Activity and Tolerability of Pazopanib in Advanced and/or Metastatic Liposarcoma. A Phase II Clinical Trial

Soft tissue and bone sarcomas are rare malignant tumors, which encompasses a large family of more than 50 histologically distinct tumor subtypes, all of which share a putative mesenchymal origin. In the case of soft tissue sarcomas (STS) surgical excision is the mainstay of treatment, but despite curative surgery, around half of patients develop distant metastases and die from disease. Few therapeutic approaches are currently available to patients with unresectable, locally advanced, or metastatic STS and only anthracyclines, ifosfamide and trabectedin have shown activity, with response rates of 20-40% in previously untreated patients. Recent and ongoing trials have investigated a variety of combination chemotherapeutic regimens (variously employing ifosfamide, doxorubicin, gemcitabine, temozolomide, vincristine, cisplatin, and dacarbazine, among others) as well as targeted therapies, which in some cases have yielded improvements in response rate but which have had little impact on survival. No other medical option is currently available, and the median survival of patients with soft-tissue sarcoma with non-resectable metastases is around 12-15 months, and approximately 8 months after second line chemotherapy. Liposarcomas are STS which account for at least 20% of all STS in adults. They can be further classified into 3 histologically and biologically different subtypes: well-differentiated liposarcoma/dedifferentiated liposarcoma (ALT-WD), myxoid or round cell liposarcoma and pleomorphic liposarcoma. ALT-WD liposarcomas are locally aggressive rarely metastasizing tumors characterized by ring or giant marker chromosomes on the cytogenetic analysis and by amplification of the 12q13-21 region on Fluorescence In Situ Hybridization (FISH) (MDM2, CDK4 and HMGIC). They account for about 40% iv of liposarcomas with a 5 year Overall survival (OS) around 80%. In a series of WD/DD treated with several regimens response rate was 12.5% OS 15 months and median PFS 3.6 months(9