Japan-based Toyama Chemical has begun Phase I clinical trials of T-5224, its proprietary drug candidate for the treatment of rheumatoid arthritis (RA).

A low-molecular compound that inhibits an activator protein 1 (AP-1), T-5224 alleviates inflammation and joint destruction so it is expected to be used as a basic remedy for RA.

The development of the drug has been sponsored by the Japan Science and Technology Agency, the company said.