181P - Pegylated liposomal doxorubicin (PLD) combined with docetaxel and trastuzumab in neoadjuvant treatment for HER2-positive breast cancer: A multicenter, randomized, phase II, open-label trial

Background

Trastuzumab based chemotherapy is the standard regimen for HER2+ breast cancer (BC) in neoadjuvant trerapy. Combination of trastuzumab and anthracycline is generally avoided clinically due to the cardiotoxicity of the two drugs. PLD is less cardiotoxic compared with traditional anthracyclines. Here, we conducted this prospective study to evaluate the efficacy and safety of PLD (A) + docetaxel (T) + trastuzumab (H) in neoadjuvant treatment for HER2+ BC.

Methods

The study recruited 54 invasive HER2+ BC patients (pts) between March 2019 and February 2021in three centers. The eligible pts were given PLD (40 mg/m²) + T (75 mg/m²) +H (8 mg/kg loading dose, 6 mg/kg maintenance dose) for neoadjuvant treatment. The primary endpoints were totally pathological complete response rate (tpCR, ypT0/isN0) and breast pathological complete response rate (bpCR, ypT0/is). Secondary endpoint was safety. Adverse events（AEs） were assessed according to NCI-CTCAE V5.0.

Results

Of the 50 eligible pts, the median age was 51 (range 44-56). 21 pts (42%) were hormone receptor - (HR-), 29 (58%) were HR+. 25(50%) pts were stage II, and 25 (50%) were stage III. 29 pts finished 6 cycles. The tpCR was 48% (24/50) [95% CI, 33.7% to 62.6%] and bpCR was 60% (30/50) [95% CI, 45.2% to 73.6%].When stratified by HR, the tpCR was 57.1% (12/21) [95% CI, 34.0% to 78.2%], and bpCR was76.2% (16/21) [95%CI, 52.8% to 91.8%]in HR- group. While in HR+ cases, tpCR and bpCR were 41.4% (12/29) [95%CI,23.5% to 61.1%] and 48.3% (14/29) [95%CI, 29.4% to 67.5%], respectively. The bpCR of HR- pts was significantly higher compared to HR+ pts (p=0.047). The most common grade 3/4 AEs were hand-foot syndrome (12.0%), leukopenia (12.0%), interstitial pneumonia (10%) and oral mucositis (8.0%). One case died of grade 4 interstitial pneumonia. Left ventricular ejection fraction （LVEF） declined in 9 pts, but did not fall below 50%, and eventually recovered. Congestive heart failure was not occurred.

Conclusions

Neoadjuvant treatment with PLD + T + H significantly improved pCR in invasive HER2+ BC pts compared with previous trastuzumab based regimen and with an acceptable safety profile.

Clinical trial identification

ChiCTR1900021473.

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.