Hey
@UpsideDownUnder.
Nice to hear from you again! I’m just not sure where the idea that AT might be “haunted by false positives” might be coming from!
Let's check some definitions and then walk through the data and information we have, and see if that claim actually holds up! Lets tie the pieces together and see if there is any logic at all in what you are suggesting!
FALSE POSITIVE SCANS — What Are They?- A false positive Cu6 scan would be when a PET scan using Clarity’s tracer (like ⁶⁴Cu-SAR-bisPSMA, ⁶⁴Cu-SAR-BOMBESIN, or ⁶⁴Cu-SARTATE) returns a positive result (indicating cancer), but this then gets proven to be false by a reliable source of truth. See Ref 1 for a primer on these terms!
- In cancer diagnostics, the source of truth is histopathology!
- So if you’re alleging false positives, you're also alleging that a source of truth was used, and that this source of truth provided reliable histopathology evidence contradicting the PET scan! Did that happen? No idea - but how could it?
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Let’s Look at the Trials1) THE CLARIFY TRIALThe Clarity trial most likely to produce large numbers of biopsies is CLARIFY! Thats because its inclusion criteria specifically require patients planned for Radical Prostatectomy AND Lymph Node Dissection (RP-LND). Those specimens (the prostate and the lymph nodes) will go to histopathology, our gold standard.
The trial schema is shown below!
BUT that trial is still ongoing. So no results are available yet. All we know is that the estimated completion date has been moved to end of 2025. We cant therefore talk about those results - they are not there!
2) THE COBRA TRIALThis trial has reported histopathology results, even though it evaluated patients with biochemical recurrence (BCR) - a group where biopsies are rare. That’s just clinical reality, not Clarity’s doing. Its the patients and their doctors who choose treatment without requiring an invasive tissue diagnosis. This is sensible.
What did COBRA show?Of patients with a positive PET scan, only 9 lesions were biopsied:
• 7 lesions were outside the prostate bed - all 7 confirmed cancer = 100%
Positive Predictive Value (PPV) for those sites!
• 2 were in the prostate bed - both came back as negative on histopathology.
So, if we stop there:
# Sensitivity: 7/9 = 78% (Illuccix and Pylarify sensitivity is around 50%)
# “False positive” rate: 2/9 = 22%.
These results have been reported!But here’s the issue! Are those 2 prostate bed cases really false positives?Not necessarily.
Why?Because prostate bed biopsies are notoriously unreliable.Clarity detailed this, and Prof. Louise Emmett emphasized it in her interview with Michael Frazis. She explained that detecting recurrence in the prostate bed is inherently difficult, both by imaging and biopsy. This is known!
To be clear: the problem isn’t with histopathology itself: it's that the biopsy sample may not contain the cancer, due to anatomical challenges like scarring, tissue distortion, or simply missing the target. This is why multiple biopsy attempts are often taken, to improve detection. Its not pleasant!
The point is: if the biopsy doesn’t catch the cancer, histopathology has nothing to find.It’s a surgeon/sampling issue, not a failure of the scan or the pathologist.
And clinicians know this.That’s why many will empirically irradiate the prostate bed, even with:
• No imaging evidence of disease recurrence!
• No histopathological proof of recurrence!
It makes no sense to call the scan result a “false positive”, while proceeding to irradiate the same area because you actually believe there's disease there.It’s a contradiction!
BUT - that's where we are! Biopsies can be difficult to obtain.
IN CONCLUSION:There is nothing in what we know so far that would suggest that Clarity’s scans are producing false positives in any meaningful way.The claim is not supported by the data so far shared, and is not supportable by science or logic.
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REFS1) TUTORIALS on Test Sensitivity, Specificity, PPV, and NPV:
https://doc-aids.com/healthcare/statistics/2) Clarity Quarterly Activity Report: 31 Jan 2025;
https://www.claritypharmaceuticals.com/wp-content/uploads/2025/01/25-01-31_Clarity-Quarterly-Activity-Report_App4C.pdf
(20min delay)