More on ARX517 in mCRPC

[Maxone73]

More info about this option for castration resistant prostate cancer

onclive.com/view/dr-shen-on...

[DrawingSnowmen]

>Study authors concluded that ARX517 monotherapy demonstrated a favorable safety profile with early efficacy, absent of PSMA imaging selection, among patients with mCRPC who experienced disease progression on multiple FDA-approved treatments. They highlighted that an expansion of cohort 8 and an escalation into the next higher dose (cohort 9) are planned.

It seems like they would have better results if they selected patients with PSMA imaging given that this is PSMA targeted. I wonder why they didn't do that as part of the trial criteria.

onclive.com/view/apex-01-lo...

[Maxone73 in reply to DrawingSnowmen]

I think that’s the point. An “unselected” population

[DrawingSnowmen in reply to Maxone73]

I guess that makes sense in a Phase 1/2 trial. Presumably they would select with PSMA imaging in Phase 3.

[Maxone73 in reply to DrawingSnowmen]

I would not do that at this point. I would still recruit “randomly” then get their PSMA and once the study is done, stratify accordingly. Drugs have complex mechanism and serendipity is always lurking 😜 they may have crated something that works also for a good number of people with no PSMA expression. I would have done that in phase 1/2 as well to be honest, so that is it was ineffective with no PSMA subjects, I could have focused phase 3 on the right subjects. But I am speculating and they know lots more than I do about this! 😀

[DrawingSnowmen in reply to Maxone73]

I actually just found the answer to this in your previous recap of a webcast on ARX517:

>Ambrx also saw in the small dataset the possibility that the treatment will work regardless of a patient’s PSMA biomarker levels, which would mean ARX517 could have access to a wide patient population.

So they do have reason to believe it will be effective either way. That should give more confidence to those participating in the trial.

[God_Loves_Me]

I am planning to do next month. let's see how it goes

[Sailing-Todd]

‘non-cell permeable payload, a noncleavable PEG linker, and a unique oxime conjugation chemistry facilitated by a genetically encoded and biosynthetically integrated synthetic amino acid’.

That’s some clever stuff!

[shaunaliz15]

Would this be a good option for someone who has failed pluvicto and exhausted all other typical treatment options (he is PSMA avid, but didn't respond to pluvicto).