CD37, tetraspanin protein, expressed on normal and transformed B-cells, on all maturational stages and demonstrates death signaling.
Otlertuzumab, CD37-specific therapeutic protein, has greater direct killing of CLL cells than rituximab and Fc mediated cellular cytotoxicity of CLL cells than either alemtuzumab or rituximab.
Phase 2 trial to investigate the combination of otlertuzumab compared to benda alone.
65 pts in total.
32 with otlertuzumab plus benda and 33 with benda alone.
44 patients evaluable by IWCLL criteria 2.5 months after completion of therapy.
ORR for combination 80%, CR rate 20%. Benda alone ORR 42%, CR rate 4%.
10% have progressed on the combination while 46% have progressed on benda.
The best response at anytime for the combination was ORR 78% and CR 16% and for benda alone ORR 52% and CR 9%.
- Of note: no responses among pts with del 17p, pts with 17p mutation both pts in the combination had a response; no pts in the benda alone.
Preliminary response rate with combination higher than benda alone by IWCLL or NCI response criteria.
The overall incidence of AEs similar, however higher incidence of pyrexia, neutropenia and thrombocytopenia with combination.
No increase of serious adverse events in combination.
Phase 2 trial looks appropriate for phase 3 trials.
Needs longer term results, however looks promising for utilizing earlier in therapy.
View the original abstract on the ASH website.
