Cerulean Announces Pricing of Public Offering of Common Stock

Cerulean Pharma Inc. (Nasdaq: CERU) today announced the pricing of an underwritten public offering of 5,840,000 shares of its common stock at a public offering price of $6.00 per share, before underwriting discounts. All of the shares in the offering are being offered by Cerulean. In addition, Cerulean has granted the underwriters an option for a period of 30 days to purchase up to 876,000 additional shares of common stock at the public offering price, less underwriting discounts.

Leerink Partners LLC and Barclays Capital Inc. are acting as joint book-running managers for the offering. Canaccord Genuity Inc., JMP Securities LLC and Wedbush PacGrow are acting as co-managers for the offering.

A registration statement on Form S-1 relating to the securities was declared effective by the Securities and Exchange Commission on April 6, 2015.

The offering is being made only by means of a prospectus, copies of which may be obtained from Leerink Partners LLC, Attention: Syndicate Department, One Federal Street, 37th Floor, Boston, MA 02110, or by e-mail at syndicate@leerink.com, or by phone at (800) 808‐7525, ext. 6142 or from Barclays Capital Inc., c/o Broadridge Financial Solutions, 1155 Long Island Ave., Edgewood, NY 11717, by calling toll-free (888) 603-5847 or by e-mail at barclaysprospectus@broadridge.com.

This press release shall not constitute an offer to sell or the solicitation of an offer to buy, nor shall there be any sale of, these securities in any state or jurisdiction in which such offer, solicitation, or sale would be unlawful prior to the registration or qualification under the securities laws of such state or jurisdiction.

About Cerulean Pharma

The Cerulean team is committed to improving treatment for people living with cancer. We apply our Dynamic Tumor TargetingTM Platform to create a portfolio of nanoparticle-drug conjugates (NDCs) designed to selectively attack tumor cells, reduce toxicity by sparing the body’s normal cells, and enable therapeutic combinations. Our first platform-generated candidate, CRLX101, is in multiple clinical trials in combination with other cancer treatments, all of which aim to unlock the power of combination therapy. Our second platform-generated candidate, CRLX301, is in a Phase 1/2a clinical trial.