Day One Biopharmaceuticals, Inc.

Ladies and gentlemen, thank you for standing by. Once again, I'd like to turn the floor over to Joey Perrone, Senior Vice President of Finance and Investor Relations. Please begin.

Thank you. Hello, everyone, and good afternoon. Welcome to Day 1's First Quarter Financial and Operating Results Conference Call. Earlier today, we issued a press release which outlines the topics we plan to discuss. You can access the press release in the slides to accompany this conference call on the Investors in Media section of our website at .day1bio.com. An audio webcast with the corresponding slides is also available on the website. Before we get started, I'd like to remind everyone that some of the statements that we make on this call and the information presented in the slide deck include forward-looking statements as outlined on slide 2. Actual events and results could differ materially from those expressed or implied by any forward-looking statements. We encourage you to review the various risks, uncertainties, and other factors included in our most recent filings with the SEC and any other future filings that we may make with the SEC. These forward-looking statements are based on our current estimates and various assumptions and reflect management's intentions, beliefs, and expectations about future events, strategies, competition, products, and product candidates, operating plans, and performance. You are cautioned not to place any undue reliance on these forward-looking statements and accept as required by law, Day 1, disclaims any obligation to update such statements. Today, I'm joined by Dr. Jeremy Bender, Chief Executive Officer, Laura Maradino, Chief Commercial Officer, Charles York, Chief Operating and Financial Officer, and Ellie Berry, Chief Medical Officer. I will now turn the call over to Jeremy.

Thank you, Joey, and good afternoon. I'm excited to share that we achieved another quarter of growth and strong financial performance to start the year. I'm thrilled by the progress we have made thus far in bringing OJEMDA to patients in need. We continue to execute on the three priorities we laid out for our business in 2025 earlier this year. The first is establishing OJEMDA as the standard of care in second-line plus pediatric low-grade glioma and driving OJEMDA revenue growth. The second is advancing our clinical development pipeline for Firefly 2 and Day 301, and the third is further expanding our portfolio. In the first quarter of 2025, OJEMDA quarterly scripts increased to over 900, representing 16% growth over total scripts in the prior quarter. This growth drove net product revenue for OJEMDA to $30.5 million for Q1 2025. Our consistent growth each quarter since launch and the market dynamics we've observed over the past 12 months have further reinforced that OJEMDA is a foundational opportunity for Day 1 that will drive durable, long-term value creation. Significant untapped potential remains for OJEMDA in relapsed refractory PLGG. Prescriber adoption continues to increase. On-label patient demand has grown steadily. Payer approval rates are high, and patients continue to experience longer treatment periods on OJEMDA as time progresses. All of these data points give us confidence that the steady increase in OJEMDA revenue will continue. Beyond OJEMDA's commercial performance, we remain focused on building value across our pipeline. We are encouraged by the enrollment progress we've observed in our Global Firefly 2 confirmatory trial. We expect the trial will be fully enrolled in the first half of 2026 as we endeavor to drive expansion of OJEMDA beyond the relapsed refractory PLGG approval and into the frontline PLGG setting. Additionally, our partner, Hipson, recently announced that their application for toborafenib was accepted by the EMA for review, bringing it one step closer to patients in that region who remain in need of a new treatment option. Our Day 301 program also continues to advance through the dose escalation portion of the Phase 1A trial. Our successful track record with OJEMDA has paved the way for us to continue to discover and develop -in-class or -in-class programs for both children and adults. We remain committed to and are actively evaluating business development opportunities that will allow us to expand our multi-program clinical stage portfolio aimed at driving sustained long-term growth. This is an exciting moment for Day 1. 2025 is off to a great start. We have a solid financial foundation that provides us with multiple options for value creation in the coming quarters, even during a period when macroeconomic factors present existential challenges and uncertainties for many biotech companies. OJEMDA's launch continues to deliver solid growth, and I am proud of the progress we have established with a clear path for long-term financial and program success for the company. I'll now turn the call over to Lauren to discuss our commercial progress in greater detail.

Thanks, Jeremy, and good afternoon. OJEMDA is off to an excellent start in 2025. As Jeremy mentioned, we delivered $30.5 million in net product revenue in Q1. Our revenue is driven by the over 2,500 total prescriptions written since launch, underscoring both growing physician confidence and the critical role OJEMDA is beginning to play in the treatment landscape of PLGG. This is a substantial foundation of physician experience from which we can grow in future quarters. Let's take a closer look at our revenue. Q1 marked another quarter of significant growth, with our team delivering 11% growth in U.S. net product revenue quarter over quarter. We delivered well this quarter despite some seasonality we observed in January. This was primarily due to the holidays impacting the timing of scans and initiating new treatments, which led to a slower start to the year. Since then, we have seen a rebound, with April being one of the strongest months for new patient starts since launch. Our launch execution continues to deliver a significant impact. Cumulative U.S. OJEMDA prescriptions grew to over 2,500 since launch, delivering 16% growth over the prior quarter. In addition to new patient starts, which we've already discussed, duration is also a key driver of our performance, and we continue to see a high percentage of on-label patients continuing on therapy each month. This speaks to the tolerability of OJEMDA and the benefit patients and physicians are seeing with our product. Through continuing to expand both breadth and depth of prescribing and supporting physicians and patients during their time on OJEMDA, we continue to drive growth in total prescriptions. Our team at day one continues to see and demonstrate a substantial market opportunity for OJEMDA. It can be complex to see the whole picture, so let's break down the growth potential that still lies ahead for our product. This slide summarizes the estimated number of relapsed-refractory PLGG patients being managed at each of our priority accounts. We've previously shared our estimate that in the U.S. there is a prevalent pool of approximately 26,000 relapsed or refractory BRAF-altered PLGG patients who have received at least one prior treatment. Based on PFS curves, we estimate that about half of these patients are likely in long-term remission and are not likely to need an additional systemic therapy. If we allocate the remaining patients proportionately across our priority groups and divide by the number of accounts in each priority, we calculate the average number of patients managed at each account, seen here. Our best estimate is that, on average, our priority one accounts manage about 230 patients each, our priority two accounts manage about 60 patients each, and priority three accounts about 40 each. This includes both those patients currently on treatment and those who are being monitored for progression and may need treatment in the future. Depth is especially important in our priority one and two accounts who have already gained experience with OGMDA. In these accounts, a substantial opportunity remains to accelerate adoption, drive increased use, and establish OGMDA as the second-line standard of care. In priority three accounts, as we would expect, prescribers tend to be more cautious and wait to hear thought leader experiences before trying a new therapy. They also manage fewer patients, so they have less frequent treatment decisions. To get their first patient started, we continue to share the experiences of other physicians and our clinical trial data to help build their confidence in OGMDA. While many accounts are already treating multiple patients with OGMDA, the overall patient volume within these accounts reinforces our strong conviction that significant growth potential remains through deepening penetration and expanding usage across all of our accounts. To fully unlock OGMDA's potential, our path forward is clear. First, as we just discussed, our greatest opportunity lies with our current prescribers and increasing the depth of their prescribing. Secondly, we must continue to expand our prescriber base by encouraging non-prescribers to try OGMDA in their first relapsed or refractory PLGG patient. Across our customer base, we must continue reinforcing the value of OGMDA in the second-line setting to drive deeper adoption and to firmly establish it as a new standard of care for these patients. We believe that our -be-released Firefly 1 two-year follow-up data will further aid in this effort. Finally, with an eye on the horizon, we want to ensure that physicians and patients are receiving the information and support that they need so that they can receive the optimal duration of treatment over time. This includes educating on managing adverse events, dose adjustments, and patient support. Through these areas of focus, we remain confident that we will continue to grow and increase the impact of OGMDA. Now I'll turn it over to Charles for more details on our financial results.

Good afternoon, everyone. Earlier today, we reported detailed first-quarter 2025 financial results in our earnings release. For today's call, I'll touch on a few highlights. In the first quarter, U.S. OGMDA revenue was $30.5 million, which grew 11% compared to the fourth quarter, driven by a 16% increase in quarterly scripts. Our operating expenses, excluding cost of sales, were $68.9 million in the first quarter of 2025, which included $12.9 million in non-cash, stock-based compensation expense. In comparison to our fourth quarter of 2024, when excluding the one-time charge of $20 million associated with the in-license of Day 301, we realized approximately 4% -over-quarter decline in operating expenses. By maintaining a disciplined financial strategy as a cornerstone to building long-term, durable growth, we anticipate that costs in operating expenses will remain relatively consistent the rest of the year with some -to-quarter variability, which allows us to invest strategically in opportunities that support growth while prioritizing our clinical development plan. We remain well-positioned financially with a cash balance of $473 million and no debt at the end of the first quarter. As we continue to grow, our ability to balance disciplined financial management with measured investment is what sets us apart. Based on our current operating plans, we do not project Day 1 will require any additional financing in the future. As Jeremy mentioned earlier, our internal expertise in oncology development, registration, and commercialization is second to none. With the continued success of the agenda launch and the disciplined investment approach, we are well-positioned to deliver long-term, sustainable value. In closing, as we look ahead, our commitment remains the same. Drive value for our shareholders. Manage our resources responsibly. And above all, don't be afraid to disrupt the status quo of traditional drug development to give better targeted medicines to patients who urgently need new options. With that, I'll turn the call over to the operator for Q&A.

Thank you. At this time, we will be conducting a question and answer session. If you would like to ask a question, please press star 1 on your telephone keypad. A confirmation tone will indicate your line is in the question queue. If, at any time, you wish to remove your question from the queue, please press star 2. For participants who need speaking equipment, it may be necessary to pick up your handset before pressing the star keys. Also, we remind participants to limit their questions to one with an opportunity to have one follow-up. Our first question comes from Anupam Rama with JPMorgan.

Hi, guys. This is Priyanka An for Anupam. Congrats on the progress for this quarter. Just one question from us. What are you seeing in terms of duration of therapy in the marketplace and how docs plan to use the drug long-term?

Priyanka, thanks for the question and the comments. I'll ask Lauren to comment on what we're seeing for duration to date.

Yeah, so we're approaching a year on the market. So it is early for us to comment on duration. What I will say is that we continue to see a very high percentage of patients continuing on therapy month after month. And the trends are similar to what we would expect considering the results we saw in the Firefly 1 study.

Thank you so much for answering the question. Thanks, Prado. Our next question is from Tara Bancroft with TD Cal.

Hi, team. Good afternoon. So I was hoping if you could give us maybe a rough percentage of revenue that's accounted for from new patients versus ongoing patients. I know last quarter you said there were roughly about 280 active patients. So getting an idea of that updated number and the relative split would be really helpful. Thanks so much.

Thanks for the question, Tara. What I can tell you is that the dynamics of our new patient starts and our patients on treatment are very similar to what we discussed in the quarterly call in February with respect to a couple of elements. The first is the rough percentage of on versus off label remains at plus minus or around 10 percent, off label 90 percent, on label. With respect to breakdown of patients, we provided that year end guidance in part because of the start we had with the EAP pool that converted post approval on mass. Going forward, our key metric really will be total scripts and of course revenues.

Okay, great. Thank you. And any, just as a follow up, any potential color you can give on any headwinds that you saw in Q1 in particular with regards to like gross tonnet and reimbursement?

So let me ask Lauren to first comment on seasonality, which she mentioned in the script and then Charles can comment on gross tonnets.

Yeah, thank you for the question. So we did see some seasonality early in January due primarily to a delay in scans and physician appointments due to the year end holiday. So we saw a slower ramp in January, but we have since seen new patient starts rebound and as I mentioned, had a very strong NPS results in April. So that was the seasonality we did see. The normal seasonality you see in Q1 is related to payer dynamics and resetting the deductible. Of course, our patients are subject to that as well. However, the programs that we put in place did an effective job and really smoothed that transition for the large majority of patients. So we consider that a success. And with that, I'll let Charles comment on gross tonnet.

Yes, so from a gross tonnet perspective, we've previously discussed the fact that we anticipate being in gross tonnet ranges of approximately 12 to 15 percent. For the first quarter, we'd remain in that range a touch closer towards the higher edge versus Q4 of last year, mostly driven by a couple of realities of our business. The first being that we took a price increase in January of this year, which results in some CPIU, excuse me, CPIU penalty associated with it. And then as Lauren just discussed, there was a modest amount of additional copay assistance required for patients, as you would expect in the first quarter of a year. Did not derive it materially, but it does

impact our number modestly.

Okay, great. I really appreciate the color. Thanks so much.

Thanks,

Charles. Our next question is from Alex Stranahan with Bank of America.

Hey, guys. Thanks for taking our questions and congrats from us on the progress as well. I guess maybe just double clicking on that prior question. How should we be thinking about new patients starts from here? Is April's trends for the run rate we should be thinking about for the rest of the year? And maybe if you could talk a bit about inventory levels across the various distribution channels and any impacts there that maybe benefited second half of last year and how we should be thinking about that going forward. Thanks.

Thanks, Alec, for the question. I'll start on your new patients start topic and then ask Charles to comment further. So what we've seen and expect to see going forward with respect to new patients starts what we've been emphasizing since launch. And that's a consistent and steady ramp of new patients starting over time as those patients either relapse or progress on other therapies and need a new therapy. I would remind you and investors that this is not a typical oncology launch trajectory. We really think of this more as akin to a rare disease launch. And that's driven by the relative infrequency of treatment decisions, the longer durations of treatment and the disease course for PLGG patients. All of that leads to, as we've said and will continue to see, a more gradual adoption and curve relative to adult oncology lapses, particularly those adult oncology launches that occur in a relapse or a salvage setting.

And then as far as

channel stock, how we've looked at it and discussed it previously, still consistent from that perspective. We, from an operational basis and how we've expressed it to the street, keep our channel stock or attempt to keep our channel stock within a two to four week of days on hand range. We do that in order as an internal target to make sure that we have adequate supply for in the channel to meet patient demand, which of course is the main goal there. We remain in that two to four weeks there, so we don't believe there is any really material effect to this current quarter from the channel stock changes itself, other than the consistent build you will get as you're increasing sales. So we'll continue to see that as we see growth on a specific dollar basis, but we'll remain within that two to four weeks on hand as much as possible. If we step out of that range, we'll certainly discuss it with yourself and other

analysts. Makes sense. Thanks for the color. Thanks, Alec.

As a reminder, if you'd like to ask a question, please press star one. Our next question is from Ami Fadia with Needham and Company.

Hi, this is Poonna on for Ami. Thank you for taking our question. Could you talk about the penetration that you have within each of the priority centers and what are you doing in order to, I guess, increase penetration into the lower accounts in each priority center? Thank you.

Really great question. Thanks for asking. I'll hand to Lauren, but really do want to reinforce the topic that you just brought up, which is that depth of prescribing multiple patients per center is really a key commercial goal for us, of course. Lauren?

Yeah. So when we think of penetration of accounts, we think of both breadth and depth. So first getting them to try it in one patient and then expanding to more patients. So as we reported last quarter, our priority one accounts, we have 100% of them who have tried OJMDA post-approval and priority two, we have three quarters of them who have tried OJMDA post-approval. And we've continued to grow that and even expand in P3. But as Jeremy mentioned, now our focus is depth. So once they have tried it, now it's about expanding their view of who is appropriate, which patients are appropriate for OJMDA. So that means expanding their thinking on the location of the tumor or where they are in therapy and what they've experienced to date. So that element of it. And then the second piece, which is even more important, is moving up in line. So many physicians try a new product in patients who have received all the other available therapies. So they're a later line patient and as their confidence builds, they will start to use it earlier in therapy. And so that's really a focus for us is to drive confidence in OJMDA and confidence in using it earlier in that second line. And with that, Jeremy?

Yeah, I want to add something to the question. And that is to really just reinforce what we've discussed in the past with respect to this particular physician community. This is a group that because of the nature of the patients and because of their considerations around sort of long term perspective for treating children are more conservative than other doctors. And for that, I'd ask Ellie if you can just comment on what you see as a pediatric oncologist.

Sure. Thanks. Thanks, Jeremy, for the question. So, yeah, when you think about children with cancer and in particular a disease like low grade glioma where children are expected to live well into adulthood, when you think about treatment options and in particular new treatments, of course, you want a drug that works and reduces tumor size, but you're also weighing that against the potential for long term effects and long term toxicities. And obviously when you have a new drug on the market, a new program, there's a lot of years down the line. So to Jeremy's point around the conservative nature of the physician community, it's one important factor that physicians will take into consideration when evaluating new treatments and how to weigh that against other options that are available.

Yeah. And I think that the key really is that giving those physicians that is deep experience with OJEMDA, we know is going to be essential for really getting them comfortable over time. And that's something that is occurring in the market. We're seeing it actively and especially among those investigators who were part of our Firefly One trial. And for the remainder, that will continue. But that's critical to that depth point.

Thanks. Thank you.

Our next question is from Sumit Roy with Jones Research.

Afternoon, everyone. Moving into the development pipeline, we'd love to get us some details on the day 301. What can you tell us about the, if possible, the tumor type, dose levels completed, when we should expect the data and how much details?

Shoma, thanks for the question. Let me kind of reiterate where we are and try to address those elements. So day 301 is in dose escalation in the Phase I trial. The patients that we're enrolling in those dose cohorts are patients that have specific tumor types that are known to express at reasonably high levels the target for that, for the 301 program, the ADC. And that target is PTK7. So it's endometrial patients, non-small cell lung cancer patients, triple negative breast cancer patients. There's an array of all adult solid tumors at this point who we're enrolling. And we have cleared the first dose cohort as we articulated in January. We are still in the dose escalation phase as we expected to be. We have not yet guided on the specific timing of when we'll have data from either dose escalation or potentially dose expansion cohorts available. But I can tell you that the plan is for us to get to those doses that we think are both safe and also in the efficacious range and begin to do two things. One is backfill patients into those dose cohorts so that we get more experience at those particular doses. And then two, once we have a body of data that's sufficient, move to dose expansion cohorts where we'll narrow to specific histologies. And we haven't really disclosed what those are until we have more clinical experience. We'll defer that disclosure in part for competitive reasons. But the dose expansion will be an important next step. And we anticipate that at that point, we'll be employing diagnostics such that we can prospectively define PTK7 expression for the patients who we put into those dose expansion cohorts.

This is very helpful. Are you finding the literature around the PTK expression to be matching up with what you're seeing in the clinic? And curious any futility hurdle you have in mind in terms of safety or efficacy that we decide to go forward and further disclosure of the data?

Also great questions. It's too early to say whether the publicly published data on PTK7 expression, and there's a couple of sources for that, are going to be consistent with what we see once we're really running trials with our own diagnostic. So I think just too early to say with any certainty whether that will be the case. You know, I think in the second part of your question, Shoma, can you just repeat it?

I'm trying to understand like what would be the go forward decision making point. Oh, yeah. Thank you.

It's going to be a combination of safety and reasonable efficacy. And so what do I mean by that? We need to see in the phase one trial a dose that we think we can move forward into a dose expansion phase and a phase two that is tolerable and has a reasonably competitive profile with other programs that may be in development for the tumors of interest. And then we also need to see at least some evidence of of anti tumor activity. And the reason we need we need that that anti tumor activity is really just to have confidence that the exposures that we're seeing at the doses that we think are reasonable and tolerable may result in in an efficacy signal that we could then pursue in registration programs.

Really. Thank you. Thanks,

Shoma.

Our next question is from Andrea Newkirk with Goldman Sachs.

Good afternoon. Thanks for taking our questions. And congratulations on the acceptance of Tovarafenib in Europe. And on that point, I was just curious if you could if you could talk a little bit more about how you see the market in that geography compared to that of the US. And are there any differences in prescribing behavior and how receptive is the community to ORR data versus outcomes endpoints like PFS or OS that probably aren't available until Firefly 2. Thanks so much.

Thanks, Andrea. Great. Great questions. Let me comment broadly. First off, the overall market dynamic with respect to patient population in Europe, particularly, is fairly similar to the US. There's no epidemiological distinction between the rates that you see in European countries versus the US. And so at a high level, you're talking about a similar patient population. And, you know, there are are some differences, of course, in pricing and reimbursement by country. But, you know, we think the overall market shape looks quite similar. As far as standards of clinical care in Europe, they are broadly fairly similar to what you see in the US, with the exception that there's much less off-label use of products across the board in Europe. And so there's less map kinase or targeted therapy use in general in Europe. All of that being said, to your question about response rate as a basis for assessing efficacy, that remains in practice how investigators and doctors who treat PLGG patients in Europe also think about what they're looking for in a product. And so it's broadly pretty similar to what you see in the US.

Thanks, Indra. Our next question comes from Andres Maldonado with HTWayne

Wright.

Hi, guys. Thank you for taking my questions and congrats on the progress. Two quick questions from us. So how should we be thinking about ogemsis positioning on the longer-term horizon, you know, with respect to MEK inhibitors or other targeted therapies, you know, potentially being used in PLGG across the front line and refractory setting? You know, what are some of the concerns or dynamics there you can highlight for us? And second, you know, with a cash position of $473 million, you know, what's the appetite to bring in a new asset or, you know, in terms of business development? Obviously, we're looking forward to 301 and a couple of other pipeline programs, but any round color there would be great. Thank you.

Of course. Thanks for the question, Andres. So let me start with your question about the sort of market dynamics and usage of targeted agents here in the US in PLGG patients. You know, I'd say broadly speaking, there's no clear standard of care in the second line setting for BRAF fusion patients who have PLGG. And that's, you know, really underpins our goal of establishing ogemsis as that second line standard of care. And, you know, the most significant hurdle to getting there is really just entrenched use and behavior for existing therapies that are used off the table, whether those are chemotherapy, they can be MEK inhibitors, you know, there's small numbers of patients who receive other targeted therapies that are not in the MAP kinase pathway as well. And to a significant extent, you know, what we're really looking to do is give physicians an experience that, you know, allows them to understand the product profile here as superior to their experiences with those other agents. And for all the reasons I've emphasized in the call earlier, you know, that is going to take time. But we think there's a real opportunity in particular in that BRAF fusion population to establish that standard of care. Now, I think it's important also to note that in the V600 segment within PLGG, there are other approved agents both in the frontline and in the relapse setting in the MAP kinase pathway. And for that reason, our focus on the V600 segment is really more on sequencing after use of those agents because those are moving towards the frontline in that V600. And as another reminder, the are BRAF fusion patients, that's the area where there aren't any approved agents other than OJMDA in the relapse setting. And then 15 to 20% of PLGG patients who have RAF alterations are the V600s where you do see Dabrafenov and Tremetnov as approved agents.

Great. Thank you very much. Oh, sorry. One other, let

me ask Charles to comment on business development as well. Thanks, Andres.

So from a business development perspective, consistent with what we've talked about previously, business development at day one is critical to what we believe can generate long-term additional growth. We continue to have a very active business development process, look at a number of different opportunities, but also continue to keep a very high bar to what we want to invest in and what we want to put both our capital resources and our human capital to work at. So as we continue that evaluation, we'll look to find opportunities that we think can continue to grow the business. The timeline associated with that is often a challenge to pick the specific time. But when we do see things, we will move forward on them. You know, an opportunity, one additional opportunity in our pipeline would be a great start for us. And it is something that we'll continue to evaluate

over time. Thank

you, ladies and gentlemen. We have reached the end of the question and answer session and are out of time for today's call. Thank you for your time and participation. You may disconnect your lines at this time.