(ASX:RCE), a company developing new classes of synthetic anti-infectives, has announced further results for its R327.
The company said the fee-for-service program is being undertaken as a collaboration between CSIRO and the Doherty Institute. It said further Stage 1B testing that was highlighted as necessary in the Company’s 12 February 2021 announcement has now been conducted by the Doherty Institute as part of the program budget.
Reece said the results confirmed and extended the findings from the previous report and allowed the half-maximal inhibitory concentration (IC50) of 2,046ppm and cytotoxicity (CC50) of 5,108ppm of R327 to be determined.
It said high concentrations of R327 (13,333ppm and 40,000ppm) showed a 4-log reduction in SARS-CoV-2 viral genome numbers as measured by reverse transcription-polymerase chain reaction (RT-PCR), but severe cellular toxicity was observed in vero cells at these concentrations.
A half maximal Cytotoxic Concentration (CC50) of 5,108ppm was calculated for R327. R327 reduced SARS-CoV-2 viral genome copy numbers at 4,444ppm and was accompanied by reduced infectious virus titres, allowing a half maximum Inhibitory Concentration (IC50) calculation of 2,046ppm. At 4,444ppm, R327 showed some toxicity, with a rounded cell morphology seen on microscopy.
The company said R327 has currently been shown to be effective and not highly toxic at a small window of concentrations in the preliminary in vitro testing in vero cells, and so received a qualified recommendation to proceed to Stage 2 of the Program for further testing in normal human bronchial epithelial (NHBE) cells grown at the air-liquid interface to be conducted by CSIRO, with anticipated results towards the end of the year.
Reece non-executive chairman Dr John Prendergast said, “These encouraging results continue to reinforce our confidence in the potential of R327 against SARS-CoV-2 as another line of defence in the arsenal against COVID-19. We are keen to continue our work with CSIRO in Stage 2 of the Anti-Viral Screening Program.”