Hematopoietic stem cell transplantation

– Conference Call Today at 4:30 p.m. ET – SEATTLE --(BUSINESS WIRE)--Mar. 31, 2025-- Omeros Corporation (Nasdaq: OMER) today announced recent highlights and developments as well as financial results for the fourth quarter and year ended December 31, 2024 , which include: Net loss for the fourth quarter of 2024 was $31.4 million , or $0.54 per share, compared to a net loss of $32.2 million , or $0.56 per share for the third quarter of 2024. For the year ended December 31, 2024 , net loss was $156.8 million , or $2.70 per share, compared to a net loss of $117.8 million , or $1.88 per share in the prior year. The change in net loss reflects a $33.2 million decrease in the noncash gain from the remeasurement of the OMIDRIA contract royalty asset, a $6.6 million decrease in interest income earned and a $4.1 million gain on the early extinguishment of debt in December 2023 , which were partially offset by a $6.2 million decrease in interest expense as a result of our debt repurchases and refinancing. At December 31, 2024 , we had $90.1 million of cash and short-term investments available for operations and debt servicing, a decrease of $81.7 million from December 31, 2023 . We incurred significant cost outlays during the year representing a total of $42.7 million . These cost outlays are comprised of $21.7 million in payments related to repurchasing our convertible senior notes maturing in 2026, $19.1 million in charges related to delivery of narsoplimab drug substance and $1.9 million of costs related to our senior debt transaction. Earlier this month, we successfully resubmitted our biologics license application (“BLA”) for narsoplimab, our lead antibody targeting MASP-2 and the lectin pathway of complement, in hematopoietic stem cell transplant-associated thrombotic microangiopathy (“TA-TMA”). The resubmitted BLA includes the previously announced results of a protocol and statistical analysis plan that we developed with input from FDA to compare survival in TA-TMA patients treated with narsoplimab to survival in an external control population of TA-TMA patients who did not receive narsoplimab. We expect the target date for FDA action under the Prescription Drug User Fee Act (“PDUFA”) to be six months following the date of resubmission to FDA, meaning, in this case, the PDUFA date would be in September 2025 . We expect to submit our European marketing authorization application (“MAA”) for narsoplimab in TA-TMA in the first half of 2025. The European Medicines Agency (“EMA”) has appointed rapporteurs from Germany and Austria responsible to coordinate review by EMA’s Committee for Human Medicinal Products of the anticipated MAA for narsoplimab. At upcoming meetings scheduled with representatives from both rapporteur countries, Omeros will orient the representatives to the data included in the application. EMA has confirmed narsoplimab’s eligibility for centralized review of a single MAA that, if approved, authorizes the product to be marketed in all EU member states and European Economic Area countries. Site activation has begun in our Phase 3 development program evaluating zaltenibart (formerly known as OMS906), our lead MASP-3 antibody targeting the key and most proximal activator of the alternative pathway of complement, for the treatment of paroxysmal nocturnal hemoglobinuria (“PNH”). Similar to our Phase 2 program in this indication, our Phase 3 program includes a study treating PNH patients who are not receiving a complement-inhibitor, as well as a “switch-over” study in PNH patients who have had an unsatisfactory response to ravulizumab, an inhibitor of complement component 5 (“C5”). “We are pleased to announce that our narsoplimab BLA for the treatment of TA-TMA was resubmitted to FDA earlier this month, with the MAA slated for European submission in the coming quarter,” stated Gregory A. Demopulos , M.D., Chairman and CEO of Omeros. “All study results in the BLA are uniformly strong across all comparative analyses and all datasets – the primary and primary-related sensitivity analyses, the 136-patient expanded access program, adults and children, and patients who had failed treatment with other off-label agents prior to receiving narsoplimab. With a six-month review cycle from the date of resubmission, we look forward to working closely with FDA toward narsoplimab’s approval and our commercial team is well-prepared to execute a successful market launch. Zaltenibart’s compelling results in our Phase 2 PNH trials are highly predictive of the similarly designed and ongoing Phase 3 program in PNH, which remains on track to readout data late next year, and we are focused on establishing ex- U.S. partnerships for both zaltenibart and narsoplimab. Also later this year, we expect data from our NIDA-funded OMS527 trial in patients with cocaine use disorder. Collectively, these programs in BLA review and with near-term clinical trial results translate to significant shareholder value.” Fourth Quarter and Recent Clinical Developments Recent developments regarding our program targeting mannan-binding lectin-associated serine protease-2 (“MASP-2”) and the lectin pathway of complement include the following: The BLA for narsoplimab resubmitted to FDA in March 2025 includes the results of a protocol and statistical analysis plan that we developed with input from FDA, including final comments received subsequent to our most recent meeting with the agency in September 2024 . The primary endpoint under the analysis plan is patient survival in our pivotal narsoplimab trial (OMS721-TMA-001) compared to that in an external registry of TA-TMA patients who were not treated with narsoplimab. Analyses similar to the primary analysis comparing survival in TA-TMA patients treated with narsoplimab under our global expanded access program (“EAP”) to that of similarly at-risk TA-TMA registry patients were also included in the analysis plan, along with sensitivity analyses related to each of the primary and EAP comparisons. All statistical analyses were conducted by an independent statistical group and the results were previously announced. Narsoplimab met its primary statistical analysis endpoint comparing overall survival in the 28 TA-TMA patients in the pivotal trial for narsoplimab in TA-TMA (OMS721-TMA-001), to that of more than 100 similarly high-risk TA-TMA patients in an external control registry of TA-TMA patients who did not receive narsoplimab treatment. OMS721-TMA-001 patients demonstrated clinically meaningful and statistically significant superiority in overall survival – a hazard ratio of 0.32 (95% confidence interval: 0.23 to 0.44) with p-value less than 0.00001 – compared to the TA-TMA patients in the external registry. The EAP-related analyses, which comprise multiple survival comparisons between narsoplimab-treated EAP patients and similarly at-risk TA-TMA patients in the external control registry, further support the robustness of the primary analysis results, with representative analyses of the combined EAP and pivotal trial patients yielding hazard ratios ranging from 0.34 (95% confidence interval: 0.21, 0.53) to 0.46 (95% confidence interval: 0.35, 0.60) and p-values ranging from less than 0.00001 to 0.00002. Results of the primary-related and EAP-related sensitivity analyses performed as part of the statistical analysis plan support the robustness of the primary results. The EAP includes adults and children and includes both treatment-naïve patients and patients who failed or stopped treatment for their TA-TMA prior to receiving narsoplimab. Analyses of survival across all of these subgroups of patients treated with narsoplimab show consistently impressive survival results regardless of age or prior treatment status. Last month, two presentations reporting real world outcomes from TA-TMA patients treated with narsoplimab supplied by Omeros under the EAP were featured at the 2025 Tandem Meetings – the Transplantation & Cellular Therapy Meetings of the American Society for Transplantation and Cellular Therapy and the Center for International Blood and Marrow Transplant Research held February 12-15, 2025 in Honolulu, Hawaii . The first, a podium presentation, reported on the impressive survival in both adult and pediatric high-risk TA-TMA patients, including those who had failed one or more other TA-TMA-directed therapies (primarily eculizumab) prior to receiving narsoplimab. The second reported on high-risk TA-TMA patients who had failed eculizumab and were subsequently treated with narsoplimab, achieving an over three-fold increase in one-year survival compared to the reported survival in eculizumab-refractory patients of 20 percent or less. Panels of leading international transplant experts have drafted two manuscripts directed to survival of narsoplimab-treated TA-TMA patients, which are under review and will be submitted for publication in premier peer-reviewed journals once finalized. The first compares survival in patients in the narsoplimab pivotal trial to survival in the same external control population of TA-TMA patients used in our BLA primary analysis and the second will detail the survival data in the 50 pediatric TA-TMA patients treated with narsoplimab under our expanded access program. We continue to explore the potential of narsoplimab and MASP-2 inhibition in severe acute respiratory distress syndrome (“ARDS”) and have generated compelling data from established animal models across bacterial, viral and chemical-induced forms of ARDS. This work includes an ongoing study in animals infected with H5N1 avian influenza or “bird flu,” which some experts regard as a threat to become a global pandemic. A manuscript has already been drafted and awaits receipt of the H5N1 data. We also continue to advance a MASP-2/C1inh proprietary diagnostic assay for lectin pathway hyperactivation for use in severe acute and long COVID-19, ARDS, and other diseases and disorders. We are identifying indications for our Phase 2 clinical development of OMS1029, our long-acting, next-generation MASP-2 inhibitor. OMS1029 drug product has been manufactured and stored in quantities sufficient to support a future Phase 2 clinical trial. Single- and multiple-ascending-dose Phase 1 studies of OMS1029 were previously completed and validate once quarterly subcutaneous administration of OMS1029 to effectively ablate MASP-2 activity in humans. OMS1029 has been well tolerated to date with no safety concerns identified. Recent developments regarding zaltenibart, our lead monoclonal antibody targeting mannan-binding lectin-associated serine protease-3 (“MASP-3”), the key activator of the alternative pathway, include the following: We have initiated our Phase 3 clinical program for zaltenibart in PNH, which is comprised of two studies: one treating PNH patients who are not receiving a complement-inhibitor, and the other treating PNH patients who have had an unsatisfactory response to the C5 inhibitor ravulizumab and utilizing a “switch-over” design similar to our Phase 2 study. Both studies in our Phase 3 program are designed to provide head-to-head comparisons with the C5 inhibitors and could produce data demonstrating the superiority of zaltenibart over the C5 inhibitors in these patient populations. These data would potentially form the basis for comparative superiority claims for promotion, enhanced market access, and pricing reflective of zaltenibart’s advantages. Results from the zaltenibart monotherapy stage of our Phase 2 “switch-over” trial evaluating two doses of zaltenibart in PNH patients who have had an unsatisfactory response to the C5 inhibitor ravulizumab were presented in December 2024 at the Annual Meeting of the American Society of Hematology . The study, now completed, enrolled PNH patients receiving ravulizumab with zaltenibart added to provide combination therapy for 24 weeks. Those patients demonstrating a hemoglobin response with the combination therapy were then switched to zaltenibart monotherapy. Twelve of 13 enrolled patients continued to the monotherapy stage of the study. The interim results showed that in PNH patients experiencing substantial extravascular hemolysis while receiving ravulizumab, zaltenibart monotherapy resulted in sustained clinically meaningful improvements in both hemoglobin and absolute reticulocyte count and prevented both intravascular and extravascular hemolysis. Our Phase 2 clinical trial evaluating zaltenibart in C3 glomerulopathy (“C3G”) is also open to enrollment in multiple countries and dosing in the study is ongoing. This study requires enrollment of a relatively small number of patients. Following completion of the Phase 2 study, and assuming strong evidence of efficacy, we plan to initiate a Phase 3 trial in C3G. Recent developments regarding OMS527, our phosphodiesterase 7 (“PDE7”) inhibitor program focused on addictions and compulsive disorders as well as movement disorders, include: In March 2025 , the National Institute on Drug Abuse (“NIDA”), part of the National Institutes of Health confirmed its funding commitment for the upcoming year commencing April 1, 2025 in the amount of $4.02 million . This amount, part of a grant originally awarded in April 2023 to support development at NIDA’s direct request of our lead orally administered PDE7 inhibitor compound for the treatment of cocaine use disorder (“CUD”), is expected to fund an inpatient clinical trial assessing safety and efficacy of OMS527 in adult patients with CUD. The funding commitment followed the successful completion of NIDA-funded OMS527-cocaine interaction safety studies in which OMS527 was co-administered with cocaine in two animal species to rule out enhancement of the detrimental effects of cocaine. In the OMS527-cocaine interaction studies, OMS527, when administered at two different doses in combination with cocaine did not enhance the adverse cocaine effects in rats or non-human primates. Instead, the higher doses of OMS527 generally lessened the severity of effects noted following intravenous administration of cocaine, most notably decreasing convulsant-related activity following the administration of cocaine. Work on the planned randomized, double-blind, parallel-group, inpatient Phase 1b clinical trial comparing the safety and efficacy of OMS527 to placebo in the treatment of adults with CUD is underway, and a preliminary data readout from that study is targeted by year-end 2025. Recent developments regarding our oncology platform comprising signaling-driven immunomodulators, oncotoxins, and an adoptive T-cell technology combined with an immunostimulator, include: In vitro and in vivo studies are rapidly advancing and support the potential of our oncology platform to deliver broadly effective and safe cancer treatments to overcome the shortcomings of currently marketed therapies. These programs are currently operating in “stealth” mode while we continue to secure our intellectual property estate around these technologies. Over the past several months we have engaged in confidential discussions to seek input and guidance from leading therapeutic-area experts and their uniformly positive response has been encouraging. We plan to share further information on these programs publicly in the near term. The BLA for narsoplimab resubmitted to FDA in March 2025 includes the results of a protocol and statistical analysis plan that we developed with input from FDA, including final comments received subsequent to our most recent meeting with the agency in September 2024 . The primary endpoint under the analysis plan is patient survival in our pivotal narsoplimab trial (OMS721-TMA-001) compared to that in an external registry of TA-TMA patients who were not treated with narsoplimab. Analyses similar to the primary analysis comparing survival in TA-TMA patients treated with narsoplimab under our global expanded access program (“EAP”) to that of similarly at-risk TA-TMA registry patients were also included in the analysis plan, along with sensitivity analyses related to each of the primary and EAP comparisons. All statistical analyses were conducted by an independent statistical group and the results were previously announced. Narsoplimab met its primary statistical analysis endpoint comparing overall survival in the 28 TA-TMA patients in the pivotal trial for narsoplimab in TA-TMA (OMS721-TMA-001), to that of more than 100 similarly high-risk TA-TMA patients in an external control registry of TA-TMA patients who did not receive narsoplimab treatment. OMS721-TMA-001 patients demonstrated clinically meaningful and statistically significant superiority in overall survival – a hazard ratio of 0.32 (95% confidence interval: 0.23 to 0.44) with p-value less than 0.00001 – compared to the TA-TMA patients in the external registry. The EAP-related analyses, which comprise multiple survival comparisons between narsoplimab-treated EAP patients and similarly at-risk TA-TMA patients in the external control registry, further support the robustness of the primary analysis results, with representative analyses of the combined EAP and pivotal trial patients yielding hazard ratios ranging from 0.34 (95% confidence interval: 0.21, 0.53) to 0.46 (95% confidence interval: 0.35, 0.60) and p-values ranging from less than 0.00001 to 0.00002. Results of the primary-related and EAP-related sensitivity analyses performed as part of the statistical analysis plan support the robustness of the primary results. The EAP includes adults and children and includes both treatment-naïve patients and patients who failed or stopped treatment for their TA-TMA prior to receiving narsoplimab. Analyses of survival across all of these subgroups of patients treated with narsoplimab show consistently impressive survival results regardless of age or prior treatment status. Last month, two presentations reporting real world outcomes from TA-TMA patients treated with narsoplimab supplied by Omeros under the EAP were featured at the 2025 Tandem Meetings – the Transplantation & Cellular Therapy Meetings of the American Society for Transplantation and Cellular Therapy and the Center for International Blood and Marrow Transplant Research held February 12-15, 2025 in Honolulu, Hawaii . The first, a podium presentation, reported on the impressive survival in both adult and pediatric high-risk TA-TMA patients, including those who had failed one or more other TA-TMA-directed therapies (primarily eculizumab) prior to receiving narsoplimab. The second reported on high-risk TA-TMA patients who had failed eculizumab and were subsequently treated with narsoplimab, achieving an over three-fold increase in one-year survival compared to the reported survival in eculizumab-refractory patients of 20 percent or less. Panels of leading international transplant experts have drafted two manuscripts directed to survival of narsoplimab-treated TA-TMA patients, which are under review and will be submitted for publication in premier peer-reviewed journals once finalized. The first compares survival in patients in the narsoplimab pivotal trial to survival in the same external control population of TA-TMA patients used in our BLA primary analysis and the second will detail the survival data in the 50 pediatric TA-TMA patients treated with narsoplimab under our expanded access program. We continue to explore the potential of narsoplimab and MASP-2 inhibition in severe acute respiratory distress syndrome (“ARDS”) and have generated compelling data from established animal models across bacterial, viral and chemical-induced forms of ARDS. This work includes an ongoing study in animals infected with H5N1 avian influenza or “bird flu,” which some experts regard as a threat to become a global pandemic. A manuscript has already been drafted and awaits receipt of the H5N1 data. We also continue to advance a MASP-2/C1inh proprietary diagnostic assay for lectin pathway hyperactivation for use in severe acute and long COVID-19, ARDS, and other diseases and disorders. We are identifying indications for our Phase 2 clinical development of OMS1029, our long-acting, next-generation MASP-2 inhibitor. OMS1029 drug product has been manufactured and stored in quantities sufficient to support a future Phase 2 clinical trial. Single- and multiple-ascending-dose Phase 1 studies of OMS1029 were previously completed and validate once quarterly subcutaneous administration of OMS1029 to effectively ablate MASP-2 activity in humans. OMS1029 has been well tolerated to date with no safety concerns identified. Narsoplimab met its primary statistical analysis endpoint comparing overall survival in the 28 TA-TMA patients in the pivotal trial for narsoplimab in TA-TMA (OMS721-TMA-001), to that of more than 100 similarly high-risk TA-TMA patients in an external control registry of TA-TMA patients who did not receive narsoplimab treatment. OMS721-TMA-001 patients demonstrated clinically meaningful and statistically significant superiority in overall survival – a hazard ratio of 0.32 (95% confidence interval: 0.23 to 0.44) with p-value less than 0.00001 – compared to the TA-TMA patients in the external registry. The EAP-related analyses, which comprise multiple survival comparisons between narsoplimab-treated EAP patients and similarly at-risk TA-TMA patients in the external control registry, further support the robustness of the primary analysis results, with representative analyses of the combined EAP and pivotal trial patients yielding hazard ratios ranging from 0.34 (95% confidence interval: 0.21, 0.53) to 0.46 (95% confidence interval: 0.35, 0.60) and p-values ranging from less than 0.00001 to 0.00002. Results of the primary-related and EAP-related sensitivity analyses performed as part of the statistical analysis plan support the robustness of the primary results. The EAP includes adults and children and includes both treatment-naïve patients and patients who failed or stopped treatment for their TA-TMA prior to receiving narsoplimab. Analyses of survival across all of these subgroups of patients treated with narsoplimab show consistently impressive survival results regardless of age or prior treatment status. We have initiated our Phase 3 clinical program for zaltenibart in PNH, which is comprised of two studies: one treating PNH patients who are not receiving a complement-inhibitor, and the other treating PNH patients who have had an unsatisfactory response to the C5 inhibitor ravulizumab and utilizing a “switch-over” design similar to our Phase 2 study. Both studies in our Phase 3 program are designed to provide head-to-head comparisons with the C5 inhibitors and could produce data demonstrating the superiority of zaltenibart over the C5 inhibitors in these patient populations. These data would potentially form the basis for comparative superiority claims for promotion, enhanced market access, and pricing reflective of zaltenibart’s advantages. Results from the zaltenibart monotherapy stage of our Phase 2 “switch-over” trial evaluating two doses of zaltenibart in PNH patients who have had an unsatisfactory response to the C5 inhibitor ravulizumab were presented in December 2024 at the Annual Meeting of the American Society of Hematology . The study, now completed, enrolled PNH patients receiving ravulizumab with zaltenibart added to provide combination therapy for 24 weeks. Those patients demonstrating a hemoglobin response with the combination therapy were then switched to zaltenibart monotherapy. Twelve of 13 enrolled patients continued to the monotherapy stage of the study. The interim results showed that in PNH patients experiencing substantial extravascular hemolysis while receiving ravulizumab, zaltenibart monotherapy resulted in sustained clinically meaningful improvements in both hemoglobin and absolute reticulocyte count and prevented both intravascular and extravascular hemolysis. Our Phase 2 clinical trial evaluating zaltenibart in C3 glomerulopathy (“C3G”) is also open to enrollment in multiple countries and dosing in the study is ongoing. This study requires enrollment of a relatively small number of patients. Following completion of the Phase 2 study, and assuming strong evidence of efficacy, we plan to initiate a Phase 3 trial in C3G. In March 2025 , the National Institute on Drug Abuse (“NIDA”), part of the National Institutes of Health confirmed its funding commitment for the upcoming year commencing April 1, 2025 in the amount of $4.02 million . This amount, part of a grant originally awarded in April 2023 to support development at NIDA’s direct request of our lead orally administered PDE7 inhibitor compound for the treatment of cocaine use disorder (“CUD”), is expected to fund an inpatient clinical trial assessing safety and efficacy of OMS527 in adult patients with CUD. The funding commitment followed the successful completion of NIDA-funded OMS527-cocaine interaction safety studies in which OMS527 was co-administered with cocaine in two animal species to rule out enhancement of the detrimental effects of cocaine. In the OMS527-cocaine interaction studies, OMS527, when administered at two different doses in combination with cocaine did not enhance the adverse cocaine effects in rats or non-human primates. Instead, the higher doses of OMS527 generally lessened the severity of effects noted following intravenous administration of cocaine, most notably decreasing convulsant-related activity following the administration of cocaine. Work on the planned randomized, double-blind, parallel-group, inpatient Phase 1b clinical trial comparing the safety and efficacy of OMS527 to placebo in the treatment of adults with CUD is underway, and a preliminary data readout from that study is targeted by year-end 2025. In vitro and in vivo studies are rapidly advancing and support the potential of our oncology platform to deliver broadly effective and safe cancer treatments to overcome the shortcomings of currently marketed therapies. These programs are currently operating in “stealth” mode while we continue to secure our intellectual property estate around these technologies. Over the past several months we have engaged in confidential discussions to seek input and guidance from leading therapeutic-area experts and their uniformly positive response has been encouraging. We plan to share further information on these programs publicly in the near term. Financial Results Net loss for the fourth quarter of 2024 was $31.4 million , or $0.54 per share, compared to a net loss of $32.2 million , or $0.56 per share for the third quarter of 2024. For the year ended December 31, 2024 , our net loss was $156.8 million , or $2.70 per share, compared to a net loss of $117.8 million , or $1.88 per share in the prior year period. The change in net loss reflects a $33.2 million decrease in the noncash gain from the remeasurement of the OMIDRIA contract royalty asset, a $6.6 million decrease in interest income earned and a $4.1 million gain on the early extinguishment of debt in December 2023 , which were partially offset by a $6.2 million decrease in interest expense as a result of our debt repurchases and refinancing. At December 31, 2024 , we had $90.1 million of cash and short-term investments available for operations and debt service, a decrease of $81.7 million from December 31, 2023 . We incurred significant cost outlays during the year representing a total of $42.7 million . These cost outlays are comprised of $21.7 million in payment related to repurchasing our convertible senior notes maturing in 2026, $19.1 million in charges related to delivery of narsoplimab drug substance and $1.9 million of costs related to our senior credit transaction. Our cash used in operations for the fourth quarter was $29.0 million . For the fourth quarter of 2024, we earned OMIDRIA royalties of $10.1 million on Rayner’s U.S. net sales of $33.6 million . This compares to earned OMIDRIA royalties of $9.3 million during the third quarter of 2024 on U.S. net sales of $31.0 million . Total operating expenses for the fourth quarter of 2024 were $35.7 million compared to $35.4 million for the third quarter of 2024. Interest expense during the fourth quarter of 2024 was $3.2 million compared to $4.1 million during the prior quarter. The decrease was primarily due to the remeasurement of the OMIDRIA royalty obligation. We earned $2.3 million , respectively, for both the fourth and third quarters of 2024 in interest and other income. Net income from discontinued operations, net of tax, was $5.2 million for the fourth quarter of 2024 compared to $4.9 million in the prior quarter. Conference Call Details Omeros’ management will host a conference call and webcast to discuss the financial results and to provide an update on business activities. The call will be held today at 1:30 p.m. Pacific Time ; 4:30 p.m. Eastern Time . For online access to the live webcast of the conference call, go to Omeros’ website at https://investor.omeros.com/upcoming-events. To access the live conference call via phone, participants must register at the following URL https://register-conf.media-server.com/register/BIfd61371fd0fb44c1a0e7bdc80c36e0f8 to receive a unique PIN. Once registered, you will have two options: (1) dial in to the conference line provided at the registration site using the PIN provided to you, or (2) choose the “Call Me” option, which will instantly dial the phone number you provide. Should you lose your PIN or registration confirmation email, simply re-register to receive a new PIN. A replay of the call will be made accessible online at https://investor.omeros.com/archived-events. About Omeros Corporation Omeros is an innovative biopharmaceutical company committed to discovering, developing and commercializing first-in-class small-molecule and protein therapeutics for large-market and orphan indications targeting immunologic disorders, including complement-mediated diseases and cancers, as well as addictive and compulsive disorders. Omeros’ lead MASP-2 inhibitor narsoplimab targets the lectin pathway of complement and is the subject of a biologics license application pending before FDA for the treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy. Omeros’ long-acting MASP-2 inhibitor OMS1029 has successfully completed Phase 1 single- and multiple-ascending dose clinical studies. Zaltenibart, Omeros’ inhibitor of MASP-3, the key activator of the alternative pathway of complement, is in Phase 3 clinical development for paroxysmal nocturnal hemoglobinuria and is being evaluated in an ongoing Phase 2 clinical trial for complement 3 glomerulopathy. Funded by the National Institute on Drug Abuse , Omeros’ lead phosphodiesterase 7 inhibitor OMS527 is in clinical development for the treatment of cocaine use disorder. Omeros also is advancing a broad portfolio of novel cellular and molecular immuno-oncology programs. For more information about Omeros and its programs, visit www.omeros.com. Forward-Looking Statements This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, which are subject to the “safe harbor” created by those sections for such statements. All statements other than statements of historical fact are forward-looking statements, which are often indicated by terms such as “anticipate,” “believe,” “could,” “estimate,” “expect,” “goal,” “intend,” “likely,” “look forward to,” “may,” “objective,” “plan,” “potential,” “predict,” “project,” “should,” “slate,” “target,” “will,” “would” and similar expressions and variations thereof. Forward-looking statements, including statements regarding the anticipated PDUFA date for FDA review of the biologics license application for narsoplimab, the anticipated submission to EMA of a marketing authorization application for narsoplimab, the prospects for obtaining FDA or EMA approval of narsoplimab in any indication, expectations regarding the initiation or continuation of clinical trials evaluating Omeros’ drug candidates and the anticipated availability of data therefrom, expectations regarding future cash expenditures, and expectations regarding the sufficiency and availability of our capital resources to fund current and planned operations including the potential commercialization of narsoplimab if it is approved by FDA or EMA, are based on management’s beliefs and assumptions and on information available to management only as of the date of this press release. Omeros’ actual results could differ materially from those anticipated in these forward-looking statements for many reasons, including, without limitation, unfavorable or unexpected interpretation of our statistical analyses relating to an external registry of TA-TMA patients, potential differences between the diagnostic criteria used in our pivotal trial and in the external registry, and whether FDA and the EMA determine the registry used in our statistical analysis is sufficiently representative of TA-TMA patients, unanticipated or unexpected outcomes of regulatory processes in relevant jurisdictions, unproven preclinical and clinical development activities, our financial condition and results of operations and our ability to raise capital when necessary to continue our operations, regulatory processes and oversight, challenges associated with manufacture or supply of our products to support clinical trials, regulatory inspections and/or commercial sale following any marketing approval, changes in reimbursement and payment policies by government and commercial payers or the application of such policies, intellectual property claims, competitive developments, litigation, and the risks, uncertainties and other factors described under the heading “Risk Factors” in our Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 31, 2025 , and in our subsequently filed quarterly reports on Form 10- Q. Given these risks, uncertainties and other factors, you should not place undue reliance on these forward-looking statements, and we assume no obligation to update these forward-looking statements, whether as a result of new information, future events or otherwise, except as required by applicable law. OMEROS CORPORATION UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (In thousands, except share and per share data) ​ Three Months Ended Year Ended ​ December 31 , December 31 , ​ 2024 2023 2024 2023 ​ ​ ​ ​ ​ Costs and expenses: ​ ​ Research and development $ 23,320 $ 28,890 $ 119,523 $ 114,870 Selling, general and administrative 12,340 10,875 49,735 49,660 Total costs and expenses 35,660 39,765 169,258 164,530 Loss from operations (35,660 ) (39,765 ) (169,258 ) (164,530 ) Interest expense (3,177 ) (7,063 ) (24,675 ) (30,844 ) Interest and other income 2,296 3,429 11,304 16,342 Gain on early extinguishment of convertible senior notes — 4,112 — 4,112 Net loss from continuing operations (36,541 ) (39,287 ) (182,629 ) (174,920 ) Net income from discontinued operations, net of tax 5,183 30,219 25,814 57,107 Net loss $ (31,358 ) $ (9,068 ) $ (156,815 ) $ (117,813 ) ​ ​ ​ ​ ​ Basic and diluted net income (loss) per share: ​ ​ ​ ​ Net loss from continuing operations $ (0.63 ) $ (0.63 ) $ (3.14 ) $ (2.79 ) Net income from discontinued operations 0.09 0.48 0.44 0.91 Net loss $ (0.54 ) $ (0.15 ) $ (2.70 ) $ (1.88 ) ​ ​ ​ ​ ​ Weighted-average shares used to compute basic and diluted net income (loss) per share 57,987,961 62,440,772 58,170,931 62,739,227 OMEROS CORPORATION UNAUDITED CONSOLIDATED BALANCE SHEET (In thousands) ​ December 31 , December 31 , ​ 2024 2023 Assets ​ ​ Current assets: ​ ​ Cash and cash equivalents $ 3,400 $ 7,105 Short-term investments 86,732 164,743 OMIDRIA contract royalty asset, short-term 29,083 29,373 Receivables 7,739 8,096 Prepaid expense and other assets 7,166 8,581 Total current assets 134,120 217,898 OMIDRIA contract royalty asset 124,266 138,736 Right of use assets 14,961 18,631 Property and equipment, net 2,678 1,950 Restricted investments 1,054 1,054 Total assets $ 277,079 $ 378,269 ​ ​ ​ Liabilities and shareholders’ equity (deficit) Current liabilities: Accounts payable $ 5,905 $ 7,712 Accrued expenses 26,005 31,868 OMIDRIA royalty obligation, current 20,645 8,576 Current portion of term debt 21,000 — Lease liabilities, current 5,971 5,160 Total current liabilities 79,526 53,316 OMIDRIA royalty obligation, non-current 195,612 116,550 Convertible senior notes, net 97,178 213,155 Long-term debt, net 69,405 — Lease liabilities, non-current 13,466 18,143 Other accrued liabilities, non-current 4,501 2,088 Shareholders’ equity (deficit): Common stock and additional paid-in capital 727,736 728,547 Accumulated deficit (910,345 ) (753,530 ) Total shareholders’ deficit (182,609 ) (24,983 ) Total liabilities and shareholders’ equity (deficit) $ 277,079 $ 378,269 View source version on businesswire.com: https://www.businesswire.com/news/home/20250331174096/en/ Jennifer Cook Williams Cook Williams Communications, Inc. Investor and Media Relations IR@omeros.com Source: Omeros Corporation

EMPAVELI's unique mechanism of targeting C3 broadens its applicability beyond PNH, including other complement-driven diseases like geographic atrophy and immune complex-mediated diseases. With a high unmet need in these areas and limited competition, EMPAVELI's market is poised for steady growth. LAS VEGAS, March 18, 2025 /PRNewswire/ -- DelveInsight's " EMPAVELI Market Size, Forecast, and Market Insight Report" highlights the details around EMPAVELI, a complement inhibitor indicated to treat adult patients with PNH. The report provides product descriptions, patent details, and competitor products (marketed and emerging therapies) of EMPAVELI. The report also highlights the historical and forecasted sales from 2020 to 2034 segmented into 7MM [the United States, the EU4 (Germany, France, Italy, and Spain), the United Kingdom, and Japan]. Apellis Pharmaceutical's EMPAVELI (pegcetacoplan) Overview EMPAVELI (pegcetacoplan) is a targeted inhibitor of C3 designed to control excessive complement activation—a key immune process that can contribute to the development and progression of serious diseases. Pegcetacoplan binds to complement protein C3 and its activation fragment C3b, helping to regulate the cleavage of C3 and the production of downstream effectors involved in complement activation. In PNH, extravascular hemolysis (EVH) is driven by C3b opsonization, while intravascular hemolysis (IVH) results from the formation of the membrane attack complex (MAC). By acting early in the complement cascade, pegcetacoplan controls both C3b-driven EVH and terminal complement-mediated IVH. EMPAVELI is approved for treating adult patients with paroxysmal nocturnal hemoglobinuria (PNH). The US FDA has granted pegcetacoplan Priority Review and Fast Track Designation (FTD) for the treatment of PNH. EMPAVELI reported US net product revenue of $23.4 million in the fourth quarter and $98.1 million for the full year of 2024. Currently, EMPAVELI is being evaluated in different phases of development for C3G & IC-MPGN, HSCT-TMA, FSGS, and DGF. Learn more about EMPAVELI projected market size for PNH @ EMPAVELI Market Potential Paroxysmal nocturnal hemoglobinuria (PNH) is a rare condition characterized by a triad of symptoms: intravascular hemolysis, thromboembolic events, and cytopenia. The disease presents differently among patients, making it difficult to classify based on typical clinical patterns due to its unpredictable nature. In 2023, there were approximately 12,000 diagnosed cases of PNH in the 7MM, with projections suggesting this number could rise to around 13,000 by 2034. Until 2007, PNH was a life-threatening disease with no effective treatment for hemolysis and thrombosis, which were the primary causes of death. However, the introduction of the anti-C5 agent eculizumab over the past decade marked a major breakthrough, significantly reducing hemolysis, decreasing the need for transfusions, and lowering the risk of thrombosis. The current standard of care for PNH involves complement inhibition therapy, with FDA-approved drugs like SOLIRIS, ULTOMIRIS, EMPAVELI, FABHALTA, VOYDEYA, and PIASKY being considered the gold standard treatments. According to DelveInsight, the total PNH market size in the 7MM was valued at USD 1.4 billion in 2023 and is expected to grow to about USD 2.5 billion by 2034. This growth is driven by advances in understanding disease mechanisms, leading to improved diagnostics and therapeutics, along with an increasing number of cases and the introduction of new treatments during the forecast period. Discover more about the paroxysmal nocturnal hemoglobinuria market in detail @ Paroxysmal Nocturnal Hemoglobinuria Market Report Emerging Competitors of EMPAVELI Only a few companies are currently working in the paroxysmal nocturnal hemoglobinuria market. Emerging PNH therapies include Pozelimab (REGN3918) + Cemdisiran (Regeneron Pharmaceuticals), OMS906 (Omeros), NM8074 (ruxoprubart) (NovelMed), and others, reflecting a dynamic evolution in treatment strategies. In December 2024, Omeros Corporation announced that two posters on zaltenibart (OMS906), its investigational MASP-3 inhibitor and a key activator of the alternative complement pathway, were presented yesterday at the 66th Annual Meeting of the American Society of Hematology (ASH) in San Diego. The posters focused on zaltenibart's use in treating paroxysmal nocturnal hemoglobinuria (PNH), a rare and life-threatening blood disorder, and highlighted positive Phase II clinical data and clinical pharmacology analyses that support dose selection for the upcoming Phase III trials in PNH. Enrollment for the Phase III trials is expected to begin in early 2025. To know more about the number of competing drugs in development, visit @ EMPAVELI Market Positioning Compared to Other Drugs Key Milestones of EMPAVELI In October 2023, Apellis Pharmaceuticals, Inc. announced that the FDA had approved the EMPAVELI Injector. In May 2021, Apellis Pharmaceuticals, Inc. announced that the FDA has approved EMPAVELI (pegcetacoplan), the first and only therapy targeting C3 for the treatment of adults with paroxysmal nocturnal hemoglobinuria (PNH). In October 2020, Apellis Pharmaceuticals and Swedish Orphan Biovitrum AB announced a strategic collaboration to accelerate the advancement of systemic pegcetacoplan. In February 2019, Apellis Pharmaceuticals announced that the FDA has awarded Fast Track designation to APL-2, the company's innovative complement factor C3 inhibitor, for treating patients with paroxysmal nocturnal hemoglobinuria (PNH). Discover how EMPAVELI is shaping the PNH treatment landscape @ EMPAVELI Paroxysmal Nocturnal Hemoglobinuria EMPAVELI Market Dynamics EMPAVELI (pegcetacoplan) is a targeted complement inhibitor developed by Apellis Pharmaceuticals for the treatment of PNH. Approved by the FDA in May 2021, EMPAVELI became the first and only C3 inhibitor available for PNH, providing a new mechanism of action compared to existing therapies like C5 inhibitors (eculizumab and ravulizumab). By targeting C3 rather than C5, EMPAVELI addresses both intravascular and extravascular hemolysis, offering broader control over the disease and reducing the need for red blood cell transfusions in patients who remain anemic despite C5 inhibition. This differentiation has positioned EMPAVELI as a compelling alternative for patients with suboptimal responses to C5 inhibitors. The market for EMPAVELI is driven by the growing prevalence of PNH, increased awareness of complement pathway disorders, and improved diagnostic capabilities. The PNH market was historically dominated by C5 inhibitors such as Alexion's SOLIRIS (eculizumab) and ULTOMIRIS (ravulizumab), which set a high pricing benchmark and established market acceptance for premium-priced orphan drugs. EMPAVELI's entry has introduced competition, particularly for patients who experience breakthrough hemolysis or insufficient control on C5 therapy. Its ability to offer a more comprehensive mechanism of action and potential for improved patient outcomes has driven adoption, although switching patients from established therapies presents a challenge due to physician familiarity and the entrenched market position of C5 inhibitors. Pricing and reimbursement dynamics also play a significant role in EMPAVELI's market performance. As a high-cost orphan drug, EMPAVELI's adoption is influenced by payer coverage and reimbursement policies, especially in markets with strict cost-control measures. Apellis has strategically positioned EMPAVELI through patient assistance programs and value-based agreements to facilitate market access. Additionally, the subcutaneous administration of EMPAVELI (versus intravenous administration for C5 inhibitors) enhances patient convenience, supporting patient preference and potentially improving adherence. Competitive pressures are also evolving as other complement inhibitors targeting C3, C5, and alternative pathways are under development. For example, Novartis and AstraZeneca are advancing next-generation C5 inhibitors with extended dosing intervals, and other biotech firms are exploring factor D and MASP-2 inhibitors, which could further fragment the complement inhibitor landscape. However, EMPAVELI's first-mover advantage in the C3 inhibition space and its differentiated clinical profile provide a strong foothold in the market. Expansion into additional indications beyond PNH, such as cold agglutinin disease (CAD) and geographic atrophy (GA), could further strengthen EMPAVELI's market position and drive future growth. Dive deeper to get more insight into EMPAVELI's strengths & weaknesses relative to competitors @ EMPAVELI Market Drug Report Table of Contents Related Reports Paroxysmal Nocturnal Hemoglobinuria Market Paroxysmal Nocturnal Hemoglobinuria Market Insights, Epidemiology, and Market Forecast – 2034 report deliver an in-depth understanding of the disease, historical and forecasted epidemiology, as well as the market trends, market drivers, market barriers, and key PNH companies including Hoffmann-La Roche, Alexion Pharmaceuticals, Novartis, Regeneron Pharmaceuticals, BioCryst Pharmaceuticals, among others. Paroxysmal Nocturnal Hemoglobinuria Pipeline Paroxysmal Nocturnal Hemoglobinuria Pipeline Insight – 2025 report provides comprehensive insights about the pipeline landscape, pipeline drug profiles, including clinical and non-clinical stage products, and the key paroxysmal nocturnal hemoglobinuria companies, including Biocad, AKARI Therapeutics, Amgen, MorphoSys, Ra Pharmaceuticals, Alnylam Pharmaceuticals, Arrowhead Pharmaceuticals, among others. Aplastic Anemia Market Aplastic Anemia Market Insights, Epidemiology, and Market Forecast – 2034 report delivers an in-depth understanding of the disease, historical and forecasted epidemiology, as well as the market trends, market drivers, market barriers, and key aplastic anemia companies, including Pfizer, BioLineRx Ltd., Regeneron Pharmaceuticals, Gamida Cell, Elixirgen, Hangzhou Zede Pharmaceutical Technology, Cellenkos, Hemogenyx Pharmaceuticals, among others. Aplastic Anemia Pipeline Aplastic Anemia Pipeline Insight – 2025 report provides comprehensive insights about the pipeline landscape, pipeline drug profiles, including clinical and non-clinical stage products, and the key aplastic anemia companies, including Pfizer, BioLineRx, Ltd., Regeneron Pharmaceuticals, Gamida Cell, Elixirgen, among others. About DelveInsight DelveInsight is a leading Business Consultant and Market Research firm focused exclusively on life sciences. It supports pharma companies by providing comprehensive end-to-end solutions to improve their performance. Get hassle-free access to all the healthcare and pharma market research reports through our subscription-based platform PharmDelve . Contact Us Shruti Thakur [email protected] +14699457679 Logo: SOURCE DelveInsight Business Research, LLP WANT YOUR COMPANY'S NEWS FEATURED ON PRNEWSWIRE.COM? 440k+ Newsrooms & Influencers 9k+ Digital Media Outlets 270k+ Journalists Opted In GET STARTED

– Results Demonstrate Marked Survival Superiority of Narsoplimab-Treated EAP Patients, in Stand-Alone and Combined Analyses with Narsoplimab Pivotal Trial Patients, over External Control Patients – Results of statistical analyses of survival in narsoplimab-treated expanded access program (EAP) TA-TMA patients compared to similarly at-risk external control registry patients were consistent with those of previously reported analyses comparing survival between narsoplimab-treated OMS721-TMA-001 pivotal trial and external control registry patients The analyses conducted on the combined population of the 49 previously untreated high-risk adult (at least 16 years of age) allogeneic-transplant EAP patients and the 28 OMS721-TMA-001 patients were the same as the complete set of primary statistical and sensitivity analyses comparing survival in the narsoplimab pivotal trial to the external control TA-TMA patients, with representative analyses demonstrating that: Narsoplimab reduced the risk of mortality in high-risk TA-TMA patients by over 2-fold (hazard ratio = 0.46 [95 percent confidence interval:0.30, 0.60]) to approximately 3-fold (hazard ratio = 0.34 [95 percent confidence interval: 0.21, 0.53]) P-values ranged from 0.00002 to less than 0.00001 Narsoplimab reduced the risk of mortality in high-risk TA-TMA patients by over 2-fold (hazard ratio = 0.46 [95 percent confidence interval:0.30, 0.60]) to approximately 3-fold (hazard ratio = 0.34 [95 percent confidence interval: 0.21, 0.53]) P-values ranged from 0.00002 to less than 0.00001 In the EAP allogeneic transplant population, 16 adult and 20 pediatric high-risk TA-TMA patients had failed one or more treatment regimens – most commonly eculizumab – prior to receiving narsoplimab, with 1-year survival of 41 and 47 percent, respectively – over 2-fold higher than the less-than-20-percent historical 1-year survival for patients who fail targeted TA-TMA therapy These results complete the set of independently conducted analyses for inclusion in the narsoplimab BLA resubmission to FDA planned for later this quarter and in the MAA submission to European regulators targeted by mid-year. Together with the previously reported primary and sensitivity analyses, the results are uniformly robust and support the clinical benefit of narsoplimab in TA-TMA, a life-threatening complication of hematopoietic stem cell transplantation with no currently approved treatment SEATTLE--(BUSINESS WIRE)--Feb. 20, 2025-- Omeros Corporation (Nasdaq: OMER) today announced statistical analysis results related to the expanded access program (EAP) for narsoplimab, Omeros’ first-in-class monoclonal antibody inhibiting the lectin pathway of complement, in the treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA), a life-threatening complication in both adult and pediatric hematopoietic stem cell transplantation (HSCT). These latest analyses, conducted by an independent statistical group, comprise multiple survival comparisons between narsoplimab-treated EAP patients and similarly at-risk TA-TMA patients in the external control registry. The results from these analyses further support the robustness of the previously reported results from the statistical analysis plan agreed with FDA, with representative analyses of the combined EAP and pivotal trial patients yielding hazard ratios ranging from 0.34 (95 percent confidence interval: 0.21, 0.53) to 0.46 (95 percent confidence interval: 0.35, 0.60) and p-values ranging from less than 0.00001 to 0.00002. Consistent with all previous clinical experience with narsoplimab, no safety signals of concern were observed. “The results from the expanded access program are further compelling evidence of the effectiveness of narsoplimab in TA-TMA,” stated Miguel-Angel Perales, MD, Chief of the Adult Bone Marrow Transplantation Service at Memorial Sloan Kettering Cancer Center and immediate past President of the American Society for Transplantation and Cellular Therapy. “The EAP accepted all-comers globally – adult and pediatric patients in the real-world setting. Many are representative of the most challenging patients that we at MSKCC and the community of transplant experts worldwide regularly attempt to treat. With the now overwhelming clinical survival data and the absence of any identified safety signal, there is a clear need for narsoplimab in the treatment of our patients with TA-TMA, and we look forward to the drug’s rapid approval.” As reported on December 19, 2024 and January 15, 2025, narsoplimab met its primary endpoint, with TA-TMA patients in its OMS721-TMA-001 pivotal trial demonstrating clinically meaningful and statistically significant superiority in overall survival – a hazard ratio of 0.32 (95 percent confidence interval: 0.23 to 0.44) with p-value less than 0.00001 – compared to the TA-TMA patients in the external control registry, with the prespecified primary-related sensitivity analyses strongly supporting the robustness of the primary analysis results. Today’s announcement reports the results of this same set of analyses on patients treated with narsoplimab in the EAP. Overall survival in the primary, primary-related, and EAP-related analyses includes an adjustment for immortal time bias. The narsoplimab EAP population at time of database lock included 136 TA-TMA patients, 128 of whom had received allogeneic versus autologous stem cell transplants. Of those allogeneic graft recipients, 84 were adult (at least 16 years of age) and 44 were children. TA-TMA risk factors are not available for all EAP patients; based on available information and using the international expert consensus criteria for high risk of death (Schoettler et al, 2023), 102 patients (65 adults and 37 children) were characterized as having “high-risk” TA-TMA, with 82 percent of adults and 86 percent of children having multiple risk factors for death. Of the 102 high-risk EAP patients, 49 adults and 13 children had received no treatment prior to narsoplimab. The narsoplimab pivotal trial (OMS721-TMA-001) enrolled 28 adult allogeneic transplant patients with high-risk TA-TMA, none of whom received prior treatment for TA-TMA. The external control registry is comprised of 121 adult patients (defined by the registry as 16 years of age or older) who underwent allogeneic transplant and developed high-risk TA-TMA, none of whom received narsoplimab, any other complement inhibitor treatment, or defibrotide. The following are representative analyses, conducted by the independent statistical group, of the 77 (49 EAP and 28 OMS721-TMA-001) allogeneic HSCT, previously untreated, high-risk adult patients who received narsoplimab compared to similarly at-risk external control registry patients; the first is the same as the previously reported primary analysis and the subsequent 4 are the same as the previously reported primary-related sensitivity analyses, all of which were prespecified in the FDA-agreed statistical analysis plan: 1. Overall survival using Inverse Probability of Treatment Weighting (IPTW) with all specified risk factors: Hazard ratio = 0.37 (95 percent confidence interval: 0.28, 0.48) P-value < 0.00001 2. Overall survival using IPTW with only treatment as a factor: Hazard ratio = 0.46 (95 percent confidence interval: 0.35, 0.60) P-value < 0.00001 3. Testing proportional hazards assumptions using IPTW in a sequence of four models in which patient follow-up is truncated at 100 days, 6 months, 1 year, and 2 years: 100 days: Hazard ratio = 0.46 (95 percent confidence interval: 0.33, 0.63) P-value < 0.00001 6 months: Hazard ratio = 0.40 (95 percent confidence interval: 0.29, 0.54) P-value < 0.00001 1 year: Hazard ratio = 0.37 (95 percent confidence interval: 0.28, 0.50) P-value < 0.00001 2 years: Hazard ratio = 0.36 (95 percent confidence interval: 0.27, 0.48) P-value < 0.00001 4. Overall survival using IPTW with day zero for the external control registry patients set at the median time between the date of TA-TMA diagnosis and the date of narsoplimab treatment initiation for the patients in the combined EAP and OMS721-TMA-001 pivotal trial population: Hazard ratio = 0.36 (95 percent confidence interval: 0.28, 0.48) P-value < 0.00001 5. Overall survival with and without all specified risk factors (RFs) using 1:1* propensity score matching (combined EAP and OMS721-TMA-001 trial patients versus external control registry patients): 1:1 with RFs: Hazard ratio = 0.34 (95 percent confidence interval: 0.21, 0.53) P-value < 0.00001 1:1 w/out RFs: Hazard ratio = 0.39 (95 percent confidence interval: 0.26, 0.60) P-value = 0.00002 *In the previously reported primary and primary-related sensitivity analyses, this analysis included 1:2 propensity score matching. The 121 external control patients, however, do not allow for 1:2 matching vs. 77 narsoplimab-treated patients. Sixteen adult and 20 pediatric allogeneic-transplant EAP patients with high-risk TA-TMA had failed treatment with one or more regimens of eculizumab, ravulizumab, pegcetacoplan, and/or defibrotide prior to administration of narsoplimab. Less than 20 percent of patients who fail these treatments are reported to reach 1-year survival. Despite this historically poor expectation, narsoplimab treatment showed the following 1-year survival in previously treated high-risk EAP patients: All: 44 percent Adult: 41 percent Children: 47 percent In the EAP, 49 adult and 13 pediatric allogeneic-transplant patients with high-risk TA-TMA did not receive complement C5 (e.g., eculizumab, ravulizumab), C3 inhibitors (e.g., pegcetacoplan), or defibrotide prior to treatment with narsoplimab. One-year survival in these patients is: All: 62 percent Adult: 58 percent Children: 79 percent “The EAP results of narsoplimab treatment for TA-TMA are exceptional, both for patients who received narsoplimab as first-line treatment and particularly in patients refractory to prior complement inhibition therapies,” stated Michelle Schoettler, MD, Assistant Professor of Pediatric Oncology and Hematopoietic Cellular Therapy at Emory University. “One-year survival in children with high-risk TA-TMA treated with narsoplimab via the EAP as a front-line agent was an impressive 79 percent and 58 percent in adults. Just as striking were results in patients previously refractory to complement inhibition, who historically had 1-year survival rates of less than 20 percent. In contrast, 1-year survival in refractory children and adults in the EAP cohort with high-risk features treated with narsoplimab (n=36) was 44 percent; more than doubling historic cohorts. These promising results suggest that narsoplimab will be an important therapeutic option for pediatric and adult hematopoietic cell transplant recipients. I look forward to publishing and further detailing the benefits of narsoplimab in children and adults enrolled in the EAP.” In addition to the manuscript on EAP-related analyses, an international group of transplant experts is preparing a manuscript directed to the primary endpoint-related analyses for submission to peer-reviewed journals. “We are pleased to see the results of the narsoplimab EAP analyses for our BLA resubmission,” said Gregory A. Demopulos, M.D., Omeros’ Chairman and Chief Executive Officer. “The EAP-related and primary sensitivity analyses uniformly support the positive results of the primary endpoint – narsoplimab demonstrating clinically meaningful and statistically significant superiority in overall survival compared to the external control. The next step is resubmission of our BLA followed by the planned submission of the narsoplimab MAA for European approval. There is more work to be done, but the entire Omeros team is driving hard to achieve approval and to launch narsoplimab, with the goal of making the drug available to patients and their transplant physicians worldwide.” About Narsoplimab Narsoplimab, also known as “OMS721,” is an investigational fully human monoclonal antibody targeting mannan-binding lectin-associated serine protease-2 (MASP-2), a novel pro-inflammatory protein target and the effector enzyme of the lectin pathway of complement. Importantly, inhibition of MASP-2 has been demonstrated to leave intact the antibody-dependent classical complement activation pathway, which is a critical component of the acquired immune response to infection. A biologics license application (BLA) is pending before the FDA for use of narsoplimab in the treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA). Omeros will resubmit the BLA for narsoplimab in TA-TMA followed by our planned submission of the corresponding European marketing authorisation application (MAA) in 2025. FDA has granted narsoplimab breakthrough therapy and orphan drug designations for TA-TMA and orphan drug status for the prevention (inhibition) of complement-mediated thrombotic microangiopathies. The European Medicines Agency (EMA) has granted orphan drug designation to narsoplimab for treatment in hematopoietic stem-cell transplant. About Hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA) Hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA) is a significant and often lethal complication of stem cell transplantation. This condition is a systemic, multifactorial disorder caused by endothelial cell damage induced by conditioning regimens, immunosuppressant therapies, infection, graft-versus-host disease, and other factors associated with stem cell transplantation. Endothelial damage, which activates the lectin pathway of complement, plays a central role in the development of TA-TMA. The condition occurs in both autologous and allogeneic transplants but is more common in the allogeneic population. In the United States and Europe, approximately 30,000 allogeneic transplants are performed annually. Recent reports in both adult and pediatric allogeneic stem cell transplant populations have found an approximately 40-percent incidence of TA-TMA, and high-risk features may be present in up to 80 percent of these patients. In severe cases of TA-TMA, mortality can exceed 90 percent and, even in those who survive, long-term renal sequalae (e.g., dialysis) are common. There is no approved therapy or standard of care for TA-TMA. About Omeros Corporation Omeros is an innovative biopharmaceutical company committed to discovering, developing and commercializing first-in-class small-molecule and protein therapeutics for large-market and orphan indications targeting immunologic disorders, including complement-mediated diseases and cancers, as well as addictive and compulsive disorders. Omeros’ lead MASP-2 inhibitor narsoplimab targets the lectin pathway of complement and is the subject of a biologics license application pending before FDA for the treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy. Omeros’ long-acting MASP-2 inhibitor OMS1029 has successfully completed Phase 1 single- and multiple-ascending dose clinical studies. Zaltenibart, Omeros’ inhibitor of MASP-3, the key activator of the alternative pathway of complement, is advancing toward Phase 3 clinical trials for paroxysmal nocturnal hemoglobinuria and complement 3 glomerulopathy. Funded by the National Institute on Drug Abuse, Omeros’ lead phosphodiesterase 7 inhibitor OMS527 is in clinical development for the treatment of cocaine use disorder. Omeros also is advancing a broad portfolio of five novel cellular and molecular immuno-oncology programs. For more information about Omeros and its programs, visit www.omeros.com. Forward-Looking Statements This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, which are subject to the “safe harbor” created by those sections for such statements. All statements other than statements of historical fact are forward-looking statements, which are often indicated by terms such as “aim,” “anticipate,” “believe,” “could,” “estimate,” “expect,” “goal,” “intend,” “likely,” “look forward to,” “may,” “objective,” “plan,” “potential,” “predict,” “project,” “should,” “slate,” “target,” “will,” “would” and similar expressions and variations thereof. Forward-looking statements, including statements regarding the anticipated resubmission of the BLA for narsoplimab in the United States and the submission of a marketing authorization application with the EMA, the timing and outcomes of regulatory events, the availability and outcomes of additional analyses, the prospects for obtaining FDA or EMA approval of narsoplimab in any indication, expectations regarding future cash expenditures, and expectations regarding the sufficiency and availability of our capital resources to fund current and planned operations, including the potential commercialization of narsoplimab if it is approved by FDA or the EMA, are based on management’s beliefs and assumptions and on information available to management only as of the date of this press release. Omeros’ actual results could differ materially from those anticipated in these forward-looking statements for many reasons, including, without limitation, unfavorable, unexpected or inconclusive results of our statistical analyses relating to an external registry of TA-TMA patients, potential differences between the diagnostic criteria used in our pivotal trial and in the external registry, and whether FDA and the EMA determine the registry used in our statistical analysis is sufficiently representative of TA-TMA patients, unanticipated or unexpected outcomes of regulatory processes in relevant jurisdictions, unproven preclinical and clinical development activities, our financial condition and results of operations, regulatory processes and oversight, challenges associated with manufacture or supply of our products to support clinical trials, regulatory inspections and/or commercial sale following any marketing approval, changes in reimbursement and payment policies by government and commercial payers or the application of such policies, intellectual property claims, competitive developments, litigation, and the risks, uncertainties and other factors described under the heading “Risk Factors” in our Annual Report on Form 10-K filed with the Securities and Exchange Commission on April 1, 2024, an in our subsequently filed Quarterly Reports on Form 10-Q. Given these risks, uncertainties and other factors, you should not place undue reliance on these forward-looking statements, and we assume no obligation to update these forward-looking statements, whether as a result of new information, future events or otherwise, except as required by applicable law. Dr. Miguel-Angel Perales has previously received advisory services compensation from, and holds a financial interest in, Omeros. Dr. Michelle Schoettler has previously received advisory services compensation from Omeros. View source version on businesswire.com: https://www.businesswire.com/news/home/20250220420439/en/ Jennifer Cook Williams Cook Williams Communications, Inc. Investor and Media Relations IR@omeros.com Source: Omeros Corporation