1171P - Real-time identification of lung adenocarcinoma tumor lesions likely to respond to vintafolide treatment by using etarfolatide

Date 28 September 2014
Event ESMO 2014
Session Poster Display session
Topics Cytotoxic agents
Thoracic malignancies
Basic Principles in the Management and Treatment (of cancer)
Biological therapy
Presenter Edward Garon
Citation Annals of Oncology (2014) 25 (suppl_4): iv406-iv408. 10.1093/annonc/mdu346
Authors E.B. Garon1, W. Harb2, P. Bonomi3, S. Yao4, B. Nguyen5, R. Mogg6, M. Edelman7
  • 1Medicine, David Geffen School of Medicine at UCLA, 90404 - Santa Monica/US
  • 2Inc., Horizon Oncology Research,, Lafayette/US
  • 3Hematology And Oncology, Rush University Medical Center, 60614 - Chicago/US
  • 4Oncology, Merck Research Laboratories, Whitehouse Station/US
  • 5Clinical Development, Endocyte, Inc., Indianapolis/US
  • 6Biostatistics And Research Decision Sciences, Merck Research Laboratories, North Wales/US
  • 7Internal Medicine/cancer Center, University of New Mexico Health Sciences Center, Albuquerque/US



Companion diagnostics for cancer are frequently inaccurate as they are tissue based and do not account for heterogeneity of metastatic lesions and/or were obtained at remote time points. Real-time imaging overcomes these problems by evaluating disease immediately before therapeutic decision making. This analysis evaluated the performance characteristics of etarfolatide (EC20), a technetium-folate imaging agent, in conjunction with vintafolide (EC145), a folate receptor targeting agent.


115 baseline lesions from 29 patients (pts) were evaluated in a phase 2, open-label, multicenter study of vintafolide in lung adenocarcinoma (NCT00511485). Pts had to have EC20 uptake in at least 1 index lesion to be eligible. Data from 9 pts (35 lesions) without follow-up and 7 pts (10 lesions) with no information on EC20 status were excluded. Final analysis set included 70 lesions from 20 pts. Any decrease and ≥30% decrease in tumor size were evaluated using positive predictive value (PPV, % of EC20+ lesion that decreased), negative predictive value (NPV, % of EC20– lesion that did not decrease), sensitivity (SEN, EC20+ to identify lesion that decreased), and specificity (SPE, EC20– to identify lesion that did not decrease).


Of 70 lesions, 53 (76%) were EC20+ and 17 (24%) were EC20–. 21 lesions decreased in size. 18 were EC20+ and the SEN and PPV were 86% and 34%, respectively. 49 lesions did not decrease in size. 14 were EC20– and the SPE and NPV were 29% and 82%, respectively. 6 lesions decreased in size by ≥30%. 5 were EC20 + ; the SEN and PPV were 83% and 9%, respectively. 64 lesions did not decrease in size by ≥30%. 16 were EC20–; the SPE and NPV were 25% and 94%, respectively.


Etarfolatide was able to identify tumors that did and did not respond to vintafolide treatment in a phase 2 lung adenocarcinoma study.


E.B. Garon: Corporate-sponsored research–Merck, Pfizer, Genentech, AstraZeneca, Novartis, PUMA; W.A. Harb: Endocyte-sponsored research for Horizon Oncology Research, Inc.; P. Bonomi: Corporate-sponsored research–Merck & Co., Inc.; S. Yao: Full-time employment–Merck Research Laboratories; B. Nguyen: Full-time employment at Endocyte, Inc., with stock ownership; R. Mogg: Full-time employment at Merck & Co., Inc., with stock ownership; M.J. Edelman: Advisory board member–BMS, Lilly, Genentech. Corporate-sponsored research–BMS, Lilly, Genentech, Endocyte. Other–Synta, BI.