Dyne Therapeutics Inc ACHIEVE Clinical Update Transcript

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

Question: Debjit Chattopadhyay - Guggenheim Securities LLC - Analyst : I've got two. First, thoughts on why CASI seems to max out in the mid-20 -- mid- to high-20% range across the two high-dose cohorts. And then could you also elaborate on CASI at month three likely to be predictive of functional benefits? Have you analyzed the individual patient data on a blinded basis?

Question: Paul Matteis - Stifel Nicolaus and Company, Incorporated - Analyst : I was wondering if you guys would be willing to elaborate a little more on the six-month splicing data at the high dose and what the effect might look like if you exclude the patient with the biopsy issue. And then just taking a step back, I guess, the clinical data looks pretty consistent. But the splicing data does have some noise in it and some variability time point to time point. Why is it the right move to rely on splicing? And what gives you the confidence that some of the signal-to-noise stuff you're seeing in this study is not going to play out in the larger ACHIEVE cohort?

Question: Edward Tenthoff - Piper Sandler - Analyst : Great. And congratulations on this update, really impressive data and I agree with respect to the consistency across all the measures. REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. JANUARY 10, 2025 / 1:00PM, DYN.OQ - Dyne Therapeutics Inc ACHIEVE Clinical Update Just if you could go back through the timing again, just to make sure that we've got this all right. So we could be getting 251 data by year-end, NDA filing next year. And the DM1 data, would you anticipate that early next year? Or when should we anticipate that data?

Question: Edward Tenthoff - Piper Sandler - Analyst : It sure does. Thanks so much and excited for the data and the filings next year.

Question: Michael Ulz - Morgan Stanley - Analyst : Just curious if you guys have had a chance to share this updated DM1 data with the FDA. And maybe secondly, if you can just talk to your level of confidence in an accelerated approval path based on the data you have so far.

Question: Francois Brisebois - Oppenheimer & Co., Inc. - Analyst : All right. Congrats on the data here. I just -- one slide that I thought was particularly interesting is this slide 23, where you adjust for baseline in balances on a lot of the functional scores. Can you just help us understand -- I think you mentioned that you're going forward with this and just maybe the FDA's perception of this adjustment. Because it does seem to have helped the data here. So a little more clarity on the MMRM would be helpful.

Question: Francois Brisebois - Oppenheimer & Co., Inc. - Analyst : Interesting. And then just one thing I just wanted to ask about -- on the CNS side, I think you guys have had data showing that you target -- you hit the CNS in the past. But just how do we feel comfortable? It seems like a potential very important differentiator here. How do we feel comfortable that this was not a fluke in terms of like slide 22 where all these CNS improvements are shown here?

Question: Luca Issi - RBC Capital Markets - Analyst : Congrats on the data. Maybe, Doug, circling back on the prior question, it sounds like you're going to fish the FDA design that you outlined on page 16. Hopefully, the FDA buys into that design and the rest is history. However, should it not be the case, what is plan B here? Like, is there a scenario where the FDA ultimately ask you to run a trial that is much larger and even vHOT as a primary endpoint as they have done one of your competitors? Any thoughts there, much appreciated.

Question: Brian Skorney - Robert W. Baird & Co lnc - Analyst : Maybe just starting to clarify on Ken's question on data rollout. I didn't quite that. Will we get three-month CASI from the pivotal cohort when it is available? Or are we waiting on the six-month results before (inaudible) so we get like three-month CASI and all the six-month functional data at one time? And then just on the safety slide, it looks like placebo and treatment are still pooled by cohort. Are you still blinded to placebo versus treatment comparisons here? Or can you comment at all on any differences between placebo and treatment? I assume that the data safety monitor more minimal has evaluated.

Question: Brian Skorney - Robert W. Baird & Co lnc - Analyst : And then the other question, I think, was will we disclose three-month CASI wait for the full data set of six months for the registrational expansion cohort?

Question: Andrew Fein - H.C. Wainwright & Co., LLC - Analyst : Congrats on all the progress in the data. Just wanted to just triple check that there is, basically for the registrational pathway, at least four other ways to win, assuming you hit CASI, even if vHOT didn't succeed. Just wanted to confirm this specific alignment since my understanding is your previous pathways in DM were slightly different. And then secondly, will the registrational portion be powered on an MMRM adjusted basis for vHOT as well as unadjusted? And will the FDA accept MMRM analysis when analyzing the pivotal data for an approval? REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. JANUARY 10, 2025 / 1:00PM, DYN.OQ - Dyne Therapeutics Inc ACHIEVE Clinical Update

Question: Ryan Deschner - Raymond James - Analyst : Regarding the invalid six-month splicing correction data point, does this occurrence change the way you're thinking about powering a biopsy protocol for the registrational cohort? And will you be reporting longer splicing correction follow-up for the 6.8 patients in today's presentation? And I have a follow-up.

Question: Ryan Deschner - Raymond James - Analyst : Got it. And then quickly, I just wanted to clarify. In the press release, you mentioned 32 patients in the 6.8 registrational cohort. Is that 24 treated 6.8 and eight additional placebo patients? Or how is that broken down?

Question: Caroline Pocher - JPMorgan - Analyst : This is Caroline Pocher on for Tess Romero with JPMorgan. Just two from us. So in the press release, you spoke to your previous dialogue with the agency around the accelerated approval pathway for DYNE-101 in the US based on splicing as a surrogate endpoint. Can you just clarify when this last interaction, what the agency was? And with these data in hand, to just be clear, when do you expect to interact with them next and get definitive sign-off that this pathway is open? And then I just have a follow-up.

Question: Caroline Pocher - JPMorgan - Analyst : Okay. Great. And then just one quick follow-up. Can you just clarify what recent means in regard to your interaction with the FDA around DYNE-251? Just clear up the timing on that.

Question: Caroline Pocher - JPMorgan - Analyst : Yeah.