Use of the peroxisome proliferator-activated receptor (PPAR) gamma ligand troglitazone as treatment for refractory breast cancer: a phase II study.
OBJECTIVE
To evaluate the therapeutic effects of the peroxisome proliferator-activated receptor (PPAR) gamma activating ligand, troglitazone, in patients with refractory metastatic breast cancer.


METHODS
Patients with advanced breast cancer refractory to at least one chemotherapy regimen (ER negative tumors) or two hormonal regimens (ER positive tumors) were treated with troglitazone at 800 mg p.o. QD until disease progression, to determine the percentage of patients free of progression at 6 months. Tumor response, toxicity, and changes in serum tumor markers (CEA, CA27.29) that might reflect alteration in tumor differentiation, were also examined.


RESULTS
Twenty-two patients were enrolled before suspension of protocol accrual and treatment when troglitazone was withdrawn from commercial availability following FDA warnings on hepatic toxicity. No objective responses (CR or PR) were observed; only three patients had SD at 8 weeks. Patients came off study for PD (16), DLT (1), FDA withdrawal (2), or other (3) reasons. No patients took troglitazone for more than 20 weeks; all had experienced disease progression or began other systemic therapy within 6 months. All patients with elevated serum tumor markers (CEA and CA27.29) at baseline had rising tumor markers within 8 weeks.


CONCLUSIONS
While clinical trials among different patient populations might uncover subtle effects on tumor differentiation, PPARgamma activation by troglitazone has little apparent clinical value among patients with treatment-refractory metastatic breast cancer.
Burstein
Harold J
HJ
Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA. hburstein@partners.org
Demetri
George D
GD
Mueller
Elisabetta
E
Sarraf
Pasha
P
Spiegelman
Bruce M
BM
Winer
Eric P
EP
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D002839:Chromans / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008099:Liver / Q000187:drug effects / Q000473:pathology; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D013844:Thiazoles / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D045162:Thiazolidinediones; D016896:Treatment Outcome; D000077288:Troglitazone
D000970:Antineoplastic Agents; D002839:Chromans; D013844:Thiazoles; D045162:Thiazolidinediones; D000077288:Troglitazone