¹⁸F-FPPRGD2 PET/CT: Pilot phase evaluation of breast cancer patients

Purpose: To present data from the first prospective pilot phase trial of breast cancer participants imaged with fluorine 18 (¹⁸F)- 2-fluoropropionyl-labeled PEGylated dimeric arginine-glycine- Aspartic acid (RGD) peptide (PEG3-E[c{RGDyk}]2) (FPPRGD2), a radiopharmaceutical agent used in positron emission tomographic (PET) imaging.

Materials and Methods: The local institutional review board approved the HIPAAcompliant protocol. Written informed consent was obtained from each patient. Eight women (age range, 44-67 years; mean age, 54.3 years±8.8 [standard deviation]) with newly diagnosed or recurrent breast cancer were recruited between November 2010 and February 2011. ¹⁸F-FPPRGD2 PET/computed tomographic (CT) and ¹⁸F-fluorodeoxyglucose (FDG) PET/CT examinations were performed within 3 weeks of each other. Dynamic ¹⁸FFPPRGD2 PET and two whole-body static ¹⁸F-FPPRGD2 PET/CT scans were obtained. During this time, vital signs and electrocardiograms were recorded at regular intervals. Blood samples were obtained before the injection of ¹⁸F-FPPRGD2 and at 24 hours and 1 week after injection to evaluate for toxicity. A nonparametric version of multivariate analysis of variance was used to assess the safety outcome measures simultaneously across time points. A paired two-sample t test was performed to compare the maximum standardized uptake values (SUV_max).

Results: ¹⁸F-FPPRGD2 was well tolerated, without noticeable changes in vital signs, on electrocardiograms, or in laboratory values. A total of 30 lesions were evaluated at ¹⁸F-FDG PET/CT and ¹⁸F-FPPRGD2 PET/CT. The primary breast lesions had ¹⁸F-FPPRGD2 uptake with SUV_max of 2.4-9.4 (mean, 5.6±2.8) 60 minutes after injection, compared with ¹⁸F-FDG uptake with SUV_max of 2.8-18.6 (mean, 10.4±7.2). Metastatic lesions also showed ¹⁸FFPPRGD2 uptake, with SUV_max of 2.4-9.7 (mean, 5.0±2.3) at 60 minutes, compared with ¹⁸F-FDG uptake with SUV_max of 2.2-14.6 (mean, 6.6±4.2).

Conclusion: Data from this pilot phase study suggest that ¹⁸F-FPPRGD2 is a safe PET radiopharmaceutical agent. Evaluation of ¹⁸F-FPPRGD2 in participants with breast cancer demonstrated significant uptake in the primary lesion and in the metastases. Larger cohorts are required to confirm these preliminary findings.