1. Circulating Tumor Cells and Biomarker Modulation with Olaratumab Monotherapy Followed by Olaratumab plus Doxorubicin: Phase Ib Study in Patients with Soft-Tissue Sarcoma
- Author
-
Hong Wang, Antonio López Pousa, Silvia Stacchiotti, Anna M. Szpurka, Andrew S. Brohl, Benjamin C. Powers, Gerard J. Oakley, Brian A. Van Tine, Gary Mo, Donna E. Levy, James S. Hu, Javier Martin-Broto, Robin L. Jones, Jean-Yves Blay, Matteo Ceccarelli, and Eli Lilly and Company
- Subjects
0301 basic medicine ,Oncology ,Adult ,Male ,Cancer Research ,medicine.medical_specialty ,Receptor, Platelet-Derived Growth Factor alpha ,Kaplan-Meier Estimate ,Ligands ,Receptor, Platelet-Derived Growth Factor beta ,03 medical and health sciences ,0302 clinical medicine ,Circulating tumor cell ,Pharmacokinetics ,Internal medicine ,medicine ,Biomarkers, Tumor ,Humans ,Doxorubicin ,Whole blood ,Aged ,Platelet-Derived Growth Factor ,business.industry ,Soft tissue sarcoma ,Antibodies, Monoclonal ,Sarcoma ,Middle Aged ,medicine.disease ,Neoplastic Cells, Circulating ,030104 developmental biology ,Treatment Outcome ,030220 oncology & carcinogenesis ,Positron-Emission Tomography ,Biomarker (medicine) ,Immunohistochemistry ,Female ,business ,Olaratumab ,medicine.drug - Abstract
This phase Ib study enumerated whole blood circulating tumor cells (CTC) and evaluated biomarkers in patients with potentially resectable soft-tissue sarcoma (STS) treated with olaratumab monotherapy (20 mg/kg) for one cycle followed by up to six cycles of olaratumab (20 mg/kg, cycles 1–2; 15 mg/kg, cycles 3–7) plus doxorubicin (75 mg/m2 on day 1). CTCs, platelet-derived growth factor receptors (PDGFR), and PDGF ligand expression in tumor tissue pre- and post-olaratumab monotherapy were evaluated. Antitumor activity, safety, pharmacokinetics, and PET/biomarker association with clinical outcome were assessed. Of 51 treated patients, 35, 43, and 37 were evaluable for CTC enumeration, PDGFRs, and PDGF ligand expression, respectively. An increase in CTCs at cycle 1 day 8 was observed, followed by a significant reduction by cycle 3 day 1 or 30-day follow-up. Decrease in CTC counts after olaratumab monotherapy was higher in patients with disease control than without disease control (57.9% vs. 31.2%). Baseline IHC expression was positive in most patients for PDGFRα [n = 31 (72.1%)] and PDGFRβ [n = 36 (83.7%)]. Similar rates were observed post-olaratumab monotherapy [PDGFRα, n = 30 (69.8%); PDGFRβ, n = 33 (76.7%)]. Eleven patients (29.7%) showed a 30% reduction by RT-PCR in PDGFRα at cycle 2. PDGFR expression and PET response showed no correlation with clinical outcome. Safety and pharmacokinetic profiles were consistent with previous reports. This study, the first to use a validated method for CTC detection, confirms that CTC enumeration in STS is feasible. However, no correlation was observed between PDGFRα expression and clinical outcome., This work was supported by Eli Lilly and Company.
- Published
- 2020