Prognostic factors of pazopanib in advanced soft tissue sarcomas
A new analysis confirmed the importance of known prognostic factors such as performance status and tumor grading for having a long-term outcome in patients treated with pazopanib for metastatic soft tissue sarcoma. In addition, hemoglobin at baseline was found to be a new prognostic factor.
Soft tissue sarcomas are a heterogeneous and relatively rare tumor with an estimated incidence of less than 1 per 100,000 people per year in the United States. The prognosis for patients with this disease is favorable if diagnosis is made at an early stage and if all of the tumor can be completely removed surgically. Unfortunately, half of all patients develop distant metastases, and the median overall survival for patients with advanced disease is only approximately 12 months.
“One approach to treat patients with advanced stage soft tissue sarcoma is to target angiogenesis, and pazopanib is a recently approved orally available angiogenesis inhibitor. We analyzed pooled data from two prospective EORTC trials, the phase 2 trial and the phase 3 PALETTE trial in which 118 patients and 226 patients, respectively, were treated with pazopanib, to characterize long-term survivors and responders,” said lead author Bernd Kasper, MD, PhD, of the Sarcoma Unit of the Interdisciplinary Tumor Center at the Mannheim University Medical Center in Germany. This study, by the European Organisation for the Research and Treatment of Cancer (EORTC), was published in the Annals of Oncology (2014; doi:10.1093/annonc/mdt586).
At a median follow-up of 2.3 years, the investigators found that 36% of the patients had a progression-free survival of 6 months or longer, defined as long-term responders, and 34% survived 18 months or longer, defined as long-term survivors.
Furthermore, 3.5% of patients remained progression-free under pazopanib for more than 2 years. Median time on pazopanib in these patients was 2.4 years with longest duration of 3.7 years.
In summary, good performance status, low or intermediate grade of the primary tumor, and a normal hemoglobin level at baseline were advantageous for long-term outcome.