• Collaborative research between Otsuka's U.K. subsidiary Astex Pharmaceuticals and Novartis, which developed ribociclib and will market it

Otsuka Pharmaceutical Co., Ltd ("Otsuka") is pleased to announce that the U.S. FDA has granted regulatory approval to Novartis for ribociclib (compound number: LEE011), on which Otsuka's Cambridge-U.K. based subsidiary Astex and Novartis Institutes for BioMedical Research (NIBR) scientists jointly developed and optimised the chemical structure of ribociclib, which was then progressed through clinical trials by Novartis. Manufacturing and marketing approval was granted to Novartis for use of the drug as a first-line treatment in combination with an aromatase inhibitor for patients with hormone receptor positive, human epidermal growth factor receptor-2 negative (HR+/HER2-) advanced breast cancer.

Novartis, which developed ribociclib, will market it in the U.S. as Kisqali^®.

(Novartis announced the contents of this news release on March 13, 2017.)

Astex will receive from Novartis a regulatory approval milestone payment and future royalty payments based on product sales in accordance with their agreement made in 2005.

Ribociclib is a cyclin-dependent kinase inhibitor developed by Novartis Institutes for Biomedical Research in a research collaboration with Astex. This drug helps slow tumor proliferation by inhibiting two proteins (CDK4 & CDK6) which, when over-activated, can enable cancer cells to grow and divide quickly. Novartis received the regulatory approval under the US FDA Breakthrough Therapy designation and Priority Review programs.

In a clinical trial, a group treated with letrozole alone, a standard therapeutic treatment, was compared to a group treated with a combination of ribociclib and letrozole. The primary endpoint of progression-free survival (the period during which cancer does not progress and is in a stable state) was extended significantly in the group treated with the combination of ribociclib and letrozole.