Fair question. Personally, I believe that strong interim results will render those official timelines irrelevant. Typically in oncology trials, the FDA allows primary endpoints (generally a measure survival horizon), secondary endpoints (often progression-free survival), and in some cases surrogate endpoints (again, PFS is sometimes used - this trial will be offering up CTC counts). The purpose of having these additional endpoints is to allow the FDA to potentially move faster towards approving drugs in situations with severe unmet medical needs, and is based on the assumption that surrogate endpoints are a reasonable proxy for or predictor of clinical benefit (survival horizon), but they can be measured much, much faster. This is the basis for the Accelerated Approval program, and oncology is the primary target/beneficiary for AA due to mortality rates and lack of effective treatments for many indications.
So how does that functionally work, and what do the timelines mean then? Well, the FDA will likely watch this trial with extremely keen interest due to the safety profile of the drug and the target (TNBC). If the FDA is impressed with the interim numbers for CTC counts, it is very possible that they will ask/allow the company to submit data for review and approval under AA while the trial is still going. The AA process doesn't stop the clinical trial process - it just allows a drug to get to market much faster while the FDA requires the company to complete in progress and, usually, post-marketing studies to demonstrate the clinical benefit and safety profile. The FDA can then revoke approval if the subsequent trials don't prove benefit, or have unacceptable side effects, etc.
If necessary, I can provide examples of where the FDA has intervened during P2's and approved drugs under AA. Google searches will get you the same thing though.
In short, the only date that really means much there in my opinion is the Estimated Study Start Date.
