LICENSE AGREEMENT

EXHIBIT 10.13

University of Pennsylvania

License Agreement

This Agreement (this “ Agreement ”) is between The Trustees of the University of Pennsylvania, a Pennsylvania nonprofit corporation (“ Penn ”), and Acuity Pharmaceuticals, Inc., a Delaware corporation (“ Company ”). This Agreement is being signed on March 31, 2003. This Agreement will become effective on March 31, 2003 (the “ Effective Date ”).

BACKGROUND

Penn owns certain intellectual property developed by Dr. Michael J. Tolentino, Mr. Samuel J. Reich and Mr. Enrico M. Surace of Penn’s School of Medicine, Department of Ophthalmology, relating to the body of work known as RNA interference (the “ RTS Intellectual Property ”). Penn also owns certain applications for United States letters patent relating to the RTS Intellectual Property. Company desires to obtain an exclusive license under the patent rights to exploit the RTS Intellectual Property. Company also desires to fund further research by Dr. Tolentino and Dr. Jean Bennett and their respective groups under a separate agreement. Penn has determined that the exploitation of the RTS Intellectual Property by Company is in the best interests of Penn and is consistent with its educational and research missions and goal.

Simultaneously with the execution of this Agreement, Penn and Company are executing an exclusive license agreement for certain intellectual property developed by Dr. Alan Gewirtz (together with the RTS Intellectual Property, the “ Intellectual Property ”), also relating to the body of work known as RNA interference (the “ Gewirtz License Agreement ”).

In consideration of the mutual obligations contained in this Agreement, and intending to be legally bound, the parties agree as follows:

1. LICENSE

     1.1. License Grant . Penn grants to Company an exclusive, world-wide license (the " License ”) to make, have made, use, import, sell and offer for sale Licensed Products during the Term (as such terms may be defined in Sections 1.2 and 6.1). The License includes the right to sublicense as permitted by this Agreement. No other rights or licenses are granted by Penn.

     1.2. Related Definitions .

     The term “ Licensed Products ” means products that are made, made for, used, imported, sold or offered for sale by Company or its Affiliates or sublicensees and that

either (i) in the absence of this Agreement, would infringe at least one claim of the Penn Patent Rights or (ii) use a process or machine covered by a claim of Penn Patent Rights.

     The term “ Sale ” means any bona fide transaction for which consideration is received or expected for the sale, use, lease, transfer or other disposition of a Licensed Product, and a Sale is deemed completed at the time that Company or its Affiliate or sublicensee invoices, ships or receives payment for a Licensed Product, whichever occurs first.

     The term “ Penn Patent Rights ” means all patent rights represented by or issuing from: (i) the United States patent applications and/or Penn docket numbers listed in Exhibit A; (ii) any continuation, divisional and re-issue applications of (i); and (ii) any foreign counterparts and extensions of (i) or (ii).

     The term “ Affiliate ” means a legal entity that is controlling, controlled by or under common control with Company and that has executed either this Agreement or a written Joinder Agreement agreeing to be bound by all of the terms and conditions of this Agreement. For purposes of this Section 1.2, the word “ control ” means (i) the direct or indirect ownership of more than fifty percent (50%) of the outstanding voting securities of a legal entity, (ii) the right to receive fifty percent (50%) or more of the profits or earnings of a legal entity or (iii) the right to determine the policy decisions of a legal entity.

     The term “ Significant Transaction ” shall mean a single transaction or series of related transactions consisting of or resulting in any of the following: (i) an assignment of the License, (ii) an exclusive worldwide sublicense of all or substantially all of the intellectual property rights granted to Company under this Agreement and a non-exclusive or exclusive, in either case, worldwide sublicense of all or substantially all of the intellectual property rights granted to Company under the Gewirtz License Agreement, (iii) an initial public offering of securities by Company or other transaction resulting in either: (a) Company becoming a public company or (b) any of Company’s securities being traded on a nationally recognized stock exchange or automated quotation system, (iv) a sale, license or other disposition of all or substantially all of Company’s assets, or (v) a reorganization, consolidation or merger of Company, or sale or transfer of the securities of Company, where the holders of Company’s outstanding voting securities before the transaction beneficially own less than fifty percent (50%) of the outstanding voting securities, or hold less than fifty percent (50%) of the voting power of the voting securityholders of the surviving entity after the transaction. Notwithstanding anything above to the contrary, a Significant Transaction shall not be deemed to occur as a result of a bona fide, arms-length equity financing for cash in which Company issues securities representing more than fifty percent (50%) of the voting power of its securityholders to venture capital or other similar investors who do not actively manage day-to-day operations of Company.

     1.3. Reservation of Rights by Penn . Penn reserves the right to use, and to permit other non-commercial entities to use, the Penn Patent Rights for educational and research purposes only.

     1.4. U.S. Government Rights . The parties acknowledge that the United States government retains rights in intellectual property funded under any grant or similar contract with a Federal agency. The License is expressly subject to all applicable United States government rights, including, but not limited to, any applicable requirement that products, which result from such intellectual property and are sold in the United States, must be substantially manufactured in the United States as conditioned by 37 CFR 401.

     1.5. Sublicense Conditions . The Company’s right to sublicense granted by Penn under the License is subject to each of the following conditions:

          (a) In each sublicense agreement, Company will prohibit the sublicensee from further sublicensing and require the sublicensee to comply with the terms and conditions of this Agreement.

          (b) Within thirty (30) days after Company enters into a sublicense agreement, Company will deliver to Penn an executed copy of the entire sublicense agreement written in the English language. Penn’s receipt of the sublicense agreement, however, will not constitute a waiver of any right of Penn or obligation of Company under this Agreement.

          (c) In the event that Company causes or experiences a Trigger Event (as defined in Section 6.4), all payments due to Company and its Affiliates or sublicensees under the sublicense agreement will, upon notice from Penn to such Affiliate or sublicensee, become payable directly to Penn for the account of Company. Upon receipt of any such funds, Penn will remit to Company the amount by which such payments exceed the amounts owed by Company to Penn.

          (d) Company’s execution of a sublicense agreement will not relieve Company of any of its obligations under this Agreement. Company is primarily liable to Penn for any act or omission of an Affiliate or sublicensee of Company that would be a breach of this Agreement if performed or omitted by Company, and Company will be deemed to be in breach of this Agreement as a result of such act or omission.

2. DILIGENCE

     2.1. Development Plan . Company will deliver to Penn, within ninety (90) days after the Effective Date, a copy of an initial development plan for the Penn Patent Rights (the " Development Plan ”). The purpose of the Development Plan is (a) to demonstrate Company’s capability to bring the Penn Patent Rights to commercialization, (b) to project the timeline for completing the necessary tasks, and (c) to measure Company’s progress against the projections. Thereafter, Company will deliver to Penn an annual updated Development Plan no later than December 1 of each year during the Term. The Development Plan will include, at a minimum, information to be mutually agreed upon by the parties hereto.

     2.2. Company’s Efforts . Company will use commercially reasonable efforts to

develop, commercialize, market and sell Licensed Products in a manner consistent with the Development Plan.

     2.3. Diligence Events . The Company will use commercially reasonable efforts to achieve each of the diligence events by the applicable completion date listed in the table below for the first product to be commercialized by the Company pursuant to this Agreement or the Gewirtz License Agreement.

3. FEES AND ROYALTIES

     3.1. Equity Issuance . In partial consideration of the License, Company will issue to Penn on the Effective Date such number of shares of Common Stock of the Company as will cause Penn to own at least twenty six and eight tenths percent (26.8%) of the capital stock of Company on a fully diluted basis, assuming the exercise, conversion and exchange of all outstanding securities of Company for or into shares of Common Stock. The issuance of equity to Penn will be pursuant to a Stock Purchase Agreement and a Stockholders Agreement between Company and Penn, the forms of which are attached as Exhibits C and D (the “ Equity Documents ”).

     3.2. Dilution Protection . In partial consideration of the License, through the closing of the equity financing round at which Company has raised cumulatively at least an aggregate of seven hundred and fifty thousand dollars ($750,000) in net proceeds to Company of equity financing from qualified investors, Company will issue to Penn, from time to time and at no additional consideration, such additional number of shares of Common Stock of Company as will cause Penn to continue to hold in the aggregate twenty six and eight tenths percent (26.8%) of the capital stock of Company on a fully diluted basis, assuming the exercise, conversion and exchange of all outstanding securities of Company for or into shares of Common Stock.

     3.3. Milestone Payments . In partial consideration of the License, Company will pay to Penn the applicable milestone payment listed in the table below after achievement of each milestone event for the first product commercialized and sold by the Company or its Affiliates pursuant to this Agreement or the Gewirtz License Agreement.

     3.4. Earned Royalties . In partial consideration of the License, Company will pay to Penn a royalty of two percent (2%) of Net Sales of a Licensed Product sold by Company or its Affiliates (but not sublicensees) during each Quarter following the occurrence of a Significant Transaction. In partial consideration of the License, Company will pay to Penn a royalty of one percent (1%) of Net Sales of each Licensed Product sold by sublicensees of the Company (and not the Company or its Affiliates) during each Quarter following the occurrence of a Significant Transaction. The term “ Quarter ” means each three-month period beginning on January 1, April 1, July 1 and October 1. The term “ Net Sales ” means the consideration received from, or fair market value attributable to, each Sale of a Licensed Product, less Qualifying Costs directly attributable to a Sale and borne by Company or its Affiliates or sublicensees. For purposes of determining Net Sales, the words “fair market value” mean the cash consideration that Company or its Affiliates or its sublicensees would realize from an unrelated buyer in an arms length sale of an identical item sold in the same quantity and at the time and place of the transaction. The term “ Qualifying Costs ” means: (a) customary discounts in the trade for quantity purchased, prompt payment or wholesalers and distributors; (b) credits or refunds for claims or returns that do not exceed the original invoice amount; (c) prepaid outbound transportation expenses and transportation insurance premiums; and (d) sales and use taxes and other fees imposed by a governmental agency.

     3.5. Reduction of Royalty . If Company is required to pay royalties to Penn and third parties that, in the aggregate, exceed four percent (4%) of Net Sales (the “ Total Royalty ”) to commercialize a Licensed Product, the royalties due to Penn for such time, with respect to such a Licensed Product shall be reduced by two tenths of one percent (0.2%) for every one percent (1%) the aggregate royalty exceeds four percent (4%) of Net Sales. To clarify, Company shall pay to Penn a royalty of 2% — (0.2*(Total Royalty — 4%)) of the Net Sales. In no event shall the royalties due to Penn be reduced below one percent (1%) of Net Sales.

     3.6. Sublicense Fees . Except as otherwise provided below, in partial consideration of the License, Company will pay to Penn a sublicense fee of two percent (2%) of all payments and the fair value of all other consideration of any kind received by Company from sublicensees.

     Notwithstanding anything above to the contrary, no sublicense fee under this Section 3.6 will be due to Penn with respect to any of the following consideration received by Company: (i) consideration received by the Company from sublicensees before the earlier of (a) the third anniversary of the Effective Date and (b) the occurrence of a Significant Transaction as long as such fees are reinvested in the development of the Intellectual Property, (ii) royalties paid to Company by a sublicensee based upon sales or net sales of Licensed Products by the sublicensee; (iii) equity investments in Company by a sublicensee, up to the amount of the fair market value of the equity purchased on the date of the investment as reasonably determined under the circumstances; (iv) sponsored research funding paid to Company by a sublicensee in a bona fide transaction for future

research to be performed by Company; (v) payments for consulting services actually performed by Company in a bona fide transaction at arms length rates; and (vi) intellectual property rights received by Company from a sublicensee, including, but not limited to, licenses or sublicenses to intellectual property rights, covenants not to compete against Company, or agreements not to assert claims against Company.

     3.7. Non-Assertion and Non-Duplication . Net Sales of any Licensed Product, including, but not limited to, Licensed Products pursuant to any other License Agreement executed by Company, shall not be subject to more than one assessment of any scheduled royalty or fee payable to Penn pursuant to this Agreement and the Gewirtz License Agreement; such assessment shall be the lowest applicable royalty and/or fee payable to Penn. Penn shall not assert any right to royalties or fees for any other Licensed Product other than the one with the lesser royalty.

     3.8. Transaction Fee . In partial consideration of the License, Company will pay to Penn, within ninety (90) days after the execution of this Agreement, a one-time, non-refundable, non-creditable transaction fee of up to $10,000 with respect to Penn’s licensing and legal expenses in connection with this Agreement, the Gewirtz License Agreement and the Equity Documents.

4. REPORTS AND PAYMENTS

     4.1. Royalty Reports . Within forty-five (45) days after the end of each Quarter, Company will deliver to Penn a report, certified by the chief financial officer of Company, detailing the calculation of all royalties and fees due to Penn for such Quarter. Unless otherwise included on a form provided to Company by Penn or otherwise agreed to by Penn, this report will include, at a minimum: (a) the number of Licensed Products involved in Sales, listed by product, by country; (b) gross consideration invoiced, billed or received for Sales in the Quarter; (c) Qualifying Costs, listed by category of cost; (d) Net Sales, listed by product, by country; (e) sublicense fees and other consideration received by Company from sublicensees, listed by product, by country; and (f) royalties and fees owed to Penn, listed by category, by product, by country.

     4.2. Payments . Company will pay all royalties and fees due to Penn under Article 3, that have not been paid in advance, within forty-five (45) days after the end of the Quarter in which the royalties or fees accrue.

     4.3. Records . Company will maintain, and will cause its Affiliates and sublicensees to maintain, adequate books and records to verify Sales, Net Sales, and all of the royalties, fees, and other payments due under this Agreement. The records for ea