CONTROVERSIES IN PATIENT MANAGEMENT
Continued Use of Trastuzumab (Herceptin) after
Progression on Prior Trastuzumab Therapy
in HER-2-Positive Metastatic Breast Cancer
Lajos Pusztai, M.D., D. Phil. and Francisco J. Esteva, M.D., Ph.D.
University of Texas MD Anderson Cancer Center, Depar tment of Breast Medical Oncology, Houston, Texas, USA.
ABSTRACT
Whether to continue trastuzumab after objective evidence of disease progression or not is
an important unanswered clinical question for women with metastatic disease. This question
is also relevant for those who relapse after adjuvant trastuzumab-containing therapy. Unfor-
tunately, there is little evidence to guide decision-making. The modest toxicity and the pos-
sible, but unproven, benefit from the continued use of trastuzumab may account for the cur-
rently wide spread practice of continued administration of this drug after progression. How-
ever, there is no convincing evidence to support the use of extended trastuzumab therapy
after progression. At least two randomized trials with no trastuzumab in the control arms were
attempted but failed to accrue patients. In the absence of results from a randomized clinical
trial, a central registry program that collects information longitudinally from a large number
of patients with HER-2 positive breast cancer during the course of their disease was initiated
(RegistHER,
www.registher.com) to learn about the long term side effects and benefits of pro-
longed trastuzumab therapy. The anticipated introduction of second generation HER2-targeted
agents into the clinic also raises a new question; will switching to these agents be more effec-
tive than continuation of trastuzumab? Clinical trials are currently planned to address question
prospectively.
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