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minutes. In a previous study, 30-minute infusions of panitumumab showed similar
safety, pharmacokinetics, and frequency of infusion reaction to 60-minute infusions.
Because Pmab consists of fully human monoclonal antibodies, infusion reactions
occur less frequently than with cetuximab, chimeric monoclonal antibodies.
Short-time infusion of Pmab has the potential to improve patient convenience and
reduce costs.
Purpose: We evaluated the safety of short-time infusion of panitumumab in a
prospective multicenter study.
Methods: Between January 2011 and December 2011, from 14 centers in Japan, a
phase II study of Pmab + irinotecan (CPT-11) or Pmab monotherapy in KRAS
wild-type metastatic colorectal cancer refractory to CPT-11, oxaliplatin, and
fluoropyrimidines was performed. As an additional study, the initial dose of Pmab
was administered over 60 minutes, followed by 30-minute infusion; then, all
subsequent doses were to be administered over 15 minutes.
Results: Forty-eight patients were enrolled. Their characteristics were median age of
62 (32-75); male/female, 27/21; Performance Status 0/1/2, 23/24/1; primary lesion in
colon/rectum, 21/27; and treatment regimen of CPT-11 + Pmab/Pmab monotherapy,
43/5. The number of patients and doses with 60-/30-/15-minute administration were
48/45/38 cases and 67/56/206 doses, respectively. In all cases with 60-/30-/15-minute
infusion, infusion reaction was not encountered. Grade 3/4 toxicities included
anorexia 8%, stomatitis 4%, diarrhea 6%, fatigue 4%, rash acneiform 6%, perionychia
4%, leucopenia 8%, neutropenia 8%, anemia 15%, hyponatremia 4%, and
hypomagnesemia 4%. This was similar to the results from previous clinical studies
on panitumumab.
Conclusion: In this study, no infusion reactions with 60-/30-/15-minute
administration of panitumumab and no increase of frequency of adverse events were
observed. This is the first prospective study describing the feasibility of short-time
infusion of panitumumab. This study suggests that 15-minute infusions of
panitumumab are feasible in patients who tolerate a 60- and then 30-minute infusion
sequence.
Disclosure: All authors have declared no conflicts of interest.
599P EARLY TUMOR SHRINKAGE (ETS) FOR THE PREDICTION OF
EFFICACY IN METASTATIC COLORECTAL CANCER (MCRC):
POST-HOC ANALYSIS FROM AN IRINOTECAN-BASED
RANDOMIZED FIRST-LINE TRIAL
C. Giessen 1 , R. Laubender 2 , S. Stintzing 1 , L. Fischer von Weikersthal 3 ,
D. Quietzsch 4 , U. Vehling-Kaiser 5 , D. Oruzio 6 , H. Lambertz 7 , A. Schalhorn 1 ,
V. Heinemann 1
1 Department of Medical Oncology and Comprehensive Cancer Center, University
of Munich, Munich, GERMANY, 2 University of Munich, Institute of Medical
Informatics, Biostatistics, and Epidemiology, München, GERMANY, 3 Department
of Medical Oncology, Klinikum St. Marien, Amberg, GERMANY, 4 Department of
Medical Oncology, Klinikum Chemnitz, Chemnitz, GERMANY, 5 Onkologische
Schwerpunktpraxis, Onkologisches und Palliativmedizinisches Netzwerk
Landshut, Landshut, GERMANY, 6 II. Medizinische Klinik, Klinikum Augsburg,
Augsburg, GERMANY, 7 Zentrum Fuer Innere Medizin - Onkologie, Klinikum
Garmisch-Partenkirchen, Garmisch-Partenkirchen, GERMANY
Background: Early tumor shrinkage (ETS) has been highlighted as a favorable
prognostic factor related to progression-free survival (PFS) and overall survival (OS)
in cytotoxic chemotherapy with or without cetuximab. We investigated ETS ≥20%
and