Dyne Therapeutics 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 : (technical difficulty) It's like the fifth time I've done that today. Apologies. Very good. Well, excited to see the next steps. Maybe before we start talking about the clinical studies, just as it relates to preclinical data, I know we've done a number of panels in the past and probably many listening are familiar, but I guess to kind of bottom line it, what do you think is fundamentally differentiated about Dyne's preclinical dataset going into the clinic than some of the other datasets historically that arguably haven't translated all that well?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Got it. Okay. Great. Can you talk about some of your recent updates on the regulatory side, and your plans for getting the DMD IND cleared, and sort of your updated strategy with the DM1 [file]?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Yeah. And Josh, I want to go back to a comment you made earlier, right? Because I guess, from our perspective, and I would imagine yours, the clinical [hope] was surprising, given your reports that you haven't reached the no-adverse-event limit in your preclinical tox studies. But some investors we've talked to have kind of speculated, okay, well, maybe this is resolvable. But the ceiling at how high they can dose might be lower, and they might have to start at lower doses. So anything else you can say on your kind of conviction level that when you start studies mid-year, you're still I guess as close to relevant proof of concept as you seem to be four or five months ago?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Yes, okay. All right. That's great. Good stuff. So to that point, do you want to just talk a little bit about DM1 and the whole kind of debate that is still sort of out there related to RNAi and ASOs? And I guess, I would sort of be curious that when we look at proof of concept data in DM1, what should we be looking at besides DMPK knockdown to kind of get a sense as to whether or not you're really modulating mutant toxic transcript? 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 / 5:00PM, DYN.OQ - Dyne Therapeutics Inc at Stifel CNS Days (Virtual)

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Okay. Great. Anything (multiple speakers)?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Yes, yes. Okay. Very good. Maybe as it relates to DMD, I think the other sort of relevant question as it relates to your nonhuman primate data, doses sort of the translatability of NHP skipping data to human skipping in dystrophin, can you sort of walk through the NHP data you generated? And what's sort of your expectations on how this might kind of recapitulate in patients?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Yes, yes. Okay. Great. Yeah, on the safety side -- again, understanding your studies didn't find any dose-limiting tox, which is really encouraging. What do you make of, I guess, a few cases of anemia in Denali's study and the theoretical risk of transferrin receptor and iron trafficking? Given that you have a high-affinity antibody, is that risk is still something we should be worried about as you dose for longer? Or do you feel like you can kind of derisk that in short-term studies if you don't see any sort of key biomarker changes? 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 / 5:00PM, DYN.OQ - Dyne Therapeutics Inc at Stifel CNS Days (Virtual)

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Yes. Okay. Makes sense. Maybe to kind of round things up, Josh. You've always talked about having a global strategy. So what can you say about your engagement with European regulators and the timelines there? I mean, I guess, dosing patients mid-year could mean that you might start ex-US, right? So maybe kind of clarify things.

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Yes, okay. Okay, great. Do you want to briefly talk about FSHD and any data you have there at this point that sort of supports your confidence in that program as you approach filings? I think second half this year, right? 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 / 5:00PM, DYN.OQ - Dyne Therapeutics Inc at Stifel CNS Days (Virtual)

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Yes, okay. Great. I have one question that came in just related to DM1. And that is just whether or not you think 40% to 50% DMPK knockdown is enough. And maybe I can sort of add, a different way to ask that is, what do we understand related to the ratio or relationship or stoichiometry between DMPK levels and then the disruption of these splicing factors? Like if you knock it down 50%, do you release 50% of the splicing factors? Or could the hurdle be lower or higher?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Okay, great. Thank you, Oxana. That was helpful context. I know we're up against time, so anything else you'd like to add? I guess we'll be expecting a handful of key updates from you guys in the next few months, Josh?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Great. Any comments, Josh, just to round it out on how well funded you are through some of these events?

Question: Paul Matteis - Stifel Financial Corp. - Analyst : Yes, okay. Very good. Well, thank you all very much. Appreciate it.