A decade ago, Daiichi-Sankyo (TYO:4568) announced its plan to acquire small molecule pharmaceutical specialist Plexxikon for $935 million.

Now, the company has announced a reorganization of its R&D structure that involves closing the R&D subsidiary Plexxikon on March 31, 2022.

Plexxikon has approximately 60 employees.

The unit was instrumental in developing two commercialized drugs, Zelboraf for malignant melanoma and Turalio for giant cell tumor of tendon sheath.

Daiichi Sankyo will integrate Plexxikon’s current R&D pipeline.

Daiichi Sankyo decided to ax the Plexxikon unit to sharpen its focus on three antibody-drug conjugates: Enhertu, Dato-DXd and HER3-DXd. The company has declared that the antibody-drug conjugates are “one of the strategic pillars” of its five-year business plan from the fiscal years 2021 to 2025.

Enhertu is now FDA approved for some patients with HER2-positive unresectable or metastatic breast cancer and patients with previously treated HER2-positive advanced gastric cancer.

Daiichi Sankyo has licensed Enhertu and Dato-DXd to AstraZeneca (LON:AZN), which made an upfront payment of $1.35 billion in 2019 for rights to the drug.

Today, Daiichi shares ticked down 1.31% to ¥2,720.00.