cGMP-compliant high-yield automated production of (18)F AlF-FAPI-74: optimization of quality control and evaluation of molar dose impact #MMPMID41391071
Storms W; Celen S; Maes J; Serdons K; Goffin K; De Groot T; Trump L; Warnier C; Gendron T; Gerardy R; Van Laere K; Deroose CM; Kleynhans J; Cleeren F
EJNMMI Radiopharm Chem 2025[Dec]; ? (?): ? PMID41391071show ga
BACKGROUND: Fibroblast activation protein inhibitor (FAPI)-based positron emission tomography (PET) radiopharmaceuticals have shown promise for imaging cancer-associated fibroblasts (CAFs), a key component of the tumor microenvironment. FAPI radiopharmaceuticals offer high tumor-to-background contrast and are not influenced by hyperglycemia. Among these, [(18)F]AlF-FAPI-74, labeled using the Al(18)F-method, offers logistical advantages over (68)Ga-labeled radiopharmaceuticals, including a longer physical half-life and suitability for large-scale, centralized production. This study reports a fully automated, efficient, and GMP-compliant synthesis of [(18)F]AlF-FAPI-74 using the Trasis AllInOne((R)) platform, alongside a refined isocratic radio-HPLC method that enhances fluorine-18 recovery and impurity resolution. Additionally, the impact of molar dose on [(18)F]AlF-FAPI-74 biodistribution is evaluated in a preclinical model and a clinical case-study highlighting the performance of [(18)F]AlF-FAPI-74 produced at high apparent molar activity is provided. RESULTS: The automated GMP-compliant production was validated in three independent runs, with an average decay-corrected yield and apparent molar activity of 50 +/- 10% and 1124 +/- 254 GBq/micromol at the end of synthesis, respectively. Total synthesis time was 30 min. Quality control used validated analytical methods, including an optimized radio-HPLC protocol, ensuring regulatory compliance and batch consistency. [(18)F]AlF-FAPI-74 was produced with a radiochemical purity >/= 95% and demonstrated excellent radiochemical stability in its final formulation for at least 10 h post-synthesis, at a concentration of 2019 MBq/mL. The in vitro binding kinetics of [(18)F]AlF-FAPI-74 were evaluated in a HEK293 cell line stably expressing human FAP, demonstrating rapid, specific uptake and internalization, along with high target affinity. In vivo biodistribution studies revealed a dose-dependent "molar amount effect," with doses > 30 nmol/kg yielding improved tumor-to-background ratios. This phenomenon was not observed in clinical imaging, where high molar activity supported excellent image contrast. CONCLUSIONS: A robust, fully automated, and GMP-compliant production process for [(18)F]AlF-FAPI-74 is reported with high yield, purity, and stability, suitable for centralized production and distribution. The improved radio-HPLC method enhances quality control precision by accurately quantifying radiochemical and chemical purity. In vivo experiments confirmed fast tumor uptake of [(18)F]AlF-FAPI-74. While a clear mass effect on tumor-to-background ratios was observed in preclinical studies, high apparent molar activity resulted in excellent contrast in a clinical setting.
EJNMMI+Radiopharm+Chem 2025 ; ? (?): ?
