Soft tissue sarcomas (STSs) gather over 80 histological entities, with even more molecular subsets, characterised by a low to very low incidence in all populations. The majority of sarcomas arise from the soft tissue (close to 75%), with 15% gastrointestinal stromal tumours (GISTs) and 10% bone sarcomas. These ESMO-EURACAN (European Society for Medical Oncology-European Reference Network for rare adult solid cancers) Clinical Practice Guidelines cover STSs, while GISTs are covered by dedicated ESMO-EURACAN Clinical Practice Guidelines [1]. Kaposi's sarcoma is not considered in the present document. Extraskeletal Ewing and Ewing-like sarcoma is covered by ESMO Clinical Practice Guidelines on bone sarcomas [2]. In general, the
Trabectedin demonstrates superior disease control versus conventional dacarbazine in patients who have advanced liposarcoma and leiomyosarcoma after they experience failure of prior chemotherapy. Because disease control in advanced sarcomas is a clinically relevant end point, this study supports the activity of trabectedin for patients with these malignancies.
Background
Median overall survival for patients with metastatic soft tissue sarcoma is 12 to 16 months. Olaratumab is a human anti–platelet-derived growth factor receptor α monoclonal antibody which has antitumour activity in human sarcoma xenografts.
Methods
We conducted an open-label phase 1b, randomised, phase 2 study of doxorubicin ± olaratumab in patients with unresectable/metastatic soft tissue sarcoma. The phase 1b primary endpoint was safety; the phase 2 primary endpoint was progression-free survival using a two-sided alpha level of 0·2 and statistical power of 0·8. This study was registered with ClinicalTrials.gov, number NCT01185964.
Findings
Fifteen patients were enrolled and treated with olaratumab+doxorubicin in the phase 1b portion; 133 patients were randomised (66 to olaratumab+doxorubicin; 67 to doxorubicin) in the phase 2 portion, 129 of whom (97%) received at least one dose of study treatment (64 olaratumab+doxorubicin; 65 doxorubicin). Median progression-free survival in phase 2 was 6·6 months (95% confidence interval [CI], 4·1–8·3) with olaratumab+doxorubicin and 4·1 months (95% CI, 2·8–5·4) with doxorubicin (stratified hazard ratio [HR], 0·672; 95% CI, 0·442–1·021; p=0·0615). Median overall survival was 26·5 months (95% CI, 20·9–31·7) with olaratumab+doxorubicin and 14·7 months (95% CI, 9·2–17·1) with doxorubicin (stratified HR, 0·463; 95% CI, 0·301–0·710; p=0·0003). Adverse events more frequent with olaratumab+doxorubicin vs doxorubicin alone included neutropenia (38 [59%] vs 25 [39%]), mucositis (34 [53%] vs 23 [35%]), nausea (47 [73%] vs 34 [52%]), vomiting (29 [45%] vs 12 [19%]), and diarrhea (22 [34%] vs 15 [23%]). Febrile neutropenia of grade ≥3 was similar in both groups (olaratumab plus doxorubicin 8 (13%) vs doxorubicin 9 (14%).
Interpretation
This study of olaratumab with doxorubicin in patients with advanced soft tissue sarcoma met its predefined primary endpoint for progression-free survival and achieved a highly significant improvement of 11·8 months in median overall survival (P=0·0003; HR 0·46).
Funding
Eli Lilly and Company.
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