LJPC La Jolla Pharmaceutical Company

Item 4.01Changes in Registrant’s Certifying Accountant.

On November 1, 2020, the audit practice of Squar Milner, LLP (“Squar Milner”), an independent registered public accounting firm, was combined with Baker Tilly US, LLP (“Baker Tilly”) in a transaction pursuant to which Squar Milner combined its operations with Baker Tilly, and certain members of the professional staff and partners of Squar Milner joined Baker Tilly either as employees or partners of Baker Tilly. On November 1, 2020, Squar Milner resigned as auditors of La Jolla Pharmaceutical Company (the “Company”), and with the approval of the Audit Committee of the Company’s Board of Directors, Baker Tilly was engaged as the Company’s independent registered public accounting firm.

Prior to engaging Baker Tilly, the Company did not consult with Baker Tilly regarding the application of accounting principles to a specific completed or proposed transaction or regarding the type of audit opinions that might be rendered by Baker Tilly on the Company’s financial statements, and Baker Tilly did not provide any written or oral advice that was an important factor considered by the Company in reaching a decision as to any such accounting, auditing or financial reporting issue.

The Report of Independent Registered Public Accounting Firm of Squar Milner regarding the Company’s financial statements for the years ended December 31, 2019 and 2018 did not contain any adverse opinion or disclaimer of opinion and were not qualified or modified as to uncertainty, audit scope or accounting principles, except that such audit report did include an explanatory paragraph regarding a change in accounting principle related to the Company’s adoption of new lease accounting standards pursuant to Accounting Standards Codification Topic 842.

During the years ended December 31, 2019 and 2018 and during the interim period from the end of the most recently completed year through November 1, 2020, the date of resignation, there were no disagreements with Squar Milner on any matter of accounting principles or practices, financial statement disclosure or auditing scope or procedures, which disagreements, if not resolved to the satisfaction of Squar Milner, would have caused Squar Milner to make reference to such disagreement in its report.

The Company provided Squar Milner with a copy of this Current Report on Form 8-K prior to its filing with the U.S. Securities and Exchange Commission (the “SEC”) and requested that Squar Milner furnish the Company with a letter addressed to the SEC stating whether it agrees with the above statements and, if it does not agree, the respects in which it does not agree. A copy of the letter, dated November 5, 2020, is filed as Exhibit 16.1 (which is incorporated by reference herein) to this Current Report on Form 8-K.