Cyclophosphamide priming reduces intestinal damage in man following high dose melphalan chemotherapy.

A small pre-treatment 'priming' dose of cyclophosphamide will reduce gut damage due to high dose i.v. melphalan in mice and sheep but efforts to demonstrate this effect in man have been hampered by difficulty in the measurement of gut damage. We have evaluated the 51CR EDTA absorption test, a new method for measuring intestinal permeability, as a means of assessing damage due to high dose melphalan. The test was reliable, with a narrow normal range, easy to use and well tolerated. It detected an increase in intestinal permeability after high dose melphalan with a maximum occurring between 9 and 15 days after treatment and subsequently returning to normal. It was shown in 19 patients that a pre-treatment dose of cyclophosphamide was capable of significantly reducing the abnormalities in intestinal permeability which resulted from high dose melphalan.