Alector Inc at Stifel CNS Days (Virtual) Transcript

The following is excerpted from the question-and-answer section of the transcript.

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Excellent. Do you mind if I start off with TREM2?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : I think the one thing I wanted to ask to start is just, when you think about activating the immune system in the brain, one key opinion leader in this space made a really interesting comment to me that he speculated that there could be times in disease where you might want to agonize TREM2 and then times in disease where you might want to tamp down microglia activity. And I'm not sure if that's an oversimplification. But as you think about neuroimmunology in general, how do you look at the window for intervention or the right time to give a drug like that?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Yes. Okay. Very interesting. We've talked about this some -- and I know you've gotten a question from different investors, but you reported area in this study, and were you surprised by this signal? And area I think is something that, when looked at on an MRI, might look like it could be just this nonspecific inflammatory signal. So how was it kind of adjudicated in this study that it's known, that this is truly driven by engagement of A-beta?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Right. What I guess, the one question just on the safety side is, is there any risk that this could be just maybe a less specific inflammatory signal that could be problematic? How was it codified specifically as ARIA, given we don't know about amyloid engagement? REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. MARCH 28, 2022 / 3:30PM, ALEC.OQ - Alector Inc at Stifel CNS Days (Virtual)

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Yes.

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Yeah. Okay. And I believe -- maybe you can clarify, I believe this study is 52 weeks placebo controls. Is that right or -- and is there a mechanism for longer follow-up?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : And other patients on placebo for two years as well?

Question: Paul Matteis - Stifel Financial Corp. - Analyst :

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Okay. Okay. And have you given any guidance on the timing of completion of this trial?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Okay. Okay. So maybe -- so a couple years after your completed enrollment, we'd get the data. Is that right?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : One year. One year. A little bit more than one year, but one year (multiple speakers).

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Yes, yes. Okay, okay. Great. Maybe let's talk a little bit about [program] AL001. I'm curious if you could give any context on the Phase 3 trial enrollment dynamics, what you're seeing right in terms of the frequency of genetic mutations, things like that, just to sort of set the stage. REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. MARCH 28, 2022 / 3:30PM, ALEC.OQ - Alector Inc at Stifel CNS Days (Virtual)

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Right. Yes. Have you talked it all about just what you're observing in terms of the GRN frequency among FTD patients? Like I guess, this will probably give us the best insight to how common FTD-GRN is outside of all frontotemporal dementia, correct?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Yes, yes. Okay. How do you think about the hypothesis of elevating progranulin levels above normal as something that's beneficial? And do you have preclinical data or some sort of data out there that shows you that more progranulin above, again, the baseline of a healthy individual, can have downstream beneficial effects on the immune system in the brain?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Yes, yes. Okay, okay. And what are the next steps for these other dementias like FTD-C9orf, but then also Alzheimer's, Parkinson's? When do you think you might initiate larger controlled trials?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Yes. Okay, okay. Do you want to briefly talk about the SIGLEC3 program? You said you were evaluating next steps there. Do you feel like you accomplished what you wanted to in Phase 1 studies to move ahead into a bigger Phase 2?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Okay. Okay. All right. Anything else you'd like to add about the rest of your pipeline before we wrap up, Arnon? REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. MARCH 28, 2022 / 3:30PM, ALEC.OQ - Alector Inc at Stifel CNS Days (Virtual)

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Awesome. Very good. Well, I know we're a couple minutes over. But thank you very much for joining. I really, really appreciate the discussion as always. REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. MARCH 28, 2022 / 3:30PM, ALEC.OQ - Alector Inc at Stifel CNS Days (Virtual)

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Thank you, guys.