Neoadjuvant Carboplatin Improved DFS for Triple-Negative Breast Cancer

Gunter von Minckwitz, MD

The addition of carboplatin to a neoadjuvant chemotherapy regimen resulted in improvements in disease-free survival for women with triple-negative breast cancer, according to the results of the GeparSixto study presented at the 2015 San Antonio Breast Cancer Symposium (SABCS).

Previous results from the GeparSixto study showed that adding carboplatin to anthracycline or taxane-based therapy improved pathologic complete response (pCR) in patients with triple-negative breast cancer (36.9% vs 53.2% with carboplatin), but no data were available on whether this improvement in response would translate to survival improvements.

“Patients with triple-negative breast cancer who received carboplatin as part of their neoadjuvant chemotherapy regimen were almost half as likely to have had disease relapse at 3 years after starting treatment compared with those who did not receive carboplatin, and it was those patients who had a pCR who were least likely to have disease relapse,” said Gunter von Minckwitz, MD, president of the German Breast Group and a professor of gynecology at the University of Frankfurt in Germany, in a prepared statement.

In the study, patients were treated for 18 weeks with paclitaxel and non-pegylated liposomal doxorubicin. The 315 patients with triple-negative disease received concurrent bevacizumab until undergoing surgery. All of the 595 patients were randomly assigned to carboplatin (n = 296) or no additional carboplatin (n = 299).

At a median follow-up of 3 years, patients with triple-negative disease assigned to carboplatin had a disease-free survival of 85.5% compared with 76.1% for those assigned no carboplatin.

Among the 129 patients with triple-negative disease who had a pCR, 5 had disease relapse after a median follow-up of 3 years compared with 50 among the 162 patients who did not have a complete response.

“These pCR data are important for the research community,” von Minckwitz said. “They show that the effect of carboplatin on disease-free survival was correctly predicted by its effect on pCR and they add to the evidence that suggests that pCR can be a surrogate for clinical benefit if the effects of an investigational agent on pCR are large.”

Von Minckwitz noted that the improvements in survival were observed mostly in patients without germline BRCA mutation, a group in which platinum compounds were thought not to be active.

“Further studies are needed to investigate this, however, because there were only 50 patients who had a germline BRCA mutation in our study,” von Minckwitz said. “We might in this group just not see an existing effect of carboplatin, or it could be there is no extra effect because of the high sensitivity of these patients to the other agents given.”