BL22 immunotoxin (CAT-3888)
No longer in clinical development. Related to GCR-8015/CAT-8015, which have increased affinity to CD22.
General information
Class/mechanism: Recombinant anti-CD22 immunotoxin fusion protein comprised of a murine anti-CD22 antibody fragment (disulphide-linked Fv, dsFv) and Pseudomonas exotoxin PE38. BL22 binds to CD22 positive cells and is endocytosed, resulting in intracellular release of the toxin and cell death.
The original manufacturer was acquired in 2005.[1] Development of this drug was discontinued in 2008, at which time it was superseded by the more potent and less toxic Moxetumomab pasudotox (HA22).
Preliminary data
Note: This is not meant to be an exhaustive list of preliminary results. References included in this section include non-randomized studies published in high-profile journals (e.g., NEJM) and experimental arms of phase 3 RCTs. Inclusion here is not an indication of impending regulatory approval, although many of these drugs do end up receiving approval by a regulatory authority.
Hairy cell leukemia
- Kreitman RJ, Wilson WH, Bergeron K, Raggio M, Stetler-Stevenson M, FitzGerald DJ, Pastan I. Efficacy of the anti-CD22 recombinant immunotoxin BL22 in chemotherapy-resistant hairy-cell leukemia. N Engl J Med. 2001 Jul 26;345(4):241-7. link to original article PubMed
- Kreitman RJ, Stetler-Stevenson M, Margulies I, Noel P, Fitzgerald DJ, Wilson WH, Pastan I. Phase II trial of recombinant immunotoxin RFB4(dsFv)-PE38 (BL22) in patients with hairy cell leukemia. J Clin Oncol. 2009 Jun 20;27(18):2983-90. Epub 2009 May 4. link to original article link to PMC article PubMed
Also known as
- Code names: CAT-3888, GCR-3888