
A New Mode of Cancer Treatment 36
The new paper shows preclinical toxicity testing in two species (mice and dogs), which is what you need to get to human trials. It seems to pass those very well, with no signs of trouble at 6x the effective dose in either species. And if you were throwing DSBs all over the place in normal tissues, believe me, you'd see tox. It is clean in an Ames test, for example. As for efficacy, in cell assays the concentration needed for 50% growth inhibition across 70 different cancer cell lines averaged around 300nM, while it showed no toxic effects on various non-cancer lines up to 10 micromolar (at least a 30x window). The affected cells show cell-cycle arrest, replication stress, apoptosis, and so on. And application of AOH1996 along with other known chemotherapy agents made the cells much more sensitive to those, presumably because they couldn't deal with those on top of the problems that AOH1996 was already causing.
It also shows growth arrest in xenograft tumors in mouse models, with a no-effect dose at least six times its effective dose, and combination therapy with a topoisomerase inhibitor showed even more significant effects. The compound has entered a Phase I trial in humans on the basis of the above data, and I very much look forward to seeing it advance to Phase II, where it will doubtless be used in combination with several existing therapies. I hope that human cancers will prove vulnerable to this new mode of attack in the clinic, and that they are not able to mutate around it with new forms of caPCNA too quickly, either. The comparison with the peptide agent mentioned above will be especially interesting, too. There's only one way to find out - good luck to everyone involved!