Oral Paclitaxel Combo Shows Higher Response Rate Than IV Paclitaxel in Breast Cancer

Treatment with oral paclitaxel and encequidar resulted in a statistically significant improvement in overall response rate (ORR) compared with intravenous (IV) paclitaxel in metastatic breast cancer, according to a phase 3 study.

The study evaluated the safety and efficacy of oral paclitaxel monotherapy versus IV paclitaxel monotherapy in patients with metastatic breast cancer, with 402 patients enrolled in a 2-to-1 ratio of oral paclitaxel to IV paclitaxel in the intent-to-treat (ITT) population. The primary efficacy endpoint was tumor ORR confirmed at 2 consecutive timepoints.

Based on ITT analysis, oral paclitaxel demonstrated a statistically significant improvement compared with IV paclitaxel on the primary efficacy endpoint, with an ORR of 36% in the oral group versus 24% in the IV group. The results also showed that the proportion of confirmed responders with a duration of response of more than 150 days was 2.5 times higher in the oral paclitaxel group than in the IV paclitaxel group.

There was also a strong trend in progression-free survival and overall survival favoring oral paclitaxel over IV paclitaxel at the data cut-off date on July 25, 2019, according to the study.

Additionally, neuropathy was less frequent and less severe in patients who were treated with oral paclitaxel compared with IV paclitaxel. The data also showed lower incidence of alopecia, arthralgia, and myalgia in the oral paclitaxel group, as well, but more incidents of grade 4 neutropenia and infection.

“There is a potential for oral paclitaxel, which is not designed to require steroid pre-medication for immunosuppression, to serve as a cornerstone in chemotherapy in combination with other small molecule anti-cancer drugs, biologics, and immune-oncology treatment approaches, including other drug candidates in our oncology pipeline,” Johnson Lau, MBBs, MD, FRCP, chief executive officer and chairman of Athenex, said in a statement.

Athenex is also evaluating oral paclitaxel in patients with angiosarcoma, as well as in combination with ramucirumab for patients with gastric cancer. Additionally, the company is testing oral paclitaxel in combination with pembrolizumab (Keytruda, Merck) in patients with advanced solid malignancies.

Reference

Athenex Announces Oral Paclitaxel and Encequidar had a Significantly Higher Response Rate Over IV Paclitaxel in a Phase 3 Pivotal Study in Metastatic Breast Cancer [news release]. Athenex.http://ir.athenex.com/news-releases/news-release-details/athenex-announces-oral-paclitaxel-and-encequidar-had. Accessed August 7, 2019.