Is Etirinotecan Pegol Superior to Chemotherapy in Treating Brain Metastases From Breast Cancer?

By: Vanessa A. Carter, BS
Posted: Monday, August 1, 2022

The phase III ATTAIN trial, conducted by Debu Tripathy, MD, of The University of Texas MD Anderson Cancer Center, Houston, and colleagues, compared the clinical outcomes of patients with breast cancer–related brain metastases treated with either etirinotecan pegol—a long-acting polymer conjugate of the topoisomerase I inhibitor irinotecan—or chemotherapy. The findings of this study, which were published in JAMA Oncology, demonstrated nonsuperiority of etirinotecan pegol.

“The results of the ATTAIN randomized clinical trial found no statistically significant difference in outcomes between treatment with etirinotecan pegol and chemotherapy in patients with brain metastases,” the study authors concluded. “However, this study represents one of the largest published trials dedicated to patients with breast cancer and brain metastases and may help to inform further research.”

This open-label, multicenter trial enrolled 178 patients with metastatic breast cancer or a history of stable pretreated brain metastases whose disease progressed on chemotherapy. Participants were randomly assigned to receive 145 mg/m² of intravenous etirinotecan pegol every 21 days (n = 92) or chemotherapy of the physician’s choice every 21 to 28 days (n = 86).

At the primary data cutoff, most patients discontinued study participation because of disease progression (88%). Baseline demographics were well balanced between treatment groups, with similar median treatment durations between the treatment arms. Each group underwent a median of three treatment cycles, with 20 and 8 participants given etirinotecan pegol and chemotherapy completing seven or more cycles, respectively.

Although the median overall survival was similar between both arms (7.8 vs. 7.5 months), the median progression-free survival for non–central nervous system (CNS) metastases was longer among those who received etirinotecan pegol (2.8 months) than among those who received chemotherapy (1.9 months); the median progression-free survival for those with CNS metastases was 3.9 versus 3.3 months, respectively. Of note, there were no significant differences in safety profiles, except for vomiting (34.4% of those given etirinotecan pegol and 19.5% of those given chemotherapy).

Disclosure: For full disclosures of the study authors, visit jamanetwork.com.

JAMA Oncology

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