The starting dose was 27 mg/m2 every 3 weeks. For the first half of the trial, the dose was escalated up to 35 mg/m2 every 3 weeks if tolerated.
Overall, 20% of women had triple-negative disease, according to results reported in a poster session. More than half each had liver metastases (52%) and lung metastases (57%). Fifty-seven percent had received a taxane as part of their adjuvant therapy.
The median number of cycles of tesetaxel received was 4 (range, 1-17). The overall response rate was 45% (49% in women with estrogen receptor–positive disease and 33% in women with triple-negative disease).
The overall response rate was nearly the same among women who received only the nonescalated dose (44%) and among women who received the escalated dose (47%).
An additional 36% of patients achieved stable disease. Median progression-free survival was 5.8 months for all treated patients and 7.3 months for those with estrogen receptor–positive disease.
"Pretty much, the tolerability profile looks really good," Dr. Itri commented. In particular, none of the patients had hypersensitivity reactions.
By far, the most common grade 3/4 adverse event was neutropenia, seen in 33% of patients overall (26% without dose escalation and 43% with it). However, "none of these patients required a colony-stimulating factor or were febrile. So this now becomes a true outpatient regimen," she said.
The rate of grade 3 peripheral neuropathy was 7% overall (0% without dose escalation and 16% with it), and there was no grade 4 peripheral neuropathy. The rate of grade 2 alopecia was 15% regardless of dose.
Genta sponsored the trial. Dr. Itri disclosed employment and stock ownership in Genta. Dr. Moulder disclosed no relevant conflicts of interest.