I would say that the possibility is high (>75%) that the FDA...

I would say that the possibility is high (>75%) that the FDA will require p3 results, but not 100%. The FDA has shown that they are willing to approve anything that shows effectiveness. How do you otherwise see the FDA briefing doc on Aducanumab (which was extremely positive) in light of the Adcom vote (where none voted in favor)? There is still a (although very small) possibility that the FDA will go for Aducanumab approval against the Adcom vote.

LLY itself has already hinted at going for FDA approval without launching a p3 trial. LLY has a second p2 trial on Donanemab, so they have different possibilities:
- go for FDA approval following the most recent p2 results
- await the data of the second p2 trial on Donanemab (expected by 2023) before going for FDA approval
- launch p3 trial

The market reaction following the most recent p2 results (LLY gained over $10 billion in market cap) suggests that the market expects LLY to go for FDA approval rather sooner than later.