Not Construed Against Drafter. The language of this Agreement shall not be interpreted in favor of or against any Party as the drafter of this Agreement.

Representations and Warranties of Each Party. Each of Merck and Licensee hereby represents, warrants and covenants to the other Party hereto as follows:

Documents Mutually Drafted. ​ and ​ agree that this Agreement each other Program Document prepared in connection with the Transactions set forth herein have been mutually drafted and negotiated by each party, and consequently such documents shall not be construed against either party as the drafter thereof.

This Agreement is the product of arm’s-length negotiations between the parties. Each of the parties agrees that neither party will claim that any ambiguity in this Agreement shall be construed against the other party or against the drafter of this Agreement.

Each U.S. Lender shall deliver to the ​ and the ​ on or before the date on which it becomes a party to this Agreement two properly completed and duly signed originals of IRS Form W-9 certifying that such Lender is exempt from U.S. federal backup withholding.

Each U.K. Revolving Borrowing, each conversion of U.K. Revolving Loans from Eurodollar Rate Loans to Domestic Base Rate Loans, each conversion of U.K. Revolving Loans from Domestic Base Rate Loans to Eurodollar Rate Loans, and each continuation of Eurodollar Rate Loans or Alternative Currency Term Rate Loans shall be made upon the applicable U.K. Borrower’s irrevocable notice to the Administrative Agent, which may be given by telephone or a U.K. Loan Notice; provided, that, any telephonic notice must be confirmed immediately by delivery to the Administrative Agent of a U.K. Loan Notice. Each U.K. Loan Notice must be received by the Administrative Agent not later than # ​ (London time) # three (3) Business Days prior to the requested date of any U.K. Revolving Borrowing of, conversion to, or continuation of Eurodollar Rate Loans, or any conversion of Eurodollar Rate Loans to Domestic Base Rate Loans, and # three (3) Business Days prior to the requested date of any U.K. Revolving Borrowing of Alternative Currency Loans, or any continuation of Alternative Currency Term Rate Loans, and # ​ (Eastern time) on the requested date of any U.K. Revolving Borrowing of Domestic Base Rate Loans; provided, that, if the applicable U.K. Borrower wishes to request U.K. Revolving Loans that are Eurodollar Rate Loans or Alternative Currency Term Rate Loans having an Interest Period other than one (1), three (3), or six (6) months in duration as provided in the definition of “Interest Period,” the applicable notice must be received by the Administrative Agent not later than ​ (London time) four (4) Business Days prior to the requested date of such U.K. Revolving Borrowing, conversion or continuation of Eurodollar Rate Loans or Alternative Currency Term Rate Loans, whereupon the Administrative Agent shall give prompt notice to the U.K. Lenders of such request and determine whether the requested Interest Period is acceptable to all of them. Not later than ​ (London time), three (3) Business Days prior to the requested date of such U.K. Revolving Borrowing, conversion or continuation of Eurodollar Rate Loans or Alternative Currency Term Rate Loans, the Administrative Agent shall notify the applicable U.K. Borrower (which notice may be by telephone) whether or not the requested Interest Period has been consented to by all the U.K. Lenders. Except as provided in [Section 2.04(c)(iii)(A)], Each U.K. Revolving Borrowing or continuation of Eurodollar Rate Loans, and each U.K. Revolving Borrowing, conversion or continuation of Alternative Currency Loans shall be in a minimum principal amount of ​ if denominated in Dollars, ​ if denominated in Sterling, or ​ if denominated in Euro or a whole multiple of ​ if denominated in Dollars, ​ if denominated in Sterling, or ​ if denominated in Euro in excess thereof. Each U.K. Revolving Borrowing of or conversion to Domestic Base Rate Loans shall be in a minimum principal amount of ​ or a whole multiple of ​ in excess thereof. Each U.K. Loan Notice shall specify # whether the applicable U.K. Borrower is requesting a U.K. Revolving Borrowing, a conversion of U.K. Revolving Loans from Eurodollar Rate Loans to Domestic Base Rate Loans, a conversion of U.K. Revolving Loans from Domestic Base Rate Loans to Eurodollar Rate Loans, a continuation of Eurodollar Rate Loans, or a continuation of Alternative Currency Term Rate Loans, # the requested date of such U.K. Revolving Borrowing or continuation, as the case may be (which shall be a Business Day), # the currency and principal amount of the U.K. Revolving Loans to be borrowed or continued, # the Type of U.K. Revolving Loans to be borrowed, # if applicable, the duration of the Interest Period with respect thereto, and # the applicable U.K. Borrower. If the applicable U.K. Borrower fails to specify a currency in a U.K. Loan Notice requesting a U.K. Revolving Borrowing, then the Revolving Loans so requested shall be made in Sterling. If the applicable U.K. Borrower fails to timely request a continuation of Eurodollar Rate Loans or Alternative Currency Term Rate Loans, as applicable, such U.K. Revolving Loans shall be continued as Eurodollar Rate Loans or Alternative Currency Term Rate Loans, as applicable in their original currency with an Interest Period of one (1) month. If the applicable U.K. Borrower requests a U.K. Revolving Borrowing of, or continuation of, Eurodollar Rate Loans or Alternative Currency Term Rate Loans in any such U.K. Loan Notice, but fails to specify an Interest Period, it will be deemed to have specified an Interest Period of one (1) month. Except as otherwise provided in this Agreement, no U.K. Revolving Loan may be converted into or continued as a U.K. Revolving Loan denominated in a different currency, but instead must be repaid in the original currency of such U.K. Revolving Loan and reborrowed in the other currency.

Each U.K. Swing Line Borrowing shall be made upon the applicable U.K. Borrower’s irrevocable notice to the U.K. Swing Line Lender and the Administrative Agent by delivery of a U.K. Swing Line Loan Notice. Each U.K. Swing Line Loan Notice must be received not later than # with respect to U.K. Swing Line Loans denominated in Sterling, ​ (London time) on the requested borrowing date and # with respect to U.K. Swing Line Loans denominated in Dollars or Euros, ​ (London time) on the requested borrowing date, and shall specify # the name of the applicable U.K. Borrower, # the amount and currency to be borrowed, which amount shall be a minimum of ​ (or the Dollar Equivalent thereof if denominated in Dollars or the Alternative Currency equivalent thereof if denominated in Euros) or such integral multiple thereof (in each case, or such smaller amount as may be agreed by the U.K. Swing Line Lender), # the requested borrowing date, which shall be a Business Day, and # the location and number of such U.K. Borrower’s account to which funds are to be disbursed. Unless the U.K. Swing Line Lender has received notice (by telephone or in writing) from the Administrative Agent (including at the request of any Lender) prior to ​ (London time), on the date of the proposed U.K. Swing Line Borrowing # directing the U.K. Swing Line Lender not to make such U.K. Swing Line Loan as a result of the limitations set forth in the first proviso to the first sentence of [[Section 2.04(a)(iii), or (2)])]])] that one or more of the applicable conditions specified in [Article IV] is not then satisfied, then, subject to the terms and conditions hereof, the U.K. Swing Line Lender shall, promptly after receipt of the applicable U.K. Swing Line Loan Notice with respect to such U.K. Swing Line Borrowing, make such U.K. Swing Line Loan to the applicable U.K. Borrower by means of a wire transfer to the account specified in such U.K. Swing Line Loan Notice.

Each U.K. Lender’s obligation to make U.K. Revolving Loans or to purchase and fund risk participations in U.K. Swing Line Loans pursuant to this [Section 2.04(c)(iii)] shall be absolute and unconditional and shall not be affected by any circumstance, including # any setoff, counterclaim, recoupment, defense or other right which such U.K. Lender may have against the U.K. Swing Line Lender, any U.K. Borrower or any other Person for any reason whatsoever, # the occurrence or continuance of a Default, or # any other occurrence, event or condition, whether or not similar to any of the foregoing; provided, that, each U.K. Lender’s obligation to make U.K. Revolving Loans pursuant to this [Section 2.04(c)(iii)] is subject to the conditions set forth in [Section 4.02]. No such funding of risk participations shall relieve or otherwise impair the obligation of the U.K. Borrowers to repay U.K. Swing Line Loans, together with interest as provided herein.

Each of [Schedule 10.1] (Permitted Existing Liens) and [Schedule 10.2] (Permitted Existing Investments) is amended and restated in the form attached to this letter agreement as [Schedules 10.1] and 10.2, respectively.

Each of the U.S. Loan Parties is validly existing and in good standing under the laws of its jurisdiction of incorporation.

Each of the U.S. Loan Parties has the corporate power and authority to execute, deliver and perform its obligations under the Loan Documents to which it is a party.

The agreement of Lenders to make any Advance requested to be made on any date (including the initial Advance), is subject to the satisfaction of the following conditions precedent as of the date such Advance is made:

Taxes, Indebtedness, etc

The agreement of each Bank to make any extension of credit requested to be made by it on any date is subject to the satisfaction of the following conditions precedent:

Each Agent agrees to hold any Collateral that can be perfected by the possession or control of such Collateral or of any account in which such Collateral is held, and if such Collateral or any such account is in fact in the possession or under the control of such Agent, or of agents or bailees of such Agent (such Collateral being referred to herein as the “Pledged Collateral”) as gratuitous bailee and sub-collateral agent for and on behalf of the other Agent solely for the purpose of perfecting the Lien granted to the other Agent in such Pledged Collateral (including, but not limited to, any securities or any deposit accounts or securities accounts, if any) pursuant to the First Lien Documents or Second Lien Documents, as applicable, subject to the terms and conditions of this [Section 6].

By Each Selling Holder. Each Selling Holder agrees severally and not jointly with any other Selling Holder to indemnify and hold harmless the Company, the Company’s directors, officers, employees and agents and each Person, who, directly or indirectly, controls the Company within the meaning of the Securities Act or of the Exchange Act to the same extent as the foregoing indemnity from the Company to the Selling Holders, but only with respect to information regarding such Selling Holder furnished in writing by or on behalf of such Selling Holder expressly for inclusion in a Registration Statement or any other registration statement contemplated by this Agreement, any preliminary prospectus, prospectus supplement or final prospectus contained therein, or any amendment or supplement thereto or any free writing prospectus relating thereto; provided, however, that the liability of each Selling Holder shall not be greater in amount than the dollar amount of the proceeds (net of any Selling Expenses) received by such Selling Holder from the sale of the Registrable Securities giving rise to such indemnification.

Conditions to Each Purchase. As a condition precedent to any purchase of a Participation Interest by ​ from ​ hereunder, in addition to all other requirements set forth herein, ​ shall deliver to ​ all of the following, each being duly executed, endorsed, notarized where applicable and delivered and in form and content satisfactory to ​ in its sole and absolute discretion:

Consultation with Independent Counsel. The Parties hereto have each consulted with and been counseled by their own legal counsel and tax advisors, and are entering into this Agreement voluntarily and with full understanding of the meaning and legal effects of each provision contained in this Agreement. Snell and Wilmer L.L.P. has acted as legal counsel to ​ and has not acted as legal counsel to any other Party. The Parties hereto and their respective legal counsel have been involved in the negotiation and drafting of this Agreement. In the event of any dispute regarding the interpretation of any provision of this Agreement, the Parties agree that this Agreement and the provisions hereof shall not be construed against any one Party as the drafter of this Agreement.