn, Yusuf Menda, Kemp Kernstine, David Bushnell, Kelley McLaughlin, Sara Miller and Kevin Berbaum. Chest (Feb 2004): p494(8).

Discussion A review of the literature suggests that the increasing role of CT in the identification of pulmonary nodules has led to an even larger group of patients in whom the diagnosis of lung cancer is indeterminate. As noted above, when calcified nodules are detected on CT, the probability is low that the lesion represents a lung cancer. However, when a noncalcified nodule is identified, and there is no evidence of metastatic disease or enlarged lymph nodes, the situation is more complex. The combination of CT and NeoTect is being employed to evaluate those patients as to the probability of malignancy. If NeoTect were to be used in a combined fashion, with CT and fusion imaging one could be able to exactly locate the position of the lesion on CT and be sure the NeoTect uptake was in the same area. In this setting, where the NeoTect is positive in a nodule seen on CT, the indications for biopsy would be much stronger.

Findings Tumor

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