autologous blood and marrow transplantation - Blog Science ...

366 Chapter 6: Breast Cancer
weeks. Progressive disease (PD) was defined as a >25% increase in the minimum
size of one or more measurable lesions or the presence of new metastatic lesions.
Only patients with CR or PR were considered to have responded to treatment.
Fisher's exact test was used to test for response difference according to HER-2
expression levels.
RESULTS
HER-2 levels during treatment
The data shown are derived from plasma samples of 57 patients with MBC
treated with HDCT and ABSC support. HER-2 plasma levels in these samples were
determined using the c-erbB-2 serum EIA kit (Chiron Diagnostics). Plasma HER-
2 levels were examined at three time points: 1) At initial enrolment to the clinical
trial; 2) after ICT, at the time of apheresis; and 3) at a 4- to 6-week restaging after
HDCT and ABSC support.
Table 1 shows the number of samples overexpressing HER-2 at each serial
measurement. The overall percentage of patients that overexpress HER-2 is within
the range of that found in the few studies that have examined overexpression in
MBC; i.e., 20-57% of patients with MBC have elevated HER-2 plasma concentrations.
11-17
Of the 57 patients examined, 27 (47.4%) overexpressed HER-2 on at
least one of the examined time points. The overall median concentration of positive
values during the course of treatment was 0.61 U/mg protein. Patients were
included if they overexpressed HER-2 at any one or more of the three time points.
A further examination of all HER-2 overexpressing patients (at any one or more of
the time points) showed that 16 of 25 (64%) evaluated patients were positive at the
first measurement (at initial enrolment to the clinical trial). At the second
measurement (following ICT, at time of apheresis), 21 of 27 (77.8%) evaluated
patients overexpressed HER-2. This included five patients (five of 27) that were
negative at the initial measurement. At the third serial measurement, following
Table 1. Plasma HER-2 overexpression in peripheral blood
Initial At apheresis Posttransplant Overall positive
n(%) 16 (32.7) 21 (37.5) 14 (29.2) 27 (47.4)
Mean 0.89 0.59 0.33 0.61
Range 0.22^1.65 0.20-3.18 0.21-0.55 0.20-4.65
Total 49 56 47 57
No., number of HER-2 positive; %, percent HER-2 positive. The lower limit for the amount
of overexpressed protein is 0.2 U/mg total protein. Overall positive plasma HER-2 refers to
patients with HER-2 levels >0.2 U/mg protein at any one or more of the three time points.