PET Imaging May Reliably Evaluate New Cancer Treatments
Targeting fibroblast activation protein (FAP) with gallium-68 FAPi-46 (68Ga-FAPi-46) PET, an experimental radiotracer, may prove to be a reliable way to evaluate new cancer treatments, according to a study published November 5, 2021, in the Journal of Nuclear Medicine.
“In this interim analysis of a prospective exploratory imaging trial, 68Ga-FAPi-46 PET biodistribution across multiple cancers strongly correlated with FAP tissue expression. These findings support further exploration of FAPi PET as a pan-cancer imaging biomarker for FAP expression and stratification tool for FAP- targeted therapies,” wrote the team of researchers at the University of California, Los Angeles (UCLA).
“Volunteer patients [n=141, with 14 different types of cancer] underwent one whole body 68Ga-FAPi-46 PET/CT scan and subsequently, surgical resection of their primary tumor and/or metastasis. 68Ga-FAPi-46 PET maximum standardized uptake value (SUVmax and SUVmean) was correlated with FAP immunohistochemistry score in cancer and non-cancer tissues for each patient. … FAP was expressed across all 14 cancers types on TMA with variable intensity and frequency, ranging from 25 to 100% (mean 76.6±25.3%),” noted the team.
Evaluation of the resected cancers showed that “FAP immunohistochemistry scores strongly correlated with 68Ga-FAPi 46 SUVmax and SUVmean: r=0.781 (95%CI 0.376-0.936; p<0.001) and r=0.783 (95%CI 0.379-0.936; p<0.001), respectively," found the team.
Lead author Mona and the team concluded, “In this interim analysis of a prospective exploratory imaging trial, 68Ga-FAPi-46.PET biodistribution correlated strongly with FAP expression in cancer and non-cancer tissues across multiple cancer types. These data support the use of 68Ga-FAPi-46 PET as a pan-cancer predictive biomarker and stratification tool for FAP-targeted therapeutic approaches and lay the foundation for future evaluation of FAPi ligand labeled with therapeutic isotopes in clinical trials.”
Sources:
Christine E. Mona, Matthias R. Benz, Firas Hikmat, Tristan R. Grogan, Katharina Lückerath, Aria Razmaria, Rana Riahi, Roger Slavik, Mark D. Girgis, Giuseppe Carlucci, Kimberly A. Kelly, Samuel W French, Johannes Czernin, David W. Dawson, Jeremie Calais. Correlation of 68Ga-FAPi-46 PET biodistribution with FAP expression by immunohistochemistry in patients with solid cancers: a prospective translational exploratory study. Journal of Nuclear Medicine Nov 2021, jnumed.121.262426; DOI: 10.2967/jnumed.121.262426 Published online November 5, 2021, at https://jnm.snmjournals.org/content/early/2021/11/04/jnumed.121.262426. Accessed November 15, 2021.
Morton, Will. PET imaging lays foundation for new cancer therapies. AuntMinnie.com. Published online November 8, 2021, at https://www.auntminnie.com/index.aspx?sec=sup&sub=mol&pag=dis&ItemID=133969. Accessed November 15, 2021.
