TERM NOTE

Exhibit 4.3

TERM NOTE

FOR VALUE RECEIVED, the undersigned BIOHAVEN PHARMACEUTICAL HOLDING COMPANY LTD., a BVI business company incorporated under the laws of the British Virgin Islands (“Borrower”), promises to pay to the order of WELLS FARGO BANK, NATIONAL ASSOCIATION, a national banking association (“Bank”), at its office at 101 Federal Street, Suite 2020, Boston, Massachusetts, 02110, or at such other place as the holder hereof may designate, in lawful money of the United States of America and in immediately available funds, the principal sum of Five Million Dollars ($5,000,000), or so much thereof as may be advanced and be outstanding pursuant to the terms of the Credit Agreement, as defined herein, with interest thereon, to be computed on each advance from the date of its disbursement as set forth herein.

DEFINITIONS:

As used herein, the following terms shall have the meanings set forth after each, and any other term defined in this Note shall have the meaning set forth at the place defined:

(a)                                 “LIBOR” means the rate of interest per annum determined by Bank based on the rate for United States dollar deposits for delivery on the first day of each LIBOR Period for a period approximately equal to such LIBOR Period published by the ICE Benchmark Administration Limited, a United Kingdom company, at approximately 11:00 a.m., London time, two London Business Days prior to the first day of such LIBOR Period (or if not so published, then as determined by Bank from another recognized source or interbank quotation); provided, however, that if LIBOR determined as provided above would be less than zero percent (0.0%), then LIBOR shall be deemed to be zero percent (0.0%).

(b)                                 “LIBOR Period” means a period commencing on a New York Business Day and continuing for one month during which the entire outstanding principal balance of this Note bears interest determined in relation to LIBOR, with the understanding, that (i) the initial LIBOR Period shall commence on the date this Note is disbursed, (ii) there shall be successive LIBOR Periods thereafter, each commencing automatically, and without notice to or consent from Borrower, immediately after the preceding LIBOR Period ends, (iii) if any LIBOR Period is scheduled to commence on a day that is not a New York Business Day, then such LIBOR Period shall commence on the next succeeding New York Business Day (and the preceding LIBOR Period shall continue up to, but shall not include, the first day of such LIBOR Period), unless the result of such extension would be to cause such LIBOR Period to begin in another calendar month, in which event such new LIBOR Period shall commence on the immediately preceding New York Business Day (and the preceding LIBOR Period shall continue up to, but shall not include, the first day of such new LIBOR Period), and (iv) if, on the first day of the last LIBOR Period applicable hereto the remaining term of this Note is less than one (1) month, said LIBOR Period shall be in effect only until the Maturity Date (as defined below).

(c)                                  “London Business Day” means any day that is a day for trading by and between banks in dollar deposits in the London interbank market.

(d)                                 “New York Business Day” means any day except a Saturday, Sunday or any other day on which commercial banks in New York are authorized or required by law to close.

(e)                                  “Prime Rate” means at any time the rate of interest most recently announced within Bank at its principal office as its Prime Rate, with the understanding that the Prime Rate is one of Bank’s base rates and serves as the basis upon which effective rates of interest are calculated for those loans making reference thereto, and is evidenced by the recording thereof after its announcement in such internal publication or publications as Bank may designate. If the rate of interest announced by Bank as its Prime Rate at any time is less than zero percent (0.0%), then for purposes of this Note the Prime Rate shall be deemed to be zero percent (0.0%).

(f)                                   “State Business Day” means any day except a Saturday, Sunday or any other day on which commercial banks in the jurisdiction described in “Governing Law’ herein are authorized or required by law to close.

INTEREST:

(a)                                 Interest. The outstanding principal balance of this Note shall bear interest (computed on the basis of a 360-day year, actual days elapsed) at a fixed rate per annum determined by Bank to be one and one-half of one percent (1.50%) above LIBOR in effect on the first day of each LIBOR Period. With respect to each LIBOR Period hereunder, Bank is hereby authorized to note the date and interest rate applicable thereto and any payments made thereon on Bank’s books and records (either manually or by electronic entry) and/or on any schedule attached to this Note, which notations shall be prima facie evidence of the accuracy of the information noted. Borrower shall reimburse Bank immediately upon demand for any loss or expense (including any loss or expense incurred by reason of the liquidation or redeployment of funds obtained to fund or maintain a LIBOR borrowing) incurred by Bank as a result of the failure of Borrower to accept or complete a LIBOR borrowing hereunder after making a request therefor. Any reasonable determination of such amounts by Bank shall be conclusive and binding upon Borrower.

(b)                                 Taxes and Regulatory Costs. Borrower shall pay to Bank immediately upon demand, in addition to any other amounts due or to become due hereunder, any and all (i) withholdings, interest equalization taxes, stamp taxes or other taxes (except income and franchise taxes) imposed by any domestic or foreign governmental authority and related in any manner to LIBOR, and (ii) costs, expenses and liabilities arising from or in connection with reserve percentages prescribed by the Board of Governors of the Federal Reserve System (or any successor) for “Eurocurrency Liabilities” (as defined in Regulation D of the Federal Reserve Board, as amended), assessment rates imposed by the Federal Deposit Insurance Corporation, or similar requirements or costs imposed by any domestic or foreign governmental authority or resulting from compliance by Bank with any request or directive (whether or not having the force of law) from any central bank or other governmental authority and related in any manner to LIBOR. In determining which of the foregoing are attributable to any LIBOR option available to Borrower hereunder, any reasonable allocation made by Bank among its operations shall be conclusive and binding upon Borrower.

(c)                                  Default Interest. From and after the Maturity Date, or such earlier date as all principal owing hereunder becomes due and payable by acceleration or otherwise, or upon the occurrence and during the continuance of an Event of Default, then at the option of Bank, in its sole and absolute discretion, the outstanding principal balance of this Note shall bear interest at an increased rate per annum (computed on the basis of a 360-day year, actual days elapsed) equal to four percent (4%) above the rate of interest from time to time applicable to this Note.

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REPAYMENT:

(a)                                 Repayment of Principal. The outstanding principal balance of this Note shall be due and payable in full on August 30, 2017 (the “Maturity Date”).

(b)                                 Payment of Interest. Interest accrued on this Note shall be payable on the 30th day of each month, commencing September 30, 2016.

(c)                                  Application of Payments. Each payment made on this Note shall be credited first, to any interest then due and second, to the outstanding principal balance hereof.

PREPAYMENT:

(a)                                 Prepayment. Borrower may prepay principal on this Note at any time and in the minimum amount of One Hundred Thousand Dollars ($100,000); provided however, that if the outstanding principal balance of this Note is less than said amount, the minimum prepayment amount shall be the entire outstanding principal balance hereof. In consideration of Bank providing this prepayment option to Borrower, or if this Note shall become due and payable at any time prior to the last day of any LIBOR Period by acceleration or otherwise, Borrower shall pay to Bank immediately upon demand a fee which is the sum of the discounted monthly differences for each month from the month of prepayment through the month in which such LIBOR Period matures, calculated as follows for each such month:

(i)                                     Determine the amount of interest which would have accrued each month on the amount prepaid at the interest rate applicable to such amount had it remained outstanding until the last day of the LIBOR Period applicable thereto.

(ii)                                  Subtract from the amount determined in (i) above the amount of interest which would have accrued for the same month on the amount prepaid for the remaining term of such LIBOR Period at LIBOR in effect on the date of prepayment for new loans made for such term and in a principal amount equal to the amount prepaid.

(iii)                               If the result obtained in (ii) for any month is greater than zero, discount that difference by LIBOR used in (ii) above.

Borrower acknowledges that prepayment of such amount may result in Bank incurring additional costs, expenses and/or liabilities, and that it is difficult to ascertain the full extent of such costs, expenses and/or liabilities. Borrower, therefore, agrees to pay the above-described prepayment fee and agrees that said amount represents a reasonable estimate of the prepayment costs, expenses and/or liabilities of Bank. If Borrower fails to pay any prepayment fee when due, the amount of such prepayment fee shall thereafter bear interest until paid at a rate per annum two percent (2.00%) above the Prime Rate in effect from time to time (computed on the basis of a 360-day year, actual days elapsed).

(b)                                 Application of Prepayments. If principal under this Note is payable in more than one installment, then any prepayments of principal shall be applied to the most remote principal installment or installments then unpaid.

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EVENTS OF DEFAULT:

This Note is made pursuant to and is subject to the terms and conditions of that certain Credit Agreement between Borrower and Bank dated as of the date hereof, as amended from time to time (the “Credit Agreement”). Any default in the payment or performance of any obligation under this Note, or any defined event of default under the Credit Agreement, shall constitute an “Event of Default” under this Note.

MISCELLANEOUS:

(a)                                 Remedies. Upon the occurrence of any Event of Default, the holder of this Note, at the holder’s option, may declare all sums of principal and interest outstanding hereunder to be immediately due and payable without presentment, demand, notice of nonperformance, notice of protest, protest or notice of dishonor, all of which are expressly waived by Borrower, and the obligation, if any, of the holder to extend any further credit hereunder shall immediately cease and terminate. Borrower shall pay to the holder immediately upon demand the full amount of all payments, advances, charges, costs and expenses, including reasonable attorneys’ fees (to include outside counsel fees and all allocated costs of the holder’s in-house counsel), expended or incurred by the holder in connection with the enforcement of the holder’s rights and/or the collection of any amounts which become due to the holder under this Note whether or not suit is brought, and the prosecution or defense of any action in any way related to this Note, including without limitation, any action for declaratory relief, whether incurred at the trial or appellate level, in an arbitration proceeding or otherwise, and including any of the foregoing incurred in connection with any bankruptcy proceeding (including without limitation, any adversary proceeding, contested matter or motion brought by Bank or any other person) relating to Borrower or any other person or entity.

(b)                                 Obligations Joint and Several. Should more than one person or entity sign this Note as a Borrower, the obligations of each such Borrower shall be joint and several.

(c)                                  Governing Law. This Note shall be governed by and construed in accordance with the laws of the State of New York, but giving effect to federal laws applicable to national banks, without reference to the conflicts of law or choice of law principles thereof.

(d)                                 Savings Clause. If at any time the interest rate set forth in this Note exceeds the maximum interest rate allowable under applicable law, the interest rate shall be deemed to be such maximum interest rate allowable under applicable law.

(e)                                  Right Of Setoff; Deposit Accounts. Upon and after the occurrence of an Event of Default, (i) Borrower hereby authorizes Bank, at any time and from time to time, without notice, which is hereby expressly waived by Borrower, and whether or not Bank shall have declared this Note to be due and payable in accordance with the terms hereof, to set off against, and to appropriate and apply to the payment of, Borrower’s obligations and liabilities under this Note (whether matured or unmatured, fixed or contingent, liquidated or unliquidated), any and all amounts owing by Bank to Borrower (whether payable in U.S. dollars or any other currency, whether matured or unmatured, and in the case of deposits, whether general or special (except trust and escrow accounts), time or demand and however evidenced), and (ii) pending any such action, to the extent necessary, to hold such amounts as collateral to secure such obligations and liabilities and to return as unpaid for insufficient funds any and all checks and other items drawn against any deposits so held as Bank, in its sole discretion, may elect. Borrower hereby grants to

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Bank a security interest in all deposits and accounts maintained with Bank to secure the payment of all obligations and liabilities of Borrower to Bank under this Note.

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IN WITNESS WHEREOF, the undersigned has executed this Note as of the date first written above.

[Signature Page to Term Note – Biohaven]