By Jim Shrine

SuperGen Inc. filed a supplemental new drug application in a move to expand the market for Nipent, its approved cancer drug.

The San Ramon, Calif.-based company is requesting approval of Nipent for treating mature T-cell lymphomas, primarily cutaneous T-cell lymphoma (CTCL) and peripheral T-cell lymphoma. Nipent already is approved for treating hairy cell leukemia.

SuperGen Chairman and CEO Joseph Rubinfeld compared Nipent to alpha interferon, which also was first approved for the relatively narrow hairy cell leukemia market.

¿Once you¿re approved and on the market you can look for other indications,¿ Rubinfeld said. ¿It¿s a lot easier to get new indications approved than the first indication approved.

¿The idea is to file now,¿ he said. ¿Under new regulations you can begin to promote once you file a supplemental NDA [new drug application]. All you¿re doing is informing the world it works in other indications.¿

Nipent is a small-molecule purine analogue that acts by blocking the enzyme adenosine deaminase in cells, and doesn¿t require the presence of surface receptors.

Rubinfeld contrasted that feature with Ontak, which was approved Feb. 7 for treating persistent or recurrent CTCL. That drug targets malignant cells expressing the CD25 component of the interleukin-2 receptor. Ontak was developed by Seragen Inc., a subsidiary of San Diego-based Ligand Pharmaceuticals Inc. (See BioWorld Today, Feb. 8, 1999, p. 1.)

¿We sort of asked [the FDA] for accelerated review,¿ Rubinfeld said. He claimed Nipent is more broadly applicable and causes fewer side effects than Ontak.

Rubinfeld said data are available from 362 CTCL patients showing an overall response rate (tumor shrinkage of at least 50 percent) in 36 percent of patients. Publication is expected soon of additional data showing even better results, including some complete cures, he said.

New Indications Could Take Annual Sales Past $50M

Nipent sales were about $3 million in 1998 and accounted for most of SuperGen¿s revenue for the year. Rubinfeld expects Nipent revenues to triple this year and in ensuing years as the drug gains greater acceptance.

¿We expect over the years this will build into a major drug ¿ meaning $50 million upwards ¿ by exploiting a variety of indications,¿ Rubinfeld said.

Nipent is the lead drug in a broad oncology portfolio at SuperGen. A major development focus involves RFS 2000, a topoisomerase inhibitor extracted from the bark and leaves of the camptotheca acuminata tree in China.

Phase III studies of RFS 2000 recently were expanded to more than 50 medical centers, and the plan is to go to 100 to 200 centers. The lead indication is in solid tumors, particularly pancreatic and ovarian cancer, but various data suggest the drug could be beneficial in blood malignancies as well, Rubinfeld said.

SuperGen is ¿working vigorously¿ toward filing for approval of RFS 2000 by the end of the year, he said.

SuperGen¿s stock (NASDAQ:SUPG) gained $1.125 Friday, or 13 percent, to close at $9.75. n