The combined use of Herceptin plus standard adjuvant chemotherapy does not improve outcomes in women with HER2-low breast cancer.
The findings were presented today at the San Antonio Breast Cancer Symposium (SABCS).
In a slide presented by Louis Fehrenbacher, MD, medical director of Kaiser Permanente Oncology Clinical Trials and oncologist at Kaiser Permanente Vallejo Medical Center, at the SABCS press conference, the lines of invasive disease-free survival (IDFS) for both arms of the study, with and without Herceptin – were drawn on top of each other and the difference was virtually indistinguishable. Fehrenbacher said the main goal of improving the IDFS was not met, that none of the secondary endpoints and "no efficacy trends were observed."
"We could expand this slide, I still could not see the difference between those two weapons at all," he said. "There was no evidence of efficacy in any of the stratification variables."
The 5-year IDFS rate was 89.6 percent among the 1,640 patients who received Herceptin and 89.2 percent among the 1,630 patients who did not receive it. The researchers said that the findings were not different if the patients were subdivided by immunohistochemistry HER2 (IHC), the degree of nodal involvement or the status of the hormone receptor.
Fehrenbacher noted that the event rate was essentially the same between the two groups: 134 for the chemotherapy arm and 130 for chemotherapy plus Herceptin. There were no statistically significant differences in the five-year estimates for the recurrence-free interval, the free recurrent free interval, and the overall survival between those who received Herceptin and those who did not.
Although the National Surgical Adiposity Project and the Intestine Study (NSABP B-47) is valuable because it makes clear that patients with this form of the disease "may unequivocally know that Herceptin" (NSABP) studied Herceptin and chemotherapy showed better results for patients with early stage HER2-low breast cancer. it is not a beneficial treatment for them, "said Fehrenbacher.
Herceptin can cause serious adverse effects such as cardiotoxicity, so these findings help ensure that patients are not treated unnecessarily, the researchers added.
the press conference pointed out that although SABCS does not normally present negative findings of the trials, an exception was made in this case due to the importance of a large number of patients whose test results are low in HER2 and for whom studies of this type offer hope for potential treatment.
"It does not answer the question completely, but certainly if there is a large suspicion or increased suspicion, one can certainly" When asked if changes in testing procedures over time could Having contributed to the findings, Fehrenbacher said that, in any case, the tests have improved, and in the case of the B-47, "said F ehrenbacher
the test became stricter to guarantee higher quality results.
He said the results were a surprise, particularly because of the sharpness of the demarcation between those who benefit from Herceptin and those who do not.