Patients with advanced breast cancer drug that has not responded to other anti-cancer drugs may soon have a new treatment option. Ixabepilone (Ixempra, Bristol-Myers Squibb) has been approved for use in combination with another cancer agent, capecitabine (generic Xeloda, Roche), in patients who no longer benefit from treatment with an anthracycline (such as doxorubicin [Adriamycin, Bedford]) and a taxane (such as paclitaxel [Taxol, Bristol-Myers Squibb] or docetaxel [Taxotere, Sanofi-Aventis]). Ixabepilone is also approved for use alone in patients who no longer benefit from an anthracycline, a taxane, and capecitabine.
In one phase 2 study, ixabepilone was evaluated alone in 126 patients, of whom 88% had received at least two lines of prior chemotherapy. Researchers found clinically significant tumor shrinkage in 12%. The responses, they report, were “durable and notable;” median durations of response and progression-free survival were 5.7 and 3.1 months, respectively. Median overall survival was 8.6 months.
In another trial involving 752 patients, a combination of ixabepilone and capecitabine was compared with capecitabine alone. The combination treatment was better at delaying cancer progression or death.
The drug binds to cancer cell microtubules, which play a role in cell division. Patients taking ixabepilone should not take drugs that are strong inhibitors of cytochrome CYP 3A4, one of the enzymes that metabolizes ixabepilone. Other women who should not take this drug are those who have had severe allergic reactions to drugs that contain Cremophor (a stabilizer) or its derivatives or women with baseline bone marrow suppression.
Side effects include peripheral neuropathy, bone marrow suppression, constipation, nausea, vomiting, muscle pain, joint pain, fatigue, and general weakness.
(Source: FDA, October 22, 2007.)