Exhibit 16.1
December 3, 2019
Securities and Exchange Commission
100 F Street N.E.
Washington, D.C. 20549
Re: Insys Therapeutics, Inc.
Commission File Number 001-35902
We have been furnished with a copy of the response to Item 4.01 of Form 8-K for the event that occurred on November 26, 2019, to be filed by our former client, Insys Therapeutics, Inc. We agree with the statements made in response to that Item insofar as they relate to our Firm.
Very truly yours,
/s/ BDO USA, LLP
BDO USA, LLP
Phoenix, Arizona
cc:Vaseem Mahboob, Chair, Audit Committee
Andrece Housley, Chief Financial Officer