Astellas Pharma has been boosted by the news that regulators in Japan have granted an additional approval for the firm’s blockbuster immunosuppressant Prograf.

The Tokyo-based group said it has been given the green light for Prograf (tacrolimus) to be used to treat moderate-to-severe refractory ulcerative colitis. Studies have shown that the drug may relieve the symptoms of the disease through reducing the inflammation in the large intestine by suppressing production of inflammatory cytokines from activated T-lymphocytes, Astellas said.

Prograf is comfortably Astellas' best-selling drug, contributing over $2.1 billion to its coffers in the last fiscal year. It is marketed as an immunosuppressant for organ transplantation in more than 80 countries and in Japan, it is also approved for bone marrow transplantation, systemic myasthenia gravis, rheumatoid arthritis and lupus nephritis.

This latest approval will boost already-healthy sales of Prograf in Japan but revenues in the USA and Europe are expected to drop off this year as the drug has lost patent protection in the USA and Europe.

Astellas sets up JV with Maxygen
The news comes days after Astellas agreed to set up a joint venture with cash-strapped US firm Maxygen which will focus on the development of protein pharmaceuticals. The latter firm will transfer most of its R&D operations, including drug candidates for autoimmune diseases and transplant rejection, plus personnel to the JV, which will be initially funded by $10 million from both companies.

Maxygen will own 83% of the venture initially, but Astellas will have the option to buy out the Redwood City-based firm’s stake, at a price that will increase each quarter from $53 million to $123 million, within three years of the venture being set up, likely in the third or fourth quarter of 2009. The Japanese firm will also fund substantially all of the operating costs of the JV, estimated at up to $30 million, over the first three years

The deal represents a lifeline for Maxygen which laid off 30% of its staff at the end of last year. Once the JV is set up, Maxygen’s chief executive, chief financial officer and chief operating officer will leave the firm, which will further “restructure and downsize” to “best align the company’s operations with its future business needs,” said chairman Issac Stein,