Has anyone come across a "PTF" filter ?

I posted few days ago as my car has had extensive smoke coming from the exhaust. I have had the egr valve checked and the turbo bearing ect seem ok but I have just been told that the PTF filter within the catalytic converter has melted and all the bits are running through exhaust. Does anyone know what sort of job this is or cost? Toyota Avensis Dcat 53plate.