Exploratory biomarker results from early investigation of PEGPH20 in combination with gemcitabine (Gem) in patients with pancreatic cancer (PDA)

• Published in: Journal of clinical oncology Vol. 33; no. 3_suppl; p. 300
• Main Authors: Hingorani, Sunil R., Harris, William Proctor, Beck, Joseph Thaddeus, Berdov, Boris A., Wagner, Stephanie Ann, Pshevlotsky, Eduard M., Tjulandin, Sergei, Gladkov, Oleg, Holcombe, Randall F., Jiang, Ping, Maneval, Daniel C., Korn, Ronald I, Shepard, Harold Michael, Devoe, Craig E.
• Format: Journal Article
• Language: English
• Published: 20-01-2015
• ISSN: 0732-183X; 1527-7755
• DOI: 10.1200/jco.2015.33.3_suppl.300

Abstract only
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Background: PEGPH20 (PEG), a PEGylated recombinant human hyaluronidase, has anti-tumor activity as a single agent and in combination with chemotherapy in preclinical models. A Phase 1b study of PEG + Gem (P+G) in patients (pts) with advanced PDA showed good anti-tumor activity, particularly in pts with HA
high
tumors (ECCO 2013). In this study, we investigated pharmacodynamic (PD) markers including plasma(soluble) HA (sHA), dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) and
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Fluorodeoxyglucose positron emission tomography (PET/CT) to explore additional correlates for PEG activity. Methods: 28 pts with stage IV PDA were treated with PEG at 1, 1.6, or 3µg/kg IV twice weekly for Wks 1-4 and Wks 5-7, followed by 1 wk rest, plus Gem at 1000 mg/m2 IV once weekly for Wks 1-7, then 1 wk rest. Thereafter, P+G was given once weekly for 3 wks in 4-wk cycles. Serial plasma samples were collected and analyzed in a quantitative assay for PEG and sHA. Exploratory imaging by DCE-MRI was performed on selection pts at baseline, 8hr, 24hr and end of cycle 1, PET/CT was performed at baseline and at the end of each cycle. Results: PEG pharmacokinetics was well-characterized by a 2-compartment PK model, peak plasma concentration increased in a dose-proportional manner after a single or repeat administration of PEG. Dose- and time-dependent increases in sHA were observed within 2-3 days after 1.0, 1.6, or 3.0 µg/kg of PEG administration. The median peak concentrations were 3,736; 48,150; and 74,950ng/mL, respectively, and increased with increasing doses. sHA reached steady state approximately 1 wk after repeated PEG administration, consistent with the expected hyaluronidase activity of PEG. Exploratory analysis with DCE-MRI from 6 pts showed an early increase (24hrs) in tumor perfusion (Ktrans) in target lesions. PET/CT from 5 pts showed an average reduction in the maximum standardized uptake value (SUVmax) of 37% at EOC1, and partial metabolic responses using EORTC criteria were achieved in 4 of 5 pts. These results suggest that P+G has measurable biological activity in metastatic PDA Conclusions: Plasma sHA concentration, DCE-MRI and PET/CT are PD markers for evaluation of P+G activity.