Paclitaxel activity in anthracycline refractory breast cancer patients.
OBJECTIVE
We investigated the efficacy and tolerability of two doses of paclitaxel, 175 mg/m2 and 135 mg/m2, over a 3-hr infusion, without prophylactic G-CSF, in heavily pretreated patients with anthracycline-resistant breast cancer. Although paclitaxel may share with anthracyclines a common mechanism of drug resistance, there is evidence that the two drugs are not completely cross resistant.


METHODS
From July 1994 to January 1996, 42 patients were treated every 3 weeks, for a maximum of 6 cycles; paclitaxel dose was established according to pretreatment extension.


RESULTS
In 41 assessable patients we observed 9 partial responses, for an overall response rate of 22% (95% CI, 10-34%). There was no difference in response rate between the two dose levels. Median duration of response was 9 months, median time to progression 5 months, and median survival 9 months. The dose-limiting toxicity was neutropenia, which was grade 3-4 in 40% (135 mg/m2) and 62% (175 mg/m2) of the patients (P = 0.28); neutropenic fever occurred in 24% of the patients, without significant differences between the two dose levels. Other toxicity was mild to moderate.


CONCLUSIONS
Paclitaxel at doses of 175 mg/m2 or 135 mg/m2 is active and well tolerated in advanced breast cancer patients resistant to anthracyclines. The prophylactic use of colony-stimulating factors seems appropriate in heavily pretreated patients given the higher dose level.
Vici
P
P
II Department of Medical Oncology, Regina Elena Institute for Cancer Research, Rome, Italy.
Di Lauro
L
L
Conti
F
F
Capomolla
E
E
Gionfra
T
T
Amodio
A
A
Lopez
M
M
D000328:Adult; D000368:Aged; D000903:Antibiotics, Antineoplastic / Q000627:therapeutic use*; D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D018450:Disease Progression; D018572:Disease-Free Survival; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D019008:Drug Resistance, Neoplasm; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000627:therapeutic use; D006801:Humans; D007262:Infusions, Intravenous; D008875:Middle Aged; D017239:Paclitaxel / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D010166:Palliative Care; D011446:Prospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome
D000903:Antibiotics, Antineoplastic; D000972:Antineoplastic Agents, Phytogenic; D016179:Granulocyte Colony-Stimulating Factor; D017239:Paclitaxel