Olaratumab is a humanized IgG1 monoclonal antibody that blocks the platelet-derived growth factor receptor alpha (PDGFRα). Its antagonistic behavior inhibits the receptor's tyrosine kinase activity, thereby, turning off the downstream signaling cascades responsible for soft tissue sarcoma tumorigenesis. In October 2016, olaratumab received Food and Drug Administration (FDA) approval for its use in combination with doxorubicin for treatment of advanced soft tissue sarcoma. Areas covered: This drug profile takes a comprehensive look at the clinical studies leading to FDA approval of olaratumab as well as its safety and efficacy as a front-line treatment option for sarcoma patients. The literature search was primarily conducted using PubMed. Expert commentary: The combination of olaratumab plus doxorubicin has provided a new front-line therapeutic option for soft tissue sarcoma patients. An open-label phase Ib and randomized phase II trial in patients with advanced soft tissue sarcoma demonstrated that the addition of olaratumab to doxorubicin prolonged progression-free survival by 2.5 months and overall survival by 11.8 months when compared to doxorubicin alone. Of importance, this clinically meaningful increase in overall survival did not come at the expense of a significantly greater number of toxicities. A phase III confirmatory trial (ClinicalTrials.gov Identifier NCT02451943) will be completed in 2020.
Keywords: Doxorubicin; Olaratumab; PDGFRα antagonist; soft tissue sarcoma; tyrosine kinase inhibitor.