TransMolecular, a biotechnology company focused on targeted therapies for cancer, presented its imaging and pharmacokinetic analysis of intravenous (131)I-TM601 in patients with primary malignant glioma or solid tumor metastases in an oral presentation at the Society for Nuclear Medicine's (SNM) 55th annual meeting this week.
According to investigators at Northwestern Memorial Hospital and Northwestern University Feinberg School of Medicine, the pharmacokinetic analysis revealed that (131)I-TM601 rapidly clears from the blood stream and is then quickly removed from the body through the urinary system.
Additionally, imaging localization analysis showed that three of five evaluable patients demonstrated tumor-specific uptake of (131)I-TM601 into known areas of tumor involvement. A subsequent analysis from this study revealed that all five glioma patients demonstrated uptake and that in a melanoma subset of this study, five out of six patients demonstrated uptake, said Stewart Spies, MD, professor of radiology and medical director of nuclear medicine at Northwestern University Medical Center in Chicago.
"The rapid clearance of radiolabled TM601 may help to explain the low systemic toxicity observed in clinical trials to-date," said Spies.
Six patients received one to three treatment doses of (131)I-TM601 intravenously, ranging from 0.2 mg of TM601 labeled with 10 mCi (131)Iodine radioisotope to 0.6 mg TM601 labeled with 30 mCi (131)iodine radioisotope. Multiple whole body images were obtained at one hour and up to 72 hours following injection, according to the researchers.
Blood samples were obtained following each whole body image and urine was collected for the first 24 hours post-injection. The blood pool and total urine activity at 24 hours were calculated and expressed as a percent of injected dose.
Michael Egan, president and CEO of TransMolecular, said that the tumor-specific binding and uptake shown in this analysis builds on similar findings from several prior clinical studies with radiolabeled TM601, and demonstrates the specific targeting of this peptide to tumor tissue.
“These positive attributes and its favorable pharmacokinetic profile contribute to the broad promise of the TM601 platform, which also includes potential efficacy in multiple cancer types, potential for treating patients with TM601 on its own as well as linked to radiation, and utility for using TM601 to deliver other treatments directly to cancer cells. We have further advanced this platform with the initiations of Phase 2 trials in melanoma and malignant glioma with radiolabeled TM601, as well as a Phase 1 trial with the unlabeled version of TM601 in malignant glioma,” Egan noted.