131I-TM-601 is a radiopharmaceutical containing a synthetic version of chlorotoxin, a substance derived from scorpion venom. Chlorotoxin, or TM-601, specifically seeks out and binds to a receptor expressed on tumor cells, but not on normal cells. TM-601 acts as the guidance system that very effectively delivers a radioactive payload to its target, precisely killing the tumor cells and minimizing collateral damage to normal cells.
The phase II study will be conducted in two parts, both involving adult patients with recurrent high-grade glioma. The first sequence is an open-label dose escalation, multi-dose study. Four cohorts of patients will be treated postoperatively at escalating dose levels until the maximum practical dose (MPD) is reached or until determination of the maximum tolerated dose (MTD). After the MPD or MTD is reached, this dose will be expanded in the second trial sequence.
The second trial sequence is an open-label, randomized study in a larger group of patients. Patients will receive either a three- or six-dose treatment cycle at the previously determined MPD or MTD to evaluate the safety, time to disease progression and survival rates after treatment.
The company anticipates that in the first sequence of the study, three patients will be enrolled in each dose cohort. An additional group of three patients may be enrolled at a given dose based on safety. In the second sequence, a total of 54 patients will be randomized in two equal groups treated with either one cycle of three or one cycle of six repeat doses of intracavitary 131I-TM-601.
131I-TM-601 has received orphan drug and fast track development program status from the FDA.