[ 89 Zr]Zr-rituximab PET/CT activity in patients with therapy refractory interstitial pneumonitis: a feasibility study

• Published in: American journal of nuclear medicine and molecular imaging Vol. 9; no. 6; pp. 296 - 308
• Main Authors: Adams, Human, van de Garde, Ewoudt Mw, van Moorsel, Coline Hm, Vugts, Danielle J, van Dongen, Guus Ams, Grutters, Jan C, Keijsers, Ruth G
• Format: Journal Article
• Language: English
• Published: United States e-Century Publishing Corporation 01.01.2019
• Subjects: Original; Rituximab; zirconium; immuno-PET; [89Zr]Zr-rituximab PET/CT; interstitial pneumonitis; pulmonary activity
• ISSN: 2160-8407; 2160-8407

Recent studies on immune-mediated inflammatory lung diseases show encouraging treatment results with rituximab, a monoclonal antibody (mAb) against CD20-expressing B lymphocytes. The present pilot study aimed to explore the possibility to image CD20-expression in the lungs as future early predictor of treatment response. We describe a series of 10 patients with therapy refractory interstitial pneumonitis who were treated with rituximab (1000 mg at day 0 and day 14) and underwent PET/CT after the administration of [ Zr]Zr- -suc-DFO-rituximab abbreviated as [ Zr]Zr-rituximab. [ Zr]-rituximab PET/CT of the chest was performed on day 3 and 6. [ Zr]Zr-rituximab PET/CT showed visual and quantifiable increased pulmonary activity in four patients. Other patients demonstrated no increased activity in the lungs. One patient developed a severe allergic reaction during infusion of the first 10% unlabeled rituximab after which rituximab infusion was ceased. Subsequent administration of [ Zr]Zr-rituximab, however, did not result in any adverse reaction. This patient demonstrated the highest uptake of [ Zr]Zr-rituximab in mediastinal lymph nodes and lung parenchyma compared to the other 9 patients who did receive the full dose rituximab before [ Zr]Zr-rituximab. This pilot study demonstrates that [ Zr]Zr-rituximab PET/CT imaging in patients with therapy refractory interstitial pneumonitis is feasible and shows lung-specific uptake in some patients. Further research with larger sample size should establish if the [ Zr]Zr-rituximab uptake correlates with treatment response to rituximab. The higher uptake in the absence of a full 1000 mg rituximab preload may suggest that future studies should consider [ Zr]Zr-rituximab imaging at low mAb dose before treatment with rituximab.