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 Anti-Cancer Agents & Biologic Therapy
Diagnostics
Lung and other Thoracic Tumours
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

Abstract

Aim

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.

Methods

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).

Results

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.

Conclusions

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

Disclosure

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.