CI I agree with your BTD and we have discussed this before (possibly before you were here). Taking it a step further, I believe the CTC test and tumor shrinkage is likely to result in Accelerated Approval (AA) if results are "significate" enough and proven in a few more trial patients.

Here is an excerpt from the FDA website on AA noting surrogate endpoints:

Quote:

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Using surrogate or intermediate clinical endpoints can save valuable time in the drug approval process. For example, instead of having to wait to learn if a drug actually extends survival for cancer patients, the FDA may approve a drug based on evidence that the drug shrinks tumors, because tumor shrinkage is considered reasonably likely to predict a real clinical benefit. In this example, an approval based upon tumor shrinkage can occur far sooner than waiting to learn whether patients actually lived longer. The drug company will still need to conduct studies to confirm that tumor shrinkage actually predicts that patients will live longer. These studies are known as phase 4 confirmatory trials.

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https://www.fda.gov/patients/fast-track-break...d-approval

Here is a good post by Trding discussing this in more detail also:

https://investorshangout.com/post/view?id=5428159