GRL-07524 (Compound 4e) is a potent HIV-1 protease inhibitor with a Ki of 0.22 nM. It contains an oxaspirocarbamate as the P2 ligand and demonstrates strong antiviral activity, with an EC50 of 210 nM. GRL-07524 can bind to the active site of HIV-1PR and crucial catalytic residues, interacting with one of four symmetric-independent molecules.