$INSY Announces FDA Orphan Drug Designation for Ovarian Cancer Treatment

Insys Therapeutics Receives FDA Orphan Drug Designation for Its Liposomal Encapsulated Paclitaxel for the Treatment of Ovarian Cancer

PHOENIX, AZ–(Marketwired – Jan 26, 2015) – Insys Therapeutics, Inc. (NASDAQ: INSY), a specialty pharmaceutical company that is developing and commercializing innovative drugs and novel drug delivery systems, today announced that the U.S. Food and Drug Administration (FDA) has granted orphan drug designation (ODD) to its Liposomal Encapsulated Paclitaxel (LEP) candidate for the treatment of ovarian cancer.

“We are pleased to have received orphan drug designation for LEP-ETU to treat ovarian cancer, a devastating and difficult-to-treat disease,” said Michael L. Babich, President and Chief Executive Officer. “By entrapping the paclitaxel with liposomes, we believe our LEP-ETU formulation could potentially have reduced toxicity, while maintaining or enhancing efficacy of the cancer-fighting paclitaxel. We are currently evaluating next steps with respect to this drug product candidate.”

Orphan drug designation is granted by the FDA Office of Orphan Products Development to novel drugs or biologics that treat rare diseases or conditions affecting fewer than 200,000 patients in the U.S. The designation provides the drug developer with a seven-year period of U.S. marketing exclusivity upon approval, as well as certain financial incentives that can help support its development.

About Ovarian Cancer

Ovarian cancer is a disease in which malignant, or cancerous cells are found in the tissues of the ovary. It is the leading cause of death from gynecologic cancers in the United States and is the fifth leading cause of cancer death among American women¹. In 2014, there were an estimated 21,980 new cases diagnosed and an estimated 14,270 deaths from ovarian cancer in the United States.

About Insys Therapeutics, Inc.

Subsys^® is a registered trademark of Insys Therapeutics, Inc.

Forward-Looking Statements

This press release contains forward-looking statements, including statements regarding our belief that our LEP-ETU formulation could potentially have reduced toxicity, while maintaining or enhancing efficacy of the cancer-fighting paclitaxel and the approval and market exclusivity in connection therewith and the development of Insys’ pipeline of sublingual sprays and pharmaceutical cannabinoids. These forward-looking statements are based on management’s expectations and assumptions as of the date of this press release, and actual results may differ materially from those in these forward-looking statements as a result of various factors, many of which are beyond our control. For a description of these risks facing the company, please see the risk factors described in our filings with the United States Securities and Exchange Commission, including those factors discussed under the caption “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2013 and any subsequent updates that may occur in our Quarterly Reports on Form 10-Q. Forward-looking statements speak only as of the date of this press release and we undertake no obligation to update or revise these statements, except as may be required by law.

¹ Ovarian Cancer Research Fund/American Cancer Society