COMMON STOCK PURCHASE AGREEMENT COMMON STOCK PURCHASE AGREEMENT (the Agreement ), dated as of

COMMON STOCK PURCHASE AGREEMENT

COMMON STOCK PURCHASE AGREEMENT (the Agreement ), dated as of October 14, 2016 by and between CERULEAN PHARMA

INC., a Delaware corporation (the Company ), and ASPIRE CAPITAL FUND, LLC, an Illinois limited liability company (the Buyer ). Capitalized terms used herein and not otherwise defined herein are

defined in Section 10 hereof.

Subject to the terms and conditions set forth in this Agreement, the Company wishes to sell to the Buyer, and the Buyer wishes to buy from the

Company, up to Twenty Million Dollars ($20,000,000) of the Company s common stock, par value $0.0001 per share (the Common Stock ). The shares of Common Stock to be purchased hereunder are referred to herein as the

NOW THEREFORE, the Company and the Buyer hereby agree as follows:

Subject to the terms and conditions set forth in this

Agreement, the Company has the right to sell to the Buyer, and the Buyer has the obligation to purchase from the Company, Purchase Shares as follows:

(a) Initial Purchase; Commencement of Purchases of Common Stock. Immediately upon Commencement (as defined below), the Buyer shall

purchase from the Company 800,000 Purchase Shares and upon receipt of such Purchase Shares shall pay to the Company as the purchase price therefor, via wire transfer, One Million Dollars ($1,000,000) (such purchase the Initial

Purchase and such Purchase Shares are referred to herein as Initial Purchase Shares ). Upon issuance and payment therefor as provided herein, such Initial Purchase Shares shall be validly issued and fully paid and

non-assessable. Thereafter, the purchase and sale of Purchase Shares hereunder shall occur from time to time upon written notices by the Company to the Buyer on the terms and conditions as set forth herein following the satisfaction of the

conditions (the Commencement ) as set forth in Sections 6 and 7 below (the date of satisfaction of such conditions, the Commencement Date ).

(b) The Company s Right to Require Regular Purchases. Subject to the terms and conditions of this Agreement, on

any given Business Day after the Commencement Date, the Company shall have the right but not the obligation to direct the Buyer by its delivery to the Buyer of a Purchase Notice from time to time, and the Buyer thereupon shall have the obligation,

to buy the number of Purchase Shares specified in such notice, up to 200,000 Purchase Shares, on such Business Day (as long as such notice is delivered on or before 5:00 p.m. Eastern time on such Business Day) (each such purchase, a Regular

Purchase ) at the Purchase Price on the Purchase Date; however, in no event shall the Purchase Amount of a Regular Purchase exceed Three Hundred Thousand Dollars ($300,000) per Business Day, unless the Buyer and the Company mutually

agree. The Company and the Buyer may mutually agree to increase the number of Purchase Shares that may be sold per Regular Purchase to as much as an additional 2,000,000 Purchase Shares per Business Day. The Company may deliver additional

Purchase Notices to the Buyer from time to time so long as the most recent purchase has been completed. The share amounts in this Section 1(b) shall be appropriately adjusted for any reorganization, recapitalization, non-cash dividend, stock

split, reverse stock split or other similar transaction.

(c) VWAP Purchases. Subject to the terms and conditions of this Agreement, in

addition to purchases of Purchase Shares as described in Section 1(b) above, with one Business Day s prior written notice, the Company shall also have the right but not the obligation to direct the Buyer by the Company s delivery to the

Buyer of a VWAP Purchase Notice from time to time, and the Buyer thereupon shall have the obligation, to buy the VWAP Purchase Share Percentage of the trading volume of the Common Stock on the VWAP Purchase Date up to the VWAP Purchase Share Volume

Maximum on the VWAP Purchase Date (each such purchase, a VWAP Purchase ) at the VWAP Purchase Price. The Company may deliver a VWAP Purchase Notice to the Buyer on or before 5:00 p.m. Eastern time on a date on which (i) the

Company also submitted a Purchase Notice for a Regular Purchase of at least 200,000 Purchase Shares to the Buyer and (ii) the Closing Sale Price is higher than $0.50. The share amount in the prior sentence shall be appropriately adjusted for

any reorganization, recapitalization, non-cash dividend, stock split, reverse stock split or other similar transaction. A VWAP Purchase shall automatically be deemed completed at such time on the VWAP Purchase Date that the Sale Price falls

below the VWAP Minimum Price Threshold; in such circumstance, the VWAP Purchase Amount shall be calculated using (i) the VWAP Purchase Share Percentage of the aggregate shares traded on the Principal Market for such portion of the VWAP Purchase

Date prior to the time that the Sale Price fell below the VWAP Minimum Price Threshold and (ii) a VWAP Purchase Price calculated using the volume weighted average price of Common Stock sold during such portion of the VWAP Purchase Date prior to the

time that the Sale Price fell below the VWAP Minimum Price Threshold. Each VWAP Purchase Notice must be accompanied by instructions to the Company s Transfer Agent to immediately issue to the Buyer an amount of Common Stock equal to the

VWAP Purchase Share Estimate, a good faith estimate by the Company of the number of Purchase Shares that the Buyer shall have the obligation to buy pursuant to the VWAP Purchase Notice. In no event shall the Buyer, pursuant to any VWAP

Purchase, purchase a number of Purchase Shares that exceeds the VWAP Purchase Share Estimate issued on the VWAP Purchase Date in connection with such VWAP Purchase Notice; however, the Buyer will immediately return to the Company any amount of

Common Stock issued pursuant to the VWAP Purchase Share Estimate that exceeds the number of Purchase Shares the Buyer actually purchases in connection with such VWAP Purchase. Upon completion of each VWAP Purchase Date, the Buyer shall submit

to the Company a confirmation of the VWAP Purchase in form and substance reasonably acceptable to the Company. The Company may deliver additional VWAP Purchase Notices to the Buyer from time to time so long as the most recent purchase has been

(d) Payment for Purchase Shares. For each Regular Purchase, the Buyer shall pay to the Company an amount equal to

the Purchase Amount as full payment for such Purchase Shares via wire transfer of immediately available funds on the same Business Day that the Buyer receives such Purchase Shares. For each VWAP Purchase, the Buyer shall pay to the Company an

amount equal to the VWAP Purchase Amount as full payment for such Purchase Shares via wire transfer of immediately available funds on the third Business Day following the VWAP Purchase Date. All payments made under this Agreement shall be made

in lawful money of the United States of America via wire transfer of immediately available funds to such account as the Company may from time to time designate by written notice in accordance with the provisions of this Agreement. Whenever any

amount expressed to be due by the terms of this Agreement is due on any day that is not a Business Day, the same shall instead be due on the next succeeding day that is a Business Day.

(e) Purchase Price Floor. The Company and the Buyer shall not effect any sales under

this Agreement on any Purchase Date where the Closing Sale Price is less than the Floor Price. Floor Price means $0.25 per share of Common Stock, which shall be appropriately adjusted for any reorganization, recapitalization,

non-cash dividend, stock split, reverse stock split or other similar transaction.

(f) Records of Purchases. The Buyer and the

Company shall each maintain records showing the remaining Available Amount at any given time and the dates and Purchase Amounts for each purchase, or shall use such other method reasonably satisfactory to the Buyer and the Company to reconcile the

remaining Available Amount.

(g) Taxes. The Company shall pay any and all transfer, stamp or similar taxes that may be payable

with respect to the issuance and delivery of any shares of Common Stock to the Buyer made under this Agreement.

Principal Market Rules. Notwithstanding anything in this Agreement to the contrary, and in addition to the limitations set forth in Section 1(e), the total number of shares of Common Stock that may be issued under this Agreement, including

the Commitment Shares (as defined in Section 4(e) hereof), shall be limited to 5,484,392 shares of Common Stock (the Exchange Cap ), which equals 19.99% of the Company s outstanding shares of Common Stock as of the date

hereof, unless stockholder approval is obtained to issue more than such 19.99%. The Exchange Cap shall be appropriately adjusted for any reorganization, recapitalization, non-cash dividend, stock split, reverse stock split or other similar

transaction. The foregoing limitation shall not apply if stockholder approval has not been obtained and at any time the Exchange Cap is reached and at all times thereafter the average price paid for all shares issued under this Agreement is

equal to or greater than $0.7505 (the Minimum Price ), a price equal to the consolidated closing bid price on the date hereof (in such circumstance, for purposes of the Principal Market, the transaction contemplated hereby would

not be below market and the Exchange Cap would not apply). The Minimum Price shall be appropriately adjusted for any reorganization, recapitalization, non-cash dividend, stock split, reverse split or other similar

transaction. Notwithstanding anything to the contrary in this Agreement or otherwise, the Company shall not be required or permitted to issue, and the Buyer shall not be required to purchase, any shares of Common Stock under this Agreement if

such issuance would breach the Company s obligations under the rules or regulations of the Principal Market. The Company may, in its sole discretion, determine whether to obtain stockholder approval to issue more than 19.99% of its

outstanding shares of Common Stock hereunder if such issuance would require stockholder approval under the rules or regulations of the Principal Market.

(i) Beneficial Ownership Limitation. The Company shall not issue, and the Buyer shall not purchase any shares of Common Stock under this

Agreement, if such shares proposed to be issued and sold, when aggregated with all other shares of Common Stock then owned beneficially (as calculated pursuant to Section 13(d) of the Securities Exchange Act of 1934, as amended (the 1934

Act ) and Rule 13d-3 promulgated thereunder) by the Buyer and its affiliates would result in the beneficial ownership by the Buyer and its affiliates of more than 19.99% of the then issued and outstanding shares of Common Stock of the

The Buyer represents and warrants to the

Company that as of the date hereof and as of the Commencement Date:

(a) Investment Purpose. The Buyer is entering into this

Agreement and acquiring the Commitment Shares and the Purchase Shares (the Purchase Shares and the Commitment Shares are collectively referred to herein as the Securities ), for its own account for investment only and not with a

view towards, or for resale in connection with, the public sale or distribution thereof; provided however, by making the representations herein, the Buyer does not agree to hold any of the Securities for any minimum or other specific term.

(b) Accredited Investor Status. The Buyer is an accredited investor as that term is defined in Rule 501(a)(3) of

Regulation D under the 1933 Act.

(c) [Intentionally Omitted.]

(d) Information. The Buyer has been furnished with all materials relating to the business, finances and operations of the Company

and materials relating to the offer and sale of the Securities that have been reasonably requested by the Buyer, including, without limitation, the SEC Documents (as defined in Section 3(f) hereof). The Buyer understands that its investment in

the Securities involves a high degree of risk. The Buyer (i) is able to bear the economic risk of an investment in the Securities including a total loss, (ii) has such knowledge and experience in financial and business matters that it is

capable of evaluating the merits and risks of the proposed investment in the Securities and (iii) has had an opportunity to ask questions of and receive answers from the officers of the Company concerning the financial condition and business of the

Company and other matters related to an investment in the Securities. Neither such inquiries nor any other due diligence investigations conducted by the Buyer or its representatives shall modify, amend or affect the Buyer s right to rely

on the Company s representations and warranties contained in Section 3 below. The Buyer has sought such accounting, legal and tax advice as it has considered necessary to make an informed investment decision with respect to its acquisition

(e) No Governmental Review. The Buyer understands that no United States federal or state agency or any

other government or governmental agency has passed on or made any recommendation or endorsement of the Securities or the fairness or suitability of the investment in the Securities nor have such authorities passed upon or endorsed the merits of the

offering of the Securities.

(f) [Intentionally Omitted.]

(g) Organization. The Buyer is a limited liability company duly organized and validly existing in good standing under the laws of the

jurisdiction in which it is organized, and has the requisite organizational power and authority to own its properties and to carry on its business as now being conducted.

(h) Validity; Enforcement. This Agreement has been duly and validly authorized, executed and delivered on behalf of the Buyer and

is a valid and binding agreement of the Buyer enforceable against the Buyer in accordance with its terms, subject as to enforceability to (i) general principles of equity and to applicable bankruptcy, insolvency, reorganization, moratorium,

liquidation and other similar laws relating to, or affecting generally, the enforcement of applicable creditors rights and remedies and (ii) public policy underlying any law, rule or regulation (including any federal or state securities law,

rule or regulation) with regards to indemnification, contribution or exculpation. The execution and delivery of the Transaction Documents (as defined in Section 3(b) hereof) by the Buyer and the consummation by it of the transactions contemplated

hereby and thereby do not conflict with the Buyer s certificate of organization or operating agreement or similar documents, and do not require further consent or authorization by the Buyer, its managers or its members.

(i) Residency. The Buyer is a resident of the State of Illinois.

(j) No Prior Short Selling. The Buyer represents and warrants to the Company that at no time prior to the date of this Agreement

has any of the Buyer, its agents, representatives or affiliates engaged in or effected, in any manner whatsoever, directly or indirectly, any (i) short sale (as such term is defined in Section 242.200 of Regulation SHO of the 1934 Act)

of the Common Stock or (ii) hedging transaction, which establishes a net short position with respect to the Common Stock.

The Company represents and warrants to

the Buyer that as of the date hereof and as of the Commencement Date:

(a) Organization and Qualification. The Company and its

Subsidiaries (which for purposes of this Agreement means any entity in which the Company, directly or indirectly, owns more than 50% of the voting stock or capital stock or other similar equity interests) are corporations or

limited liability companies duly organized and validly existing in good standing under the laws of the jurisdiction in which they are incorporated or organized, and have the requisite corporate or organizational power and authority to own their

properties and to carry on their business as now being conducted. Each of the Company and its Subsidiaries is duly qualified as a foreign corporation or limited liability company to do business and is in good standing in every jurisdiction in

which its ownership of property or the nature of the business conducted by it makes such qualification necessary, except to the extent that the failure to be so qualified or be in good standing would not reasonably be expected to have a Material

Adverse Effect. As used in this Agreement, Material Adverse Effect means any material adverse effect on any of: (i) the business, properties, assets, operations, results of operations or financial condition of the Company and

its Subsidiaries, if any, taken as a whole, or (ii) the authority or ability of the Company to perform its obligations under the Transaction Documents. The Company has no material Subsidiaries except as set forth on Schedule 3(a).

(b) Authorization; Enforcement; Validity. (i) The Company has the requisite corporate power and authority to enter into and perform

its obligations under this Agreement, the Registration Rights Agreement and each of the other agreements entered into by the parties on the Commencement Date and attached hereto as exhibits to this Agreement (collectively, the Transaction

Documents ), and to issue the Securities in accordance with the terms hereof and thereof, (ii) the execution and delivery of the Transaction Documents by the Company and the consummation by it of the transactions contemplated hereby and