Our goal is to evaluate clinical activity of rcombinant immunotoxins in patients. HA22 ia licensed to MedImmune who are sponsoring trial in B cell malignancies. A multi center phase 1 trial of HA22 (CAT-8015, moxetumomab pasudotox) in drug resistant hairy cell leukemia is completed and is now being expanded at the MTD. There have been no dose limiting toxicities and about 40% of patients have achieved a complete remission. A multi center phase 1 trial of HA22 in refectory ALL has opened and 12 patients treated. Clinical activity with 3 complete remissions has been observed. This is a collaboration with Dr. Alan Wayne of the Pediatric Oncology Branch. Fourteen patients with mesothelioma have been treated with SS1P plus chemotherapy. No dose limiting toxicity has occurred and six partial responses observed. We are now at the MTD and will treat 6 more patients this dose level. A multi-center phase 2 trial in mesothelioma combining MORAB-009 with chemotherapy has opened. Dr Hassan is PI on this trial. Trial with LMB2 in CTL and ATL are ongoing.