
Ifosfamide is quite toxic to the bone marrow and urinary system, and occasionally, to the brain. It MUST be given with mesna to protect the urinary system. As a single agent, its effectiveness in terms of response and duration of response is probably approximately equivalent to doxorubicin's.

During the pre-Gleevec years, GIST was included in the NON-uterine LMS statistics, which may account for Ifosfamide's low response rate against this category. GastroIntestinal Stromal Tumors are very difficult to treat. It is hard to know what Ifosfamide's record with extremity or other LMS is, because of the confounding inclusion of GIST in the earlier studies. 

Ifosfamide might actually be the agent of choice, given equal effectiveness with Adriamycin, if there is to be radiation to the left chest or mediastinum. It would decrease the additive cardiotoxicity. 

In Uterine LMS, doxorubicin and ifosfamide are about equivalent in their single agent abilities. Both as single agents with response rates approximately in the late teens, and somewhat short-lived, but LMS is a resistant cancer.   If they are used together, or even sequentially, however, the response rate can go up as high as around 30%. This is the idea behind the AIM [adriamycin, ifosfamide, mesna] regimen.  There is no survival advantage in their being used together, and there is a much increased toxicity if they are used together.
