Rj. Kreitman et al., Efficacy of the anti-CD22 recombinant immunotoxin BL22 in chemotherapy-resistant hairy-cell leukemia, N ENG J MED, 345(4), 2001, pp. 241-247
Citations number
44
Categorie Soggetti
General & Internal Medicine","Medical Research General Topics
Background Hairy-cell leukemia that is resistant to treatment with purine a
nalogues, including cladribine, has a poor prognosis. We tested the safety
and efficacy of an immunotoxin directed against a surface antigen that is s
trongly expressed by leukemic hairy cells.
Methods RFB4(dsFv)-PE38 (BL22), a recombinant immunotoxin containing an ant
i-CD22 variable domain (Fv) fused to truncated pseudomonas exotoxin, was ad
ministered in a dose-escalation trial by intravenous infusion every other d
ay for a total of three doses.
Results Of 16 patients who were resistant to cladribine, 11 had a complete
remission and 2 had a partial remission with BL22. The three patients who d
id not have a response received low doses of BL22 or had preexisting toxin-
neutralizing antibodies. Of the 11 patients in complete remission, 2 had mi
nimal residual disease in the bone marrow or blood. During a median follow-
up of 16 months ( range, 10 to 23), 3 of the 11 patients who had a complete
response relapsed and were retreated; all of these patients had a second c
omplete remission. In 2 of the 16 patients, a serious but completely revers
ible hemolytic uremic syndrome developed during the second cycle of treatme
nt with BL22. Common toxic effects included transient hypoalbuminemia and e
levated aminotransferase levels.
Conclusions BL22 can induce complete remissions in patients with hairy-cell
leukemia that is resistant to treatment with purine analogues. (N Engl J M
ed 2001; 345: 241-7.) Copyright (C) 2001 Massachusetts Medical Society.