The Health Insurance Review and Assessment Service (HIRA) said it has disapproved the off-label use of Mabthera Inj. (ingredient: rituximab). Off-label use refers to the use of a drug to treat a condition in ways other than it was officially authorized for.

On Wednesday, the agency disclosed the case of Mabthera Inj. which was not allowed for off-label use in patients with neuromyelitis optica spectrum disorder (NMOSD), who had a relapse while planning for pregnancy or during pregnancy (except for those in the first trimester).

The HIRA discloses the cases of off-label use disapprovals to prevent the use of medicines that lack in medical evidence or have safety concerns and to inform the public and medical institutions.

The reason for the disapproval was “lack of medical evidence in submitted data,” the HIRA said. The agency has disapproved 167 cases of off-label use since 2014.

Twelve of them were related with medicines containing rituximab – nine cases regarding Roche’s Mabthera Inj and three regarding Celltrion’s biosimilar drug Truxima Inj.

Rituximab is used for the treatment of lymphoma, chronic lymphocytic leukemia, rheumatoid arthritis, Wegener's granulomatosis, and microscopic polyangiitis. In Korea, Mabthera Inj. and Truxima Inj. use rituximab as the main ingredient.