RE: Science Day - possible new lines of development?26 Apr 2026 11:14
Somewhere between doing the investigative work and putting that post together, the focus of my thoughts got diverted.
Beyond the Topoisomerase inhibitors doxorubicin and exatecan, the chemotherapies that Avacta is taking to market, there are possibilities to affect the intracellular pathways of cancer cells, either pathway agonists (such as STING agonists) that work by binding to specific cell receptors and activating them to produce a biological response or pathway inhibitors (such as proteasome inhibitors) that work by binding to enzymes and reducing or blocking their activity, effectively controlling cellular metabolism, slowing down specific chemical reactions, or stopping the function of enzymes. These last work by either binding directly to the enzyme's active site (competitive) or to a separate site that changes the enzyme's shape (allosteric/non-competitive).
So...
3. should really be headed 'Pathway agonists (STING agonists, etc.)' rather than 'STING agonists & other classes of agents acting off-target'.
and
4. should really be headed 'Pathway inhibitors (proteasome inhibitors, etc.) rather than 'Checkpoint inhibitors'. There are many pathway inhibitors, including inhibitors of tyrosine kinases (VEGFR, EGFR, ALK), the PI3K/AKT/mTOR pathway, the MAPK pathway (BRAF, MEK), and the Hedgehog signaling pathway as well as the ubiquitin-proteasome pathway. This last one is the pathway inhibited by bortezomib (Velcade) and our own bortezomib analogue, AVA3996.
There are also pathway antagonists, which work by disrupting specific cellular signaling pathways that drive disease, such as cancer growth, inflammation, or overactive metabolism, so why not include them in Avacta's development plans? These act as "off-switches" (so the opposite of agonists) by blocking key protein receptors or enzymes, preventing natural agonists from sending messages that tell cells to divide or survive, thus stopping pathological processes.
5. now becomes 'Pathway agonists, inhibitors or antagonists paired with a complementary warhead (or two)'...
So, in summary, even more possibilities than in my original post!, which was prompted by rediscovering a seemingly forgotten interview that I'll link in the next post.