Omeros Announces Pricing of Public Offerings --6,900,000 Shares of Common Stock-- --$210,000,000 of 5.25% Convertible Senior Notes due 2026-- SEATTLE--(BUSINESS WIRE)

Omeros Announces Pricing of Public Offerings

--6,900,000 Shares of Common Stock--

--$210,000,000 of 5.25% Convertible

Senior Notes due 2026--

SEATTLE--(BUSINESS WIRE)-August 12, 2020 -- Omeros

Corporation (Nasdaq: OMER) ("Omeros") today announced that it has priced concurrent underwritten public offerings of

6,900,000 of shares of its common stock (the "Shares") at a public offering price of $14.50 per Share for proceeds

of approximately $100,050,000, prior to the deduction of underwriting discounts and commissions and estimated offering expenses

payable by Omeros (the "Equity Offering"), and $210,000,000 aggregate principal amount of 5.25% convertible senior

notes due 2026 (the "2026 Convertible Notes" and such offering, the "Notes Offering"). In addition, Omeros

has granted to the underwriters of the Equity Offering a 30-day option to purchase up to an additional 1,035,000 Shares and to

the underwriters of the Notes Offering a 30-day option, solely to cover over-allotments, to purchase up to an additional $31,500,000

aggregate principal amount of 2026 Convertible Notes. The Equity Offering and the Notes Offering are each expected to close on

August 14, 2020, subject to customary closing conditions. Neither offering is contingent on the completion of the other offering.

BofA Securities and JP Morgan are acting as the book-running

managers for the Equity Offering. Cantor Fitzgerald is also acting as a book-running manager, and WBB Securities is acting as co-manager,

for the Equity Offering. BofA Securities, JP Morgan and RBC Capital Markets are acting as the book-running managers for the Notes

The 2026 Convertible Notes will be senior unsecured obligations

of Omeros and will bear interest at a rate of 5.25% per year, payable semi-annually in arrears. The 2026 Convertible Notes will

mature on February 15, 2026, unless earlier converted, repurchased or redeemed in accordance with their terms, and will be convertible,

subject to the satisfaction of certain conditions, into cash, shares of Omeros' common stock or a combination thereof as

elected by Omeros in its sole discretion.

The initial conversion rate for the 2026 Convertible Notes is

54.0906 shares of Omeros' common stock per $1,000 principal amount of 2026 Convertible Notes (which is equivalent to an initial

conversion price of approximately $18.49 per share, which represents a premium of approximately 27.5% over the public offering

price of Omeros' common stock in the Equity Offering of $14.50 per share). Omeros will have the right to redeem the 2026

Convertible Notes on or after August 15, 2023, subject to certain conditions and limitations.

The Equity Offering is expected to result in approximately $93.7

million in net proceeds to Omeros, and the Notes Offering is expected to result in approximately $203.7 million in net proceeds

to Omeros, in each case, after deducting underwriting discounts and commissions and estimated offering expenses payable by Omeros,

and in each case, assuming no exercise of the underwriters' option to purchase additional Shares or 2026 Convertible Notes.

Omeros intends to use approximately $21.7 million of the net

proceeds of the Notes Offering to fund the cost of entering into capped call transactions with the option counterparties, as described

below. In addition, Omeros intends to use approximately $127.4 million of the net proceeds of the Notes Offering to repurchase

approximately $115 million aggregate principal amount of its existing 6.25% Convertible Senior Notes due 2023 (the "2023

Convertible Notes") in privately negotiated transactions as described below, and expects to receive approximately $8.4 million

from unwinding a proportionate amount of the capped call transaction that it entered into with a financial institution (the "existing

option counterparty") in connection with the issuance of the 2023 Convertible Notes (the "existing capped call transaction").

Omeros intends to use the net proceeds from the Equity Offering

and the remainder of the net proceeds from the Notes Offering for general corporate purposes, including funding clinical trials,

pre-clinical studies, manufacturing, build-out of commercial infrastructure and other costs associated with advancing its development

programs and product candidates toward regulatory submissions and potential commercialization.

In connection with the pricing of the 2026 Convertible Notes,

Omeros entered into privately negotiated capped call transactions with certain financial institutions ("option counterparties").

The capped call transactions are intended to reduce the potential dilution with respect to Omeros' common stock or, at its

election (subject to certain conditions), offset potential cash payments in excess of the principal amount of the converted 2026

Convertible Notes, upon conversion of the 2026 Convertible Notes, with such reduction or offset subject to a cap of $26.10, representing

a premium of 80% over the public offering price of Omeros' common stock in the Equity Offering. If the underwriters exercise

their option to purchase additional 2026 Convertible Notes, Omeros expects to enter into additional capped call transactions with

the option counterparties.

Omeros has been informed that in connection with establishing

their initial hedges of the capped call transactions, the option counterparties and/or their affiliates expect to purchase shares

of Omeros' common stock and/or enter into various derivative transactions with respect to Omeros' common stock concurrently

with or shortly after the pricing of the 2026 Convertible Notes. This activity could increase (or reduce the size of any decrease

in) the market price of Omeros' common stock or the 2026 Convertible Notes at that time.

In addition, the option counterparties and/or their

affiliates may modify their hedge positions by entering into or unwinding various derivatives with respect to Omeros'

common stock and/or purchasing or selling Omeros' common stock or other securities of Omeros' in secondary market

transactions prior to the maturity of the 2026 Convertible Notes (and are likely to do so on each exercise date of the capped

call transactions, which are expected to occur during the 50-trading day period beginning on the 51st scheduled trading day

prior to the maturity date of the notes, or following any termination of any portion of the capped call transactions in

connection with any repurchase, redemption or conversion of the 2026 Convertible Notes if Omeros makes the relevant election

under the capped call transactions). This activity could also cause or avoid an increase or a decrease in the market price of

Omeros' common stock or the 2026 Convertible Notes, which could affect a noteholder's ability to convert the 2026

Convertible Notes and, to the extent the activity occurs during any observation period related to a conversion of the 2026

Convertible Notes, could affect the amount and value of the consideration that a noteholder will receive upon conversion of

the 2026 Convertible Notes.

Concurrently with the Notes Offering, Omeros intends to use

approximately $127.4 million of the proceeds from the offering to repurchase approximately $115 million aggregate principal amount

of its outstanding 2023 Convertible Notes in privately negotiated transactions. Omeros expects that holders of the 2023 Convertible

Notes that sell their 2023 Convertible Notes to Omeros in any note repurchase transaction may enter into or unwind various derivatives

with respect to Omeros' common stock and/or purchase or sell shares of Omeros' common stock in the market to hedge

their exposure in connection with these transactions. This activity could increase (or reduce the size of any decrease in) the

market price of Omeros' common stock or the 2026 Convertible Notes at that time and could result in a higher effective conversion

price for the 2026 Convertible Notes.

In connection with the repurchase of the 2023 Convertible Notes,

Omeros intends to terminate a portion of the existing capped call transaction in a notional amount corresponding to the amount

of such 2023 Convertible Notes repurchased. In connection with the partial termination of the existing capped call transaction

and the related unwinding of the existing hedge position of the existing option counterparty with respect to such transaction,

the existing option counterparty and/or its respective affiliates are expected to sell shares of Omeros' common stock in

secondary market transactions, and/or enter into or unwind various derivative transactions with respect to Omeros' common

stock. This activity could decrease (or reduce the size of any increase in) the market price of Omeros' common stock or the

2026 Convertible Notes at that time.

The Equity Offering and the Notes Offering are being made pursuant

to Omeros' shelf registration statement on Form S-3 (File No. 333-235349) including the base prospectus contained therein,

and a prospectus supplement related to the Equity Offering (together with such base prospectus, the "Equity Prospectus")

and a prospectus supplement related to the Notes Offering (together with such base prospectus, the "Notes Prospectus"),

all of which Omeros filed or will file with the Securities and Exchange Commission ("SEC"). Before investing in the

Shares or the 2026 Convertible Notes, investors should read the Equity Prospectus and the Notes Prospectus, respectively, in each

case, including the documents incorporated by reference therein, and any free writing prospectus related to the Equity Offering

and the Notes Offering, as the case may be. These documents may be freely obtained by visiting EDGAR on the SEC website at www.sec.gov.

Alternatively, copies may be obtained, when available, from BofA Securities, NC1-004-03-43, 200 North College Street, 3rd floor,

Charlotte, NC 28255-0001, Attn: Prospectus Department, or via email: dg.prospectus_requests@bofa.com and J.P. Morgan Securities

LLC, Attention: Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, NY 11717, by telephone at (866) 803-9204, or

by e-mail at prospectus-eq_fi@jpmorgan.com.

This press release does not constitute an offer to sell or

the solicitation of an offer to buy any securities of Omeros. The Shares and the 2026 Convertible Notes (and any shares of Omeros'

common stock issuable upon conversion of the 2026 Convertible Notes) are not being offered in any state or jurisdiction in which

such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of such state

About Omeros Corporation