U.S. health regulators have accepted the application for Pfizer Inc's closely watched experimental rheumatoid arthritis drug, the drugmaker said on Tuesday.

The Food and Drug Administration is due to decide on the drug, tofacitinib, in August. Pfizer said it has also submitted an application for tofacitinib to regulatory authorities in Japan.

Tofacitinib is one of Pfizer's most important experimental drugs. An oral medicine, it could provide a more convenient alternative to a lucrative class of injected medicines for rheumatoid arthritis and other inflammatory conditions.