Response criteria for NHL: importance of 'normal' lymph node size and correlations with response rates.
BACKGROUND
Oncologic literature cites many different definitions of critical response measurements.


METHODS
Response criteria (RC) for non-Hodgkin's lymphoma (NHL) were developed by lymphoma experts, endorsed by international lymphoma clinicians, and applied to a 166-patient rituximab (Rituxan, MabThera) trial by a third-party, blinded panel of NHL experts (LEXCOR). Retrospectively, we analyzed this data using variations of the original RC and comparing with recently published RC.


RESULTS
The definition of a 'normal' lymph node affected the complete response (CR) rate (< or = 1.0 x 1.0 cm, 6%; < or = 1.5 x 1.5 cm, 18%; < or = 2.0 x 2.0 cm, 28%); overall response rate (ORR) was not affected. CR rates increased progressively without > or = 28 days response confirmation: 12% vs. 6% (< or = 1.0 x 1.0 cm), 26% vs. 18% (< or = 1.5 x 1.5 cm), and 36% vs. 28% (< or = 2.0 x 2.0 cm). CR rate and duration of response (DR) were unaffected when only the six largest, rather than all lesions, were measured. When the new RC were applied, CR rate (32%) was higher and DR (13.9 months) and time to progression (15.6 months) were shorter in complete responders.


CONCLUSIONS
Standard RC must be consistently and rigorously applied for accurate comparisons between studies.
Grillo-López
A J
AJ
IDEC Pharmaceuticals Corp., San Diego, California 92121, USA. agrillo@idecpharm.com
Cheson
B D
BD
Horning
S J
SJ
Peterson
B A
BA
Carter
W D
WD
Varns
C L
CL
Klippenstein
D L
DL
Shen
C D
CD
D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D058846:Antibodies, Monoclonal, Murine-Derived; D000970:Antineoplastic Agents / Q000627:therapeutic use; D018450:Disease Progression; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008228:Lymphoma, Non-Hodgkin / Q000145:classification / Q000188:drug therapy* / Q000473:pathology*; D012016:Reference Values; D012189:Retrospective Studies; D000069283:Rituximab; D016896:Treatment Outcome
D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; D000970:Antineoplastic Agents; D000069283:Rituximab