Posluma

[notsdr]

I also tried to figure out what the advantage of this newly approved scan is compared to the Gallium 68, Axumin and Pylarify scans. Thanks for directing me to Ben’s blog. Although I understood only about 5% of what Ben discussed, perhaps the advantage is the dual nature of the ligand for both theranostics and diagnostics. Presently, before using Lutetium 177 as a theranostic, the patient has a Gallium 68 PSMA PET scan (which must be positive to a certain degree), and an FDG PET scan (which must be negative to a certain degree). But even if the patient passes those two tests, there is a potential disconnect between what the Gallium 68 PSMA PET detects and what the Lutetium 177 ligand targets. I presume that with Posluma, there will be no disconnect because the PSMA detected with the diagnostic will be the same PSMA detected by the theranostic, making for a more precise delivery of the radioligand. The additional precise targeting comes with an additional risk because, according to Blue Earth’s website, the patient is exposed to radiation during the diagnostic phase too.

[Ben Nathanson]

Thanks for reading the blog and for your comments!

The radiation Blue Earth mentions is only the radiation from a PET scan. Nothing’s added by the other payload. A ligand with two hot payloads would indeed expose patients to unnecessary radiation, so there are two ligands — one for PET, with the PET payload hot and the therapy payload cold, and one for therapy, with the therapy payload hot and the PET payload cold.

In honesty, Blue Earth probably doesn’t care about identical imaging/therapy coverage the way the Munich researchers may have. The company saw a way to acquire two valuable medical applications at once with nearly identical manufacturing requirements. I imagine they’ve modified the design to use a cheaper metal than lutetium as the cold payload. No evidence I know of shows identical coverage leading to better outcomes, so they couldn’t expect anyone to pay for it. On the other hand, if the evidence emerges, they’re poised to take advantage.

Thanks to Rick for pointing out the cost of incorporating lutetium when it isn’t needed for scans.

[Author]

Posts