FDA gives a nod to Turalio as the first treatment for rare joint tumor

Japanese drug developer Daiichi Sankyo received the approval from the US Food and Drug Administration (FDA) for Turalio (pexidartinib), an oral small molecule tyrosine kinase inhibitor (TKI) indicated as a treatment for symptomatic tenosynovial giant cell tumor (TGCT). 

Daiichi Sankyo was granted an orphan drug designation for the development of Turalio, while the application to the FDA had received breakthrough therapy and priority review designation.

TGCT is a rare, non-malignant tumor that affects the joints causing debilitating symptoms such as pain, stiffness and limitation of movement. 

The annual incidence of new cases in the US is estimated to be about 15,000 for localized TGCT and about 1,500 for diffuse TGCT, a subset of which may be candidates for Turalio, a spokesperson for the company told us.

With TGCT, a number of cells in the lining of the joint have a defect which makes them produce too much of colony-stimulating factor 1 (CSF-1), a protein that attracts other cell types to merge and form the tumor.

Pexidartinib targets CSF-1 receptor, obstructing cell proliferation and accumulation in the synovium, as shown in the picture. 

The product is available in the US, however, Daichi Sankyo has selected Biologics by McKesson as the exclusive pharmacy provider, and only certified healthcare providers will be able to prescribe it.

Daiichi Sankyo holds a portfolio of oncology treatments for many types of cancer, as well as specialty medicines, treatments for cardiovascular diseases and vaccines.

A company's spokesperson told us that Turalio is the second of seven new products which Daiichi Sankyo plans to deliver from its oncology pipeline by 2025.

"Our proprietary technologies have been specifically designed to potentially address various limitations of two critical components of an ADC: the payload and linker,"​ the spokesperson said.

Daiichi Sankyo's ADC’s, including DS-8201, U3-1402 and DS-1062 are currently in various stages of clinical development, which "support the broad applicability of Daiichi Sankyo’s ADC technology in different targets and tumor types,"​ according to the spokesperson.