Baylor-Charles A. Sammons Cancer Center and Physician Reliance
Network (PRN) Research recently announced data demonstrating that one
in five patients with hard-to-treat metastatic breast cancers
responded to capecitabine (Xeloda) even though they had previously
not responded to treatment with paclitaxel (Taxol) and an
anthracycline-containing regimen. Capecitabine is the first
chemotherapy for metastatic breast cancer that is biochemically
targeted to attack cancer cells.
The data are part of the results of a phase II study of capecitabine
that appeared in the February 1999 issue of the Journal of Clinical
Oncology. The large, phase II, multicenter trial, conducted at 25
hospitals and cancer centers in the United States and Canada,
established that capecitabine is effective even in heavily pretreated
patients with metastatic breast cancer. In the study, capecitabine
demonstrated a favorable side effect profile.
Therapy Activated by Enzymes Found Primarily in Tumors
Xeloda is an exciting new option for the treatment of
metastatic breast cancer, said Joanne Blum, MD, PhD, lead
investigator of the study. It is unique among currently
available therapies, as it is activated by enzymes in the body that
are primarily found in tumors, thus focusing the cancer killing agent
primarily at the site of the cancer while limiting adverse events and
damage to healthy issue. Xelodas pill form permits patients to
be treated at home and live more normal lives.
The clinical trial, involving 163 patients, tested the efficacy and
safety of capecitabine at 2,510 mg/m²/d, divided into two daily
doses over a period of 2 weeks, followed by a 1-week rest period, and
repeated in 3-week cycles. Of the 135 patients with measurable
disease, 27 (20%) had complete or partial responses, and 3 achieved a
complete remission. The data from this trial were the basis for the
approval of capecitabine by FDA in May 1998.
Side Effects Profile
Adverse events associated with the dosing schedule of capecitabine
used in this study were predictable and controllable. There were no
treatment-related deaths and few treatment-related serious adverse
events (12%). Of the 54 serious adverse events, only 18 were
considered to be related to the study treatment. The majority of
treatment-related adverse events were rated as mild or moderate in
intensity (grade 1 or 2) and were generally manageable and reversible
after dosage adjustment or drug discontinuation.
Dosage was adjusted at any time during the study on the basis of
grade 2 or greater treatment-related adverse events. Treatment was
discontinued in only 7% of patients. The most frequent
treatment-related adverse events were, in decreasing order of
frequency: hand-foot syndrome, diarrhea, nausea, vomiting, and
fatigue. Significant hair loss was not reported; rather, hair
regrowth occurred in most patients with alopecia at baseline.