Effects of pegfilgrastim on normal biodistribution of 18F-FDG: preclinical and clinical studies.
The purpose of this study was to evaluate the effects of pegfilgrastim, a long-acting granulocyte colony-stimulating factor, on the normal biodistribution of (18)F-FDG in an animal model and in humans.


METHODS
Two groups of 12 rats received a single subcutaneous injection of either normal saline or pegfilgrastim. One, 7, 14, and 21 d after injection, biodistribution studies were performed 1 h after (18)F-FDG injection. Sixteen breast cancer patients underwent baseline (18)F-FDG PET/CT and, approximately 1 wk after receiving 1 dose of docetaxel and adjunctive pegfilgrastim, follow-up (18)F-FDG PET/CT (scan 2). Standardized uptake values corrected for lean body mass (SUL) were determined for several normal organs before and after therapy.


RESULTS
In rats, bone marrow (18)F-FDG uptake (standardized uptake value) was higher in the pegfilgrastim group 1 d after injection (mean +/- SD, 8.3 +/- 4.1 vs. 2.5 +/- 0.2, P < 0.05), whereas (18)F-FDG uptake in blood was lower (0.41 +/- 0.06 vs. 0.49 +/- 0.01, P < 0.05). In patients, mean SUL was higher in bone marrow (4.49 +/- 1.50 vs. 1.33 +/- 0.22, P < 0.0001), spleen (3.29 +/- 0.83 vs. 1.23 +/- 0.23, P < 0.0001), and liver (1.45 +/- 0.25 vs. 1.31 +/- 0.23, P = 0.01) but lower in brain (4.18 +/- 0.76 vs. 5.14 +/- 1.44, P < 0.01) on scan 2 than on the baseline scan.


CONCLUSIONS
In both the animal model and humans, pegfilgrastim markedly increased bone marrow uptake of (18)F-FDG and reduced (18)F-FDG uptake in some normal tissues. These profound alterations in (18)F-FDG biodistribution induced by pegfilgrastim must be considered when one is evaluating quantitative (18)F-FDG PET scans for tumor response to therapy.
Jacene
Heather A
HA
Division of Nuclear Medicine, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA.
Ishimori
Takayoshi
T
Engles
James M
JM
Leboulleux
Sophie
S
Stearns
Vered
V
Wahl
Richard L
RL
D000818:Animals; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000378:metabolism*; D004341:Drug Evaluation; D004353:Drug Evaluation, Preclinical; D005260:Female; D000069585:Filgrastim; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D016179:Granulocyte Colony-Stimulating Factor / Q000008:administration & dosage*; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage; D008657:Metabolic Clearance Rate / Q000187:drug effects; D009928:Organ Specificity / Q000187:drug effects; D010865:Pilot Projects; D011092:Polyethylene Glycols; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D011917:Rats, Inbred Lew; D011994:Recombinant Proteins; D012016:Reference Values; D012189:Retrospective Studies; D014018:Tissue Distribution / Q000187:drug effects
D007166:Immunosuppressive Agents; D019275:Radiopharmaceuticals; D011994:Recombinant Proteins; D019788:Fluorodeoxyglucose F18; D016179:Granulocyte Colony-Stimulating Factor; C455861:pegfilgrastim; D011092:Polyethylene Glycols; D000069585:Filgrastim