BACKGROUND: @entity5734 that is resistant to treatment with @entity10043 analogues, including @entity8778 , has a poor prognosis. We tested the safety and efficacy of an immunotoxin directed against a surface antigen that is strongly expressed by leukemic hairy cells. METHODS: RFB4(dsFv)-PE38 (BL22), a recombinant immunotoxin containing an anti- @entity10317 variable domain (Fv) fused to truncated @entity2782 exotoxin, was administered in a dose-escalation trial by intravenous infusion every other day for a total of three doses. RESULTS: Of 16 @entity1 who were resistant to @entity8778 , 11 had a complete remission and 2 had a partial remission with BL22. The three @entity1 who did not have a response received low doses of BL22 or had preexisting toxin-neutralizing antibodies. Of the 11 @entity1 in complete remission, 2 had minimal @entity66 in the bone marrow or blood. During a median follow-up of 16 months (range, 10 to 23), 3 of the 11 @entity1 who had a complete response relapsed and were retreated; all of these @entity1 had a second complete remission. In 2 of the 16 @entity1 , a serious but completely reversible @entity1381 developed during the second cycle of treatment with BL22. Common toxic effects included transient @entity4988 and elevated aminotransferase levels. CONCLUSIONS: BL22 can induce complete remissions in @entity1 with @entity5734 that is resistant to treatment with @entity10043 analogues.

Efficacy of the anti- @entity10317 recombinant immunotoxin BL22 in chemotherapy-resistant XXXX .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity8778 :: ('MESH:D017338', 'Chemical') :: ['cladribine'] @entity2782 :: ('MESH:D011552', 'Disease') :: ['pseudomonas'] @entity66 :: ('MESH:D004194', 'Disease') :: ['residual disease'] @entity4988 :: ('MESH:D034141', 'Disease') :: ['hypoalbuminemia'] @entity10043 :: ('MESH:C030985', 'Chemical') :: ['purine'] @entity5734 :: ('MESH:D007943', 'Disease') :: ['hairy-cell leukemia', 'Hairy-cell leukemia'] @entity1381 :: ('MESH:D006463', 'Disease') :: ['hemolytic-uremic syndrome'] @entity10317 :: ('933', 'Gene') :: ['CD22']
@entity5734 :: (MESH:D007943,Disease) :: ['hairy-cell leukemia']
