Shionogi Presents Results from a Phase 2 Proof-of-Concept Clinical Trial and Non-Clinical Studies of S-033188, a Novel Cap-Dependent Endonuclease Inhibitor for Treatment of Influenza

OSAKA, Japan–(BUSINESS WIRE)– Shionogi & Co., Ltd. (hereafter “Shionogi”) reported clinical and non-clinical data for S-033188, a cap-dependent endonuclease inhibitor targeting influenza. In a Phase 2 proof-of-concept study, one-day, single oral dose of S-033188 demonstrated favorable safety and efficacy results that support moving forward into a global Phase 3 program. These results were presented at Options IX for the control of influenza, held in Chicago August 24-28, 2016.

Epidemic and pandemic influenza remain a major public health concern and novel influenza drugs that will offer significant improvement over current therapy are urgently needed. Worldwide, annual influenza epidemics are estimated to result in 3 to 5 million cases of severe illness, and about 250,000 to 500,000 deaths1.

S-033188 is a cap-dependent endonuclease inhibitor with a novel mechanism of action for treatment of influenza. S-033188 is being developed for one-time dosing, and has the potential to be more effective than existing marketed anti-influenza products. Development and commercialization are in collaboration with F. Hoffmann-La Roche Ltd.

Key findings for S-033188 reported at Options IX include the following results:

  • In a 400-patient Phase 2 proof-of-concept study conducted in Japan, treatment with a single dose (10 mg, 20 mg or 40 mg) of S-033188 given one time was compared to placebo with respect to time to alleviation of symptoms. Although no statistically significant difference was found using the Cox proportional hazard model, all 3 doses showed significant reductions in time to alleviation of symptoms compared to placebo using the pre-specified stratified generalized Wilcoxon test (p
  • Viral load reduction from baseline was statistically significant 24 and 48 hours post dose for all active doses when compared to placebo (p
  • S-033188 was well tolerated in all dose groups.
  • Preclinical data demonstrated broad and profound antiviral activity against influenza A and B viruses including oseltamivir-resistant virus (NA/H274Y).
  • In a mouse lethal infection model, single-day dosing of S-033188 prevented mortality and was superior to multiple-day dosing of oseltamivir.

Global Phase 3 clinical studies for S-033188 are planned to begin in the 2016-2017 influenza season.

About Shionogi

Shionogi & Co., Ltd. is a major research-driven pharmaceutical company dedicated to bringing benefits to patients based on its corporate philosophy of “supplying the best possible medicine to protect the health and wellbeing of the patients we serve,” Shionogi’s research and development currently targets two therapeutic areas: infectious diseases, and pain/CNS disorders. For over 50 years, Shionogi has developed and commercialized innovative oral and parenteral anti-infectives. In addition, Shionogi is engaged in new research areas, such as obesity/geriatric metabolic disease and oncology/immunology. Contributing to the health and QOL of patients around the world through development in these therapeutic areas is Shionogi’s primary goal. For more details, please visit For more information on Shionogi Inc., the U.S. –based subsidiary of Shionogi & Co., Ltd., headquartered in Florham Park, NJ, USA, please visit For more information on Shionogi Ltd., the UK-based subsidiary of Shionogi & Co. Ltd., headquartered in London, England, please visit

Forward Looking Statement

This announcement contains forward-looking statements. These statements are based on expectations in light of the information currently available, assumptions that are subject to risks and uncertainties which could cause actual results to differ materially from these statements. Risks and uncertainties include general domestic and international economic conditions such as general industry and market conditions, and changes of interest rate and currency exchange rate. These risks and uncertainties particularly apply with respect to product-related forward-looking statements. Product risks and uncertainties include, but are not limited to, completion and discontinuation of clinical trials; obtaining regulatory approvals; claims and concerns about product safety and efficacy; technological advances; adverse outcome of important litigation; domestic and foreign healthcare reforms and changes of laws and regulations. Also for existing products, there are manufacturing and marketing risks, which include, but are not limited to, inability to build production capacity to meet demand, unavailability of raw materials and entry of competitive products. The company disclaims any intention or obligation to update or revise any forward-looking statements whether as a result of new information, future events or otherwise.


1. WHO website, Influenza (Seasonal), Fact sheet N°211, March 2014