A Phase II Trial of Older Adults With Metastatic Breast Cancer Receiving nab-Paclitaxel: Melding the Fields of Geriatrics and Oncology

Abstract

Introduction: Phase II clinical trials including geriatric assessment (GA) measures are critical for improving the evidence base for older adults with cancer. We assessed the efficacy and tolerability of nab-paclitaxel in older adults with metastatic breast cancer (MBC).

Patients and methods: Patients aged ≥ 65 years with MBC and ≤ 1 previous line of chemotherapy received 100 mg of nab-paclitaxel on days 1, 8, and 15 of a 28-day cycle. A GA was completed pre-chemotherapy, and the validated Cancer and Aging Research Group (CARG) chemotherapy toxicity risk score was calculated. Relationships between tolerability (number of courses, hospitalizations, dose reductions, and toxicity) and risk score were assessed using general linear models, Student t tests, and the Fisher test. Response rate and progression-free survival were evaluated using the Kaplan-Meier method.

Results: Forty patients (mean age, 73 years; range, 65-87 years) were included. The median number of cycles was 6, 75% (n = 30) of patients had ≥ 1 dose hold, and 50% (n = 20) had ≥ 1 dose reduction. Fifty-eight percent (n = 23) had treatment-related ≥ grade 3 toxicities, and 30% (n = 12) were hospitalized owing to toxicity. Thirty-five percent (n = 14) responded, and the median progression-free survival was 6.5 months (95% confidence interval, 5.5 months to undefined). Patients with intermediate/high toxicity risk scores had higher risk of grade ≥ 3 toxicity than those with low risk scores (odds ratio, 5.8; 95% confidence interval, 1.3-33.1; P = .01). A higher mean risk score was associated with higher likelihood of dose reductions and hospitalizations.

Conclusions: Among older adults with MBC receiving weekly nab-paclitaxel, more than one-half experienced ≥ grade 3 chemotherapy toxicity. However, a GA-based risk score could predict treatment tolerability.

Keywords: Drug Toxicity; Elderly; Geriatric assessment; Hospitalizations; Taxane.

Copyright © 2018 Elsevier Inc. All rights reserved.

Figures

Figure 1:

a) Prediction Model and Scoring Algorithm for Chemotherapy Toxicity b) Percent Risk of Toxicity by Score

Figure 2:

Number of participants with Grade 3–4 National Cancer Institute Common Terminology Criteria for Adverse Events by Cancer and Aging Research Group (CARG) risk category

Figure 3:

Association between toxicity risk and a) dose reductions, and b) hospitalizations. The blue dot represents the mean; red dots represent individual participant results. The line within the box represents the median, the upper and lower ends of the boxes represent the 25th and 75th percentiles and the ends of the whiskers represent the individual result within 1.5 times the interquartile range.

Figure 4:

Association between toxicity risk score and number of courses completed