To observe the clinical efficacy and safety of 2 chemotherapy regimens in the treatment of metastatic breast carcinoma with overexpression of human epidermal growth factor receptor 2 (HER2): one was the dual-targeted therapy with herceptin injection + pertuzumab injection (herceptin + pertuzumab, HP) combined with paclitaxel injection (albumin-bound) + carboplatin injection, and the other was HP dual-targeted therapy combined with paclitaxel injection alone.

Patients were divided into control group and treatment group based on the treatment regimen. Control group received HP dual-targeted therapy (herceptin for injection: initial dose of 8 mg·kg^-1, followed by 6 mg·kg^-1; pertuzumab injection: initial dose of 840 mg, followed by 420 mg) combined with paclitaxel injection (125 mg·m^-2) for chemotherapy. Treatment group additionally received carboplatin injection with an area under the curve (AUC) of 6 on the basis of the treatment regimen of control group, with 21 days as one cycle, for a total of 6 cycles. The clinical efficacy, levels of tumor markers, survival benefits of the 2 groups were compared, and safety evaluation was also conducted.

The control and treatment groups comprised 52 and 54 subjects, respectively. After treatment, the objective response rates of the treatment group and the control group were 74.07% (40 cases/54 cases) and 53.85% (28 cases/52 cases), respectively, the carbohydrate antigen 15-3 (CA153) levels were (21.82±3.22) and (23.56±3.43) U·mL^-1, respectively; the carcinoembryonic antigen (CEA) were (2.22±0.53) and (2.51±0.63) μg·L^-1, respectively; the levels of vascular endothelial growth factor A (VEGFA) were (53.51±7.44) and (57.43±8.04) ng·mL^-1, respectively; trefoil factor 1 (TFF1) were (1.51±0.43) and (1.74±0.59) mg·L^-1, respectively; there were significant differences in the above indexes between experimental group and control group (all P<0.05); the positive rates of anti-drug antibody (ADA) were 3.85% and 1.85%, respectively and the positive rates of neutralizing antibody (NAB) were 1.92% and 1.85% respectively, without statistically significant differences (all P>0.05). The median progression free survival (PFS) of treatment group was 14.5 months, which was significantly higher than that of control group (11.3 months); the median overall survival (OS) of treatment group was 30.0 months, which was significantly higher than 25.4 months of control group (all P<0.05). Survival advantage was observed in treatment group (75.93%) compared to control group (57.69%), win statistically significant difference (P<0.05). During treatment, 34 patients (62.96%) in treatment group experienced alopecia, 25 (46.30%) had nausea and 19 (35.19%) had vomiting; in control group, 43 patients (82.69%) had alopecia, 11 patients (21.15%) had nausea, and 8 patients (15.38%) had vomiting. Compared with control group, treatment group had statistically significantly higher incidence of nausea and vomiting, and statistically significantly lower incidence of alopecia (all P<0.05).

Compared with the regimen of HP dual-targeted therapy combined with paclitaxel injection alone, the regimen of HP dual-targeted therapy combined with paclitaxel injection + carboplatin injection can more effectively reduce the levels of tumor markers in patients with HER2-positive metastatic breast cancer, improve the short-term and long-term efficacy and prognosis of patients, and the two regimens have similar serum immunogenic characteristics.