Recombinant HIV type 1 gp140 (SHIV SF162P3) (a.a. 30-668) [His]

QF-036 is an HIV-1 maturation inhibitor in pre-clinical development, and its antiviral activity against a laboratory HIV-1 strain and two drug-resistant strains was determined in the C8166 line. QF-036 was also subjected to absorption, distribution and metabolism (ADM) assessment in vitro, and pharmacokinetic profiles were evaluated in rats and monkeys. The 50% effective concentrations (EC50) of QF-036 against the three strains were 20.36 nM, 0.39 mu M and 2.11 nM, respectively, demonstrating better antiviral potential than the first-generation antiviral maturation inhibitor bevirimat. QF-036 demonstrated moderate cell permeability, high plasma protein binding ability and good metabolic stability in vitro. After oral QF-036 administration to rats and monkeys, both species exhibited moderate bioavailability, and the plasma drug exposure increased in an approximately dose-proportional manner. When administered orally (30 mg/kg) to monkeys, the QF-036 plasma concentration (C-max) peaked at 3671 ng/mL (4.82 mu M), 12 to 2410 times higher than the EC50 of laboratory or resistant HIV-1 strains. Moreover, the plasma concentration of QF-036 at 12 hours after administration was 263 ng/mL (0.35 mu M), which approximately matched the highest EC(50)value of the three test strains. The favourable viral inhibitory activity and pharmacokinetic properties provide critical support for QF-036 as a promising anti-HIV therapeutic candidate.

Merkel cell polyomavirus (MCPyV) viral protein 1 (VP1) is the capsid protein that mediates virus attachment to host cell receptors and is the major immune target. Given the limited data on MCPyV VP1 mutations, the VP1 genetic variability was examined in 100 plasma and 100 urine samples from 100 HIV+ individuals. Sequencing of VP1 DNA in 17 urine and 17 plasma specimens, simultaneously MCPyV DNA positive, revealed that 27 samples displayed sequences identical to VP1 of MCC350 strain. VP1 from two urine specimens had either Thr47Ser or Ile115Phe substitution, whereas VP1 of one plasma contained Asp69Val and Ser251Phe substitutions plus deletion ( increment ) of Tyr79. VP1 DNA in the remaining samples had mutations encoding truncated protein. Three-dimensional prediction models revealed that Asp69Val, Ser251Phe, and Ile115Phe caused neutral effects while Thr47Ser and Tyr79 increment produced a deleterious effect reducing VP1 stability. A549 cells infected with urine or plasma samples containing full-length VP1 variants with substitutions, sustained viral DNA replication and VP1 expression. Moreover, medium harvested from these cells was able to infect new A549 cells. In cells infected by samples with truncated VP1, MCPyV replication was hampered. In conclusion, MCPyV strains with unique mutations in the VP1 gene are circulating in HIV+ patients. These strains display altered replication efficiency compared to the MCC350 prototype strain in A549 cells.