SPARK THERAPEUTICS, INC.3737 MARKET STREET, SUITE 1300"PHILADELPHIA, PA 19104P215.220.9300SPARKTX.COM

Spark is entitled to grant sublicenses through multiple tiers under the Spark Sublicensed Rights to Affiliates and Third Parties, as provided in the Spark Agreement (“Permitted Spark Sublicensees”).

Spark and each Permitted Spark Sublicensee will be considered a SUBLICENSEE for the purposes of the M.I.T. Agreement. For the avoidance of doubt, and not in limitation of the foregoing or any other provisions of the M.I.T. Agreement, any consideration that COMPANY or an AFFILIATE of COMPANY receives from a SUBLICENSEE in consideration of the sublicense of the licenses and rights granted COMPANY and its AFFILIATES under Section 2.1 (including without limitation the sublicense of such rights under a Permitted Spark Sublicense), excluding (i) royalties on NET SALES otherwise payable to M.I.T. under Section 4.1(c) of the M.I.T. Agreement, (ii) RESEARCH SUPPORT PAYMENTS and (iii) payments made as consideration for debt or equity securities (excluding amounts in excess of the FAIR MARKET VALUE of such securities), shall be considered SUBLICENSE INCOME. In accordance with Section 4.1(e) of the MIT License Agreement, COMPANY hereby agrees to pay M.I.T. [***] of all SUBLICENSE INCOME related to the Spark Agreement and Permitted Spark Sublicenses.

In the event that non-monetary consideration is received by COMPANY or its AFFILIATES for the Spark Agreement or a Permitted Spark Sublicense, SUBLICENSE INCOME shall be calculated based on and shall include the fair market value of such non-monetary consideration, including all elements of such consideration. Notwithstanding the foregoing, if Spark settles a portion of its obligation to make any Development Milestone Payment or Regulatory Milestone Payment under the Spark Agreement by issuing to Selecta Spark Common Stock having a Fair Market Value equal to such portion of such Development Milestone Payment or Regulatory Milestone Payment, as applicable, being settled thereby in accordance with Section 6.8 of the Spark Agreement, then (i) Selecta will use the Fair Market Value of such issuance for the purposes of calculating the amount of SUBLICENSE INCOME received by and portion thereof required to be shared with M.I.T. under the M.I.T. Agreement, and (ii) Selecta will not be required to make any payment to M.I.T. with respect to such issuance until Selecta has sold the portion of such issuance required to be shared with M.I.T, provided that Selecta will use best efforts to sell such portion of such issuance as soon as practicable.

Any sublicense granted by Spark under the Spark Sublicensed Rights (a “Spark Sublicense Agreement”) will satisfy the requirements of Section 2.6 of the M.I.T. Agreement; notwithstanding and without limiting the foregoing, any Spark

Except for sublicenses granted by Spark to third party service providers, Selecta will, and ensures that Spark will, (i) furnish M.I.T. with a fully signed photocopy of any Spark Sublicense Agreement promptly after it is executed, and (ii) deliver to M.I.T. reports containing the information described in Article 5 of the M.I.T. Agreement with respect to Permitted Spark Sublicensees. Notwithstanding the foregoing, Spark may reasonably redact the items provided per the foregoing clauses (i) and (ii) to remove Spark and third party confidential information, except that terms (including financial terms) that are directly relevant to COMPANY’s, its AFFILIATE’s and Spark’s obligations under the M.I.T. Agreement and this Letter Agreement may not be redacted by Spark. Upon request by M.I.T., Spark shall provide a copy of any sublicense granted by Spark to a third party service provider to M.I.T.

Spark shall notify M.I.T. in writing of its request for a license agreement under the MIT Patents within [***] of written notification from Selecta or M.I.T. of termination of the M.I.T. Agreement.

M.I.T. will not be obliged to [***].

Spark and Permitted Spark Sublicensees are not [***].

Under the New License and Option Agreement, Spark will be obligated to pay M.I.T. the following license fees, royalty payments and milestone payments, and patent cost reimbursement:

The [***].

[***] For example, [***]. As an illustration [***].

[***]

[***]

The New License and Option Agreement will include substantially similar terms and conditions to the following provisions of the M.I.T. Agreement:

Spark will comply with the insurance requirements applicable to Selecta set forth in Section 8.2 of the M.I.T. Agreement. Within [***] of execution of the Spark Agreement and thereafter promptly upon M.I.T.’s request, Spark will provide to M.I.T. a written certificate evidencing that insurance coverage meeting the above criteria is effectively in place.

Notwithstanding anything to the contrary, Selecta will continue to comply with the insurance requirements set forth in Section 8.2 of the M.I.T. Agreement.