SAN ANTONIO -- The combination of investigational Tykerb (lapatinib) and Taxol (paclitaxel) as neoadjuant chemotherapy appears effective against inflammatory breast cancer, according to a small study.
SAN ANTONIO, Dec. 18 -- The combination of investigational Tykerb (lapatinib) and Taxol (paclitaxel) as neoadjuant chemotherapy appears effective against inflammatory breast cancer, according to a small study.
Among 35 participants with the aggressive but rare tumor, 86% had tumor shrinkage of 50% or more, said Massimo Cristofanilli, M.D., of the M.D., Anderson Cancer Center in Houston, in a presentation at the San Antonio Breast Cancer Symposium.
While the findings of the phase II trial are far from conclusive, they are encouraging because there are no effective therapeutic options for the condition and none has even been studied in multicenter trials, he said. The FDA is giving Tykerb a priority review.
The researchers stratified newly diagnosed patients into two cohorts-those with HER2 overexpressing tumors and those with EGFR-positive, HER2 non-over-expressing tumors. The patients were given 1,500 mg of the investigational agent Tykerb daily for two weeks followed by another 12 weeks of Tykerb plus paclitaxel at a dose of 80 mg/m2 weekly.
Patients had a tumor biopsy at baseline and on day 14 before starting combination therapy. At the end, patients had surgery and then adjuvant chemotherapy, radiotherapy, or hormonal therapy at the treating oncologist's discretion.
Most patients (mean age 53) had hormone-receptor negative disease (77%) but the rest had estrogen- or progestin- or both hormone-receptor positive tumors. A quarter already had metastatic disease and nearly a third had stage IV tumors (26%) while 34% were stage IIIC and 40% stage IIIB.
Among the 30 HER2 positive patients, there was an overall response rate of 77%. The findings were:
Among the five HER2 negative patients, none had a complete response, pathological complete response or stable disease, and one patient in this group had progressive disease. However, the majority (80%, four of five) had a partial response in the skin or chest wall.
Notably, 25% to 30% of the patients had a response in the first two weeks while on Tykerb alone. Functional imaging done for some of the patients at the end of week two also showed evidence of metabolic response, Dr. Cristofanilli said.
Toxicity of the combination regimen appeared to be "predictable and manageable," he added. About 60% of patients (21 of 35) had grade three or higher diarrhea and the same level of fatigue and asthenia affected 20% of patients each. One patient discontinued due to toxicity.
The researchers acknowledged that further study will be needed to define a role for Tykerb in inflammatory breast cancer, which
Session moderator Eric Winer, M.D., of the Dana-Farber Cancer Institute in Boston, cautioned that while these preliminary findings indicated that the combination could be effective as an initial treatment they also apply to a specific subtype of breast cancer that comprises only 1% to 2% of all breast cancers diagnosed.
"This is something that really needs much more in the way of investigation," he added.
Dr. Winer said other trials are beginning that will look at Tykerb versus Herceptin (trastuzumab, which is indicated for the treatment of HER2 positive, early breast cancer) and the combination of the two.