Link AACR 16th Avacta27 Mar 2023 08:53
https://www.abstractsonline.com/pp8/#!/10828/presentation/2606
We have demonstrated that the pre|CISION™ substrate is exquisitely sensitive to FAP and is not cleaved by related proteases. The active AVA3996 warhead should therefore be released primarily following FAP cleavage in the tumor microenvironment.
Cancer cell lines were assessed for their sensitivity to AVA3996 in vitro: activity was typically 100-fold less than the active warhead or Bortezomib alone. Upon co-incubation with soluble FAP, potency of AVA3996 increased to similar levels as seen for the warhead alone demonstrating the masking effect of the pre|CISION™ substrate. A DRF/MTD study established the maximum tolerated dose in rats was around 6-fold higher for AVA3996 compared to warhead alone. This provides further evidence that AVA3996 can be dosed at higher levels than proteasome inhibitor alone, with the potential for greater tumor targeting and hence reduced systemic toxicity.
Ongoing in vivo and co-culture studies aim to further validate the efficacy and tolerability profile of AVA3996 to direct future development of this drug. In addition, the data supports wider utility of the pre|CISION™ platform to target therapeutics to the tumor while reducing systemic dose-limiting toxicities.