Molecular Imaging Informs Kidney Cancer Treatment

ImmunoSPECT imaging shows that the effectiveness of a newly developed radioimmunotherapy for treating a resistant form of kidney cancer could be diminished when used after another anti-cancer therapy, researchers found.

The therapy, radiolabeled monoclonal antibody girentuximab (cG250), has been shown to kill the cancer by delivering radiation directly, but it may not be as effective if it is preceded by treatment with sorafenib or similar tyrosine kinase inhibitors (TKIs), according to a study presented at the Society of Nuclear Medicine’s 2012 Annual Meeting, in Miami Beach, Fla.

Researchers from Radboud University Nijmegen Medical Center in Nijmegen, the Netherlands, recruited 15 patients with renal masses to participate to evaluate the effect of TKIs on the targeting of In-111-cG250 in patients with clear cell renal carcinoma. Of the 15 patients, 13 had clear cell renal carcinoma and 10 were also treated with sorafenib.

The patients underwent immunoSPECT imaging, using In-111-cG250 at the start of the study. The 10 patients who took sorafenib were imaged again after completing treatment. The results showed that the 10 patients who received sorafenib had remarkably lower targeting of In-111-cG250 to their tumors. This suggests that imaging and radioimmunotherapy with cG250 drug compounds should begin before treatments with sorafenib or similar TKIs, noted the researchers.

“This research has important implications for future therapeutic regimens for patients with clear cell renal carcinoma,” said Stijn Muselaers, MD, lead physician of the study. “This study indicates that imaging and therapy of tumors with radiolabeled antibodies could be hampered in patients that are being treated with TKIs such as sorafenib. This informs clinicals about the most appropriate sequence of treatments for patients with clear cell renal carcinoma in order to improve the care and potential survival for these patients.”