Dyne Therapeutics Inc at Guggenheim Healthcare Talks: Genomic Medicines and Rare Disease Days (Virtual) Transcript

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

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : Given the limited time, let's get straight to it on the thoughts on the FORCE platform and how the technology differentiates itself versus non-specific approaches in neuromuscular diseases?

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : Thanks for that overview, Jonathan, so maybe quickly on the Transferrin receptor mediated drug uptake. This has been a tried method, but not many people have actually delivered something across the finish line. Anything that gives you a pause to date or how are you feeling about your second half data events?

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : So let's switch to the DM1 program because obviously we have had a lot of incoming questions on DYNE-101. Let's start with the molecular composition of the antisense oligo. I know it's gapmer but anything you can expand on that would be helpful.

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : So you guys are going after the DMPK gain of function. There is a competitor, which is specifically going after the MBNL. And why the choice of DMPK, whereas going after, let's say, steric blocking?

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : Got it. Thanks for that. So three questions in one, given the recent publication of competitor data, we are trying to sort of understand relevance of drug concentrations in vivo, specifically tissue concentrations, the relevance of the splicing index as it relates to functional outcomes. And then you are confident of the lower dose pharmacological activity in humans.

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : Thanks for that. Well, given the heterogeneity that we see in DM1 molecular pathology, is there anything in the ACHIEVE study where you could screen for patients to have or deliver the best outcome?

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : Got it. DMD, there seems to be a well-established path to market, but in DM1 is their communication from the agency as it relates to what they would like to see for a registrational product, whether it's splicing index correction or improvement in DM1 symptoms?

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : And last question on DM1's data second half of this year, any thoughts on the number of patients or the duration of follow-up that we could possibly see to get at? Is there going to be sort of a cumulative benefit because there have been hints at a cumulative benefit from competitor data? REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. APRIL 04, 2023 / 2:10PM, DYN.OQ - Dyne Therapeutics Inc at Guggenheim Healthcare Talks: Genomic Medicines and Rare Disease Days (Virtual)

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : Got it. And then moving on to DMD, the FORCE-M23D mdx mouse. Help us understand the translation from mouse to humans here? And where do you need to be from dystrophin expression?

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : So given the similarity, since you're using transferrin receptors for both the ACHIEVE and the DELIVER program, are the doses going to be comparable across the two studies or what determines the doses?

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : Got it. But if you don't mind, remind me what the -- from a biopsy perspective in the DM1 study there're three biopsies, how many are you doing in DMD and what's the interval?

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : Got it, at six months.

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : And the biopsies, are both the baseline and the six-month biopsy the same muscle groups or different muscle groups in different locations?

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : Okay. So let's say, it if it's a bicep, but if you do a left hand then you have to do the right hand or can you do the left hand both the times.

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : Got it. And in the DMD program, you have both ambulant and non-ambulatory boys obviously different level of fibrosis. Are you going to look at these data sets differently from both exon skipping, efficiency, dystrophin expression, et cetera?

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : And then to wrap it up, if FDA does approve the first gene therapy within the next couple of months, how does that change the outlook for exon skipping therapies, I mean, especially from a payer coverage perspective? REFINITIV STREETEVENTS | www.refinitiv.com | Contact Us consent of Refinitiv. 'Refinitiv' and the Refinitiv logo are registered trademarks of Refinitiv and its affiliated companies. APRIL 04, 2023 / 2:10PM, DYN.OQ - Dyne Therapeutics Inc at Guggenheim Healthcare Talks: Genomic Medicines and Rare Disease Days (Virtual)

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : Well, thank you so much. I think we are running out of time here and you guys have to hit for some meetings, I believe. Good luck; second half of the year, ACHIEVE and DELIVER; hopefully, we hit on both those out of the park.

Question: Debjit Chattopadhyay - Guggenheim Securities, LLC - Analyst : Thank you so much, Jonathan. Thank you, Wildon.