The only reason that the TPO's are not first line treatments are because they are newer drugs and are expensive. Personally, I think they should be first-line treatments (not first, but on the list). Many doctors have not used them or are unfamiliar with them because they are old school. I still see many newly diagnosed patients whose doctors recommend the same three things available forty years ago; IVIG, Prednisone and splenectomy. Many doctors are also using the TPO's improperly which is quite scary if you ask me. Prednisone is almost always used first and probably always will be, because it's cheap and could put an acute case in a quick remission. I don't see that often but it does happen. Those people probably never make it to the Forum.
Rituxan used to be last on the list. I was my doctor's first ITP Rituxan patient in 2003. He initially turned me down because he thought that patients had to have had a splenectomy before they could use Rituxan. I had to prove that was not the case and it took a while for Rituxan to catch on. It's not unusual for an off-label treatment to be used for other disorders. It happens all the time and that doesn't make it an invalid treatment. I'm not a huge Rituxan advocate because of the toxicity. I haven't seen this lately, but there have been some doctors who actually used Rituxan as a maintenance treatment, giving an infusion every three months for years to keep counts up. I could not understand the reasoning behind that, because how would you know if the counts would have just stayed up without the treatment? Totally unnecessary, especially since dropping counts are not life or death.
Anyway, yes, 'response' is a loaded word and it has only been defined by R, PR or NR. Some people are happy with a PR and some are not. I define a successful Rituxan response as a year without treatment. Your definition may be different.