New FAPi tracer for PET-CT scans for difficult-to-image cancers

Some cancers are difficult=to-image on PET-CT scans with the current tracer called FDG which is glucose based. In most cancers, including breast cancer, the FDG tracer 'sticks' to the glucose on the surface of the cancer cells which in turn lights up on the scan to show where the cancer is.
However, there are some cancers that don't light up with the FDG glucose tracer. My breast cancer, metastatic pleomorphic invasive lobular carcinoma, triple negative, is one of them.
I found a clinical trial for the experimental FAPi tracer at UCLA, a 7 hour round trip from my location. I worked for 8 months to get enrolled in a clinical trial and was successful in August when UCLA opened a new clinical trial for only 30 patients.
FAPi stands for Fibroblast Activation Protein inhibitor. Fibroblasts exist on the surface of cancer cells. The experimental FAPi tracer sticks to the fibroblasts and lights up on the PET-CT scan showing where the cancer is. The PET-CT portion is the same as any other. It is only the tracer that is different. However, it is not necessary to fast prior to the test as FAPi does not involve glucose. Nor does the patient need to allow an hour for the FAPi tracer to move around the body as as required for the current FDG tracer. I felt fine after the PET-CT, no side effects or problems. Only dreading the long drive home through the afternoon LA traffic!
RESULTS: I had a right side mastectomy in 2022. The FAPi scan showed residual cancer around the right side chest wall that had ncver shown on an FDG scan. FAPi showed a great deal of cancer in my left breast. Note that the left breast cancer was verified via punch biopsy in April 2025 so it was known, just never visible on the FDG PET-CT scans which I have every 3 months.
FAPi also showed cancer in lymph nodes in my left axila (underarm) area and in my right groin. These cancerous nodes were never visible on the FDG scans, the most recent being just 4 weeks before the FAPi scan.
I am now on my 7th chemo which is sacituzumab govitecan "SG" (brand name Trodelvy). SG is the only chemo that has done anything to hold the cancer back. The earlier neoadjuvant (pre-surgery) and adjuvant (post surgery) chemos did nothing. I had to wait until I was already metastatic to be eligible for the SG and it held the cancer at bay for about 9 months. After SG, there are no other chemos that exist specifically for metastatic triple negative cancer. My chemo options are limited by my triple negative status.
FAPi is already used in some countries. However the FDA in the US and the FDA counterpart in Europe have not yet approved FAPi. But the clinical trials are going well everywhere. Many medical journal articles, easily accessible online, show the efficacy and safety of FAPi. I hope it will only be a few more years until this excellent tracer is available to help those with difficult-to-image cancers.