Item 4.01. Changes in Registrant’s Certifying Accountant.

(a) Dismissal of Independent Registered Public Accounting Firm

On June 24, 2020, the Audit Committee (the “Audit Committee”) of the Board of Directors of Sorrento Therapeutics, Inc., a Delaware corporation (the “Company”), dismissed Deloitte & Touche LLP (“Deloitte”) as the Company’s independent registered public accounting firm, effective immediately.

The reports of Deloitte on the Company’s consolidated financial statements for the fiscal years ended December 31, 2019 and 2018 did not contain an adverse opinion or a disclaimer of opinion and were not qualified or modified as to uncertainty, audit scope or accounting principles, except that the report of Deloitte on the Company’s consolidated financial statements for each of the fiscal years ended December 31, 2019 and 2018 contained an explanatory paragraph describing conditions that raise substantial doubt about the Company’s ability to continue as a going concern and included an emphasis-of-matter paragraph stating that, “As discussed in Note 1 to the financial statements, effective January 1, 2019, the Company adopted FASB Accounting Standards Update 2016-02, Leases, using the modified retrospective approach.”

During the fiscal years ended December 31, 2019 and 2018 and the subsequent interim period through June 24, 2020, there have been no “disagreements” (as defined in Item 304(a)(1)(iv) of Regulation S-K and related instructions) with Deloitte on any matter of accounting principles or practices, financial statement disclosure or auditing scope or procedure, which disagreements, if not resolved to the satisfaction of Deloitte, would have caused Deloitte to make reference thereto in their reports on the consolidated financial statements for such fiscal years.

During the fiscal years ended December 31, 2019 and 2018 and the subsequent interim period through June 24, 2020, there have been no “reportable events” (as defined in Item 304(a)(1)(v) of Regulation S-K), except that, as of December 31, 2018, the Company identified the following three material weaknesses in the Company’s internal control over financial reporting: (i) the Company did not attract, develop and retain sufficient accounting resources, including a Chief Accounting Officer, with appropriate knowledge and expertise commensurate with the Company’s corporate structure and financial reporting requirements to effectively operate internal controls over financial reporting in a timely manner, which caused the Company’s control activities in certain process or control areas to not operate effectively and resulted in certain deficiencies, including a lack of precise reviews of significant assumptions underlying fair value of embedded derivatives, fair value of indefinite-lived intangible assets and income tax related balances, (ii) a deficiency in evaluating the underlying assumptions associated with the accounting for key terms identified in significant transactions, which included convertible note and debt agreements during the fiscal year ended December 31, 2018, and (iii) a deficiency in reviewing and assessing assumptions underlying the determination of fair value of contingent consideration liabilities. As reported in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019, as filed with the Securities and Exchange Commission (the “SEC”) on March 3, 2020, the Company remediated each of these material weaknesses as of December 31, 2019.

The Company provided Deloitte with a copy of the disclosure it is making herein in response to Item 304(a) of Regulation S-K and requested that Deloitte furnish the Company with a copy of its letter addressed to the SEC, pursuant to Item 304(a)(3) of Regulation S-K, stating whether Deloitte agrees with the statements made by the Company in response to Item 304(a) of Regulation S-K. A copy of Deloitte’s letter to the SEC dated June 30, 2020 is filed as Exhibit 16.1 to this Current Report on Form 8-K.

(b) Engagement of Independent Registered Public Accounting Firm

On June 24, 2020, the Audit Committee approved the appointment of Ernst & Young LLP (“EY”) as the Company’s new independent registered public accounting firm, effective as of June 26, 2020. During the fiscal years ended December 31, 2019 and 2018 and the subsequent interim period through June 24, 2020, neither the Company, nor anyone on its behalf, consulted EY regarding either (i) the application of accounting principles to a specified transaction, either completed or proposed, or the type of audit opinion that might be rendered on the financial statements of the Company, and no written report or oral advice was provided to the Company by EY that EY concluded was an important factor considered by the Company in reaching a decision as to any accounting, auditing or financial reporting issue; or (ii) any matter that was either the subject of a “disagreement” (as defined in Item 304(a)(1)(iv) of Regulation S-K and the related instructions) or a “reportable event” (as that term is defined in Item 304(a)(1)(v) of Regulation S-K).