Pyrotinib Versus Lapatinib in Combination Therapy for Metastatic Breast Cancer: Survival Update From PHOEBE Trial

By: Lauren Harrison, MS
Posted: Monday, February 14, 2022

Among patients with HER2-positive metastatic breast cancer who had already received trastuzumab and chemotherapy, the use of pyrotinib plus capecitabine led to statistically significant improvement in overall survival compared with lapatinib plus capecitabine. Pyrotinib is an irreversible tyrosine kinase inhibitor targeting EGFR, HER2, and HER4. Binghe Xu, MD, PhD, of the Chinese Academy of Medical Sciences in Beijing, presented these results from the phase III PHOEBE trial on behalf of his colleagues at the 2021 San Antonio Breast Cancer Symposium (SABCS; Abstract GS3-02).

“This updated analysis of overall survival in the PHOEBE trial reaffirmed pyrotinib plus capecitabine as an established treatment option in this patient population,” concluded the authors.

The trial enrolled 267 patients with HER2-positive metastatic breast cancer. All patients had received prior trastuzumab and taxanes and up to two prior lines of chemotherapy for metastatic disease. Patients were randomly assigned 1:1 to receive either 400 mg of oral pyrotinib (n = 134) or 1,250 mg of oral lapatinib (n = 132) once a day plus 1,000 mg/m² of oral capecitabine twice a day for days 1 through 14 of a 21-day cycle.

At the time of data cutoff, the median follow-up duration was 33.2 months in the pyrotinib group and 31.8 months in the lapatinib group. Median overall survival was not yet reached in the pyrotinib group and was 26.9 months in the lapatinib group (hazard ratio = 0.69; P = .019). The estimated overall survival at 24 months was 66.6% with pyrotinib plus capecitabine and 58.8% with lapatinib and capecitabine. Disease progression or death was observed in 73.9% and 91.7% of the patients receiving pyrotinib and lapatinib therapies, respectively. Progression-free survival was significantly improved in the pyrotinib group as compared with the lapatinib group (12.5 vs. 5.6 months; P < .0001).

Disclosures: For a full list of authors’ disclosures, visit abstractsonline.com.

2021 San Antonio Breast Cancer Symposium

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