The FDA has granted orphan drug designation to LMP744, a small molecule indenoisoquinoline-based topoisomerase I inhibitor, for the treatment of gliomas. This designation aims to encourage the development of treatments for rare diseases affecting fewer than 200,000 people in the U.S.
LMP744's Mechanism of Action
LMP744 has demonstrated the ability to cross the blood-brain barrier (BBB) at concentrations 10 times higher than required to kill cancer cells, with sustained levels for at least 24 hours per dose. LMP744, along with LMP400 (Indotecan), selectively targets topoisomerase I and the cMyc oncogene by binding to the G4 quadruplex of cMyc, regulating key drivers of cancer.
Clinical Development Plans
Gibson Oncology, the drug's developer, plans a phase 2 trial in collaboration with the National Institutes of Health (NIH) to evaluate both LMP744 and LMP400 in patients with recurrent gliomas. This trial aims to address the unmet need in glioblastoma treatment, where overall survival rates have not significantly improved with the current standard-of-care, temozolomide.
Prior Clinical Data
LMP744 is being evaluated in a multicenter phase 1 study (NCT03030417) in adult patients with metastatic solid tumors or lymphomas that have progressed after initial therapy. Patients received intravenous LMP744 daily on days 1 to 5 of 28-day cycles, starting at 6 mg/m2.
The primary objective of the phase 1 study was to establish the safety, tolerability, and maximum tolerated dose (MTD) of LMP744. At the 2023 ASCO Annual Meeting, investigators reported that the MTD of LMP744 was 190 mg/m2 daily on days 1 to 5 of each 28-day cycle. The agent displayed limited activity as monotherapy in a heavily pretreated patient population. Among 23 response-evaluable patients, 1 patient with small cell lung cancer achieved a partial response (PR), and 16 patients achieved stable disease (SD). The median duration of response for patients who achieved SD was 4.5 cycles (range, 1-28).
