Treatment strategies in patients with AML or high-risk myelodysplastic syndrome relapsed after Allo-SCT.

Non-relapse mortality after Allo-SCT has significantly decreased over the last years. Nevertheless, relapse remains a major cause for post SCT mortality in patients with AML and high-risk myelodysplastic syndrome (MDS). In this retrospective single-center analysis, we have analyzed the treatment outcomes of 108 patients with AML or MDS, who relapsed after Allo-SCT. Seventy of these patients (65%) were treated with salvage therapies containing chemotherapy alone, allogeneic cell-based treatment or the combination of both. Thirty-eight patients (35%) received palliative treatment. Median OS after diagnosis of relapse was 130 days. Compared with patients who received chemotherapy alone, response to salvage therapy was significantly improved in patients treated with a combination of chemo- and allogeneic cell-based therapy (CR rate 57% vs 13%, P=0.002). Among risk factors concerning pretreatment characteristics, disease status before first Allo-SCT, and details of transplantation, only the time interval from Allo-SCT to relapse was an independent predictor of response to salvage therapy and OS. These data confirmed that time to relapse after transplantation is an important prognostic factor. Up to now, only patients eligible for treatment regimens containing allogeneic cell-based interventions achieved relevant response rates.

A national validation project of alternative methods to the Draize rabbit eye test.

In June 1988, a 2.5-yr inter-laboratory study involving 13 toxicology laboratories was started in West Germany to validate alternative methods to the Draize rabbit eye test. The aim of this collaborative study is to validate the classification of chemicals with regard to their irritation potential using the neutral red/kenacid blue (NR/KB) cytotoxicity assay and the hen's egg test-chorioallantoic membrane (HET-CAM) assay. The results should make it possible to decide whether and to what extent the NR/KB cytotoxicity test and the HET-CAM assay can replace the Draize test. After two test trials, standard testing procedures and protocols were agreed on. In addition, to facilitate management of the data and to reduce costs, personal computer (PC) software was developed for both tests, which allows storage of all data on floppy discs and statistical analysis on PCs. During the preliminary phase, the applicability of the software was tested and corrected according to the experimental conditions of the validation study. Tests on the following chemicals have so far been completed, and reproducibility and repeatability have been determined: sodium dodecyl sulphate, triethanolamine, zinc pyridinethione, dimethylsulphoxide and butoxyethanol. Only zinc pyridinethione, which is severely irritating in vivo, could not be tested in the HET-CAM test. The preliminary phase has shown that the number of chemicals that can be tested in the HET-CAM test during the validation project will be limited by costs and management problems of manpower and time.