Inhibrx's INBRX-105 Shows Dose-Limiting Toxicities In Early-Stage Solid Tumors Study

Inhibrx Inc (NASDAQ: INBX) has announced results from the dose escalation of the Phase 1 study evaluating INBRX-105 in locally advanced or metastatic solid tumors.

• INBRX-105 is a precisely engineered multi-specific therapeutic candidate based on a single-domain antibody platform.
• It is designed to agonize 4-1BB selectively in the presence of programmed death-ligand 1, a protein that is typically found in the tumor microenvironment and lymphoid tissues.
• The 32-subject trial was designed to determine the safety profile and identify the maximum tolerated dose and/or recommended Phase 2 dose of INBRX-105 administered as a single agent or in combination with Merck & Co's (NYSE: MRK) Keytruda (pembrolizumab).
• Dose-limiting toxicities were observed at several dose levels and determined the 1 mg/kg dose level as the maximum tolerated dose of INBRX-105.
• Eight out of 18 evaluable patients (44%) receiving INBRX-105 achieved stable disease, with the greatest reduction in tumor volume observed to be 20%.
• The longest duration of the treatment with INBRX-105 was 41 weeks or approximately nine and a half months.
• The Dose-escalation cohort of INBRX-105, in combination with Keytruda, will start enrollment during the second quarter of 2021.
• Initial data is expected during the fourth quarter of 2021.
• Additionally, the company reported cash and cash equivalents of $128.7 million as of 31 December 2020.
• Price Action: INBX shares are down 4% at $24.1 in market trading hours on the last check Friday.