Cisplatin shows greater efficacy than gemcitabine when combined with nab-paclitaxel in metastatic triple-negative breast cancer

Our study aimed to compare the efficacy and safety of nab-paclitaxel plus cisplatin (AP) with nab-paclitaxel plus gemcitabine (AG) in patients with metastatic breast cancer (MBC). We collected data from two single-arm, phase II MBC studies. In NCT01149798, seventy-three MBC patients received 125 mg/m(2) nab-paclitaxel on days 1, 8 and 15 followed by 75 mg/m(2) cisplatin on day 1 of a 28-day cycle. In NCT01550848, eighty-four MBC patients received 125 mg/m(2) nab-paclitaxel and 800 mg/m(2) gemcitabine on days 1, 8, and 15 of a 28-day cycle. The endpoints were the overall response rate (ORR), progression-free survival (PFS), overall survival (OS) and safety profiles of these regimens. Among the 157 patients included, the ORR were 67.1% and 52.4% for the AP and AG arms, respectively (odds ratio [OR] = 0.246; hazard ratio [HR] = 1.485; 95% confidence interval [CI], 0.762–2.985). After median follow-up periods of 26.3 and 23.3 months in the AP and AG arms, the median PFS were 9.8 months (95%CI, 8.1–11.6) and 8.1 months (95%CI, 6.8–9.4), respectively, while the median OS were 26.9 months (95%CI, 22.4–31.4) and 25.5 months (95%CI, 19.3–31.4), respectively. Neither PFS nor OS adjusted for the number of metastases, occurrence of liver metastasis and chemotherapeutic lines differed significantly between the two arms (PFS:HR = 0.769; 95%CI, 0.541–1.092; p = 0.142; OS:HR = 0.686; 95%CI, 0.426–1.104; p = 0.120). However, PFS was significantly better with AP than with AG in metastatic triple-negative breast cancer (mTNBC) patients (HR = 0.308; 95%CI, 0.129–0.732; p = 0.008). Adverse events were more common with AP than with AG, except for edema and myalgia. Both regimens showed substantial efficacy and were tolerated well in MBC patients. mTNBC who received AP rather than AG showed longer PFS. However, adverse events were more common with AP. Thus, AP may be worth recommending to mTNBC, while AG may be a better alternative for MBC patients with other subtypes.