|
The use of trastuzumab in the treatment
of early breast cancer: results from the HERA trial
The overexpression of HER-2, a transmembrane protein with tyrosine kinase
activity, in 20 % to 30 % of breast cancers (BC) is associated with a
greater risk for disease progression and death. The humanised antibody
trastuzumab (Herceptin®), designed to target and block the function of
HER-2, has been shown to improve time to progression and overall survival
in the metastatic setting, when given in combination with chemotherapy
(CT). Five randomised trials have recently investigated the role of
trastuzumab in early breast cancer. More than 14,000 patients with node
positive or high risk node negative, HER-2 overexpressing tumours were
recruited worldwide. The results are highly consistent, with an impressive 39% to 52% reduction in the risk of
recurrence at median follow-up periods ranging from 12 to 36 months. The
international HERA (HERceptin
Adjuvant) trial enrolled nearly
5,100 HER-2 positive early BC patients at 480 sites in 39 countries across
the world. In
this study’s 3-arm design, trastuzumab administered every 3 weeks after
completion of CT for either 1 or 2 years was compared with an observation
arm. According to the
first analysis, at a median follow-up of one year, the primary efficacy
endpoint was met: patients who received one year of trastuzumab had a
statistically significant improvement in disease-free survival (HR 0.54;
p<0.0001). This impressive decrease of early recurrences at distant sites prompted the
release of the results at an unusually short follow-up time. As expected,
overall survival had
not yet reached statistical significance. The cumulative incidence of severe cardiac
events was very low (0.5% in the trastuzumab arm vs. 0% in the observation
arm). The comparison
between the one-year and two-year arms may be available by 2008 or earlier.
In contrast to the other trials of adjuvant trastuzumab, the results of
the HERA study are widely applicable, as a considerable range of adjuvant
CT regimens were used prior to treatment with trastuzumab. Bibliographical reference:
Daniela D. Rosa, Lissandra Dal Lago, Chantal Bernard and Martine J. Piccart Medicine Department, Jules Bordet Institute, Brussels, Belgium
|