Thank you and good afternoon everyone. Before we begin, please note that today's discussion will include forward-looking statements.

These statements reflect management's current expectations and beliefs as of today and are subject to risks and uncertainties that could cause actual results to differ materially. For a detailed discussion of these risks and uncertainties, please refer to the special note regarding forward-looking statements and the Risk Factors sections in our quarterly report on Form 10-Q filed today with the SEC, as well as our most recent annual report on Form 10-K.

Today's call will include a discussion of certain non-GAAP financial measures. A reconciliation of these non-GAAP measures to the corresponding GAAP measures is included with Omeros' earnings press release issued earlier today, which is available on the Investor Relations page of our website and has been furnished with the Form 8-K we filed with the SEC earlier today.

With that, I'll turn the call over to Dr. Gregory Demopulos, Chairman and CEO of Omeros.

Thank you, Jennifer, and good afternoon everyone. Joining me today are David Borges, our Chief Accounting Officer; Dr.

Cathy Melfi, our Chief Regulatory Officer; and Dr. Steve Whitaker, Vice President of Clinical.

I'll start with an overview of our first quarter 2026 operations and financial results, followed by program updates. After that, David will cover the financials in more detail and then we'll open the call for questions.

We entered 2026 with two catalysts: the closing of our previously announced transaction with Novo Nordisk for zaltenibart, our lead investigational MASP-3 inhibitor, and the FDA approval of Yartemlia, our lead MASP-2 inhibitor, for the treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy, or TA-TMA. This approval made Yartemlia the first and only approved treatment for this often-fatal complication and the first and only approved inhibitor of the lectin pathway of complement.

We launched in January with initial shipments to distributors beginning mid-month, followed shortly by first sales. In the first quarter, Yartemlia gross revenues were $11.1 million, with net revenues of $9.9 million, reflecting gross-to-net adjustments of approximately 11%.

Early demand and uptake are strong. Yartemlia became cash flow positive in the first quarter despite a mid-January launch, and we expect it to drive company-wide positive cash flow within 18 months.

Net income for the first quarter was $56.1 million or 78 cents per share, including a $73.1 million non-cash mark-to-market gain on the embedded derivative associated with our 2029 convertible notes. Excluding this non-cash item, adjusted net loss was $17.1 million or 24 cents per share.

We ended the quarter with $135.3 million in cash and investments after retiring our remaining 2026 convertible notes. During the first quarter, we repurchased and retired approximately 360,000 shares of our common stock at an average price of $11.70 per share for a total of $4.2 million.

We may continue to repurchase shares from time to time subject to market conditions and other considerations. Our transaction with Novo Nordisk provided substantial non-dilutive capital to support our growth.

At closing, we received $240 million in upfront cash, funding operations, including the Yartemlia launch. We're also eligible for another $100 million in near-term milestone payments from Novo.

The deal is valued at up to $2.1 billion in upfront and milestone payments, plus royalties in the high single-digit to high teen range. Our early launch has been focused on four priorities: first, educating transplant care teams to drive earlier recognition and treatment of TA-TMA; second, securing rapid institutional access through pharmacy and therapeutics, or P&T, committee approvals and streamlined ordering; third, ensuring consistent, timely reimbursement; and finally, demonstrating strong economic value through health economics and outcomes research, or HEOR.

Execution is ahead of plan. Our field force is fully deployed, detailing all 175 transplant centers nationwide.

By March 31, 30 unique accounts had ordered Yartemlia, reflecting accelerated adoption. Despite the typical 6- to 9-month timeline for P&T committee approvals, accounts are moving faster than expected.

By quarter-end, we understand that 60% of the top 10 centers, 40% of the top 20, 38% of the top 40, and approximately 30% of the top 80 U.S. centers had received P&T committee approval.

Looking at reimbursement, all prior authorization requests submitted to third-party commercial payers to date have been approved and centers have begun receiving full payment. HEOR analyses, which support Yartemlia pricing and show compelling quality of life improvements, are being finalized and prepared for publication.

Early indicators, including strong receptivity from transplant centers, formulary momentum, and payer alignment with the label, support our expectation that Yartemlia can become standard of care for TA-TMA. In April, the U.S.

Centers for Medicare & Medicaid Services, or CMS, assigned a permanent Healthcare Common Procedure Coding System J-code for Yartemlia. This simplifies billing and reimbursement across payers, reduces administrative burden, supports faster patient access, and improves reimbursement predictability.

The J-code becomes effective July 1. Also in April, CMS, in its Inpatient Prospective Payment System proposed rule, recommended approval of the New Technology Add-on Payment, or NTAP, for Yartemlia.

NTAP provides additional payments to hospitals for certain high-cost innovative technologies, helping bridge the gap until standard payment systems incorporate them. The final rule is expected in August with NTAP effective October 1 of this year.

We remain focused on expansion opportunities for Yartemlia and our MASP-2 program. Beyond the U.S., our marketing authorization application for Yartemlia in TA-TMA is under review by the European Medicines Agency.

We continue to expect a decision mid-year. We are evaluating potential partnerships, including broad ex-U.S.

and regional collaborations, to support commercialization outside the U.S. Beyond TA-TMA, we're assessing opportunities to expand the Yartemlia label to other indications involving lectin pathway activation, including acute respiratory distress syndrome, or ARDS, sickle cell disease, acute kidney injury, solid organ transplant-related TMA, and delayed graft function.

We're also broadening our MASP-2 inhibitor platform beyond Yartemlia, advancing both our Phase 2-ready long-acting MASP-2 antibody, OMS1029, and our oral MASP-2 small-molecule program. Both are well-suited for chronic indications, including membranous nephropathy, other renal diseases, and neurological disorders such as Parkinson's and Alzheimer's.

We're finalizing the initial Phase 2 indication for once-quarterly OMS1029. We're now also working to advance our small-molecule program to IND-enabling studies targeting once-daily oral delivery.

Let's now turn to development programs beyond our complement inhibitor franchise. Our PDE7 inhibitor program evaluating OMS527 for cocaine use disorder remains fully funded by a grant from the National Institute on Drug Abuse, or NIDA.

We successfully completed animal cocaine interaction studies, supporting a scheduled inpatient human study evaluating OMS527 in cocaine users. Recently, together with NIDA representation, we met with FDA to discuss the agency's request for additional non-clinical information before starting the inpatient study.

The meeting was productive and we are working with FDA to streamline the path to initiate the inpatient clinical trial, which is targeted to start by year-end. Based on its mechanism of action and our extensive preclinical data, we believe that OMS527 could be effective across a wide range of addictions and compulsive disorders.

Turning to our targeted complement-activating therapy, or T-CAT, platform, this represents a novel class of recombinant antibodies designed to target and directly kill pathogens, including bacteria, fungi, viruses, and parasites. Our initial focus is on multidrug-resistant organisms, or MDROs, one of the most critical unmet needs in medicine.

Unlike marketed antimicrobials, T-CAT is designed to kill pathogens regardless of resistance profile without promoting resistance. Data from our T-CAT platform were recently featured in a podium presentation at the annual congress of the European Society of Clinical Microbiology and Infectious Diseases, and the seminal manuscript describing our T-CAT technology was accepted for publication in Science Translational Medicine.

Last, but not least, we're pleased with the continued progress of Oncotox-AML, the lead development program in our Oncotox oncology platform. Oncotox-AML is an engineered biologic agent designed to treat acute myeloid leukemia, or AML, the most common and deadliest form of adult leukemia.

In both human tumor-bearing animal and in vitro human AML cell line studies, Oncotox-AML has consistently shown superior efficacy to current standard of care treatments, even at very low doses and across mutations associated with AML such as TP53 and FLT3, which have historically been difficult to treat. In a non-human primate study, a single course of Oncotox-AML demonstrated the desired pharmacologic response: a marked, selective, reversible, and dose-related reduction in myeloid progenitor cells, the cells that can mutate and lead to AML, by up to 99%.

Safety was equally strong: the treatment was well tolerated, with no safety signal of concern. IND-enabling studies are underway and we are preparing for a first-in-human trial targeted for late 2027.

That concludes our financial, corporate, and development program update. I'll now turn the call over to David Borges, our Chief Accounting Officer, for a detailed discussion of our financial results.

David?

Thanks, Greg. Net income for the first quarter of 2026 was $56.1 million or 78 cents per share, compared to net income of $86.5 million or $1.22 per share in the fourth quarter of 2025.

First quarter results include a $73.1 million non-cash gain related to the mark-to-market adjustment on the embedded derivative associated with our 2029 convertible notes. By comparison, fourth quarter results included a net gain of $237.6 million on the sale of zaltenibart to Novo Nordisk, partially offset by a $136 million non-cash loss related to mark-to-market adjustments on embedded derivatives associated with our 2029 convertible notes and term loan.

A clearer view of the company's operating performance excludes the non-cash remeasurements of our embedded derivatives. Excluding the $73.1 million embedded derivative adjustment, non-GAAP adjusted net loss for the first quarter of '26 was $17.1 million and non-GAAP adjusted net loss per share was 24 cents per share.

As of March 31, 2026, we had $135.3 million in cash and investments. This balance includes the repayment of the remaining $17.1 million principal on our 2026 notes at maturity in February of 2026.

Following that repayment, our only remaining debt is $70.8 million of principal outstanding on our unsecured 2029 convertible notes, which are due in June 2029. During the first quarter, we repurchased and retired approximately 360,000 shares of our common stock at an average price of $11.70 per share for a total of $4.2 million.

As Greg mentioned, Yartemlia launched in mid-January 2026. Gross revenues for the first quarter were $11.1 million, all from Yartemlia product sales, reflecting strong early demand following launch.

Uptake was driven by prescriber adoption and increasing market penetration, and we continue to expand access and build awareness. Net revenues were $9.9 million, reflecting gross-to-net adjustments of approximately 11%.

Gross-to-net adjustments were relatively modest and consisted of chargebacks and distribution fees. Costs and expenses from continuing operations for the first quarter before interest and other income were $27.3 million, a decrease of $1.8 million from the fourth quarter of 2025.

Concurrently with the closing of the sale of zaltenibart to Novo Nordisk, we entered into a transition services agreement to facilitate the transfer of the acquired assets and support the continued operation of relevant studies and program activities. Costs incurred by Omeros under the transition services agreement, including third-party expenses and internal full-time employee, or FTE, costs, are being reimbursed by Novo Nordisk.

Interest expense in the first quarter was $5.9 million. The primary components of interest expense include the DRI royalty obligation and interest on the 2029 convertible notes.

Excluding the DRI OMIDRIA royalty obligation, which represents pass-through interest from Rayner to DRI and has no economic impact to us, and excluding non-cash amortization of debt issuance costs and discounts, contractual cash interest expense for the first quarter of '26 was $1.8 million, compared to $3.2 million in the prior quarter. The decrease was primarily due to the full repayment of our secured term loan in November 2025.

Interest and other income totaled $1.5 million in the first quarter, up from $1.1 million in the fourth quarter of '25, primarily reflecting higher average cash balances. As previously mentioned, during the first quarter we recorded a $73.1 million non-cash gain from mark-to-market adjustment on the embedded derivative related to our 2029 convertible notes.

The change in valuation was primarily driven by the decline in our stock price during the quarter, which decreased from $17.18 per share at December 31, 2025, to $10.56 per share at March 31, 2026. An increase in stock price in the second quarter would similarly result in a non-cash loss during the quarter; conversely, a decrease in our stock price during the second quarter would result in a non-cash gain.

This embedded derivative reflects certain features of the notes, including the conversion option and interest make-whole provision available to the note holders. Because evaluation of this derivative is influenced by our stock price and other market inputs, it can introduce significant volatility in our reported results from quarter to quarter.

This adjustment is non-cash and does not affect our operating performance or liquidity. Accordingly, we present non-GAAP adjusted net income and net loss to exclude the non-cash nature of these volatile swings.

Income from discontinued operations in the first quarter was $4.8 million, a decrease of $1.8 million from the fourth quarter, primarily reflecting lower than forecasted U.S.-based OMIDRIA royalties. Because U.S.-based OMIDRIA royalties are fully passed through to DRI, fluctuation in these payments do not affect our cash position.

Now let's look at our expected second quarter 2026 results. We anticipate that overall operating expenses from continuing operations will be slightly higher compared to the first quarter of '26.

Sales and marketing expenses are expected to increase, reflecting costs associated with building our commercial infrastructure, including marketing expenses and other commercial launch activities for Yartemlia. As Yartemlia is in the early stages of launch, we are not providing revenue guidance at this time.

This is consistent with our approach following a new product launch while market access and physician adoption are still developing and until we are able to estimate revenue with greater accuracy. We remain focused on building physician awareness, expanding disease education, and ensuring continued timely reimbursement.

Interest and other income are expected to be higher than in the first quarter. Interest expense is expected to be approximately $7.1 million, reflecting the reduction in our outstanding debt and excludes any potential non-cash adjustments related to the OMIDRIA royalty obligation.

Income from discontinued operations is expected to be in the $5 million to $6 million range, excluding any non-cash remeasurement adjustment related to the OMIDRIA contract royalty asset. Finally, as a reminder, our reported results will continue to reflect mark-to-market adjustments on the embedded derivative tied to our 2029 convertible notes.

These adjustments are non-cash, can be volatile, and are largely driven by changes in our stock price and other market inputs. As a result, we present non-GAAP adjusted net income and loss measures to provide additional visibility into our underlying operating performance.

With that, turn the call back over to Greg.

Thanks, David. Operator, please open the call to questions.

Hi. Thanks for taking the question.

I'd like to go into some granularity on Yartemlia. First question has to deal with from the time the clinician requests drug to the time you get it to the hospitals, can you detail us how long it takes and the process, please?

Sure. Thanks, Steve.

The distributors deliver drug to the sites within about 24 hours of receipt of the request.

Okay. And-

The process is pretty straightforward: the request is made to the distributors, distributors deliver within 24 hours.

Okay. Can you give us some detail on cuz typically on stem cell TA-TMA, on the transplant side you're looking at about roughly 15% of the population are peds.

How does that reflect in terms of what you've seen so far on the requests for Yartemlia, please?

Right. You're correct about that.

The split between adult and pediatric patients in TA-TMA is roughly 85/15, as you noted. We only have, again, through the first quarter, a little over 2 months of data, these data may be skewed.

We are seeing a greater percentage of these patients being pediatric than the 15% that you cited. It appears that we're having really rapid adoption across both adult and pediatric patients.

Okay. Now, I don't want to put words in your mouth, but typically you would see the pediatric hematological oncologists being the most conservative.

You're saying that they are asking for Yartemlia in a greater number than the distribution. Look, I know it's only a partial quarter, but so far you're seeing a trend that these more conservative prescribers are asking for drug at a greater rate than you would expect.

Is that what I'm hearing?

I'm not sure that a point would create a trend, but what we're seeing is what I said, which is that there is a larger percentage of pediatric trasplanters than is represented by the overall split in TA-TMA between adults and pediatrics. We are seeing those pediatric transplanters requesting narsoplimab or Yartemlia.

Okay. [laughter] Thanks.

I thought I was the only person that was mixing narsoplimab and Yartemlia. You might have stated this earlier, but out of how many facilities out of the total targeted have you started to get requests from so far?

We have, at the end of March, by March 31, we had 30 separate accounts requesting Yartemlia.

And-

Of that 30, let me just give you a little more color. We went through this in the prepared comments, but we were speaking there in percentages, I think if I put it in absolute numbers, it may be helpful.

Maybe

helpful to everyone. Of the top 10, If you could, yeah.

Six of the top 10 sites had ordered by March 31. 24 of the top 80 centers had ordered by March 31.

Okay. Last question, I'll get back in the queue.

What kind of feedback, even if it's anecdotal, are you getting from the hematological oncologists and prescribing, or anyone else on the clinician side? Thank you, I'll jump back in the queue.

Sure. Again, it's early, but the feedback that we have received has been effectively, uniformly positive.

I think that the results that are being seen with Yartemlia are impressive. Again, we're early in the launch, but as I said, all signs look very encouraging and we do expect that Yartemlia will become standard of care for the treatment of TA-TMA.

Great. Thank you for the granularity and I'm looking forward to the next call to see the trend after one point.

How's that? [laughter]

Very good. Thanks.

Yep, we look forward to that as well.

Hi, good afternoon, guys, and thank you for the question. I know it's early, but Greg, how are you thinking about the split between inventory versus U.S.

wholesaler sales versus hospital demand? How that might play out over the course of the year just in terms of how we should think about the proportion of reported sales?

Any comments on how many patients are actually on drug as of today?

Sorry, I lost the second question, Olivia. What was that?

It

was a little muted on my end maybe.

It was just a question about how many patients are actually on drug as of today that are being treated with Yartemlia.

Sure. With respect to inventory, given the short delivery process, which as I explained in the last response is 24 hours, the amount of inventory carried at the distributors, and certainly at the centers, is relatively small.

On the distributor side, we're seeing 1, 1 and 1/2 weeks of inventory on average across those distributors. I think your next question was the number of patients on drug.

That's a difficult number to provide because often the centers don't share the specific information about the number of patients or the type of patients or really any patient-specific information. Really what we see is how many vials are going into a center and from which center those vials are being requested.

I'm not trying to dodge the question, I'm trying to give you the best information we have. We expect that it is a larger number of patients obviously than the number of accounts.

With respect to specific number, we just don't have that information.

Fair enough. Can I ask how are you thinking about the AstraZeneca Ultomiris Phase 3 study that they're running in TMA?

I think they're using disease relapse as an end point and it is a randomized study. I'm just curious if you have any thoughts on how that might fit into the landscape.

Right. I understand that they've changed their end point.

Their initial end point, as I understand it, and again, I want to caveat that this is my understanding, but the initial end point, as I understand it, was response. Following the readout of their pediatric open-label trial, which used response as the end point, that response was not clearly what AstraZeneca had hoped to see.

I think it had had a 17% response rate. As I understand it, subsequently they revised the end point for their adult trial from response to survival.

I don't know if they're looking at relapse. Our understanding is that the patients in that controlled adult trial by definition need to be less severe than the patients we treated by virtue of the fact that in the patients we treated running a controlled trial would really not be possible.

I think there's a difference in the severity of the patients. Don't know if they're looking at relapse.

I'll open the question up to Steve and/or Cathy if you have any other information about AstraZeneca and their data.

Hi, Greg. This is Steve.

We only know what's on ClinicalTrials.gov at this point. The primary end point is event-free survival, and that is death or clinical worsening.

It's not really relapses as Greg said. It'd be worsening from their baseline condition.

They do look at duration of response and the relapse, but those are lower secondary end points. Obviously I don't have the protocol, I don't know how these were ranked hierarchically, but those are pretty far down the line, if that helps.

Yep, that's great. Thank you, guys.

Appreciate it.

Thanks too, Olivia. I think also that there have been a number of recent publications and data presentations around the increased infection rates and increased infection-related mortality with C5 inhibition.

I know coming out of an adult study at MSK, Memorial Sloan Kettering, a pediatric study out of Children's Hospital in Atlanta associated with Emory, and I understand that there also has been additional data generated and presented by Dana-Farber and Boston Children's, again, in the pediatric center. All of those data align quite nicely with each other.

Those might be something that would help you as well.

Greg, you had mentioned the change in the end point and I did confirm that on ClinicalTrials.gov. Your understanding was correct.

It had been response and currently it's, as Steve said, event-free survival.

Thank you, Cathy. Yes, they had changed from response to survival.

Okay. Anything else, Olivia?

Nope, that's perfect. Thank you guys, appreciate the help.

Thank you very much.

Hi, thanks for taking my questions and congrats on all the progress. Maybe just one for me, Greg.

I think I heard you say you're working on efforts to recognize TMA earlier. Can you just elaborate on those efforts and whether you believe once NTAP comes into practice that may facilitate less friction to earlier intervention?

Or what do you think drives earlier intervention? Thank you.

Hi, Brandon. Thank you.

Certainly, we're interested in earlier intervention. We want to save as many patients as possible.

Our expectation and the data support that the earlier one jumps on this problem, the greater the likelihood of success in outcome. I think that there certainly seems to be an increasing awareness of that within the transplant community.

We are receiving incoming questions about the temporally upstream administration of Yartemlia. All of that I think bodes well for patients.

With respect to will the NTAP assist that, yes, the NTAP increases the subsidization, actually subsidizes in good part for Medicare patients, the payment on the inpatient side. That's where you would expect that earliest treatment to begin.

I think your thought around whether the NTAP would help in that respect I think is insightful. We're waiting to see, but we do expect that there will be an increasing move to earlier treatment, particularly given that initially a good number of the patients we were treating were eculizumab failures.

We were really catching patients and in the first quarter, catching patients who were falling knives. Yet those patients, very many of them responded very well to Yartemlia.

I think that there's a greater understanding and increasing awareness of moving temporally upstream in the administration process. I think that's a good thing.

I think it's good for patients. Does that help?

Okay.

It does. Thanks so much, Greg.

Sorry.

Thanks, Brandon.

Sorry, just dealing with the mute button.

No, that's fine. Any other questions?

Hi, good afternoon. Thanks for taking my questions.

I guess just to get a little more granularity on the 1Q sales number. Greg, can you disclose what the number of vials that were, I guess, dispersed from your distributor over the quarter?

Then, secondly, I think you talked about a gross-to-nets of 11% for the first quarter here. Just curious where you expect that gross-to-net to go once you have more comprehensive formulary coverage.

Then I have a couple reimbursement questions.

Sure. In response to your first question, no, we aren't providing the number of vials.

We're providing gross and net revenue numbers. With respect to your second, around what constitutes that gross-to-net number, that really is made up of chargebacks and fees.

Chargebacks meaning governmental programs, 340B, and fees being largely bona fide fees to distributors. That's largely it.

We would expect that over time to increase as 340B participation increases. With respect to a target, I would not expect that to be reaching the 20 percentile.

I would be thinking we're going to remain in the teens on that, Serge, but we'll have to see how that plays out. We are not planning at all to discount the drug, and I don't think we've had any, but I think that will be negligible.

Going forward, I would expect the components of the gross-to-net to be what they were in Q1, which is the chargebacks and the fees only.

Got it. Then regarding P&T approvals, clearly got some good traction through the end of the first quarter here with the numbers you gave us.

Curious when do you expect the rest of them to go through the P&T approval process. Are they already scheduled?

Then, secondly, you talked that you got approval for a J-code, as well as the NTAP for later this year. Curious since you said that most centers have had some very good access to the product, access hasn't been an issue, will these J-codes and NTAP, what kind of impact could they have on further uptake once they are in effect?

With respect to P&T committees, there are a number of them that are in process. Remember, we launched this in mid-January, third week of January.

We are really still very early in the process and the P&T committee approvals that we've seen, as I mentioned, are quite satisfying in that they are well ahead of what we would have expected in terms of just timeline and number of P&T approvals. Clearly there is an urgency I think that's being recognized and manifest across the sites with physicians and pharmacists recognizing the value of Yartemlia and moving quickly to make it available.

There are centers, obviously, that are approving access to the drug absent P&T approvals, but additional P&T approvals will certainly help that access, streamline it, make it more quick, more efficient. With respect to when we would expect all of those to have gone through the P&T process, "all" is an absolute number.

I would expect that the large majority of them will be coming through in the next few months. Your second question about the J-code and the NTAP: well, the J-code certainly streamlines the billing process and the reimbursement process.

Certainly having the J-code now awarded and going into effect on July 1 I think will be very helpful. CMS has in its proposed Inpatient Prospective Payment Systems rule indicated that they support the approval of the NTAP for Yartemlia.

That we expect will be finalized in the inpatient final rule in August. Assuming that's the case, it should become finalized and available for use on November 1st or sometime very close to November 1st, it runs on CMS's schedule.

Both of those, the J-code and the NTAP, I expect will obviously help with reimbursement. Anytime you have secured reimbursement, that certainly helps with utilization.

I think it's been quite surprising frankly how broadly Yartemlia has been used in the absence of the historical reimbursement already in place. Serge, once that reimbursement becomes much more standard and much more well recognized, that just drives front-end utilization as it should.

Great. Thank you.

All right. Thank you.

All right. Thank you, Operator, and thank you all for joining us this afternoon.

As we've said, we're pleased with the strength of the Yartemlia launch and the continued progress across our pipeline and our platform programs. With expanding commercial momentum, multiple near-term catalysts, and continued execution across the organization, we believe Omeros is well-positioned for continued growth and long-term value creation.

As always, we appreciate your continued support and confidence. Have a good evening.