Oops, you're using an old version of your browser so some of the features on this page may not be displaying properly.

MINIMAL Requirements: Google Chrome 24+Mozilla Firefox 20+Internet Explorer 11Opera 15–18Apple Safari 7SeaMonkey 2.15-2.23

Developmental therapeutics

3156 - Early FDG-PET Response Correlates With Dose and Clinical Efficacy in Patients With Microsatellite Stable (MSS) Metastatic CRC (mCRC) Treated With the CEA-CD3 T-cell Bispecific Antibody plus Atezolizumab


09 Sep 2017


Developmental therapeutics


Federico Sandoval


Annals of Oncology (2017) 28 (suppl_5): v122-v141. 10.1093/annonc/mdx367


F. Sandoval1, D. Sabanes Bove2, S. Bouseida3, V. Karanikas4, A. Keelara1, J. Saro4, T. Nayak3

Author affiliations

  • 1 Roche Pharmaceutical Research And Early Development, Roche Innovation Center, CH-4070 - Basel/CH
  • 2 Biostatistics, F. Hoffmann-La Roche Ltd., Basel/CH
  • 3 Roche Pharmaceutical Research And Early Development, Roche Innovation Center, Basel/CH
  • 4 Roche Pharmaceutical Research And Early Development, Roche Innovation Centre, Zurich/CH


Abstract 3156


CEA-CD3 TCB (RG7802, RO6958688) is a novel T-cell bispecific antibody targeting CEA on tumor cells and CD3 on T cells. An ongoing phase Ib study (NCT02650713) is exploring the safety, tolerability and efficacy of CEA-CD3 TCB in combination with atezolizumab. We report preliminary results of FDG-PET imaging as an early pharmacodynamic marker for this novel cancer immunotherapy combination in MSS mCRC patients.


In this study, CEA-CD3 TCB is given QW in combination with atezolizumab 1200 mg Q3W in patients with CEA-expressing solid tumors. As of March 3, 2017, a total of 35 MSS mCRC patients have been treated with CEA-CD3 TCB doses of 5-160 mg; 15 patients were evaluable for PET image analysis. On-treatment FDG-PET scans were performed at week 4 and compared with baseline. On-treatment changes in SUVmax, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were analyzed in up to 10 measurable lesions per patient, identified at baseline by an independent reviewer. The exploratory statistical analyses used semiparametric Gaussian regression models and Cox PH landmark analyses (for progression-free survival [PFS]).


Early changes in FDG-PET parameters showed a dose-response relationship (MTV: P = 0.0022; TLG: P = 0.0054; SUVmax: P = 0.0081); notably all patients receiving doses ≥ 80 mg (n = 7) showed decreases in SUVmax, TLG and MTV at week 4. Furthermore, week 4 reductions in FDG uptake (MTV: P < 0.001; TLG: P < 0.001; SUVmax: P = 0.0061) correlated with later tumor shrinkage (best change from baseline per RECIST v1.1). Reduction in MTV and TLG, but not SUVmax, correlated with decreases in soluble CEA levels measured at week 6 (MTV: P = 0.013; TLG: P = 0.034; SUVmax: P = 0.54) and longer PFS (MTV: P = 0.013; TLG: P = 0.052; SUVmax: P = 0.85).


In MSS mCRC patients, changes in MTV, TLG and SUVmax correlated with dose and tumor shrinkage. Decreases in 2 FDG parameters (MTV and TLG) correlated with a reduction in soluble CEA levels. Early on-treatment changes in FDG-PET can serve as a pharmacodynamic biomarker related to treatment efficacy.

Clinical trial identification


Legal entity responsible for the study

F. Hoffmann-La Roche Ltd.


F. Hoffmann-La Roche Ltd.


F. Sandoval, D. Sabanes Bove, S. Bouseida, V. Karanikas, A. Keelara: Roche employee. J. Saro: Employee of Roche and stock holder of Roche. T. Nayak: Roche stock.

This site uses cookies. Some of these cookies are essential, while others help us improve your experience by providing insights into how the site is being used.

For more detailed information on the cookies we use, please check our Privacy Policy.

Customise settings
  • Necessary cookies enable core functionality. The website cannot function properly without these cookies, and you can only disable them by changing your browser preferences.