It Works™ - but PDC competition for Avacta?30 Nov 2025 14:18
CC was adsked about our competitor PDCs at this year's Interims IMC meeting on 30 Sept, reproduced below verbatim.
Question 10: How does a factor think about competing peptide drug conjugate platforms at Philogen and bicycle?
Answer from Meeting: "So, our precision platform has a couple of key differences, compared to, these other peptide drug conjugates. We often get this, question from, institutional investors.
"So, let me take bicycle first. The bicycle, peptide drug conjugates don't use a cleavable technology...[I've edited the rest of this part out]
"And then to take the second part of that one, it's similar, but, the phylogen approach also uses a fat cleavable linker, so much closer to, the precision technology. However, they do substitute out the alanine residue. Remember, ours is an alanine prolene, and it's a post FA is a post-prolene, cleaving enzyme, and so that substitution actually greatly reduces the specificity for FA cleavage, so it will be. Cleavable by other postprolene cleaving enzymes and so that reduces the specificity of, the phylogen approach and so we would predict that their results would be similar to the bicycle. Lower specificity would mean lower concentration in the tumor microenvironment, but, also it, could result in, higher rates of toxicities because those cleavage points would be,. The, the cleavage would be not just specific in the tumor, but you could see, you know, more of those ADC like toxicities there."
https://www.investormeetcompany.com/meetings/interim-results-491
Yeah, I know. No one could be rsed to clean up the transcript.
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The nub of what CC said is that whilst the natural substrate for FAP is a Gly-Pro dipeptide sequence, that sequence is not specific for just FAP and can be cleaved, but to a lesser extent, by prolyl oligopeptidase (POP), aka prolyl endopeptidase (PREP).
The Philogen/Philochem PDC has that sequence: OncoFAP-GlyPro-MMAE - https://www.philogen.com/pipeline/oncofap-glypro-mmae/ - so that means some non-FAP cleavage, and hence potential side-effects/toxicity.
Gly contains H-C-H, whilst Ala contains H-C-CH3 around their alpha carbons. The D-Ala of the pre|CISION substrate's D-Ala-L-Pro* dipeptide sequence will partly mimic Gly in the FAP receptor pocket when the small methyl (-CH3) group on D-Ala points away from the pocket. The consequence of that is that a substrate with D-Ala is not as efficiently cleaved as one with Gly. That's on the negative side. On the positive side, having D-Ala instead of Gly means that the substrate is not cleavable by POP/PREP. In other words it's a trade-off with pre|CISION: less FAP cleavage efficiency for no cleavage by POP/PREP.
This means the dose can be increased without fear of non-FAP cleavage (re: no MTD found for AVA6000) and, as they are doing, altering the chemistry so that the pre|CISION substrate hangs around near to FAP for longer will increase total cleavage and hence efficacy.
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* https://www.google.com/search?q=D+and+