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Withholding chemotherapy in first-line treatment does not compromise overall survival (OS) in patients with HER2-positive advanced breast cancer, according to research published in JAMA Oncology.
Researchers found similar OS rates at 2 years for patients who received first-line treatment with trastuzumab plus pertuzumab and for patients who received trastuzumab plus pertuzumab and chemotherapy. However, patients who received the chemotherapy-free regimen had inferior progression-free survival (PFS).
This secondary analysis of a phase 2 trial (ClinicalTrials.gov identifier: NCT01835236) included 210 patients with HER2-positive, locally advanced or metastatic breast cancer. The patients’ median age at baseline was 58 (range, 26-85) years, 63.8% had hormone receptor-positive disease, and 62.9% had liver or lung metastases.
The patients were randomly assigned to receive pertuzumab and trastuzumab (n=105) or chemotherapy (paclitaxel or vinorelbine) plus pertuzumab and trastuzumab (n=103). Patients in either arm whose disease progressed received trastuzumab plus emtansine as second-line therapy.
The 2-year OS rate was 79.0% in the chemotherapy-free arm and 78.1% in the chemotherapy arm. The median OS was 60.5 months and 68.8 months, respectively.
The median PFS on first-line therapy was 8.4 months in the chemotherapy-free arm and 23.3 months in the chemotherapy arm. The median PFS on second-line treatment was 8.9 months and 6.4 months, respectively.
The greatest difference in PFS occurred during the first year. The 1-year rate PFS rate was 40.4% in the chemotherapy-free arm and 71.6% in the chemotherapy arm. The 3-year PFS rate was 22.4% and 36.9%, respectively. The 5-year PFS rate was 16.8% and 26.5%, respectively.
Patients in the chemotherapy-free arm reported fewer adverse events (AEs) than those in the chemotherapy arm. The most common AEs in the chemotherapy-free arm were diarrhea, fatigue, and nausea. The most common AEs in the chemotherapy arm were diarrhea, fatigue, peripheral sensory neuropathy, and alopecia.
“The findings of this secondary analysis of a randomized clinical trial suggest that selected de-escalation with pertuzumab plus trastuzumab alone without chemotherapy as first-line treatment followed by trastuzumab plus emtansine at progression … may be a reasonable treatment option for some patients,” the researchers wrote. “Overall survival was not compromised by delaying chemotherapy to later treatment lines, despite a much shorter first-line PFS.”
The researchers did note, however, that they were unable to determine which patients might be best suited to de-escalation.
Disclosures: This study was partly supported by Hoffmann-La Roche AG. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Reference
Huober J, Weder P, Ribi K, et al. Pertuzumab plus trastuzumab with or without chemotherapy followed by emtansine in ERBB2-positive metastatic breast cancer: A secondary analysis of a randomized clinical trial. JAMA Oncol. Published online August 10, 2023. doi:10.1001/jamaoncol.2023.2909
This article originally appeared on Cancer Therapy Advisor
