Tolerability of Pertuzumab in Older Patients with HER2+ Breast Cancer

The current study examined the tolerability of pertuzumab plus trastuzumab and systemic chemotherapy in patients aged >65 years with HER2+ breast cancer in the real-world setting.

This Institutional Review Board–approved retrospective medical records review identified patients aged >65 years with early or advanced HER2+ breast cancer who were treated with pertuzumab at The Ohio State University Comprehensive Cancer center from January 1, 2015, to May 1, 2020.

A total of 71 patients were enrolled in the study. The mean age of the study population was 76 years; the majority of patients were White (n=59), had stage I to III disease (n=62), and estrogen receptor–positive disease (n=48).

Of the patients with nonmetastatic disease (n=62), 81% received neoadjuvant systemic therapy (n=50) and 19% (n=12) received adjuvant therapy. In the neoadjuvant cohort, patients completed a median of 5.4 neoadjuvant cycles of chemotherapy plus trastuzumab and pertuzumab; of these, 46% (23/50) achieved a pathologic complete response. In the adjuvant cohort (n=12), patients completed a median of 4.9 adjuvant cycles consisting of chemotherapy plus trastuzumab and pertuzumab. Overall, patients with stage I to Ill disease completed a mean of 8.7 cycles of pertuzumab/trastuzumab. In the metastatic cohort (n=9) by ER status, pCR rate of 13% was achieved by patients in the ER-positive cohort, and 10% in the ER-negative cohort.

Overall, treatment delay (by ≥7 days) was reported in 8 (11%) patients and early treatment discontinuation in 18 (25%) patients. The most common reasons for treatment discontinuation were toxicity (44%), metastasis (11%), and other causes (44%).

The most common toxicities (grades 1-4) experienced by patients during pertuzumab therapy included anorexia, neuropathy, pain, depression, dyspnea, constipation, edema, mucositis, and rash; the majority of which were grade 1/2 severity. Grade 3/4 events that resulted in pertuzumab termination included grade 3 pain 25% (n=1); 25% (2/8) reported grade 3 fatigue (n=2), and grade 4 diarrhea 12% (n=1).

Based on the results of this single-center experience, it was concluded that pertuzumab was well tolerated in older patients with HER2+ breast cancer in the real-world setting; however, 25% of patients discontinued treatment due to toxicities, highlighting the importance of identifying patients who are at higher risk for toxicities prior to treatment initiation.

Source:

Williams N, Warmbier A, Doto D, et al. Tolerability of pertuzumab in older adults with HER2 positive breast cancer: a single institution experience. Presented at the 46th San Antonio Breast Cancer Symposium Annual Meeting, December 5-9, 2023; San Antonio, TX: Abstract PO5-17-04.