Here is a full report of the combined trials and history of Chemosat. They didn't get the FDA approval last time because the filter efficiency wasn't high enough and side effect was a problem. Now with generation two filters efficiency was up to 93% and side effects were manageable. They need a formal phase 3 to get the data for FDA approval. There is nothing that shows this isn't a viable treatment. Instead the reports all shows Chemosat was an effective treatment. The value of this treatment is there.
"Toxicity data were reported in the noncomparative study by Vogl et al. [41]. Toxicities following CS-PHP were consistent with the toxicity profile seen in the clinical trials of CS-PHP with melphalan. The most common adverse effects were hematologic events (thrombocytopenia, anemia, neutropenia), which were managed effectively with supportive measures. Three patients were initially treated with the first-generation filter, then switched to the second-generation filter, providing an opportunity for a comparison of toxicity profiles with the two systems. Toxicity was less severe and patients required fewer supportive measures (i.e., no transfusions, shorter courses of colony stimulating factors) with the second-generation filter than the first-generation filter."