On October 31, 2023 (the ?Fourth Amendment Effective Date?), Akebia Therapeutics, Inc. (the ?Company?), BioPharma Credit PLC (the ?Collateral Agent?), BPCR Limited Partnership (as a ?Lender?) and BioPharma Credit Investments V (Master) LP (as a ?Lender?) entered into the Fourth Amendment to Loan Agreement (the ?Fourth Amendment?), which amends certain provisions of the Loan Agreement, dated November 11, 2019, as amended by the First Amendment and Waiver, dated February 18, 2022, the Second Amendment and Waiver, dated July 15, 2022 and the Third Amendment dated June 30, 2023, between the parties (as amended, the ?Loan Agreement?). As of October 31, 2023, there was $35.0 million of principal outstanding under the Term Loans (as defined in the Loan Agreement). The Fourth Amendment extends the maturity date of each Term Loan from November 11, 2024 to March 31, 2025 (the ?New Maturity Date?).

The Fourth Amendment also delays the payment of additional principal of each Term Loan until October 31, 2024, at which time the Company will make monthly payments of principal; provided that, if certain pre-specified events occur, the Company will (a) make payments of principal of such Term Loans commencing on the Payment Date (as defined in the Loan Agreement) immediately following the occurrence of such event and continuing on a quarterly basis on each Payment Date thereafter through the New Maturity Date and (b) repay, on a specified date on or after July 1, 2024, all unpaid principal that would have been due and payable during the period commencing on the Payment Date immediately following the Fourth Amendment Effective Date and ending on the Payment Date immediately following such date (including all accrued and unpaid interest thereon, if any), as if the Company had been required to make equal quarterly payments of principal of such Term Loans commencing on the Payment Date immediately following the Fourth Amendment Effective Date. The Term Loans bear interest through maturity at a variable rate based upon the three-month Secured Overnight Financing Rate (?SOFR?) rate, plus a SOFR adjustment of 0.3%, plus 7.50%. Prior to the Fourth Amendment, the three-month SOFR rate was subject to a 3.35% cap (the ?SOFR Cap?).

The Fourth Amendment removed the SOFR Cap as of the Fourth Amendment Effective Date. The SOFR rate as of the Fourth Amendment Effective Date was 5.35%.