Olaratumab and doxorubicin versus doxorubicin alone for treatment of soft-tissue sarcoma: an open-label phase 1b and randomised phase 2 trial.

Abstract

BACKGROUND:

Treatment with doxorubicin is a present standard of care for patients with metastatic soft-tissue sarcoma and median overall survival for those treated is 12-16 months, but few, if any, novel treatments or chemotherapy combinations have been able to improve these poor outcomes. Olaratumab is a human antiplatelet-derived growth factor receptor α monoclonal antibody that has antitumour activity in human sarcoma xenografts. We aimed to assess the efficacy of olaratumab plus doxorubicin in patients with advanced or metastatic soft-tissue sarcoma.

METHODS:

We did an open-label phase 1b and randomised phase 2 study of doxorubicin plus olaratumab treatment in patients with unresectable or metastatic soft-tissue sarcoma at 16 clinical sites in the USA. For both the phase 1b and phase 2 parts of the study, eligible patients were aged 18 years or older and had a histologically confirmed diagnosis of locally advanced or metastatic soft-tissue sarcoma not previously treated with an anthracycline, an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2, and available tumour tissue to determine PDGFRα expression by immunohistochemistry. In the phase 2 part of the study, patients were randomly assigned in a 1:1 ratio to receive either olaratumab (15 mg/kg) intravenously on day 1 and day 8 plus doxorubicin (75 mg/m(2)) or doxorubicin alone (75 mg/m(2)) on day 1 of each 21-day cycle for up to eight cycles. Randomisation was dynamic and used the minimisation randomisation technique. The phase 1b primary endpoint was safety and the phase 2 primary endpoint was progression-free survival using a two-sided α level of 0.2 and statistical power of 0.8. This study was registered with ClinicalTrials.gov, number NCT01185964.

FINDINGS:

15 patients were enrolled and treated with olaratumab plus doxorubicin in the phase 1b study, and 133 patients were randomised (66 to olaratumab plus doxorubicin; 67 to doxorubicin alone) in the phase 2 trial, 129 (97%) of whom received at least one dose of study treatment (64 received olaratumab plus doxorubicin, 65 received doxorubicin). Median progression-free survival in phase 2 was 6.6 months (95% CI 4.1-8.3) with olaratumab plus doxorubicin and 4.1 months (2.8-5.4) with doxorubicin (stratified hazard ratio [HR] 0.67; 0.44-1.02, p=0.0615). Median overall survival was 26.5 months (20.9-31.7) with olaratumab plus doxorubicin and 14.7 months (9.2-17.1) with doxorubicin (stratified HR 0.46, 0.30-0.71, p=0.0003). The objective response rate was 18.2% (9.8-29.6) with olaratumab plus doxorubicin and 11.9% (5.3-22.2) with doxorubicin (p=0.3421). Steady state olaratumab serum concentrations were reached during cycle 3 with mean maximum and trough concentrations ranging from 419 μg/mL (geometric coefficient of variation in percentage [CV%] 26.2) to 487 μg/mL (CV% 33.0) and from 123 μg/mL (CV% 31.2) to 156 μg/mL (CV% 38.0), respectively. Adverse events that were more frequent with olaratumab plus doxorubicin versus doxorubicin alone included neutropenia (37 [58%] vs 23 [35%]), mucositis (34 [53%] vs 23 [35%]), nausea (47 [73%] vs 34 [52%]), vomiting (29 [45%] vs 12 [18%]), and diarrhoea (22 [34%] vs 15 [23%]). Febrile neutropenia of grade 3 or higher was similar in both groups (olaratumab plus doxorubicin: eight [13%] of 64 patients vs doxorubicin: nine [14%] of 65 patients).

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, suggesting a potential shift in the treatment of soft-tissue sarcoma.

FUNDING:

Eli Lilly and Company.

• Authors: William D Tap, Robin L Jones, Brian A Van Tine, Bartosz Chmielowski, Anthony D Elias, Douglas Adkins, Mark Agulnik, Matthew M Cooney, Michael B Livingston, Gregory Pennock, Meera R Hameed, Gaurav D Shah, Amy Qin, Ashwin Shahir, Damien M Cronier, Robert Ilaria Jr, Ilaria Conti, Jan Cosaert, Gary K Schwartz
• Journal: Lancet (London, England) (Lancet) Vol. 388 Issue 10043 Pg. 488-97 (Jul 30 2016) ISSN: 1474-547X [Electronic] England
• PMID: 27291997 (Publication Type: Clinical Trial, Phase I, Clinical Trial, Phase II, Journal Article, Multicenter Study, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2016 Elsevier Ltd. All rights reserved.

Chemical References

• Antibiotics, Antineoplastic
• Antibodies, Monoclonal
• Doxorubicin
• olaratumab

Topics

• Adult
• Aged
• Aged, 80 and over
• Antibiotics, Antineoplastic (administration & dosage, therapeutic use)
• Antibodies, Monoclonal (administration & dosage)
• Antineoplastic Combined Chemotherapy Protocols (therapeutic use)
• Disease-Free Survival
• Doxorubicin (administration & dosage, therapeutic use)
• Drug Administration Schedule
• Female
• Humans
• Kaplan-Meier Estimate
• Male
• Middle Aged
• Patient Selection
• Sarcoma (drug therapy)
• Treatment Outcome
• United States