Oral Formulation of Paclitaxel Improves Breast Cancer Response Compared With IV

An investigational oral formulation of paclitaxel improved response compared with the intravenous (IV) formulation in women with metastatic breast cancer, according to a study presented at the San Antonio Breast Cancer Symposium. However, the oral form is taken with encequidar, which has a time-consuming administration that requires nine consecutive hours of fasting.

The pivotal, open-label, randomized, phase III study randomized 402 patients 2:1 to receive oral paclitaxel 205 mg/m² plus encequidar for three days per week (n=265) or IV paclitaxel 175 mg/m² every three weeks (n=137).

Improved survival with oral formulation of paclitaxel

Patients receiving the oral formulation had a better overall response rate (primary endpoint) compared with IV (35.8% vs. 23.4%; P=0.011). Responses in the oral paclitaxel cohort were also durable: Confirmed responses of more than 150 days occurred in 51% of responders in the oral group and 38% of responders in the IV group.

Ongoing analysis of overall survival favored the oral paclitaxel formulation at the time of reporting (P=0.035), with a median of 27.9 months in the oral cohort compared with 16.9 months in the IV cohort. Ongoing progression-free survival analysis also favored the oral cohort (9.3 months vs. 8.3 months, respectively; P=0.077).

There was a lower incidence and severity of neuropathy in the oral cohort compared with IV; at week 23, 17% of the oral group reported any-grade neuropathy compared with 57% of the IV group. Grade 3 neuropathic symptoms were observed in 1% of the oral group and 8% of the IV group.

The oral formulation had higher rates of neutropenia, infection, and gastrointestinal adverse events.