Radioligand PSMA therapy with the lutetium isotope ¹⁷⁷Lu has proven to be very effective against metastatic prostate cancer. Nevertheless, there is still a share of patients who do not respond to this treatment. A possible reason may be insufficient radiation dose delivered to the cancer cells so that they are able to survive. So scientists are now experimenting with another isotope terbium-161 (¹⁶¹Tb) that emits a wider range of energies, namely conversion and Auger electrons next to beta radiation. It has decay properties similar to 177-Lutetium, half-life of about 7 days, but higher destructive power due to co-emission of conversion and Auger electrons. Their short radiation range allows it to release all their power directly in the cancer cells with almost no damage to the neighbouring healthy cells.

¹⁶¹Tb has shown superior preclinical results in comparison with 177-Lutetium, and there are currently several ongoing clinical studies looking into the application of ¹⁶¹Tb to treat prostate cancer. One of them is PROGNOSTICS in Switzerland financed to the tune of CHF 2 million & VIOLET in Australia (Young Investigator Award James Buteau, MD).

We hope to be able to offer radioligand therapies with terbium-161 to our patients soon enough.