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Next-Generation TherapeuticsTransforming Patient Care Today

Leonard M. BlumChief Business and Commercial Officer

Ophthalmology Innovation Summit

Chicago, IL October 13, 2016

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Safe HarborThis presentation contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements are based on the current intent and expectations of the management of Omeros Corporation. These statements are not guarantees of future performance and involve risks and uncertainties that are difficult to predict. Omeros’actual results

and the timing and outcome of events may differ materially from those expressed in or implied by the forward-looking statements because of risks associated with Omeros’unproven preclinical and clinical development activities, regulatory oversight, product commercialization, intellectual property claims, competitive developments, litigation and other factors. For additional information about the factors that affect the company's business, please see the company's latest Forms 10-K and 10-Q filed with the Securities and Exchange Commission. Except as required by law, Omeros undertakes no obligation to update any forward-looking statements in this presentation, whether as a result of new information, future events or otherwise.

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Ophthalmic Surgery: OMIDRIA®

Intraocular product to prevent miosis and to reduce postoperative ocular pain in adults undergoing cataract surgery or refractive lens exchange

NSAID-containing product for intraocular administration during cataract surgery

OMIDRIA is the first and only FDA-approved…

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Early Focus at Launch: Patient Access to OMIDRIA®

OMIDRIA was granted pass-through status by CMS– Paid separately (ASP + 6%) outside of the facility’s packaged

payment for cataract surgery – Budget-neutral to the healthcare system

Covered and reimbursed by 100% of Medicare Administrative Contractors

Expanding coverage by Medicare Advantage plans and commercial payers

Patient access further expanded through OMIDRIAssure™ and 340b programs

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OMIDRIA® Net Revenue

3Q 2015 4Q 2015 1Q 2016 2Q 2016

$3.2 M

$6.7 M$7.2 M

$10.0 M

Net Revenue by Quarter

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OMIDRIA® Real-World Evidence Shows Improved Outcomes

Decrease in complications associated with small pupils1

Reduction in usage of pupil-expanding devices1-3

Prevention of miosis during femtosecond laser-assisted surgery4

Shorter surgical times1,2

Improvement in uncorrected visual acuity on postoperative Day 11

1. Rosenberg E, et al. Abstract presented at 2016 American Society of Cataract and Refractive Surgeons. 2016. 2. Visco D. Abstract presented at 2016 American Society of Cataract and Refractive Surgeons. 2016. 3. Bucci F. Abstract presented at 2016 Association for Research in Vision and Ophthalmology. 2016. 4. Gayton J, et al. Manuscript submitted for publication.

Post-launch, case-controlled, single-center analyses, with and without femtosecond laser, resulted in statistically significant . . .Additional manuscripts in preparation include effects of

OMIDRIA on prostaglandin inhibition and need for topical NSAIDs

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Marketed OMIDRIA® Driving the PipelineProduct/Program Targeted Disease Pre-

clinical Phase 1 Phase 2 Phase 3 MarketingApproval

Economic Rights

Clinical Programs

MASP-2 (OMS721) - Lectin Pathway Disorders

Atypical Hemolytic Uremic Syndrome

MASP-2 (OMS721) - Lectin Pathway Disorders

IgA Nephropathy and Other Renal Diseases; TMAs

PDE10 (OMS824) - CNS Disorders Huntington's and Schizophrenia

PPARγ (OMS405) - Addiction Opioid and Nicotine Addiction

OMS201 - Urology Ureteroscopy

Preclinical Programs

PDE7 (OMS527) - CNS DisordersAddictions and Compulsive Disorders; Movement Disorders

Plasmin (OMS616) - Bleeding Disorders

Surgical and Traumatic Bleeding

MASP-3 (OMS906) – Alternative Pathway Disorders

PNH and a Wide Range of Other Alternative Pathway Disorders

GPR17, GPR101, GPR151, GPR161, GPR174, GPR183

Demyelinating Disorders; Eating Disorders; Pain; Breast Cancer; Osteoporosis and EBV; T-Regs

GPCR PlatformCNS, Metabolic, CV, Oncologic, Musculoskeletal & Other Disorders

Antibody PlatformMetabolic, CV, Oncologic, Musculoskeletal & Other Disorders

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OMS721 Targets Mannan-Binding Lectin-Associated Serine Protease-2, the Effector Enzyme of the Lectin Pathway

Classical Pathway

AlternativePathway

Coagulation

Lectin Pathway

Platelet ActivationLeukocyte Recruitment

Cell Lysis

Immune Complex Infection, Tissue Injury

C3a

Factor D

Thrombin

OMS721

MASP-2

C1r/sC4, C2

C4b/2aC3 C3b Factor B

C5aMAC*C5b

C1q MBL*, Ficolins, CL-11

C5

*MAC = membrane attack complex*MBL = mannose-binding lectin

OMS721

Phase 3

Atypical hemolytic uremic syndrome (aHUS)

Phase 2 Complement-

associated nephropathies

Thrombotic microangiopathies

Ophthalmic Indications

AMD Uveitis Diabetic macular

edema

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Next-Generation TherapeuticsTransforming Patient Care Today

Leonard M. BlumChief Business and Commercial Officer

Ophthalmology Innovation Summit

Chicago, IL October 13, 2016

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