Secured Promissory Note dated May 11, 2017 between Adamas Pharma, LLC and Healthcare Royalty Partners III, L.P

FOR VALUE RECEIVED, the undersigned, Adamas Pharma, LLC, a Delaware limited liability company, with offices located at 1900 Powell Street, Emeryville, California 94608 (“Borrower”) HEREBY PROMISES TO PAY to the order of HEALTHCARE ROYALTY PARTNERS III, L.P. (“Lender”) the principal amount of THIRTY FIVE MILLION DOLLARS ($35,000,000.00) or such lesser amount as shall equal the outstanding principal balance of the Initial Tranche Loan made to Borrower by Lender, plus interest on the aggregate unpaid principal amount of such Initial Tranche Loan, at the rates and in accordance with the terms of the Loan Agreement, dated as of May 11, 2017 by and between Borrower and Lender (as amended, restated, supplemented or otherwise modified from time to time, the “Loan Agreement”). If not sooner paid, the entire principal amount and all accrued and unpaid interest hereunder shall be due and payable on the Maturity Date as set forth in the Loan Agreement. Any capitalized term not otherwise defined herein shall have the meaning attributed to such term in the Loan Agreement.

Principal, interest, and all other amounts (including but not limited to additional amounts, if any, payable under Section 3.02 of the Loan Agreement) due with respect to the Initial Tranche Loan under the Loan Agreement or the other Loan Documents, are payable in lawful money of the United States of America to Lender as set forth in the Loan Agreement and this Secured Promissory Note (this “Note”). The principal amount of this Note and the interest rate applicable thereto, and all payments made with respect thereto, shall be recorded by Lender and, prior to any transfer hereof, endorsed on the grid attached hereto which is part of this Note.

The Loan Agreement, among other things, (a) provides for the making of an Initial Tranche Loan by Lender to Borrower, and (b) contains provisions for acceleration of the maturity hereof upon the happening of certain stated events and also for prepayments on account of the principal hereof, together with interest and other amounts, upon the terms and conditions specified therein.

This Note may not be prepaid except as set forth in Section 3.02 of the Loan Agreement.

This Note and the obligation of Borrower to repay the unpaid principal amount of the Initial Tranche Loan, interest on the Initial Tranche Loan and all other amounts due Lender under the Loan Agreement and other Loan Documents, is secured under the Security Agreement and by the pledge under the Stock Pledge Agreement.

Presentment for payment, demand, notice of protest and all other demands and notices of any kind in connection with the execution, delivery, performance and enforcement of this Note are hereby waived.

THIS NOTE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK, INCLUDING GENERAL OBLIGATIONS LAW SECTIONS 5-1401 AND 5-1402 BUT OTHERWISE WITHOUT GIVING EFFECT TO LAWS CONCERNING CONFLICTS OF LAWS OR CHOICE OF FORUM THAT WOULD REQUIRE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION.

Sections 1.02 (Rules of Construction), 4.03 (Interest on Late Payments), 4.05 (Administration and Enforcement Expenses), 8.10 (Waiver of Stay, Extension or Usury Laws), 12.11 (Jurisdiction), 12.12 (Waiver of Jury Trial) and 12.13 (Waiver of Immunity) of the Loan Agreement shall be deemed incorporated herein mutatis mutandis.

The ownership of an interest in this Note shall be registered on a record of ownership maintained by Borrower or its agent. Notwithstanding anything else in this Note to the contrary, the right to the principal of, and stated interest on, this Note may be transferred only if the transfer is registered on such record of ownership and the transferee is identified as the owner of an interest in the obligation. Borrower shall be entitled to treat the registered holder of this Note (as recorded on such record of ownership) as the owner in fact thereof for all purposes and shall not be bound to recognize any equitable or other claim to or interest in this Note on the part of any other person or entity.

IN WITNESS WHEREOF, Borrower has caused this Note to be duly executed by one of its officers thereunto duly authorized on the date hereof.