An analysis of the GeparSixto trial in triple-negative breast cancer showed that adding carboplatin to neoadjuvant therapy improved pathologic complete response rate in patients without BRCA1/2 mutation and that response rates were higher overall in those with mutations, without additive effects observed for carboplatin. The analysis was reported by Eric Hahnen, PhD, of the Center for Hereditary Breast and Ovarian Cancer, University Hospital Cologne, and colleagues in JAMA Oncology. GeparSixto showed the addition of neoadjuvant carboplatin to anthracycline, taxane, and bevacizumab (Avastin) increased pathologic complete response rates among all patients.
The current analysis included 291 patients, of whom 146 received carboplatin. Pathogenic BRCA1 and BRCA2 germline mutations were present in 50 patients (17.2%), including 26 patients who received carboplatin and 24 patients who did not.
Pathologic Complete Response Rate
The pathologic complete response rate was 56.8% in the carboplatin group vs 41.4% in the group that did not receive carboplatin (odds ratio [OR] = 1.87, P = .009). Among patients in the group that did not receive carboplatin, pathologic complete response rates were 66.7% in patients with mutations and 36.4% in patients without mutations (OR = 3.50, P = .008). Among patients in the carboplatin group, pathologic complete response rates were 65.4% in those with mutations and 55% in those without mutations (OR = 2.14, P = .004, vs those without mutations in the group that did not receive carboplatin). After a median follow-up of 35 months, disease-free survival among patients without mutations was 85.3% in the carboplatin group and 73.5% in the group that did not receive carboplatin (hazard ratio = 0.53, P = .04).
The investigators concluded: “Under the nonstandard GeparSixto polychemotherapy regimen, patients without BRCA1 and BRCA2 germline mutations benefited from the addition of carboplatin and those with BRCA1 and BRCA2 mutations showed superior response rates without additive effects observed for carboplatin.” ■