Experimental studies have demonstrated that thalidomide has anti-tumor activity 
mediated by blockage of angiogenesis, with clinical efficacy in multiple 
myeloma, glioblastoma multiforme, and renal cell cancer. We investigated the 
therapeutic activity and toxicity of thalidomide in patients with progressive 
metastatic breast cancer pretreated with chemotherapy. Inclusion criteria were 
metastatic breast cancer in progression of disease after at least two lines of 
chemotherapy, age > or = 18 years, performance status < or = 2, and adequate 
hematologic, renal, and hepatic functions. Twelve patients entered the study, 
eight of whom were pretreated with three or more lines of chemotherapy (66.7%). 
Thalidomide was well tolerated: the most common side effects were constipation 
and somnolence (58.3% of patients). No objective response or durable stable 
disease was observed. Median time to progression and median overall survival 
were 8 weeks (range, 4-10 weeks) and 16 weeks (range, 8-54 weeks), respectively. 
In conclusion, thalidomide is an ineffective treatment in patients with 
progressive metastatic breast cancer heavily pretreated with chemotherapy.