TOKYO (Reuters) - Japan's Astellas Pharma Inc said on Friday that U.S. authorities have requested more information on its key kidney transplant drug Advagraf, meaning it will face further delays in receiving approval there.
The request to the drug maker's U.S. subsidiary received from the Food and Drug Administration means approval for the immunosuppressant drug will be delayed for at least another six months, an Astellas spokesman said.
Gaining approval for Advagraf is vital for the drug maker, as its U.S. patent for existing transplant drug Prograf, used to prevent organ rejection, will expire in April.
Advagraf, a modified release version of Prograf, needs to be given once a day and was approved in Europe last April. Prograf is taken twice a day.
Astellas said the FDA asked about the effectiveness and safety of Advagraf compared with Prograf and for more data.
Prograf is used as the primary drug for 84 percent of first-time kidney transplant patients in the United States.
Its U.S. sales are expected to account for 10 percent of Astellas's overall revenue in the business year to March 31, and its global sales will likely account for around 21 percent of total revenue, the company spokesman said.
Immunosuppressant drugs differ from other drugs in that the risk of organ rejection means doctors are more cautious about using generics.
Prior to the announcement, shares of Astellas closed flat at 4,110 yen, against benchmark Nikkei's 1.5 percent drop.
Reporting by Yoko Kubota, Editing by Michael Watson