Dyne Therapeutics Inc at Jefferies CNS & Neuro Summit Transcript

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

Question: Mack Chandler - Jefferies LLC - Analyst : So thank you all for joining us today. We're very excited about the upcoming data that Dyne will present here shortly. Before we get into some of the programs and our expectations or your expectations for them, Wildon or Oxana, would mind just giving us a quick overview of the FORCE

Question: Mack Chandler - Jefferies LLC - Analyst : Great, thank you. So as I mentioned, we're expecting data from both of the co-lead programs, DYNE-101 in DM1 and DYNE-251 in DMD amenable to exon 51 skipping here in the fourth quarter. Starting with DYNE-101 in myotonic dystrophy type 1 or DM1, what is the exact data we're going to see this quarter? I know you've previously committed to showing the first cohort of 16 patients at the lowest dose level. Will this be the full six-month data for all 16 patients, and I guess what are some of the measures we might see? REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. OCTOBER 12, 2023 / 1:30PM, DYN.OQ - Dyne Therapeutics Inc at Jefferies CNS & Neuro Summit

Question: Mack Chandler - Jefferies LLC - Analyst : Great, any updates on whether we might see a second cohort with this data?

Question: Mack Chandler - Jefferies LLC - Analyst : Got it. And so we're going to get this proof-of-concept data. What do you need to see in terms of the splicing correction to really be confident that you have proved the concept. Is it statistically significant, difference from placebo? Is there a number in mind that you think is kind of the bogey?

Question: Mack Chandler - Jefferies LLC - Analyst : Got it. And on the DM1 program, we've seen pharmacologically active conjugated ASOs for DM1. I guess what are some of the points of differentiation that you see for DYNE-101 compared to the data that's been presented so far?

Question: Mack Chandler - Jefferies LLC - Analyst : Great, and then you've alluded to the fact that this ACHIEVE study could become registrational if you're able to correlate the splicing correction with functional endpoints. What are some of the most important functional endpoints that you're trying to correlate with and is there a delay between the splicing correction and seeing those improvements?

Question: Mack Chandler - Jefferies LLC - Analyst : So would we expect it to be pretty in sync with the splicing correction and this improvement in function? REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. OCTOBER 12, 2023 / 1:30PM, DYN.OQ - Dyne Therapeutics Inc at Jefferies CNS & Neuro Summit

Question: Mack Chandler - Jefferies LLC - Analyst : So could we see improvements in CNS with the ability to cross the blood-brain barrier this year in that data? Is that something that might be read out?

Question: Mack Chandler - Jefferies LLC - Analyst : Got it. And I know mechanistically, part of the hypothesis is knocking down DMPK leads to this pricing correction. So will we be able to correlate or see a consistent DMPK knockdown translating to this splicing correction in the data at the end of this year?

Question: Mack Chandler - Jefferies LLC - Analyst : Okay, but it won't be a patient-level correlations at this time, will it? REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. OCTOBER 12, 2023 / 1:30PM, DYN.OQ - Dyne Therapeutics Inc at Jefferies CNS & Neuro Summit

Question: Mack Chandler - Jefferies LLC - Analyst : Okay, and then before moving on to DYNE-251, with this just being the first cohort potentially, at least the first cohort for DYNE-101, what is the expected cadence of future readouts? When could we see the next set of data?

Question: Mack Chandler - Jefferies LLC - Analyst : Great, thank you. And then switching gears to Duchenne muscular dystrophy, with DYNE-251 also reading out later this year, the first in-human data, the initial dose level, 0.7 mgs per kg on a monthly IV, you've previously said that you expect this to eclipse the standard of care in terms of increasing the normal dystrophin production. I guess how much higher can we go and what other data besides that lowest dose level should we expect to see this year?

Question: Mack Chandler - Jefferies LLC - Analyst : And then with the evolution of new modalities and Duchenne in muscular dystrophy, how do you, I guess, expect a exon skipping therapy can fit into that market opportunity? REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. OCTOBER 12, 2023 / 1:30PM, DYN.OQ - Dyne Therapeutics Inc at Jefferies CNS & Neuro Summit

Question: Mack Chandler - Jefferies LLC - Analyst : Great, and then lastly, with the remaining time, I want to touch on the exciting data earlier this year for the ability of the FORCE platform to cross the blood-brain barrier. I guess it's exciting in DM1, firstly. But outside of that, what are some of the implications of these results and where do you see Dyne being able to go in the future?

Question: Mack Chandler - Jefferies LLC - Analyst : Great, well, that's unfortunately all the time we have with you today. Very excited to see the proof-of-concept data here at the end of this year, and look forward to a catalyst-rich 12 to 18 months as you said. Thank you.